Looking for tiny U-channel - Page 1
Forum section: electronics / projects

author: ataradov
author_rank: Super Contributor
timestamp: May 21, 2022, 04:37:46 am
content: I'm trying to find tiny U-channel. I need the inside opening to be ~1.6 mm to accept a typical PCB. The sides must be tall enough to grip and hold the PCB, bun not obscure significant parts of it, so no more than 1 mm. The wall thickness - does not matter that much, I imagine that being rolled from sheet metal. Material is probably going to be steel given the requirements, but any metal would do.Ability to get in bulk is great, but I'm fine with ripping it out of something cheap for the prototype. I only need a few inches.The closest I could think of is hardware on umbrellas. But it is not easy to find, since Amazon pictures don't show the hardware close enough and local stores don't tend to carry umbrellas in CaliforniaI want to make a low profile PCB holder/vice of sorts, but I need the actual holders to be as non-intrusive as possible.It probably does not need to be U-channel, it probably can be just an angle. But I'm not sure an angle this tiny would be structurally sound.Ideas are welcome.

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: May 21, 2022, 05:08:58 am
content: Does it need to be metal? I'd look for plastic grommet strips.https://www.alliedelec.com/view/search/?keyword=nylon+caterpillar+grommet+stripsOtherwise you're looking for an extruded channel, although I don't know if they go that small.https://eagle-aluminum.com/products/channels/

author: ataradov
author_rank: Super Contributor
timestamp: May 21, 2022, 05:20:29 am
content: It has to survive soldering temperatures, so plastics are probably out.Extruded aluminum is too bulky and I don't think commonly available stuff is that small.I was thinking more of folded sheet metal like in the picture. Lightweight, simple and rigid enough. No idea if it is available as a standalone product though.

author: ConKbot
author_rank: Super Contributor
timestamp: May 21, 2022, 05:42:08 am
content: 1439-1330-ND seems reasonable, kind of has flange you could bolt to vice jaws. Datasheet is a little sparse on details though

author: ataradov
author_rank: Super Contributor
timestamp: May 21, 2022, 05:48:50 am
content: This is still too heavy duty. I need this for a vice for soldering under the microscope.The holder must be as much out of the way as possible. The goal is to have the vice body outside of the field of view, so it could be bulky, but it will not obstruct the view.I don't think any sort of extrusion would work, they all just too bulky. The maximum length it needs to support is 100 mm or even less.

author: Someone
author_rank: Super Contributor
timestamp: May 21, 2022, 06:31:05 am
content: Commercial PCB holding vice/fixtures use tiny little extrusions. But plastics aren't impossible:https://www.bivar.com/product/DC-250/Usual question, do you wantsmall quality? just machine something from bulkhuge quantity? get a die made for extrusion

author: ataradov
author_rank: Super Contributor
timestamp: May 21, 2022, 06:38:56 am
content: "pcb card guides" is a good search term that yields some results. But still, all I see is too bulky. I need to hold 10 x 20 mm PCBs. Those guides will cover them entirely them.I guess I'll hunt for umbrellas.

author: mclute0
author_rank: Regular Contributor
timestamp: May 21, 2022, 08:00:07 am
content: Maybe try Bakelite, you can buy sheets on amazon and machine on it all you want. All the old Weller soldering guns were made from it as were most vacuum tube sockets. There are companies that will make it into whatever part you want. You can buy it from China too.

author: JohnGi
author_rank: Newbie
timestamp: May 21, 2022, 08:26:49 am
content: Miniature brass sections sold for making model girder bridges etc.Examplehttps://www.chronos.ltd.uk/product-category/round-square-tube-sheet-metal-ptfe-nylon/albion-alloys-precision-metals/albion-alloys-brass-channel/As you're in US try somewhere likewww.micromark.com

author: jc101
author_rank: Frequent Contributor
timestamp: May 21, 2022, 08:29:09 am
content: This kind of thing any good?https://www.waveroomplus.com/WaveRoom-Plus-TF-3-Titanium-Edge-Finger-Mask_p_2361.htmlThere are wave solder strips, used to hold/protect the edge of the PCB, but might be workable?

author: Ian.M
author_rank: Super Contributor
timestamp: May 21, 2022, 08:35:57 am
content: You should be able to get small brass box and angle section strips from any good modelmaking supplier. 1/16" square section tube is fairly commonly available and would be a good start towards holding a PCB that small.Notch the ends of the tube to grip the PCB end-on, and glue the other end in fractionally undersize holes in your vice jaws using a high temperature adhesive. Alternatively, braze or silver solder the tube stubs to your vice mechanism.

author: beanflying
author_rank: Super Contributor
timestamp: May 21, 2022, 09:16:01 am
content: Apart from getting someone to bend you a custom look at K&S as you are in the USA. Tower Hobbies and most of the R/C mail order guys will carry most of the range. They also carry Brass is a few different sections in small size square or channelhttps://ksmetals.com/collections/aluminum/products/als014-3-32

author: Conrad Hoffman
author_rank: Super Contributor
timestamp: May 21, 2022, 02:01:23 pm
content: Cut a piece of aluminum slightly thicker than your PCB and some size that will fit in your vise. Cut a strip of heavy brass shim stock to the desired width. Clamp the shim and the aluminum in your vise such that the narrow edge of the aluminum is in the center of the brass strip. Using a flat blade to start, then small hammer, wood blocks or whatever, fold the edges of the brass against the aluminum plate. Voila, U-channel. Since the project is small, you don't need terribly thick brass to be strong enough, maybe 0.010" at worst. 0.005" might be good enough. It's a compromise between strength and being able to easily bend it. The brass is nice because you can then solder up a whole frame or whatever you want. If you need to go really shallow, so it makes bending difficult, make it a bit deeper and file it down to the desired depth.

author: Marco
author_rank: Super Contributor
timestamp: May 21, 2022, 02:34:44 pm
content: Why not just take square stock nylon or phenolic and mill slots?

author: MarkF
author_rank: Super Contributor
timestamp: May 21, 2022, 02:46:59 pm
content: Quote from: ataradov on May 21, 2022, 05:20:29 amAssuming you are just hand soldering, I don't see that the edges would get too hot for plastic.Maybe, 3D print jaw covers with a slot for your vise?Probably not what you had in mind but I'm going to toss it out there:- A single blade kerf from a table saw in a piece of hard wood would be about the right thickness.I use a small set of wooden clamps without a slot to hold my PCBs while soldering.You could take a set apart and cut a slot or get the pieces and cut your own wood jaws to suit.Or rabbet the top edge on each side to the depth of a PCB.

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: May 21, 2022, 02:50:47 pm
content: Just buy some brass shim stock of a few mils thickness and fold it with a metal ruler?

author: JDubU
author_rank: Frequent Contributor
timestamp: May 21, 2022, 03:08:46 pm
content: Quote from: Conrad Hoffman on May 21, 2022, 02:01:23 pmInstead of the aluminum form, why not just use a spare 1.6mm PCB?

author: themadhippy
author_rank: Super Contributor
timestamp: May 21, 2022, 04:01:13 pm
content: couple of bits of wood with a slot cut in the side,and 2 bits of threaded rod to clamp it together

author: LaserSteve
author_rank: Super Contributor
timestamp: May 21, 2022, 04:05:09 pm
content: K&S Hobby or McMaster CarrYou may also find it in model airplane or model race car carbon fiber extrusions.S.

author: JDubU
author_rank: Frequent Contributor
timestamp: May 21, 2022, 04:18:04 pm
content: Glue three pieces of scrap 1.6mm PCB's together as a sandwich with the center piece offset inward from the edges of the two outer pieces to form a channel. Cut off the length/width that you don't want.

author: ataradov
author_rank: Super Contributor
timestamp: May 21, 2022, 04:19:09 pm
content: Model stuff is a bit closer. I'll research that.Any machining is out, I don't have the equipment and I don't want to bother custom ordering stuff.Wood and plastics are out. Soldering also involved heated air.I don't want to have a conventional PCB vice, there are lots of them and I don't like any of them. The idea here is to have the actual vice away from the view and have those channels to be extended jaws that are as small as possible. At this time I don't care how the actual body is made. It might be just a custom 3D printed clamp to hold those things as a set distance.

author: JDubU
author_rank: Frequent Contributor
timestamp: May 21, 2022, 04:46:24 pm
content: Something like this?https://ksmetals.com/collections/brass/products/brchan-1-8x1-8

author: langwadt
author_rank: Super Contributor
timestamp: May 21, 2022, 04:49:54 pm
content: Quote from: ataradov on May 21, 2022, 04:19:09 pmbit hard to guess the exact measurements buthttps://www.ebay.com/itm/174288271580https://www.ebay.com/itm/360884811825

author: ataradov
author_rank: Super Contributor
timestamp: May 21, 2022, 04:52:06 pm
content: Quote from: JDubU on May 21, 2022, 04:46:24 pmNot really. This is too huge. 1/8" square results in ~2.5 mm internal channel. This is too much.Model railroad tracks may end up closer to what I need. I'm currently figuring out how they are sized.

author: ConKbot
author_rank: Super Contributor
timestamp: May 21, 2022, 05:05:18 pm
content: Quote from: ataradov on May 21, 2022, 06:38:56 amLook into watchmakers vices thenhttps://www.amazon.com/Hand-Free-Universal-Holder-HOL-173-00/dp/B0058EDVXQ/ref=asc_df_B0058EDVXQ/Remove it from the base and cut off the stem to get something that fits under a microscope and just sits on a bench.

author: Marco
author_rank: Super Contributor
timestamp: May 21, 2022, 05:14:36 pm
content: You could always order some slotted PCB with your next PCBs

author: ataradov
author_rank: Super Contributor
timestamp: May 21, 2022, 05:23:45 pm
content: Quote from: Marco on May 21, 2022, 05:14:36 pmI'm not sure I understand how that would help here. I doubt PCB vendors would do a partial depth slot. And full slow is not too useful or I'm missing something.

author: bill_c
author_rank: Regular Contributor
timestamp: May 21, 2022, 06:13:11 pm
content: I made this a while ago, can hold 3 or 4 boards at a time. Can turn to each board to populate the same sections before going to next, can flip to populate both sides. Easy to make and nearly indestructible, hot air and soldering iron proof.

author: ataradov
author_rank: Super Contributor
timestamp: May 21, 2022, 06:17:57 pm
content: I have the Hakko one for this. But again, for 10x20 mm boards this does not work at all. There is no place to grip on the board surface and the metal gets in a way when soldering.

author: Marco
author_rank: Super Contributor
timestamp: May 21, 2022, 10:59:27 pm
content: Why can't you clamp some metal sheet together with nuts&bolts with a PCB in between 1mm from the edge?Or just epoxy it, doubt you'll heat it enough to decompose the epoxy.

author: spostma
author_rank: Regular Contributor
timestamp: May 22, 2022, 06:55:11 pm
content: I think these milled Reely brass profiles with 0.4/0.45mm wall thickness are suitable for you:https://www.conrad.com/p/brass-u-l-x-w-x-h-500-x-25-x-1-mm-1-pcs-236159https://www.conrad.com/p/brass-u-l-x-w-x-h-500-x-25-x-15-mm-1-pcs-221809https://www.conrad.com/p/brass-u-l-x-w-x-h-500-x-25-x-25-mm-1-pcs-295930You could try to search on the EAN numbers for other suppliers of these profiles.

author: Buriedcode
author_rank: Super Contributor
timestamp: May 23, 2022, 03:56:42 am
content: Perhaps "edging" would be a good search term. I believe edge frames for bathroom mirrors can have slots quite small, perhaps down to <2mm.Some photo frames also use quite thin glass, so the thinner edge frames should be ideal.

author: ajb
author_rank: Super Contributor
timestamp: May 24, 2022, 05:51:21 pm
content: Quote from: ataradov on May 21, 2022, 04:19:09 pmWell, there's machining and then there's machining...Aluminum can be worked with a lot of woodworking tools, so you could certainly put a slot in a piece of aluminum flat bar with a table saw or a router. You could either use a very thin blade, or tilt the blade 45° and cut a V-slot instead. I would be leery of using a 1/16" bit to cut aluminum in a handheld router, but if you have a router table it might be okay with multiple passes, or again you could use a V-grooving bit. Simple hand tools could also work. Start with a hacksaw, clean up with some files. Would suck if you wanted a vise that was like 12" wide or something, but for something smaller it could be doable. Or, again, make a V-groove rather than a rectangular slot, which means you could do it with a triangular file.Or build the channel section up from other pieces. You could probably even solder together some brass strips from K&S or similar into the right section--as long as you're not really blasting the board and the vise jaws are reasonably large you'd probably be fine, or you could look for a higher temperature alloy to join them.

author: geggi1
author_rank: Frequent Contributor
timestamp: May 25, 2022, 03:48:45 am
content: Get a few strips of aluminium sheet metall that is the thickness of the slot you want.Stack 3 together with the middle sheet offset the dept you want in the channel.Clamp the sheets together and drill some holes through the stack.Put in machine screws or poprivits and thighten it up.You can probably get away with about 10mm wide metal strips.

author: Zoli
author_rank: Frequent Contributor
timestamp: May 25, 2022, 06:37:10 am
content: A quick search landed me a term of grooved metal for the umbrella ribs; I hope is helping a few day later.

author: ataradov
author_rank: Super Contributor
timestamp: May 25, 2022, 06:51:23 am
content: Quote from: Zoli on May 25, 2022, 06:37:10 amIt does look like those things are called ribs and stretchers, but It does not look like anyone actually sells them. There are hints of companies manufacturing umbrellas, but everything I find reads like SEO nonsense.

author: MadScientist
author_rank: Frequent Contributor
timestamp: May 25, 2022, 06:53:33 am
content: Quote from: ataradov on May 21, 2022, 04:37:46 amAny mail order model railroad shop will carry small aluminium or brass profiles of what you want

author: Zoli
author_rank: Frequent Contributor
timestamp: May 25, 2022, 05:32:55 pm
content: Quote from: ataradov on May 25, 2022, 06:51:23 amThen dismount a real umbrella:https://www.ikea.com/us/en/p/groessby-umbrella-blue-yellow-40129058/; you can't really beat this price...And this one has grooved metal ribs, unlike the better ones, which tend to have fibreglass rods as ribs;example.

author: Gregg
author_rank: Super Contributor
timestamp: May 26, 2022, 02:25:35 am
content: In looking for something else in our basement I came across a white umbrella for photography light bounce that belongs to my wife. The ribs are sturdier than most and almost perfect slot width plus they are either non magnetic stainless or heavily chrome plated brass. It may be a possibility to find similar in a thrift store. Other possibilities may be larger umbrellas like golf umbrellas. Newer umbrellas probably have fiberglass or really tiny metal ribs.In any case, thrift stores or estate sales may be your best places to shop. I’ll look in my storage; I think I have an old golf umbrella needing fixing that could be parted out.

author: Nominal Animal
author_rank: Super Contributor
timestamp: May 26, 2022, 05:56:34 am
content: My recommendation is to use brass, copper, or aluminium pipe instead, the kind modelmakers use. (Here in Finland, I've bought this stuff from HobbyPoint; something like 3mm to 5mm outer diameter and half a millimeter to millimeter wall thickness. I actually have some of this stuff on hand right now.)The tricky thing is to use a dremel with a cut-off disk or two to cut a 1.7mm to 2.0mm wide slot lengthwise. A hacksaw may work even better, if you do a quick jig out if wood with pre-cut saw slot at ends, pipe held in a groove between the ends, and a high-TPI blade with a suitable thickness (including teeth set; 1.8mm or so should be relatively easy to find). Put a bamboo grill skewer or something inside the pipe while cutting, to both protect the other side of the tube (so you don't split it) and to avoid deforming the tube with too much pressure. Gently file the burrs off using a small square or triangle file.That gives you a round C channel with the opening at about 2mm. However, the shape is such that you can easily clamp it closed. If the length of the C channel, outer diameter, and wall thickness is right, you can use normal alligator clips as clamps. The outer diameter of the pipe only affects how deep the PCB will sit inside the channel; the idea is to let it seat all the way to the back inner wall of the pipe.If you don't have the tools or the time to do it yourself, contact your local Hackspace (mailing list or forum) and ask if there is someone there to do some different pieces for you for a reasonable price, explaining the use case. Reason is not that hackspace people like to do commissions, but that this kind of tool is something I suspect a lot of hack-makers would find useful and interesting, too.

author: janoc
author_rank: Super Contributor
timestamp: May 26, 2022, 09:27:46 am
content: Why not to take the approach the Stickvise uses? I.e. don't use a channel which would be hard to find and not work for different thicknesses of the board but jaws with a V-groove where the edges of the board slot in. That works well even for tiny boards. Been there, done that - I have the Stickvise specifically for soldering under a microscope because it is nicely flat and out of the way.The original Stickvise has plastic jaws that can be damaged by heat but teflon jaws are also available. Or one can make their own - I have made heat-resistant jaws out of stacked strips of flat aluminium stock with one layer drilled slightly off-center to create that groove (I don't have a milling machine to mill it out of a solid piece) - exactly as geggi1 described above.https://www.stickvise.com/

author: ataradov
author_rank: Super Contributor
timestamp: May 26, 2022, 05:08:06 pm
content: I've used stickvise. It is better than nothing, but it was still bulkier than I like. I did not like the long stick, but I guess it can be shortened if the boards are expected to be small.Thanks for all the ideas, this was helpful. I'll need to think about the design for a bit. I''ve got an idea for how I want it to look, I just need to figure out mechanics.I've ordered stickvise and teflon jaws. I'll shorten the stick and try it out that way. I might be fine with it this way.

author: langwadt
author_rank: Super Contributor
timestamp: May 26, 2022, 07:50:48 pm
content: Quote from: ataradov on May 26, 2022, 05:08:06 pmafaict for a stickvise you could easily make jaws by stacking some strips of PCB

author: TC
author_rank: Contributor
timestamp: May 26, 2022, 08:52:09 pm
content: Digikey product category "card guides"

author: jpanhalt
author_rank: Super Contributor
timestamp: May 26, 2022, 08:59:27 pm
content: @ataradovWe are up to 45 replies and you apparently don't have an answer. Frankly, you had your answer many posts ago. Design something and pay to have it made.

author: ataradov
author_rank: Super Contributor
timestamp: May 26, 2022, 09:06:05 pm
content: I have plenty of good answers. I'm not in a hurry, I don't need to have this instantly. And my design idea evolved with the answers I've got. Once I think about it and design something I think works, I'll figure out how to make it.

author: Doctorandus_P
author_rank: Super Contributor
timestamp: May 30, 2022, 11:35:44 am
content: If you have thin metal strips you can lay them over a slot and then just hammer some material in, and it will bend in a U shape.Thin metal sheets such as cans or brass sheet can be cut with household scissors.

author: Ian.M
author_rank: Super Contributor
timestamp: May 30, 2022, 12:15:10 pm
content: Oh for FFS! Build yourself a DIY stickvice. Buy an offcut of 8mm PTFE sheet, screw it down to a wooden sled to hold the work and cut two ~1.6mm grooves across it with whatever power saw with a thin blade you have available, or with a 90 deg pointed router bit. Saw off two ~8mm wide strips offset so the groove is within 3mm of the edge. Take two short lengths of 9.5mm aluminum angle to stiffen the rather floppy PTFE strips, and drill it and the strips for self-tapping screws to hold the PTFE to the aluminum. Assemble the strips to the aluminum angle to make the jaws. Drill both jaws in the center 2 mm, taking care to get the hole at the same height in both jaws and at least 1mm below the groove, and tap one side M3 right through using a thread-forming tap not a cutting tap. Drill out the other side for a close sliding fit over M3 allthread. Thread the allthread into the tapped jaw from the PTFE side, and lock it in place with a nut on the back. Assemble the moving jaw on the allthread, with a short coil spring, a washer and a wing nut. Result: one miniature stickvice clone, good up to 290°C for several minutes or 260°C indefinitely. Sleeve the protruding allthread with silicone tubing so you can handle it without burning yourself.

author: ataradov
author_rank: Super Contributor
timestamp: May 30, 2022, 04:08:09 pm
content: Quote from: Ian.M on May 30, 2022, 12:15:10 pmChill. There are other criteria that the original stickvice does not meet. And the question was not about the vice, I'll handle that myself. The question was about the U channel and it was answered.

author: ataradov
author_rank: Super Contributor
timestamp: August 08, 2022, 02:09:27 am
content: After a number of iterations I arrived at a design that I like a lot. I have a 3D printed version for now, and I'm looking into making that from metal. I've already melted a pair of jaws forgetting that they can't take heat.This design is low profile, but leaves enough space under the board to fit typical 0.1" connectors (10 mm). This is the highest component on majority of my boards. There is also no central stick like in a stick vice.I found a couple places with automated quoting system based on the STEP file, but the price is not great. I'm guessing automatic system is conservative and I need to find some place with a manual quote. Recommendations are welcome here.

author: beanflying
author_rank: Super Contributor
timestamp: August 08, 2022, 02:20:14 am
content: Get a price on having it 3D metal Printed as you have gone with a one piece block design and already have it in STL format. So Shapeways or a similar more local service depending on what is nearby.By the time a job shop runs a few operations and cuts your dovetail you will chew up a fair bit of labour even though the material cost is minimal. A small solo operator job shop will be likely cheaper here because of the fiddle factor too.

author: ataradov
author_rank: Super Contributor
timestamp: August 08, 2022, 02:51:01 am
content: PCBWay quotes $600 for machining of 20 parts. The same part 3D printed is $400 for aluminum and $800 for the cheapest steel. Shapeways quotes $1200 for the same part in steel (20 pcs as well).I also need to figure out the requirements. I think all those auto-quoting services assume minimal radius of 2 mm. My part as is is not possible using endmills. That corner is 60 degrees and is trivially machined using 60 degree cutter.I don't mind redesigning the part for the process, there is no real reason to have those sharp corners. But I don't know what to design for. I don't think those automated quoting systems are that smart anyway.Ultimately $600 is not that expensive. But there is nothing in this part that really needs CNC and a job shop may be able to handle it better. But those obviously don't have auto quoting.

author: beanflying
author_rank: Super Contributor
timestamp: August 08, 2022, 03:05:03 am
content: Pricing for low volume then Printed seems not to bad.I would think twice about setting up a Router/Mill to make it for that price for a one off. Doing a run is a different thing.Rough cut the stock (check what is a readilly available size available to reduce costs) so 1-2mm longer than finished. Generally extruded section will already have a broken corner so no radius needed. If they need to machine to your size will add a lot of cost.'Generally' Dovetail cutters are a hard sharp corner (there is in reality a tiny radius on most of them) so this will be ONE setup assuming there is no squaring up or dimensioning of raw stock other than to length. A second bit will generally be required here to finish it to length (so a bit swap) So these two operations will be done vertically.After this the part will need to be rotated 90 degrees (unless they are using a 4th or 5th axis which is really unlikely for this) to have the holes drilled/bored and or reamed (depending on what tolerance you want.So machining it is a fiddle.

author: JohanH
author_rank: Frequent Contributor
timestamp: August 08, 2022, 07:40:32 am
content: Here are some great tips how to reduce costhttps://www.hubs.com/knowledge-base/reducing-cnc-machining-costs-design-tips/You could also ask local CNC companies (they are everywhere). I had a stainless steel plate water cut by a local company and it was really affordable.I once ordered a prototype for a special aluminium part fromhttps://www.jevny.com/.They were not expensive, but shipping wasn't cheap. It was a straightforward cut, though, no turning of parts.

author: Ian.M
author_rank: Super Contributor
timestamp: August 08, 2022, 09:28:45 am
content: Why does the jaw have to be one piece? If you use a separate plate with a beveled edge on top of the jaw block to make the asymmetric V groove, it would be well within the capability of what can be made with hand tools in a home workshop. Drill and tap the jaw block for a bunch of small countersunk machine screws to hold the top plate rigidly in place.Whether it works out cheaper than sending it out for machining or 3D metal printing depends on how competent you are in a workshop, and the cost of your time. If you cant file or grind to a line while maintaining a reasonably constant angle, then $600 for 20 parts is a good deal!

author: ataradov
author_rank: Super Contributor
timestamp: August 08, 2022, 04:07:26 pm
content: I live in an apartment in downtown San Jose. I have no access to any machining equipment. Otherwise it would not be a problem and instead of spending $600 on parts, I'd spend that on a Grizzly mill and slowly make them myself.I'll ask for "manual" quotes after I get back from vacation. Almost none of the dimensions are critical. The part is 12 mm high right now. It could be made out of 1/2"x1/2" square stock without doing any machining to the stock sides. Just cut the groove and drill the holes. But those things can only be worked out with a person on the other end.

author: Nominal Animal
author_rank: Super Contributor
timestamp: August 08, 2022, 06:58:42 pm
content: I'd consider it in two parts, too. One part would be the ½"×½" square with four holes; two horizontally for the threaded rods, and two vertically for fastening to the ftop part.The top part would be e.g. ½"×⅛" flat bar, with one edge milled to the 60° angle (30° off vertical) needed. Two short countersunk bolts would fasten it to the first part.I live in a city apartment also, and don't have any power tools at all right now, but I do have enough aluminium to do a few pairs if I wanted to. I happen to have 12mm×12mm anodized aluminium square tubing (Alfer brand, from a hobby store) with 1mm wall thickness, and 2mm flat bar (actually 20mm×20mm L profile or something).I should even have a suitable 3mm tap and 5mm long 3mm countersunk machine screws, and a couple of 20cm pieces of 4mm or 5mm threaded rod with matching nuts.Aluminium is soft enough to file by hand to the desired angle, and even a hand whisk drill is enough to drill the needed holes with a good sharp bit; no problem. Instead of a file, I'd actually use wet or dry sand paper at 120, 240, and 400 grit, on top of a mirror, with WD-40 as the lubricant, as that's easier and faster than hand filing. Even the angle is easier to control. (I do have some wood chisels I use elsewhere, that I keep sharp using that same method. I even have all my fingers left, with just a couple of dozen old battle scars here and there; nothing bigger than three or four stitches, though.)For the countersink, a larger drill bit will do fine.

author: ataradov
author_rank: Super Contributor
timestamp: August 08, 2022, 07:15:51 pm
content: If I'm doing it at home, then I don't see why two parts are particularly easier. And I think the slot does not really need to be that shape. I'm pretty sure even ~2mm diameter groove would work too. And in a pinch that can be carved with a dremel fixed to the bench.It is just at $30/part, it appears too expensive. For $15/part I would not think twice ordering them. But may be that price is not viable indeed.

author: Nominal Animal
author_rank: Super Contributor
timestamp: August 08, 2022, 10:34:54 pm
content: Quote from: ataradov on August 08, 2022, 07:15:51 pmSanding the edge (or edge and corner, if you want) on a sheet of sandpaper on top of a mirror is quick work, just a couple of minutes; and no dust or such if you use WD-40 or just Windex as the lubricant. You can get surprisingly accurate groove between the two parts this way. Plus you can just change the top part if you nick it, need a different edge angle or something.Quote from: ataradov on August 08, 2022, 07:15:51 pmOne would probably need to make several dozen pairs to recoup the setup costs. Someone with a Bridgeport mill and suitable alu stock could batch them out in an hour, and then it might make sense.If you use OpenSCAD, here's a quick sketch of what I was thinking about:Code:$fn = 64;color([0.5,0.6,0.6, 1]) difference() {translate([-6,0,-6]) cube([12,200,12], center=true);translate([-6,0,-6]) cube([10,210,10], center=true);translate([0,-80,-6]) rotate([0,90,0]) cylinder(h=50, r=3, center=true);translate([0,+80,-6]) rotate([0,90,0]) cylinder(h=50, r=3, center=true);translate([-6,-60,-5]) cylinder(h=10, r=1.5, center=true);translate([-6,60,-5]) cylinder(h=10, r=1.5, center=true);}color([0.5,0.7,0.7, 1]) difference() {translate([-6,0,0.5]) cube([12,200,1], center=true);rotate([0,30,0]) translate([0,0,1]) cube([2,210,4], center=true);translate([-6,-60,2]) cylinder(h=4, r1=1, r2=4, center=true);translate([-6,60,2]) cylinder(h=4, r1=1, r2=4, center=true);}If you use countersink machine screws with nuts and washers for the top side, you can adjust the exact placement of the top by drilling slightly oversized holes to the square tubing. May need needle-nose pliers or sticks of wood to hold the nut while you tighten it, though.

author: beanflying
author_rank: Super Contributor
timestamp: August 15, 2022, 10:49:05 am
content: While this is away from the OP wanting a DIY option I ran across this on Aliexpress and it might be a good option for othershttps://www.aliexpress.com/item/4000180543028.html?spm=a2g0s.8937460.0.0.3eb62e0efNkm3Eand it is sort on the same basic concept.

author: ataradov
author_rank: Super Contributor
timestamp: August 15, 2022, 03:57:03 pm
content: One of my iterations had this "frame" design. I did not like it at all. The unused part of the frame and the handle stick out a lot and it get hang up on the stuff around, including the microscope stand. And it is very frustrating when you get carried away while looking though the microscope and one position adjustment clears the table for you.Even with my design, the plan is to have multiple versions with bolts shortened as needed. And possibly jaws shortened too, although that was not a real problem and 80 mm jaws worked fine for all the boards I tried.It might be a good candidate for parts though. I'll need to look into it.

author: Jay_Diddy_B
author_rank: Super Contributor
timestamp: August 15, 2022, 09:34:02 pm
content: Hi ataradov and the group,This is my version of a PCB holder for microscope work:This is a link to the thread:https://www.eevblog.com/forum/projects/pcb-holder-for-smd-assembly-microscope/I cut a small dovetail in the jaw:It cut it square on the milling machine and then filed the angle by hand.I also made a plastic version, 3D printed:Thread:https://www.eevblog.com/forum/projects/pcb-holder-for-smd-assembly-3d-printed-edition/Both have there uses, the metal one is better for soldering, the plastic one is useful for testing.I would make the prototypes with a 3D printer. I was able to print the 1/4-20 thread, but I had to clean it with a hand tap.I have used both on a daily basis for the last 7 years.Jay_Diddy_B

author: ataradov
author_rank: Super Contributor
timestamp: August 15, 2022, 09:42:12 pm
content: Oh, wow, this is the same exact design.I've been experimenting a bit, and it looks like you don't even need an angled undercut. Just a straight cut is mostly enough to hold the board. The pressure when soldering is minimal and is mostly directed downwards.

author: thm_w
author_rank: Super Contributor
timestamp: August 15, 2022, 10:32:18 pm
content: Jay_Diddy's thread has a lot of good info, the stickvise is interesting:https://www.digikey.com/en/products/detail/3197/1528-1747-ND/6198266https://www.stickvise.com/hacks/diy-upgradesIts more complex to build but allows faster adjustment of the width. You could buy a few of those and cut one of them down to a smaller size.But I think you have to swap the nylon jaws out for alu or ptfe as well?Also:https://www.aliexpress.com/item/1005002494437140.htmlhttps://www.aliexpress.com/item/1005004378477193.html

author: ataradov
author_rank: Super Contributor
timestamp: August 15, 2022, 11:22:23 pm
content: I already explained why stickvise does not work for me - the central rod interferes with the components on the board. It only works for one side, but once you have components and flip the board, the stick starts to get in a way. And in practice adjustment of the width is not something I do a lot. That is not a real issue.And those "Mijing" things are horrible. There is a reason they only show 3D renders. The actual hardware is really bad. The fit and finish is very poor, so they always jam and lock up.

author: thm_w
author_rank: Super Contributor
timestamp: August 15, 2022, 11:33:46 pm
content: Quote from: ataradov on August 15, 2022, 11:22:23 pmThat would just mean making a taller jaw to clear the component in question (since the stock nylon jaw is not usable regardless), not saying its an option for you, just something DIY'able for others.But yes good point, that is the downside of the single rod.Would be possible to have the quick adjust system and two thinner rods on either side then.

author: ataradov
author_rank: Super Contributor
timestamp: August 16, 2022, 12:10:32 am
content: Quote from: thm_w on August 15, 2022, 11:33:46 pmThis was one of my prototypes. Instead of where threaded rod is now have two smooth rods and then the system changes to 2 actual jaws (one fixed and one floating on the rods) and one clamp on the size of the floating jaw. There are springs between the floating jaw and a clamp. So, you still have wide open working area and can adjust spring tension using the clamp position relative to the floating jaw.I prototyped that using 3D printed parts and it worked, but was not ideal, since plastic jammed on the floating jaw. I assume with metal and tighter tolerances it might work.Then the design evolved into what I have now and I really see no issues with it. If you need spring jaws, then you can add springs between the nuts and the floating jaw.But again, given the minimal grip, all you need is half a turn on one side to free the board. Large travel adjustment is a bit more annoying, but how often do you readjust it? I typically have one board I'm working on at a time.

author: thm_w
author_rank: Super Contributor
timestamp: August 16, 2022, 12:40:41 am
content: True, if you have one board and multiple size vices, then wouldn't need to adjust much.You used steel rivnuts right, no issues with sticking when turning at all?Two options I can think of for rod, threaded rod and the thumb-nut or just using a cap screw + 3D printing a thumb knob for it. Second requires no cutting, but might not look as nice.

author: ataradov
author_rank: Super Contributor
timestamp: August 16, 2022, 12:51:31 am
content: Quote from: thm_w on August 16, 2022, 12:40:41 amNope, it is very smooth. I originally tried to tap the 3D printed hole, but it was very hard to tap it straight, especially by hand. And without straight holes this square frame becomes wobbly.The only issue that I have with this design is that when travelling large distance, you need to turn the knobs at about the same rate if you want to push the jaw, otherwise it tends to jam. But in a typical operation you just slide the jaws together and then adjust the nuts however you need, it is not a problem. And I expect it to be less of a problem with a hole drilled in a metal.

author: Jay_Diddy_B
author_rank: Super Contributor
timestamp: August 16, 2022, 02:14:36 am
content: HiQuote from: ataradov on August 16, 2022, 12:51:31 amI spent some time messing with the size of the holes.I just checked the one on my bench, the 1/4-20 threaded rods measure 0.240". The holes measure 0.277", this is an odd size in imperial, but it is 7mm in metric. The over-sized hole on the loose jaw causes the jaw to twist when the clamping pressure is applied, this why I used the dove-tailed notch.The jaws are 5.00 inches wide, the rods are on 4.250" centers. The jaws were made from 6061 Aluminum.Jay_Diddy_B

author: beanflying
author_rank: Super Contributor
timestamp: August 16, 2022, 02:33:13 am
content: Maybe dump the threads all together. Thumb screws are easy to make or buy, 6mm parallel rod is common as muck all over evilbay for 3D Printers and a couple of 2mm Roll Pins to lock the fixed jaw to them.Coffee break over back to the real job

author: ataradov
author_rank: Super Contributor
timestamp: August 16, 2022, 02:52:40 am
content: Quote from: beanflying on August 16, 2022, 02:33:13 amI thought about that and did a crude prototype. This does not work too well. There is nothing maintaining the clamping pressure. And screw turning action loosens the clamping. Again, it is possible that metal version will actually work. Or a version with a more complicated clamp design, not a simple screw pushing on a rod.In the screw design there is enough flexibility that things just wedge together and provide solid pressure.And so that screws are not in a way, they can be placed on the side of the block.

author: beanflying
author_rank: Super Contributor
timestamp: August 16, 2022, 03:05:55 am
content: You really don't want clamping 'pressure' you only need to hold the board in place and resist 'sliding' along the jaw. The board held down by the dovetail against the rail is plenty of contact area but it could easily be increased with a scuff up with 80 or 120 grit sandpaper on the shelf (I really don't think it would be needed)You would be surprised the deflection you can get in a PCB when you clamp in from the sides to aggressively, depending on the method used this is one of the issues with holding them for PCB Milling (skunkworks project in progress). Depending on what you are soldering or reworking this might cause you other issues with component failure from physical stress.

author: ataradov
author_rank: Super Contributor
timestamp: August 16, 2022, 03:11:30 am
content: That's what I meant by the "pressure". I did not mean cranking like a real vice. But in my experiments (with a single rod), the board would still slide. But I need to try that with metal jaws. 3D printed jaws did not work for that. But I can imagine that plastic is not ideal for this case.

author: ataradov
author_rank: Super Contributor
timestamp: August 16, 2022, 03:32:19 am
content: Ok, this is cool. I prototyped a metal version from random stuff I had around. And it actually works quite well.The key here seems to be that the holes in a free jaw are larger than the rod. This way when you are clamping and applying hand pressure before tightening the screws, the jaw is slightly crooked. Tightening the screw straightens the jaw, simultaneously clamping the board. Slightly "tugging" on the board still loosens it, but the "jaws" here are not ideal either. Full groove may be better. And the tugging necessary may be harsher than what you will get with soldering. But wicking, may cause that amount force.So, more experimentation is required and this is worth investigating for sure. I like this design more than the screws.

author: beanflying
author_rank: Super Contributor
timestamp: August 16, 2022, 04:14:42 am
content: Take a glance at the Mitee-Bite assortment for low profile clamping solutions. Very different level of workholding (Mill and Lathe workholding) but the jaw designs and clamp mechanics are worth a look and read abouthttps://www.miteebite.com/products/The point to take away from this is maybe your jaw might be better not entirely straight and if you are making these on a CNC mill then it is fairly trivial to do over a straight solution.Those when used with a SMW low profile vice which effectively used the taper on a countersunk screw for the clamp are really effective.https://saundersmachineworks.com/products/modular-viseMore of a point contact will likely solve any sliding issues which is a little counterintuitive but the jaw will tend to softly bite into the upper surface if machined like this.LINK to the Fusion Model 3D viewer and downloadable model if you want to play or makehttps://a360.co/3w7nXv3

author: ataradov
author_rank: Super Contributor
timestamp: August 16, 2022, 04:22:53 am
content: Yes, I've seen YT machinists (and John specifically) use them, but I was afraid that sharp edges would damage the PCB. But may be sharp rare points would work better indeed without causing too much damage.I'll have to experiment.In case if the sharp biting jaws, they would need to bite into the side of the PCB. I doubt simply wavy surface would do much to increase friction.

author: Nominal Animal
author_rank: Super Contributor
timestamp: August 16, 2022, 06:15:49 am
content: I have another idea: take four quick connect cross dowels or tall barrel nuts (cylindrical pieces of metal with a threaded cross hole), and use high temperature gasket silicone (like Permatex Supra Blue/Black or Copper) to cast it a wider, cylindrical or mushroom-shaped head. It'll take several days for it to cure, and it'll stink, but when it's cured, you can make a very shallow horizontal cut (in the plane of the axis of the threaded cross hole) for the edge of the PCB to slip into.Permatex Supra Blue can handle 260°C/500°F, and Permatex Supra Copper 370°C/700°F, and they're very rubbery, so should grip nice. Here, one can find them in all hardware stores, but car part stores definitely have them too.I was also thinking of seeing if I could modify some alligator clips by trimming out the tips off the teeth, and coating/casting them in the same stuff. Stubby muzzles with rubber dentures. I got some of the adjustable hose I can attach three or four to, for work holding.

author: ataradov
author_rank: Super Contributor
timestamp: August 16, 2022, 06:22:36 am
content: I'm not sure how that high temp gasket silicon behaves, but regular silicon in soldering mats deforms like crazy under the temperature. It withstands it, no problem and returns to the original shape after cooling, but it definitely does not hold its shape.This is not an issue for gaskets, as they are clamped between two solid chunks of metal.

author: thm_w
author_rank: Super Contributor
timestamp: August 17, 2022, 12:16:42 am
content: I like the side knobs idea. Although you wouldn't get the same bending action as the vertical knobs.To get that, can place knob at an angle, forcing the two jaws together, but then you'd have to have a complex shape shim to apply even pressure to your sliding rod..I tried a few edges in 2020 aluminum, as mentioned earlier, the dovetail or wavy edges doesn't seem necessary for my PCB. It might be necessary if board has really bad mouse bite stickouts though.The first was 1mm depth with a countersink bit, I think it needs to be just a bit deeper, 1.5mm or so.Second is the plain square edge, 2mm cut depth, 1.6mm inset. Depth is good, inset can be 1-2mm depending on how close you put parts to the edge of your boards.

author: ataradov
author_rank: Super Contributor
timestamp: August 17, 2022, 01:08:07 am
content: It looks like you don't even need the groove. The design from #74 works really well if instead of screw heads I use the threaded part of the bolt. I have 10 mm set screws on a way to remove the bolt heads, so they are not in a way. Other than this, moving to 5 mm rods made them match the holes much better. You still don't get that feeling of clamping pressure control as with the screw design, but it holds the board pretty well. I'll test drive this with real boards once I have any. And if This lets me get away with standard components like this, it is great.The screw threads act similar to Mitee-Bite, so the clamping pressure for reliable holding is reduced a lot.So generally yes, it looks like the undercut is not necessary and just straight jaws are sufficient for this.

author: Nominal Animal
author_rank: Super Contributor
timestamp: August 17, 2022, 01:50:22 am
content: Maybe it's just me, but I don't like the idea of small hard metal contact area at the edge of the PCB: I want a wider, more positive contact, and would prefer something pliable instead of metal, for easier control of the clamping force. (I might get that in yourreply #74design, by using clamping rings and some stiff springs between the moving jaw and the clamping rings. I'm currently using the cheap Pro'sKit SN-390 PCB holder, and it is "good enough" for a ham-fingered hobbyist like me, but definitely not ideal. That uses a spring in one jaw to help control the pressure.)McMaster-Carr has high-temperature silicone rubber strips in 1/2" by 1/2" that they claim can be used in -100°F/-73°C to +500°F/260°C:1462N18. If you punch a hole through that (or1/2" by 1/4", 1462N16) that is a bit smaller than the screw heads you use, it might make suitable soft square gripper heads for your screw heads inreply #74.If you want the threads to grip the board, then use long grub screws instead; then there is no head to interfere with the board contact. I might consider dremeling a suitable horizontal groove in the bolt head, though. Looks very interesting, though. Please do keep us informed of your tests and what worked or not for you!

author: ataradov
author_rank: Super Contributor
timestamp: August 17, 2022, 02:00:48 am
content: As I said, I ordered long set screws. The head just gets in a way. I see no visible damage on the side of the board from the contact with the threads. I'm sure there is a microscopic contact point, but there is no visible damage cosmetically, much less functionally. I don't see it as an issue. Rolled threads are not that sharp, but they grip well.I experimented with silicon from the soldering mats. While it can absolutely withstand soldering temperatures, it still expands and warps while hot. Solid teflon would probably work better here if soft jaws are needed.

author: Nominal Animal
author_rank: Super Contributor
timestamp: August 17, 2022, 03:11:48 am
content: Quote from: ataradov on August 17, 2022, 02:00:48 amNow that is an excellent suggestion for me to try, thanks!PTFE rod in 1/2" or 3/4" diameter should not be expensive at all, and if I make say 1/2" tall heads, I can make a counterbore at the other end so the bolt head sits inside the PTFE, and still have various edge grooves on the cylindrical PTFE head –– even add them as needed.In particular, a shape that has a small ledge below, a groove, and relief above (for components near the edge) seems perfect for my needs, and is easy to do with a fret saw and a scalpel or knife. This way, the groove and the ledge are responsible for holding the board level, even with zero force on the edge of the board, and the clamping force just ensures the board does not slide in the horizontal plane.(And, I guess, I could do the same from aluminium round or hex rod later, if I find a hat shape that works well for me.)

author: ataradov
author_rank: Super Contributor
timestamp: August 17, 2022, 11:13:18 pm
content: Here is the last "complete" iteration. I don't have anything real to assemble at the moment, but I tested this with random low value components on a scrap board, and it works like a charm.So far I noted a couple issues. First of all, the corners of the brass parts are a bit sharp. This is trivially solvable, of course.The second issue is with a grip. For soldering I used minimal amount of clamping pressure. This worked without any issues, even pretty aggressive solder wick action did not cause the board to move. But when I went to clean the board with alcohol, the pressure required was a bit much and the board started to slide. Slightly increased, but still very reasonable clamping pressure solved that.Another good thing I noticed is very good heat handling. I used a heat gun on a board for much longer than I normally would to see how hot the vice would get. The parts between the bars where the board is got hot, which is expected. But the hanging parts outside of the vice, which you naturally use fo handling only got slightly warm and could still be handled without burning the fingers.I'll keep it as it is right now and I will use it with real boards to see if any other issues come up. And obviously the set screws can be positioned to accommodate the board size.

author: beanflying
author_rank: Super Contributor
timestamp: August 18, 2022, 01:24:51 am
content: Nice lash upAlso have this small vice saved on an ideas list with a view to it doing small parts or even PCB fixturing on the bench. The standard jaw width would be 'ok' for smaller PCB's on the screws but it is a neat swivel base that a larger frame could be fitted to.eBay auction: #224778809118

author: ataradov
author_rank: Super Contributor
timestamp: August 18, 2022, 01:58:07 am
content: Quote from: beanflying on August 18, 2022, 01:24:51 amThis is awesome. I was looking for a replacement for this piece of junkhttps://www.ebay.com/itm/302164028130I currently use for quick work holding.I'm not too interested in the swivel part, but the base cube is exactly what I wanted for a long time. This does not look like a wide spread product, so I ordered one while they are still available.

author: beanflying
author_rank: Super Contributor
timestamp: August 18, 2022, 02:47:31 am
content: Not that common but I did find them on AliX toohttps://www.aliexpress.com/item/32838702283.html?spm=a2g0s.8937460.0.0.46922e0efV1YDR