How hard is a 1911 slide? HSS or Carbide?

[RemingtonAI]

Hey guys,
I was wondering if any of you were familiar with milling 1911 slides. I have a para ordinance scrap slide I was going to practice on and wanted to know if carbide was typically used for this. I'm not a gunsmith nor do I want to be but I am a studying machinist and just thought this would be fun. I didn't think it would be too hard so I set it up in my horizontal mill and used a HSS 1/4" radius arbor cutter to take a cut and it just didn't like it. Tried some more and it really wasn't cutting, not producing chips like it should, lots of vibration.
I put a piece of stainless in the vice and it cut ok but seemed to be a bit dull. It's an old cutter so that could be it. Tried another form cutter in the stainless and it cut much better, and I was going to try it on the slide but thought it might have been the slide that made the first one dull.
I've never used carbide with this mill before. It's a 1942 Burke #4 restored and I'm always machining raw material so HSS works great for me whether it be aluminum or steels. Is this just simply a job for carbide or should the HSS work,under the right conditions? Are 1911 slides pretty standard in their hardness or do you see a lot of variance? I know I have a few questions there but I don't want to dump a list of specific questions on anyone. Any feed back, recommendations, past observations, or thoughts would be greatly appreciated! Thanks, Jesse

 

[Knotwild]

I would join and post the question here:

https://forums.1911forum.com/forumdisplay.php?s=6ca8555c7dba8e3af8e4a2d51cc5b5bc&f=18

 

[Ggmac]

Each manufacturer has different metal composition and hardness .
Chinese , yes the old import 1980s were extremely hard . Colt 70 and earlier were hardened mainly in the lug area and when the light is just right you can see the difference in color where the tempered line is .
I hope this makes sense , no coffee yet .
I'd like to add , if milling I use to add a few jack screws in it to help stabilize the rail .

 

[msinc]

I don't know about Para-Ordnance specifically, but I do know that the U.S. GI WWII type 1911A1 slides were up there pretty good on the Rockwell scale...I think something like 59 or so, which is like Buck knife blade hard. Many manufacturers follow the G.I. or "mil-spec" on the original blue prints and so the slide may be hardened. The early Colt 1911's were not. Like today's aftermarket AR upper and lower receivers...the blueprint calls out a specific "hard" anodized finish and most have it.
If milling 1911 slides is something you really want/need to do, I would suggest the carbide tooling so you are covered for all of them.

 

[RemingtonAI]

Thanks guys. MSINC, that's good info to know and would certainly make sense given what I have seen with this one. I know carbide should be run fast, probably faster than my little Burke mill can go, think it will still work at slower speeds? I'll be reaching out to the other machinist groups I belong to but would love to hear your input if you have any on running carbide at slower speeds. Can't give you an RPM because I don't recall what my 3 positions will yield but it's typical of old machines. Thanks again. Jesse

 

[Toolbreaker]

Carbide will cut just fine at slower speeds. You just have to adjust your feed accordingly. What will kill carbide though, is a non-rigid setup. I'd take Ggmac's advice and brace up the slide. A big plus with HSS is it is very forgiving on shaky setups.

 

[RemingtonAI]

That's good to know, I'll try the carbide. Just made a little screw jack a couple weekends ago but I believe it's too big to fit under the slide when it's in the vice. I'll make sure to find another way to get every bit supported. Thanks for that advice. Ok, so I'm off to find a suitable 1/4" carbide ball end mill from Amazon. I'll let you know what happens just for fun. Jesse