Gunsmithing Pistol frame and slide hardness

[Munimula]

This is a mildly nerdy question. I am a machinist by trade and love of the job and also have a serious of love of firearms.

I'm looking into building a 1911 and 2011 and am curious about hardness of of materials for slides. Its easy enough to start with hard material or harden the stuff I work to a certain number. But what about the difference in hardness between the slide and frame? If my training has taught me anything, one surface should be slightly harder then the other to prevent marring the surface.

This is discussed from time to time on rifle bolts and receivers but rarely on pistols. If I wanted to make the absolute best thing I possibly could I want every aspect of it to be perfect.

So what are your thoughts on which piece should be harder? The slide or the frame.

Currently I am going to start with pre hardened 4140 or 4142 that should be in the 28-32 rockwell neighborhood. I will be checking each piece individually. Some of STI and Caspian parts are listed at 28-32 rockwell which I'm guessing they are going to be using the same material I have planned.

 

[blackfoot]

I would go over to the 1911forum and ask in their gunsmithing forum. Some of the best pistolsmiths in the country frequent there. Rob Schauland with Alchemy Custom was looking at sourcing forgings so he'd be very familiar with the specs on the slides and frames. Gunsmithing & Troubleshooting - 1911Forum

 

[Munimula]

I'll check it out. I referenced 1911's but this would apply to any pistol.

 

[NXS338]

If you are speaking of a 1911/2011 the slide and frame should not be riding on each other at any time, they should ride on the layer of oil that is in the clearances that are built in when these 2 parts are properly fit up. Also for what it is worth the Caspian slides are best your going to find, STI are not even close as far as quality and durability. The frames are usually harder than the slides, slides take a beating and if they are too hard they crack. Are you figuring on building these from scratch? as in you make the frame and slide from bar stock?

 

[Munimula]

Building the frame at least. Maybe a slide later.

As mentioned my plan is to mill them from pre hardened material.

 

[NXS338]

Building the frame at least. Maybe a slide later.

As mentioned my plan is to mill them from pre hardened material.

I thought that was what you were saying just wanted to make sure. The frame should be harder than the slide, as the slide wears over time it can be tightened but if it is fit correctly they should never really make hard contact enough to wear.

 

[Munimula]

Sorry for any confusion. I wrote that after a very long day and may or may not have been on drink number two before bed.

Trying to source some steel. Having some trouble finding the size I need without getting nailed with massive shipping fees.

 

[blackfoot]

I'd be curious to know when you find out, just for my bank of knowledge that I'll never put to use

 

[Gunsmith Dan]

4140 is the way to go for steels and as far as which for which you definitely want the slide to be tougher than the frame as it is where most of the stress is. So much so that there is companies that make the frame out of Aluminum with a steel slide if that gives you any idea.

BUT

In firearms you DO NOT want to make it to be to hard (makes it brittle) but want it to be able to take a lot of shock without deforming or cracking. In the case of firearms if you want it to last a long time then your would just heat treat certain areas that have a lot of friction contact to be hard while the rest is left as it is to resist shock.