New fastening method?

you can also plug weld the pieces.

OK, but they need to be disassemble-able--I shoulda stated that earlier.

Thread mill?

Do you mean not a lot of room as in screw heads sticking up, or that there just isn't room because the plate is being used/covered by the components it locates? Either way, maybe flat head screws are the answer.

Later,

Charlie

The surface must be smooth, which would in fact allow for a flat head, but in addition the perimeter is very tight. Think pinning, but with positive engagement.

Wether you would use 2 pieces of 1/4in to make up a 1/2in thick piece would depend on wether you could get a proper 1/2in thick piece,easily, how urgent the job was and wether using 2 pieces would meet any design criteria. ie strength etc.

Since you ask your hypothetical question heres my answer No practical metalworker would waste his time going about joining your 2 pieces your suggested way. He would either weld around the 4 edges or if he didnt have that kind of kit, would drill through, countersink both sides and hot rivet it flush as many times as he thought fit.

You can get 4-40 flat heads in enough variety of lengths that you should be able to find 1/2 inch or something slightly under that pretty easy.

combo Drill countersink the one with your depth set engaged, drill and tap the other side. Little superglue or locktite and your good to go.

I would not trust the set screw arrangement, but its feasibility probably falls under what its designed to do. If its not moving/ vibrating/stressing you may be ok. But why chance it.

Well my Newsbrowser has just posted your addition request IE the goal posts have been moved, be that as it may, Ive some 1/4in bsf threaded shallow angle countersunk allen key set screws that would do the job. Id counter sink one plate right through to match the angle and tap the other plate the correct thread. you could then pull down one plate on top of the other as tight as the allen key would do so. How many set screws youd need would depend on the application and plate size.

Is the allowable materials budget measured in pocket change? Unless you've got big money for some cool stuff found in labs, I don't know of a reusable and compact fastener system better than small screws. You could always go 0-80 if space is really at a premium. Your biggest headache there (once you get the feel for how hard is too hard when turning those little boogers) might be getting decent hexs in your screw heads. It don't take much slop before that .050" allen wrench starts spinning in the hole.

Later,

Charlie

They make small sizes to order.

Use two pitches on the setscrew. The course thread is toward the bottom of the screw. Tap the top plate with the fine thread and the coarse thread on the bottom plate. As you tighten the screw the plates will draw together.

John

If you are using only one screw then this will work well. Put the two pieces together but twisted about 1/2 turn out of desired alignment. Drill and tap. Install the screw in one part and then thread the other on. The parts will come together when out of alignment and will get tight when the parts are aligned. It could also be done with shims if more than one screw is needed. But this would be harder. You must first determine how much axial slop your screws have in holes you tap. Let's say it's .010". Use a .012" shim between the parts, clamp tight, drill and tap. Now remove the shim, clamp the parts together and install the screws. The screw should start in the second part and the farther it screws in the tighter it holds. Different materials will require different amounts of offset. ERS

They make low profile soc. head caps. I'm not sure how small they go. Button heads also have a lower profile.

"John" wrote: Use two pitches on the setscrew. (clip) ^^^^^^^^^^^^^^^^^ I didn't see a ;-) or a :-) or a . I will gladly donate my entire supply of dual-pitch set screws to anyone who can use them. I can't use them myself, because I haven't figured out how to assemble them to their respective screw holes.

According to Charlie Gary :

Or counterbores for Allen head cap screws.

Enjoy, DoN.

I might even cold rivet it, as that's simpler in the "it's either a home shop or a remote location if you're even contemplating 'making 1/2 inch' out of 2 1/4 inch plates". And it still won't be "the same as", even if edge welded and plug welded, though the combination would at least be getting there. But it's a foolish waste of time and effort in a world where 1/2 inch plate is available.

According to Leo Lichtman :

How about setscrews with left-hand threads on one end and right-hand threads on the other end. put them between the two plates, each appropriately tapped, and reach through one tapped hole with an Allen wrench to turn the screw. This would draw the two halves together. The real trick would be getting more than one of these started at the same time (aside from finding a place to buy left/right-hand threaded setscrews. :-)

If you could make your own screws on the lathe, this might work, but most home shops are at best equipped to make a slotted screw head, not a hex socket head.

Enjoy, DoN.

It seems to me that you would wind up with .022" of clearance doing this. I think you would need to add the shim after tapping or use a shim of -.012" and I think those minus shims are hard to find.

You might be able to shim it just a little less than the thread pitch and make it work. Or maybe I am just wrong? I have been before.

Don Young

Of course it is. Just as foolish as milling a one inch plate into a 1/2" plate.

But the objective here is not in making a 1/2" plate out of two 1/4" plates but in determining if the fastening method proposed is reasonable.

I think it should work if any potential gap between the plates are tolerable. I also think half the screws should be inserted from the opposite side, if the design allows for it.