making screws and such

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Theycallmejohnnycash

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Hey guys,
so I wanna try my hand at fabricating some screws, mainly a screw for a side plate on an old Taurus revolver, I'm sure I could easily buy one someplace. but I wouldn't learn anything that way. so my questions are as follows.

1. thread pitch and diameter, is this special/unique to firearms ? or are they just specific length/diameter machine screws but with standard or common metric/s.a.e thread ?

2. where would a person buy a good tap and die set specificly for use with firearms ?
 
I think for the most part screws are a special thread (In North America a National Special thread).

Brownell's in the US usually have in stock taps and dies associated with firearms. Sometimes these sizes can be ordered from a machine shop supplier in Canada.

It is considerably easier to buy a better quality replacement screw than it is to make one. I would not waste my time making a screw unless I had no other choice.
 
Making small fasteners is challenging and time consuming on a lathe. A standard tap and die set won't be able to produce threads tight to the cap/head typically. If you buy a good quality vernier caliper and take a look for common thread pitches for that size fastener you could buy a few to verify the size/pitch.
 
As mentioned above, you really need a lathe to make gun screws. Dies won't work in many instances due to there inability to cut threads tight up to the head. And generally you need to be able to turn stock to the right diameter to thread anyway. I've made lots of screws that i couldn't buy, but it is a last resort.

I wouldn't want to make screws without a collet set either, they allow you a way to hold the screw by the threads without damaging them, while you machine the heads. There are a number of ways to cut slots in the screw heads, but a milling machine is best to get good results.

Its good you're interested in learning new skills, and in gun restoration, screw making is a good skill. So i wouldn't want to dissuade you. But wanted to let you know it can be expensive to get set-up to do properly, unless you do other machining as well.
 
The one thing you will learn is choosing what to make and what to buy, and what to modify. Screws you buy or modify unless absolutely necessary. Trying to make a small screw with a hand die is near impossible
 
Fargone4sure said:
As mentioned above, you really need a lathe to make gun screws. Dies won't work in many instances due to there inability to cut threads tight up to the head. And generally you need to be able to turn stock to the right diameter to thread anyway. I've made lots of screws that i couldn't buy, but it is a last resort.

I wouldn't want to make screws without a collet set either, they allow you a way to hold the screw by the threads without damaging them, while you machine the heads. There are a number of ways to cut slots in the screw heads, but a milling machine is best to get good results.

Its good you're interested in learning new skills, and in gun restoration, screw making is a good skill. So i wouldn't want to dissuade you. But wanted to let you know it can be expensive to get set-up to do properly, unless you do other machining as well.
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One thing you learn real quick, thin soft stock tends to deform when you apply tool pressure. :redface:

Grizz
 
Many screws used in firearms are not threaded all the way to the head.
Thread pitches are often not hardware store standards, and may be unique to the particular firearm.
A lathe may be the only way to obtain a screw, but is most likely a last resort. It is so much easier to buy or adapt a replacement. I have used the lathe when I could not see any other option. A 1600 pound lathe is a bit of overkill when making a small screw, but if it is the only way, so be it.
 
I have seen screw sets for different firearms...ask your gunsmith, they usually have a box full of screws, nuts, bolts, pins etc.
 
Quite correct Griz. For some applications mild steel is fine. But if the screw is going to be torqued a bit, they really need to be made from better steel. I mostly use O1 tool steel, and heat treat the screw after machining.

Also, as Dogzilla touched on, modifying an existing screw is an option. Often i can get the right thread pitch screw, but not the right head shape/ size, especially now that slot head screws aren't as popular as they once were. A number of times I've welded various other head designs up, resphaped and cut a new slot.

And i totally agree, if at all possible, buying is by far preferable.
 
Dad has an Atlas/Craftsman model 618 and a Unimat Lathe...

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Both tiny and kind of ideal for cutting small parts :) the only drawback is having to fart around with gears to get your thread count right ... :)
 
Theycallmejohnnycash said:
1. thread pitch and diameter, is this special/unique to firearms ? or are they just specific length/diameter machine screws but with standard or common metric/s.a.e thread ?
Click to expand...

As mentioned by many others, generally "NO" - the newer the gun the more likely ~some~ of the screws will be of a common thread pitch, but for receiver parts, pretty much no chance. The older the gun, the weirder the sizes and pitches are gonna get - I distinctly remember having to do a bunch of math and buy a specific gear for my Atlas 10f because my QC gearbox would not cut that particular pitch (I believe it was 13.5TPI.???) and just wait till you trip over one of those English left hand threads!! argh.

Theycallmejohnnycash said:
2. where would a person buy a good tap and die set specificly for use with firearms ?
Click to expand...

Whenever I get lucky like that I buy the specific sizes I need as I need them from KBC Tools as a set (plug, tap and taper - not a set of different sizes.) because what you are probably going to trip over is class of fit (which to be honest, I don't fully understand), your common Crappy Tire/Princess Auto/Busy Bee utility sets are just that ... very utilitarian. Buy the brand names, the KBC house brand is probably the same as crappy tire/PA/BB etc. You will find if you buy a set, you will never use most of them, this way you get much better quality.
 
Gun screws are sorta like the English Language. You can make a lot of statements about all the 'rules' that are followed, then you gotta write all the bloody exceptions down.

As far as tap and die kits specific for gun use, nope. Buy taps or dies only on an 'as-needed' basis, else you spend a LOT of money on stuff you don't actually have a need for. Spending $15 on a tap may sting, but not like spending a couple grand on a box full of taps and dies that you will never use!

Threads on guns can be normal Standard threads, but are often finer, and you pretty much have to look at each one as a separate item, to figure out what you need to look at to reproduce it. A good example is the 35 & a 1/2 threads per inch, specified on several Winchester Drawings, that a lot of guys used to think were just bad fitting 36TPI threads.

Reading up on thread cutting in a Lathe is going to go a long ways. Learning to recognize thread forms like the BA threads, assorted inch and metric threads, different threading forms like 55 degree and 60 degree Vee threads, square and half height square threads, etc., and learning how to measure odd thread pitches, are all skills worth learning.

If you have a Lathe, it's a matter of practicing cutting threads until they no longer scare you, and practicing some more.
 
i make my own screws . a have been putting togther some 94s ..i can make a screw in 10 mins . i cut the bigger screws on my lathe . smaller one no . 4 and 6 i use a die .
 
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