1911 Frame fitting to slide


May 18, 2012, 03:19 PM

I guess you could call me just a amature gunsmith (mostly do duracoating for myself) but my cousin asked me to put together her husbands fathers Vietnam era Colt 1911 slide (all he has is the slide/barrel & link/extractor/striker pin). So i bought all the "bottom" parts (frame, parts kit).

Now the frame is a brand new blued "match" frame from Numrich. I guess the rails are made larger than necessary to accomodate different slides and the frame rails need to be filed down.

Since im on a tight budget (or my cousin is) and gunsmithing services in my area cost $90.00/hr, im hoping i can "fit" this frame to the existing slide.

I saw a $50.00 (frame/slide file) tool at Brownells. Is that worth it? or will any bastard file work, or perhaps fine grit sand paper?

just looking for pointers/advice/instructions on his project.


If you enjoyed reading about "1911 Frame fitting to slide" here in TheHighRoad.org archive, you'll LOVE our community. Come join TheHighRoad.org today for the full version!
May 18, 2012, 03:29 PM
All I have ever used in 50 years is fine cut 6" & 10" Nicholson files from the hardware store.
I made frame guide rollers to fit in the slide stop and grip safety pin holes. That keeps the file running straight with the rails and prevents slipping and filing on the frame itself.

Use Dykem steel layout fluid on the frame and try & fit where the Dykem rubs off.
DO NOT touch the slide rails as you apparently have a GI slide, and it is in spec all ready.

However, I have never seen a Numrich frame in my life, so I have no idea how much filing & fitting will be needed.


May 18, 2012, 03:57 PM
Cool, thanks RC, I didnt plan on fileing the slide, only the frame, but thanks for the heads up on that. Any help is appreciated.

I guess the prudent thing to do is just measure w/ calipers the height and wideth of the frame rails and then file accordingly.

Now do you file only the top (for height)? or do you file the inside as well? or does that depend on the measurements of the slide?

And do you file the sides (width)? or again is that dependent on the slide measurements.

I think Im answering my own questions but still the more help the merrier.

Thanks again,

May 18, 2012, 04:10 PM
Measure the slide and start with width so you can get the slide started on the frame and read the Dykem layout fluid wear marks.

Then off the top if that is necessary too.

Measure the slide rail groove thickness, compared to the frame rails to figure out what doesn't fit where.

Bottom line is measure everything you can measure before you make the first file stroke on anything.


May 18, 2012, 04:31 PM
Ok, i just came in from the garage and tried measuring. I cannot measure the inside of the slide because the calipers wont fit it there... Is there another accurate measure to get the numbers from the slide? (I could get the calipers in on the very end/rear of the slide... it measures .100 of an inch, the frame measured .105 of an inch).

Also I was looking at the frame and I noticed the inside middle of the frame itself is as high as the rails. Does that middle portion get filed down as well? or just the portion of the rails that will fit into the slide?

I dont supposse you have a Youtube video on how you do your frame fitting?


May 18, 2012, 04:39 PM
If you have to file the top of the frame, you have to file the whole top of the frame equally.

I use tool steel frame & slide tightening gages I made on a surface grinder.
Like these:

However, without them, I'm not exactly sure what to tell you about measuring them.

An inside caliper might work but wouldn't be very precise.

A stack of automotive feeler gages or cut to size shim stock would work more better.


May 18, 2012, 04:47 PM
Whoa! those Bownells shims are 350 BUCKS!!, can't do that. Ill keep researching how to measure those bad boys!

You dont by chance live in San Antonio, Texas do you?


May 18, 2012, 10:13 PM
First make sure that the slide is not bent. Look at the part of the slide on the left slide that is behind the thumb safety. Make sure that part of the slide is not bent in. It was common for some one who was trying to fit a frame slide to bent that small exposed part if the slide. This area needs be O.K. because that is where the frame starts into the slide.
Get a Sharpie to use as machinist dye. That will tell you where the "rub" is taking place. Get a rubber mallet to move the slide when it gets stuck. If you want to smooth every thing in get some rubbing compound to final fit the slide/frame.
The interference between each slide/frame is different. You will need to determine where material needs to be removed. As said a 6" and 10" file is all you should need. IIRC a 6" file fits down in the groove in the frame to remove material.
A good set of calibers should allow you to make all the measurements that will determine where you need to start to remove material. In my Experience the military slide has pretty loose tolerances and the oversize "match" frame needed very little material removed for the slide to fit.

May 18, 2012, 11:36 PM
These are pretty good articles on the matter.


Buying Jerry Kuhnhausen's books on the 1911 will also be money well spent before you attempt anything.

If you go over to Rugerforum.net you may be able to procure the IBOKs on the 1911s. They are no longer being printed though and you will have to ask around to see if one is available.

May 19, 2012, 11:21 AM
Alot of slides have a degree of warp to them, more or less. The frames are softer than the slide. I use a nylon hammer as a aid in removing drag points. Once you have filed the rails to where the slide goes on most of the way, dont be afraid of smacking the slide hard left, right and down once it hanges up on a drag. You only hold the frame in your hand when hammer tuning the slide. You may still need a little filing here and there but dont over do it filing! A good nylon hammer will not damage the blueing so dont be afraid to give it a good shot (the slides are made to take serious hits!). Sounds crude but it will help you get a nice no slop fit.

May 19, 2012, 12:15 PM

A couple of years ago, on a (ahem) similar forum, I recall someone posting his progress on a 1911 where he was doing the fitting (http://www.gunrightsmedia.com/showthread.php?415155-1911-frame). Starting around post #18, you may find some details that help you with ideas on how to proceed.

Good luck!

May 20, 2012, 12:27 PM
I just finished fitting my Caspain build 1 month ago. Used a craftsman 8 inch mill file, a brownells rail file and 600 grit lapping compound, but didn't used dykem, used a Sharpie instead:eek:. Worked like a charm and its very smooth. The trick is go slow and even. PATIENCE

If you enjoyed reading about "1911 Frame fitting to slide" here in TheHighRoad.org archive, you'll LOVE our community. Come join TheHighRoad.org today for the full version!