Looking for tiny U-channel

[Marco]

You could always order some slotted PCB with your next PCBs

[ataradov]

You could always order some slotted PCB with your next PCBs

I'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.

[bill_c]

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.

[ataradov]

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.

[Marco]

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.

[spostma]

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-236159
https://www.conrad.com/p/brass-u-l-x-w-x-h-500-x-25-x-15-mm-1-pcs-221809
https://www.conrad.com/p/brass-u-l-x-w-x-h-500-x-25-x-25-mm-1-pcs-295930

You could try to search on the EAN numbers for other suppliers of these profiles.

[Buriedcode]

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.

[ajb]

Any machining is out, I don't have the equipment and I don't want to bother custom ordering stuff.

Well, 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. 

[geggi1]

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.

[Zoli]

A quick search landed me a term of grooved metal for the umbrella ribs; I hope is helping a few day later.

[ataradov]

A quick search landed me a term of grooved metal for the umbrella ribs; I hope is helping a few day later.

It 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.

 

[MadScientist]

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 California

I 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.

Any mail order model railroad shop will carry small aluminium or brass profiles of what you want

[Zoli]

A quick search landed me a term of grooved metal for the umbrella ribs; I hope is helping a few day later.

It 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.

Then 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.

[Gregg]

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. 

[Nominal Animal]

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.

[janoc]

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/

[ataradov]

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.

[langwadt]

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.

afaict for a stickvise you could easily make jaws by stacking some strips of PCB

[TC]

Digikey product category "card guides"

[jpanhalt]

@ataradov

We 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.

[ataradov]

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.

[Doctorandus_P]

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.

[Ian.M]

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.

[ataradov]

Oh for FFS!

Chill. 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.

[ataradov]

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.