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80% STI frame - 4140 steel or 416 stainless?

gt1guy

Apparently a racist
Joined
May 19, 2020
Member Number
241
Messages
2,809
Loc
New Iberia, La.
I'm looking to build up a 80% Rouge Tactical STI frame. Going to be a 10mm. I can get the frame in 4140 steel, 416 stainless and 7075 T-651 aluminum.

I've ruled out aluminum cause I'm not going for max lightness. So, I'm down to the two steel options. I'd like to go with the stainless but I'm concerned that cutting the slide rails might turn into a nightmare.

I'll be using the Matrix rail cutter, so no mill. I have no access to a mill. It comes with a hand crank or you can use a drill to turn the drive screw.

It looks like this.


Click image for larger version Name:	Matrix-Rail-Cutter-f.jpg?format=1000w.jpg Views:	20 Size:	160.5 KB ID:	188005


edit: Link to tool

https://www.matrixprecisionparts.com/19112011-tools-and-jigs/2011-tooling-package-2


What say the folks here? Do I have a hope in hell of cutting quality slide rails in stainless with this thing?
 
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Their page is no help. Video says yes, tips page says no. Only take the final "compliance cut" in SS. Kinda weird, since even a 100% frame may require some stoning to work. But it's the gov, so it's not supposed to make sense.

This ones a tough call. I love making stuff, but that jig is spendy and I'd still want a full set of stones, and lapping compound for the final fit. (and a nice set of calipers or a depth mic). Crazy investment for 1 frame. If I had 5+ maybe. I have a mill, and I still lean towards buying a 100%.

If I absolutely HAD to have SS, I'd order a couple extra cutters, take light passes, cutting fluid of course, and hand crank. Take your time and remember each pass is taking off 2x material. Easy to screw that math up if you get distracted.

If you care about rust, cerakote it. I did a rifle in Duracote in the kitchen oven and it's held up damn well. Or pay a pro. bare frame should be cheap.

That'll be one hell of a beast in 10mm though. Good luck!
 
I talked to them today, going to go with the 4140. They said the 4140 takes a pounding better and if it's coated, it cancels out the advantage of the stainless for corosion resistance.

Also their slides are 4140, so it can't hurt having both the same.
 
I talked to them today, going to go with the 4140. They said the 4140 takes a pounding better and if it's coated, it cancels out the advantage of the stainless for corosion resistance.

Also their slides are 4140, so it can't hurt having both the same.

Guess you made your decision but I was going to say unless your going to leave it natural stainless is a waste. Today's coatings are so good that it won't rust. Proper steel will be better than stainless for durability and machinabilty
 
Guess you made your decision but I was going to say unless your going to leave it natural stainless is a waste. Today's coatings are so good that it won't rust. Proper steel will be better than stainless for durability and machinabilty

That's good to know. I do plan to send everything out to get a cerakote finish put on it. I did receive the Matrix drill jig and rail cutter and also the Brownells (Starrett) rail mic today.
 
Please don't be a 9mm

Please don't be a 9mm

For the love of all things that are holy please don't make a 9mm



Going to be a 10mm.

Bless you.

4140 should be just fine. Even if you wear through a fancy finish it's easy enough to keep oiled.
 
Please don't be a 9mm

Please don't be a 9mm

For the love of all things that are holy please don't make a 9mm





Bless you.

4140 should be just fine. Even if you wear through a fancy finish it's easy enough to keep oiled.

I have a 9mm SV, I love it. actually I have two.
 
I have a 9mm SV, I love it. actually I have two.

Congrats!
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:flipoff2:
 
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