what tool to cut this? - Page 1
Forum section: electronics / projects

author: innkeeper
author_rank: Unknown
timestamp: February 26, 2022, 06:29:11 pm
content: I am wanting to inset an lcd panel into this case I have and need to cut down part of the X lattice you see in the picture by about 1/4" in the shape of an LCD panel. it is plastic and easy to cut but coming up with a way of cutting the entire area and be a constant depth across it is the challenge. the exact depth isn't as important as it is to have a fairly consistent depth as the back of the LCD will sit against it.. id like to hear some ideas on how you would approach it. I wish I had access to a mill where I could do this, that would certainly be an easy way. maybe there is some tool that I am not thinking of that might work well. ..., any ideas?

author: Domagoj T
author_rank: Frequent Contributor
timestamp: February 26, 2022, 07:33:40 pm
content: A woodworking router, optionally mounted on a larger piece of wood to bridge the gaps.Start from the middle and work your way out. If accuracy is important, make a jig to guide the cut along the edges.

author: PartialDischarge
author_rank: Super Contributor
timestamp: February 26, 2022, 08:08:39 pm
content: If you are retired and enjoy machining I don’t see a more perfect time to get a small mill, other than that slowly with a dremel

author: strawberry
author_rank: Super Contributor
timestamp: February 26, 2022, 08:22:15 pm
content: pliers , take with force

author: Benta
author_rank: Super Contributor
timestamp: February 26, 2022, 08:27:52 pm
content: Any model steam engine clubs in your area? They, or their members certainly have a small mill for this job.You might even make new friends.

author: Cerebus
author_rank: Super Contributor
timestamp: February 26, 2022, 09:14:11 pm
content: It's very difficult to tell from that picture (actually from any picture) but that plastic (ABS? PP?) has a sheen in places that suggests that it might be glass filled, possibly quite heavily. Be aware that this will blunt the edges of cutting tools in record time if it is. You'll usually find a moulded in stamp somewhere that will give the material properties indicating if there's glass reinforcement, if you look hard enough.If it is glass filled, carbide tooling is probably the only thing that will make it to the end of the job without losing so much sharpness over the job so as to be cutting significantly differently at the end of the job compared to the start. Obviously if the amount to be cut away is small this may not be significant, but bear it in mind.If it isn't glass filled you could consider hot wire/hot knife cutting.

author: jpanhalt
author_rank: Super Contributor
timestamp: February 26, 2022, 09:33:02 pm
content: Get a "nibbler" (picture attached). They come in various sizes, HD version is about $15.00, which seems about right.Razor saw (hobby shops) for the cuts vertical to the back, and nibbler for the cuts parallel to the back. Finish with a file, if needed.

author: innkeeper
author_rank: Unknown
timestamp: February 26, 2022, 10:48:23 pm
content: i am not sure what it is made of, but, it's not fiber filled, I did the knife test on it ... it started out as thishttps://www.harborfreight.com/18-in-toolbox-56681.htmli have put some feelers out seeing if i can find someone with a mill... one never knows.I have a nibbler, and it won't work for this as I am jsut cutting down the height of hose X members, though good thought. the biggest challenge here is consistent depth into the x members. cutting it isn't a challenge, the plastic is soft enough, it can be pretty easily cut. the challenge is consistent depth plus i don't think the nibbler has enough depth bite to cut the plastic anyway.a router seems like a good idea, but I jsut can't figure out how that would play out once you cut any distance from the starting point .. eventually your floating in the air. .. I was thinking of maybe making a jig off the bottom and using some kind of rotary tool/Dremel to cut and use the jig as a depth guide? like a piece of wood cut to fit within the x and then use the rotary tool with a cutting disc pressed against the wood to limit depth? ... might work but kinda janky at best.is there some kind of cutting tool that cuts a limited depth? i thoguth about maybe using miniature end cutting pliers in that way...https://www.homedepot.com/p/TEKTON-Mini-End-Nipper-Pliers-3522/207096549#overlay

author: jpanhalt
author_rank: Super Contributor
timestamp: February 26, 2022, 11:27:21 pm
content: Consistent depth is your problem?Make a jig, That's what anyone without a mill would do. As for what's a jig? I piece of wood cut to the correct height and used to scribe a line or set your nibbler against will work. More than 100 years ago -- probably back to antiquity --, carpenters used scribe to fit mantels (etc.) to the very uneven walls of the time.Which plane do you want to match? Use that plane for your scribe reference.

author: Bud
author_rank: Super Contributor
timestamp: February 26, 2022, 11:28:23 pm
content: Remove everything with a nibbler or pliers and then glue 4 support standoffs ?

author: themadhippy
author_rank: Super Contributor
timestamp: February 27, 2022, 12:46:17 am
content: bit of steel the size you want cutting out ,heat till red hot and drop it in ,best not to do it in the kitchen as it may get a bit whiffy

author: innkeeper
author_rank: Unknown
timestamp: February 27, 2022, 12:55:23 am
content: the plane I want to reference would be the top of the x structure, the side facing the camera. though I think the depth is consistent and could use the base of the x structure as a reference as well.but to just to scribe, yea that be easy to make a jig for that and reference off the topI do not think I want to remove all the x structures as the x structure provides rigidity to the top. all I need is to remove the thickness of the LCD panel which like 1/4" or less. This is because that clearance is needed to be able to shut the lid, though that's, not a bad thought.. i could maybe not care too much about the depth and still use standoffs to mount it then i can jsut worry about cutting enough to give the clearance and the depth is set by the standoffs.

author: Ground_Loop
author_rank: Frequent Contributor
timestamp: February 27, 2022, 12:58:38 am
content: Dremel saw blade against a guide block.

author: innkeeper
author_rank: Unknown
timestamp: February 27, 2022, 01:07:23 am
content: maybe scribe it, and use the guide block this way I can keep tabs on if I am going wonky with the cut.

author: jpanhalt
author_rank: Super Contributor
timestamp: February 27, 2022, 01:19:44 am
content: Exactly. Remember, measure once and cut twice.* Don't try to cut to the scribe line on the first nip. Edge up in it. It takes time, but hand tools are adequate.John*I know that is "backward" from the usual advice, but it applies to fitting something to reasonable accuracy.

author: nctnico
author_rank: Super Contributor
timestamp: February 27, 2022, 02:06:07 am
content: A wood router is probably the best option. It likely won't fit under a mill anyway.

author: JDubU
author_rank: Frequent Contributor
timestamp: February 27, 2022, 02:25:36 am
content: Do a Google search for "Router Sled".You can easily build one to use a custom reference surface.

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: February 27, 2022, 02:39:06 am
content: Hot knife?https://www.goldstartool.com/new-tech-hs-10-8-hot-knife-cutter.htm$$$ though.

author: innkeeper
author_rank: Unknown
timestamp: February 27, 2022, 03:11:42 am
content: Quote from: JDubU on February 27, 2022, 02:25:36 amI didn't even know such a thing existed. that seems very promising ... looking at some DIY plans.

author: MarkF
author_rank: Super Contributor
timestamp: February 27, 2022, 03:16:27 am
content: I've done a lot of woodworking and I would bet that a router bit would shatter those thin honeycomb fins in the center of the panel before actually cutting them. The same would occur with a metal milling bit. Although the small saws available on a mill would be my first attempt instead of a bit.You might get away with a router bit if you filled the honeycomb with spay foam insulation. Anything to dampen the oscillation from the bit. As far as router mount, you would need a support to span the panel with bit that can reach through. I recently did a similar thing to make a flush cut where I used two 3/4" boards to rest the router on with the bit down the center.

author: Muttley Snickers
author_rank: Unknown
timestamp: February 27, 2022, 04:19:43 am
content: I have a milling machine in addition to a collection of die grinders, routers, Dremel and other tools and would likely tackle the job in a similar manner to what MarkF has suggested. As you don't have access to a mill I would recommend using a plunge router or laminate trimmer with a suitable arbor and a small slitting saw.Clamp two parallel sheets of ply or aluminium as a base/ guide plate on top of the surface to be trimmed and set the depth of cut. Then run parallel cuts in one direction (X) and rotate the base/ guide plates 90 degrees and do the final cuts in the other direction (Y).Regardless of the method you choose just be sure to wear suitable protection and clamp down all surfaces properly whilst machining as high speed cutting tools don't give you much time to duck should something come adrift.Edit: Added warning.

author: Nominal Animal
author_rank: Super Contributor
timestamp: February 27, 2022, 09:14:35 am
content: I would draw the parts to be removed, carefully, with a sharpie first. Anything colored to be removed. Both sides on each divider, all sides on each stud. Use tape for a clear divider line before coloring the tops, so you can use calipers to verify the measurement if the current top surface is planar. (Tape can slide during working.)Then, I'd go at it with sharp woodworking chisels, and a metal hand saw blade. The idea is toshavethe plastic off, not take it out in large chunks. After reducing the height of the plastic between the studs around each stud, use the metal hand saw blade (suitably shortened via shattering in a vise if necessary) to cut the stud off. Maybe leave just a bit to shave off to perfect height.It will be slow and take a lot of time, and if you get in any kind of a hurry and take too large a cut, you're likely to shatter the plastic.This is how I modify plastic enclosures, anyway. I don't like using scalpels, because the blade can shatter. You can use wet-or-dry sandpaper (high grits) on top of a mirror to sharpen woodworking chisels to scalpel-like sharpness ("scary sharp"). When you buy them, they're not that sharp to begin with.

author: nctnico
author_rank: Super Contributor
timestamp: February 27, 2022, 11:30:06 pm
content: Quote from: MarkF on February 27, 2022, 03:16:27 amI don't think so. I have done a fair bit of milling plastics. It takes a sharp tool / bit and suitable speed. A wood milling bit would need to turn at high speed so the plastic will be cut away before it breaks away.

author: Smokey
author_rank: Super Contributor
timestamp: March 01, 2022, 09:49:20 am
content: Quote from: jpanhalt on February 26, 2022, 09:33:02 pmok.. Now what?

author: Gyro
author_rank: Super Contributor
timestamp: March 01, 2022, 11:36:13 am
content: Quote from: nctnico on February 27, 2022, 11:30:06 pmYou can get plastic specific cutting bits for uPVC window frame work and similar, but they're more about finish than anything. I agree, a nice sharp carbide wood bit at high speed should work fine.