Best screw material?

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walterwoj

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I want to single-point thread some 8-32 knurled-head screws for my Sheldon Lathe. The only material I have on hand is cold rolled steel stock which I don't think will do a very good job.... So I have to order something. Any recommendations for what material to get and where to get it from?

Details: 8-32 Screw with 1/2 Knurled head - Approx 1" long
QTY: 2
Tooling: Carbide or HSS (I have single point threaders for both)
Speed: 50-1600 rpm (probably on the slow side since I'm a noob)

Thanks in advance!
 
12L14 is sometimes described as ultra-machinable and is also heat-treatable.

Alternatively, if the intended "head" is tall enough and full threaded shank is acceptable, I would make the head with a bottom tapped hole and use a socket head setscrew, loctited, for the thread.
 
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If the size of the head allows, you can just make a knurled head with a counter bore and press it onto the socket head screw. The serrations on the head of the socket head are excellent for a press fit.

David
 
I know there are easier ways to do this but: I own a lathe! :cool: (I haven't gotten over saying that yet) I work in a hardware store so I have the screws (and dies) to do it the easy way but I don't like the way they would come out. I also want to practice screw making, so yea, I'm going to do this the hard way.
 
extropic said:
12L14 is sometimes described as ultra-machinable and is also heat-treatable
Click to expand...
Really? You mean to case harden it?
I know it's great to machine but the carbon content is something like .14% as I recall??
 
walterwoj said:
I know there are easier ways to do this but: I own a lathe! :cool: (I haven't gotten over saying that yet) I work in a hardware store so I have the screws (and dies) to do it the easy way but I don't like the way they would come out. I also want to practice screw making, so yea, I'm going to do this the hard way.
Click to expand...

Absolutely no problem! If I had a quick change gear box I would probably do more single point threading as well. 12L14 is very nice to machine especially on smaller lathes.

Don't forget to show us the completed project.

David
 
Depends on the size of the knurled head, let's go to the extreme and say a 6" head. At that point you would twist off even the best material. So let's be reasonable and say about 1/2" or 3/4" head, the amount of torque your fingers could supply would probably not be enough to twist off CR(1020) unless you really tried. Single pointing a 8-32 would be a challenge because if the tool catches it will just bend the stock. If you go to stronger material then it makes threading more difficult too. I would say start with some material you have and see how it goes then work from there. Don't get frustrated you have picked a sub optimum diameter to practice single point.
 
I think 12l14 is not a good steel for hardening, though I have not tried it.
 
Stressproofis good, I have used 0-1 as well harden it up then draw it back
 
Although the cost is a bit higher, I use 41L40 for 95% of the steel turning jobs I do (unless someone requests another material). It is quite strong and machines beautifully. If you prefer to not work with leaded steels, 4140 is great but can be tough to machine.
 
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