Need some itty bitty machine screws

I'm trying to fix up a 1940s-vintage small-frame Llama.
It needs at least one grips screw, though I'd buy a hundred to get that one.
I have 5 of these guns, and most of them have some buggered slots, or threads or both.
The screw I need measures at M3 x .7mm, 5mm long
I think I can also use 5-36 US.
Both of those appear to be like hen's teeth.
If I can get the thread, I can adjust the length and the head diameter.
Need to be slotted pan heads
I have looked at MSC, McMaster-Carr, and Fastenal.
I have also dug through my lifetime accumulation of little fasteners until my fingers are raw.
Any suggestions on where I can source those?
Reply to
Rex
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These probably won't pan out, but:
Amazon bought out Small Parts, and still has some of the good stuff.
Also try:
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Reply to
Tim Wescott
Are you sure that is a M3-.7 ? I ask as my tap charts list only a M3-.5 thread. (But perhaps my thread chart is not complete)
Reply to
John B. Slocomb
I can get A2 304 stainless M3X6 or M3X8 with DIN85 pan heads part # 421-137 or 421-042 from Spae Naur in Kitchener Ontario. Call 1-800-265-8772 for their order desk.
Reply to
clare
Odd; 1940s would usually be post-standardization, and the M3 x 0.7 thread is an oddball. Could it be M3.5 x 0.6? Or M4 x 0.7? There's also 5-40, but I've only ever seen that in lefthand...
It sounds like you might have to warm up a lathe and turn them out yourself. Panhead and slotted is the easy part.
Make a few dozen extras, and you can offer 'em on eBay to others that might want to do restorations.
Reply to
whit3rd
5-40 is the thread size of the prop screw on Cox 049 engines. I have a bag of them for that reason.
It's also popular with railroad modelers, because it's nominal diameter is 1/8", and so perfect if you're doing a 1/8 scale model of a locomotive with 1" bolts.
Reply to
Tim Wescott
#5 screws will temporarily assemble sheet metal panels prior to riveting, if you don't have Clecos. -jsw
Reply to
Jim Wilkins
Tim, I will try those, thanks
Reply to
Rex
John, I have checked and double-checked with a Bausch & Lomb measuring loup. It sure does look like .7, or .75. definitely not .5.
Reply to
Rex
Clare, I did not see those sizes anywhere on the various thread charts I have. I'd buy a few just to try them. I wonder if they have an order minimum?
Reply to
Rex
That's a last resort. I'm no machinist, but I'd give it a shot if I have to. If I find a way to source these, or make them, I'll definitely make some extras.
Reply to
Rex
there's a model railroading shop on the way to Mom's house, maybe I'll run by there. Good suggestion, thanks
Reply to
Rex
Not when I walk in to the customer desk and pay cash.. Missed the pitch though, they are .5
Reply to
clare
5-40 is standard coarse thread. 5-44 is standard fine thread 5-44 x5/8 is available in binder head - ms-289 3/4" in fillister head is ms-1144 No fine threads listed as available 5-40 1 inch round heads ms-270
Reply to
clare
If I was appearing to argue I wasn't. My question was due to me not finding a M3-.7 on any of my thread charts. Although I'm sure that my charts do not include every thread that was ever cut :-)
But a metric thread gauge would tell the story. I resisted buying one until I tapped M5 - .8 hole for a M5-.5 screw :-)
Reply to
John B. Slocomb
Being you said they were for the grips and shouldn't be important safety wise...
I talented weldor may be able to tig over the screw head. Then you could cut a new slot in the old screw. I was thinking to turn/clamp the screw threads in a heavy block of steel, maybe cast iron to suck heat away from the thread portion and then tig, reform the top. Maybe use stainless filler rod?
Hopefully some of the tig wizards in the group will chime in if they have tried anything like this or not...
Reply to
Leon Fisk
Let us know how it pans out. 1/8 scale model train enthusiasts aren't going to have many brick-and-mortar shops catering to them: that's the scale where you go to some special park and find guys riding the tender behind the engine, with a track gauge that's a bit over six inches.
Reply to
Tim Wescott
The heads aren't that much of an issue. A few are burred, but can be dressed with a file and re-blued. The immediate issue is an otherwise complete gun needing one (1) screw. Well, that and a recoil spring, but I'm working that with Wolff
Reply to
Rex
If it measures M3 x 0.7mm, the 5-40 thread, at M3.175 x 0.635mm is the closest. You ought to at least buy a few and try that size...
Reply to
whit3rd
When I have a slotted gun screw with a burr in the slot, I put the screw in an aluminum jaw vise, then use a narrow flat face punch and a small brass hammer to tap the metal back into place. This gives a stronger and better looking slot. A touch of cold blue and its good to go.
David
Reply to
David R. Birch

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