Dremel accessory for routing PCBs? - Page 1
Forum section: electronics / general

author: MrSlack
author_rank: Frequent Contributor
timestamp: May 31, 2016, 03:25:23 pm
content: I've been using FR4 and an X-Acto for cutting PCBs for about 6 months now I am doing one off SMD stuff. It's getting laborious manually slicing and peeling copper now, so Dremel time! I'm not doing proper PCBs for this stuff or dealing with etching - it's usually one shots.Can anyone suggest an accessory tip that will actually groove FR4 easily freehand?

author: DimitriP
author_rank: Super Contributor
timestamp: May 31, 2016, 06:54:30 pm
content: I've used this, but you have to have an "engraver's hand" if you are going to do a whole board.I don'thttp://www.amazon.com/Dremel-107-Engraving-Cutter-Shank/dp/B00008Z9ZV

author: MrSlack
author_rank: Frequent Contributor
timestamp: May 31, 2016, 07:58:12 pm
content: Thanks will try one of them.

author: rob77
author_rank: Super Contributor
timestamp: May 31, 2016, 08:19:23 pm
content: "V" shaped or spear shaped bits are the best for cutting isolation routing in FR4. not sure if dremel makes them but proxxon does them in various sizes (0.8mm smallest dia but you can use the very tip of the V shaped bit only to make really narrow isolation grooves) they make them with a 2.35mm shank. other option is a small diamod ball engraver bit, i use them both.

author: MrSlack
author_rank: Frequent Contributor
timestamp: May 31, 2016, 08:25:07 pm
content: Was looking at an engraver bit for the large traces and a milling bit held at an angle for narrower ones. Will see how it goes. Have just ordered 5 different bits.My wife doesn't know I'm going to steal her Dremel yet

author: KL27x
author_rank: Super Contributor
timestamp: June 01, 2016, 02:10:32 am
content: For what you are doing, I have found the engraving ball is what will work best. But the diamond dust coated ball will last longer than the high speed steel ones the first responder linked. The larger the ball, the easier to use. But the best you're going to get is like 30/50 or so. Trace/isolation in mils. A very cheap battery powered engraving tool will work just as well as a high powered dremel, IME.QuoteCertainly don't bother with pointed V-groove cutters. They will only work with a very rigid platform, not by hand. And even then, they wear out super fast. A regular end mill turned 45 degrees will cut circles around this kind of bit. So unless for a CNC machine, I wouldn't waste any time/money on V-groove cuttters. Even when I tried using them in a router table setup, the cutting is super herky jerky and needs a lot of force (special holder) to move the board in a controlled fashion.

author: joeqsmith
author_rank: Super Contributor
timestamp: June 01, 2016, 03:25:49 am
content: For PCB mods, I use a very small V cutter you can see in the attached video. I also use some small saw blades that are maybe 0.1" diameter. If I need to remove a lot of material, I use the X-acto knife, soldering iron and needle nose pliers. One thing that would really help me when I do this sort of work is a better tool than the Dremel.https://youtu.be/QNRFTMk8MVI?t=1752

author: KL27x
author_rank: Super Contributor
timestamp: June 01, 2016, 04:53:13 am
content: A steel ruler and a carbide tile cutter might be helpful, too.A small hole saw to cut out insulated copper clad discs that you can glue or solder down onto a ground plane may also come in handy.QuoteYou're still going to need to buy/make breakout boards. There's no way you're going to easily manually score pcb down to 0.065" pitch. Point-to-point wire jumpers will be easier than that.

author: Raj
author_rank: Frequent Contributor
timestamp: June 01, 2016, 05:26:47 am
content: This tool (you'll need something equally thick as your pcb to surround it while using it)its model 230 router attachment...and its older than me, so might me difficult to find

author: MrSlack
author_rank: Frequent Contributor
timestamp: June 01, 2016, 07:48:11 am
content: Quote from: KL27x on June 01, 2016, 04:53:13 amI'm only doing sot23, 0805 and ~8 pin soic. Don't need anything too small.

author: tautech
author_rank: Super Contributor
timestamp: June 01, 2016, 08:09:36 am
content: Nobody's mentioned dust masks !

author: MrSlack
author_rank: Frequent Contributor
timestamp: June 01, 2016, 08:24:26 am
content: Already have one of them, and safety glasses, don't worry

author: rob77
author_rank: Super Contributor
timestamp: June 01, 2016, 01:04:48 pm
content: Quote from: KL27x on June 01, 2016, 02:10:32 amactually works perfectly for cutting straight long isolation lines - i'm using V bits at 20k rpm with my proxxon FBS240 mounted in a MB140 drill stand. and even moving the board under the V bit without a guide is pretty easy. diamond ball engraver bits are great for small areas but not for long lines, that's why i'm using both. and of course for anything more complex than 10 components your best friends are riston & dynamask

author: KL27x
author_rank: Super Contributor
timestamp: June 01, 2016, 08:55:22 pm
content: ^ +1.I stand corrected.Previously, I used the 60 degree v cutter in a proxxon rotary tool at 20K. In a router table. With the height carefully adjusted. But I was using it with the bit directly perpendicular to the board, and also I was cutting deep enough to snap the board.So I just tried it by hand, and I jumped to the wrong conclusion. It works a lot smoother by hand when the bit is tilted and you are just scoring through the copper. Indeed good enough to be better than an engraving ball - faster, finer, and still easy to control without much jumping. At least in a proxxon, and yeah, I see that the higher the rpm the smoother it works. We'll see how long they last, but I have about a dozen, anyway.It looks like even 0.05" pitch is doable with this bit!

author: joeqsmith
author_rank: Super Contributor
timestamp: June 02, 2016, 01:25:27 am
content: Welcome to the dark side of PCB cutting with a pointed tip. Really, I think you just need to use what you are comfortable with. I had a friend who had a cutter that was more like a dental office tool. The hand tool would very small and it used good bearings, not like my cheapo Dremel. The Dremel is just too bulky for me.I thought I would post some pictures of a few of my cutters. Note the size of the smaller tips I use...Quote from: KL27x on June 01, 2016, 08:55:22 pm

author: joeqsmith
author_rank: Super Contributor
timestamp: June 02, 2016, 01:28:43 am
content: In the first picture, there are two very small ball cutters towards the bottom. let's compare those with the cutters I use for PCBs.Oops...Top left is the spear tip you see me with in some of the videos.2nd down is a ball cutter3rd down is an inverted cone4th down is a saw blade

author: joeqsmith
author_rank: Super Contributor
timestamp: June 02, 2016, 01:33:27 am
content: It's a little hard to see, so here are the four cutters next to the smallest under the microscope. Note the chips. Tip is broken off the V cutter. Lots of abuse....

author: Ian.M
author_rank: Super Contributor
timestamp: June 02, 2016, 02:07:22 am
content: Has anyone tried the guide from the Dremel 566 Wall Tile Cutting Kit, to provide router-like depth control for cutting isolation gaps in bare copper PCBs without digging into the underlying laminate excessively?

author: KL27x
author_rank: Super Contributor
timestamp: June 02, 2016, 03:44:59 am
content: Interesting collection joeqsmith.The V groove cutters I bought are carbide. They look like this. Just one cutting edge on the bit. You can see some of the hand-carved lines I made in the corner of the pcb. I don't remember what the isolation gap settings I used on this pcb; it is pretty generous, seeing as no soldermask. Anyhow, I could easily match it by hand, under good lighting, say under a microscope. (You can't really tell in the pic, but those lines all have a very clear isolation, visually.) The small ball cutters with the multiple facets work great, too, but I find they dull very quickly. This bit was still sharp enough to poke a hole through my finger when I put it away.QuoteFor the sake of science, I just free-handed this on my router table. Obviously I couldn't see what I was doing, but as you can see it was pretty smooth. I guess these bits are somewhat limited to depth of cut. Going even halfway through the FR-4, things get really dicey. Or maybe it's the material, copper being easy to machine. I think most of the time you rework a pcb, it's going to be populated, though. So I wonder how often you are going to get to use a router guide.QuoteWell, I have yet to use a Dremel tool with as little runout as my proxxons. I have indeed used a proxxon tool to grind on a tooth, before. Smooth!I have a couple Dremels and a couple proxxons. With my Dremels, I can manage an endmill on plastic by hand, but not wood. With the proxxons, I can manage wood, no problem.QuoteIf I had known it was this easy, I would have used it the other day. I broke out the sharpie to make a quick and dirty board for wiring up a multi cell battery... and it turned out pretty horrible. I guess I have the wrong kind of pens. This would have done a much neater job.

author: joeqsmith
author_rank: Super Contributor
timestamp: June 02, 2016, 05:19:49 pm
content: That's an interesting looking tip. Post a mfg and pn and I'll pick up a few to try. Drew a couple of guide lines with a marker and made two cuts free hand. Left is from the saw blade, right from my pointed tip. Scale is 0.01"/mark. Razor blade along with a straightedge would have been the tools to use but gives some idea how they cut.

author: KL27x
author_rank: Super Contributor
timestamp: June 02, 2016, 11:23:32 pm
content: I bought them on amazon, no longer available. The lot description says "30 degree carbide PCB cutter bit."They look the same as this, except these cost twice as much as what I paid per unit.http://www.amazon.com/EnPoint-High-precision-Engraving-Diameter-Aluminum/dp/B00QNIXAOQ/ref=sr_1_7?s=hi&ie=UTF8&qid=1464909715&sr=1-7&keywords=carbide+pcb+cutterI bought them specifically with the intent to score/cut the FR-4, so I figured the thinner the kerf the better. I don't know if the 30, 45, or 60 degree is best for removing copper?I'm no machinist. But for me the steel bits don't last too long vs FR-4.FWIW, thanks to this thread, I get to junk my little Proxxon ball-end engraving tool. The carbide "pointy bit" in a regular proxxon definitely works better and faster. Almost 4 years, I had these bits without trying them for this.

author: joeqsmith
author_rank: Super Contributor
timestamp: June 03, 2016, 01:56:52 am
content: Thanks! I checked and saw they have many similar ones. I'll pick up a few different ones to try out.I tried to find out what my old friends tool was. Sorry, no luck. He used it for cutting wood and was pretty good with it. He let me try it out and I have not liked the Dremel since.I was better off not knowing.....I have a few different guides for my Dremel. Picture showing how much straighter I can cut a line with one of them. Shown with the broken point cutter. Right to left was 1st through 3rd attempt. Was getting fair results once I got the depth sorted out. All plastic.

author: joeqsmith
author_rank: Super Contributor
timestamp: June 10, 2016, 02:13:11 am
content: These came in. Looks like they may work alright. Also got some cheaper ones below. I'll give them a try over the weekend.https://www.amazon.com/Autek-Titanium-Carbide-Engraving-J3-3001Tix10/dp/B00HC98K2C/ref=pd_sim_469_3?ie=UTF8&dpID=41PXkOwZ3dL&dpSrc=sims&preST=_AC_UL160_SR160%2C160_&refRID=V0F05BGVC0CA37VVZT68https://www.amazon.com/Generic-Degree-Carbide-Engraving-Router/dp/B00EQ1XMSQ/ref=pd_sim_469_8?ie=UTF8&dpID=41--jeqWaTL&dpSrc=sims&preST=_AC_UL160_SR160%2C160_&refRID=Q80PN3A1KBVN3HZ5ZH25

author: KL27x
author_rank: Super Contributor
timestamp: June 10, 2016, 03:50:32 am
content: Coincidentally, I wired up another battery pack the other day. So I tried using this cutter, and the line is TOO small (for this). Under the microscope, I can also see a lot of tiny copper particles that don't wipe out, easily.I ended up using the old diamond dust ball engraver bit. The kerf is relatively huge in comparison, but still a bit too fine for this particular job. The larger radius also lets you wipe away the copper cleaner, without digging and leaving little embedded particles or chewing up the surface of the FR-4 as much.Certainly for finer pitch and rework of a factory board, these V grooves will be the cat's meow.

author: joeqsmith
author_rank: Super Contributor
timestamp: June 25, 2016, 03:44:00 pm
content: I finally received the second set of cutters and tried them both out. The last set are not coated, carbide about $8.00 for a box. They do make a bit of a mess as you suggest. I am not sure it's any worse than some of my other cutters. Working free hand, I can control the cutting fairly well with them. They are not made to remove a lot of material fast but seem to do a good job with fine cutting.I give them the thumbs up.I have used the find grinders (green colored stones) for removing large areas. Really large, I am back to the knife and heat gun....Quote

author: joeqsmith
author_rank: Super Contributor
timestamp: December 23, 2016, 07:54:52 pm
content: Quote from: KL27x on June 02, 2016, 03:44:59 amI just pulled the Dremel out and have been meaning to post a quick note about my progress using these cutters. I have been using them a fair amount by hand and I have given up on all of my other cutters that I show. I drill holes, modify boards and have carved complete boards by hand with them. I have more control and can make finer cuts with these tips than any others that I have. I am still using the first two cutters I pulled out and there is no signs of any wear.This was some excellent advice! Thanks!

author: KL27x
author_rank: Super Contributor
timestamp: December 23, 2016, 10:55:59 pm
content: Glad that worked out for you. Ironically, I find I'm still usually using larger diamond coated ball engraving bit. For reworking a printed circuit board, I'm usually using small hand-chisels. For me, it takes special need to pull out this pointy V-cutter. Diamond ball is much larger kerf, and a bit slower, but it is smoother and easier to keep the lines straight; which for me, if diamond ball is too big/crude, it's often easier for me to make PCB, anyway. So crude and simple and easy is mostly all I do with a dremel. No smaller than 0.1" pitch, usually.The kerf is so thin with the V cutter, it also takes a little more time/effort for me to even verify it's clear of copper debris. Even with microscope, this slows me down a little. But trace size/density is great, if you have the need to do this by hand. Perhaps adding circuitry to piece of ground place, for instance.Oh, in case you ever have need, I also stumbled across a pretty cool way to make these crude boards neater. I sometimes save cutoffs from toner transfer boards. I might sometimes trim some blank copper clad off of them before etching, but after they have been pre-etched. So they are dark copper oxide. After carving crude board with this, I can scrape the places where I want to have "pads," using a tiny rounded sole chisel. Then solder only sticks there, as long as you remove iron in reasonable time. Sometimes some of the traces of these crude little boards is huge... half the board might be used as one trace. So in this case, the copper oxide soldermask helps out and makes the board more neat and easy to rework.My latest hand chisel has just a 1.2mm wide cutting edge. This seems to be a good size for cutting and removing a small section of 12/12 traces. And it works great with my personal DIY veroboards. But I think I need to make an even smaller one for finer rework.

author: Marc M.
author_rank: Regular Contributor
timestamp: December 24, 2016, 09:11:46 am
content: Quote from: joeqsmith on June 01, 2016, 03:25:49 amHey Joe, where ya goin' with that Dremel in your hand? ... sorry, couldn't resist.For the most part, I ditched my Dremel many years ago. If you have shop air, a much better alternative is a pencil die grinder. They are a lot smaller in diameter, lighter, get cold rather than hot (used to burn Dremels up back in the day drilling home made PCB's), and have a higher speed (this one is 56k rpm). This is a Harbor Freight cheapie, but for the amount I use it, it's fine. I looked up the # on it and it looks like that's changed to 69745 @ $29.99.

author: jonatanrullman
author_rank: Contributor
timestamp: December 24, 2016, 10:40:01 am
content: I have a related suggestion which has really helped me improve my results with the Dremel, not least the fiddly pcb milling jobs.First of all I always use the small pen adaptor Dremel calls Flex Shaft Attachment (p/n 225-01). The Dremel itself hangs off a hook on a stand temporarily bolted to the table. This makes it a lot easier to begin with. But it is still incredibly hard because of the speed.So a few years ago I stumbled across a box of sewing machine pedals at a thrift store. Really old ones. The ones that is basically a variable voltage drop in series with the power cord. So I picked one up for $5, opened it up and replaced the sewing machine cord with two new ones. One for the wall and one with a regular extension cord socket that I can plug my Dremel into. The neutral I soldered together with some shrink and stuck in a corner and the phase went through the circuit just like on the sewing machine.I set my Dremel to the speed interval I want to use, on a scale from 1 to 6, and the pedal then smoothly varies the speed between zero and the maximum for that interval. Works really well, the control you have over speed is just incredible. It is entirely possible to get the Dremel down to double digit rpms if you like and then press down hard and get it into the thousands in a second. I am not aware that the motor should take any damage from being driven at lower voltage, so I suppose there are very few downsides except for electrocution if something fails inside. Although the actual pedal cover is in plastic and the bottom is metal so that risk should be negligible.See attached photos for illustration.Cheers