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Discussion Starter · #1 · (Edited)
I am working on fitting a JEM carbon steel slide to a 100% JEM stainless steel frame and it’s going well. The slide will go onto the frame by hand with very little force, but it will not slide freely when the frame is tipped front to back.

Some builders shoot for a .0002" side-to-side fit - I’m not sure I can even reliably measure that small!

But I’m thinking about stopping with the fitting at this point and building the gun out for test firing. If the slide ‘wears in’ during testing, I’m good to go. If it does not, I can stone a tiny bit more off the frame rails and the bottom of the slide (the places that there is the slightest contact now).

How bad an idea is that?

@Integrity Arms @wrmiller @azpoolguy
 

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The Tinker
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Does there appear to be full contact on the frame and slide rails? If not, there could be some break-in/loosing up as you build the pistol. If you already have full contact, I'd just burnish the fit a bit more. But that's just me as I'm not done until the slide will slide back and forth on the frame from it's own weight. I've fit slides too tight and paid the price.

Just a FYI, but I would keep the frame and slide rails lightly lubed during the build.
 

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Discussion Starter · #3 ·
Does there appear to be full contact on the frame and slide rails? If not, there could be some break-in/loosing up as you build the pistol. If you already have full contact, I'd just burnish the fit a bit more. But that's just me as I'm not done until the slide will slide back and forth on the frame from it's own weight. I've fit slides too tight and paid the price.

Just a FYI, but I would keep the frame and slide rails lightly lubed during the build.
Thanks for the comments. I will keep it lubed.

There is full contact along the outside of the frame rail and the bottom of the slide, as evidenced by black magic marker. So it sounds as if I need to give it just a touch more stoning.
 

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Discussion Starter · #5 ·
JB Bore Compound
I am tempted, but have heard stories of the grit staying in the gun for a long time and I don't have an ultra-sonic cleaner. But if that's how you do it, then that's a very strong recommendation!
 
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Hi,
In Kuhnhausen's book he talks about oil lapping the frame and slide after fitting 200 times or cycles.

Sounds like a lot, but does not really take that long.

If after, I lap till the slide will pass the tilt test and there feels like there is a little side to side play.

I will pinch the slide in the vise with some bars I made.

I only do this if needed and admittedly it is a "feel" kind of thing!

Some people caution against this and no doubt there is a chance to crack the slide but it does not take much to make a difference and I have had no problems.

Of course after tightening the slide, it is back to oil lapping again, until the tilt test works again.

All of that, but you get that "roller bearing" feel a bench made pistol should have, and people have commented on how smooth my 1911's feel, compared to a commercial pistol.

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Discussion Starter · #8 ·
I know that once you think you’re close, you are REAL close. A little goes a long way at that point.
 

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Putting the slide on backwards and working it WILL NOT put material back on... so don't go to far.
I just keep it wet and by the time I'm done fondling my new accomplishment.... it ends up right where it ought to be.
 

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Discussion Starter · #10 ·
Putting the slide on backwards and working it WILL NOT put material back on...
But wouldn't that be nice!

I stoned the contact surfaces just a touch and it seems like a real good smooth fit now - the slide will slide due to its own weight. Time to stop and keep it oiled.
 

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Don’t ask me. I just make this **** up as I go. I’m just a rank amateur that has some op ions on how things should be a new a slightly above average understanding of the inter workings of the 1911. 😂😂😂

That’s why I had Jason Burton do my slide to frame fit. He used what I could only images was a few thousand dollars of measuring tools first to determine a plan then did some very intricate machining.

I can fit parts like a grip safety with the best of them but slide to frame fit I leave to the professionals.
 

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Don’t ask me. I just make this **** up as I go. I’m just a rank amateur that has some op ions on how things should be a new a slightly above average understanding of the inter workings of the 1911. 😂😂😂

That’s why I had Jason Burton do my slide to frame fit. He used what I could only images was a few thousand dollars of measuring tools first to determine a plan then did some very intricate machining.

I can fit parts like a grip safety with the best of them but slide to frame fit I leave to the professionals.
When I did my last build, I bought an unfinished frame so I could try my hand at machining a frame to fit a slide. There was some minor drama involved, but it worked out in the end. If I ever do decide to build another 1911 pistol, the frame will already be cut for a ramped barrel, checkered at 30 lpi, and machine fit so that I only have to do the fine tuning on the slide-to-frame fitment. I can get the slide already machined for sights or a RMR, with cocking serrations, and a reverse spring plug cut.

With all of that already done, I can concentrate on the more critical stuff like hand fitting the barrel and the frame internals. Heck, I don't even need a mill or lathe anymore, unless I want to fabricate fancy stuff.

Anyone have a spare grand laying around? :LOL: :ROFLMAO:
 

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Heck, I don't even need a mill or lathe anymore, unless I want to fabricate fancy stuff.
Anyone have a spare grand laying around? :LOL: :ROFLMAO:
I have a grand I could spare... I just don't have room for your mill & lathe right now.
o_Oo_O :ROFLMAO:
 

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Hi,
The last time I bought some frames from Caspian...

I bought 3 of the Foster GM frames.

The nice folks at Caspian said, they would take a GM frame and cut it to Colt Commander specs for $25!

I had 2 of the three frames cut, Hell, I've got a BP Mill and probably can't machine them for that, everything included!
 

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Doesn't JEM offer a slide to frame fit service?
They do (did? I ordered a slide and frame fit from them a couple months ago but can't find the option for a slide to frame fit on their site anymore). And I think Bob may have used it. But if you ordered it "machine fit" they basically got it to an interference fit and you'd still have to do a tiny bit of work to get it ready to actually shoot. They also offered a "run ready" fit but at that point you better make sure their view of a proper final fit is the same as what you want.
 

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I use Iosso orJB Bore compound as well. I have used auto polishing compound as well as a final polishing step.

Okay, the clearance given from the first post is .0002”. Is that accurate?I have gotten as close as as .0008” clearance. So is the .0002” operating clearance correct?
 
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