1911a1 Frame to Barrel Fit - Oh So Close...

[Jkrem]

My Govt size .45ACP Caspian frame arrived today, and I applied some high quality grease to both it and a surplus Brazilian army slide. To my pleasant surprise, with hand pressure only I was able to move the slide fully to the rear without overly tight binding until the last 1”-2” when it gets real stiff. I then fully assembled the slide, using an 18 lb recoil spring, and installed it to the frame using the slide stop. I’m able to fully work the slide by hand with some difficulty, and the recoil spring will not return the slide to battery without giving the rear of the slide a bump with the heel of my hand. It appears I have a bit of material to remove from the top rail on the frame.

I’m considering using some lapping compound to smooth out the fit until the slide closes on its own. I have some 180 grit grease based lapping compound, but have never used lapping compound before and am wondering if the compound I have is too rough for this application? I’d appreciate any thoughts and suggestions, I’m feeling very lucky so far and don’t want to mess this us. Would some abrasive stones or extra fine file be preferable?

I’m also short a couple of grip screw bushings, if anybody has a few to trade...

[country gent]

If its close enough to go together Id start with much finer grit. Maybe 320 and work slow. I would also hit the slide rails with a light coat of bearing blue ( dykem 109) and assemble working carefully and then look at the inks pattern. Rails may not need clean up full length but just at a few points . Here small fine stones working the inked areas will bring in full fit and best bearing. also pay close attention to the corners of the frames rail in the slide worn cutters leave a radius in those corners and this can cause binding tight spots also.
The bearing blue will show a lot of things and is helpful when fitting. Even a sharpie can show a lot.

[samari46]

Bought a custom 1911A1 based on a Springfield Armory 1911A1. Forget what they call them but there are two wires one on each side in the channel. Couldn't have had many rounds through it as it was tight. Greased the heck out of it and 300 rounds of hardball smoothed thinks out. Shoots lights out as well. Frank

[Der Gebirgsjager]

From your description it doesn't sound like it will take much. I'd almost bet that a little of your lapping compound applied to the area where the rails seem tight, then running the slide full cycle several times will be enough to do the job. Of course the frame and slide should be completely stripped, and after it works you should be sure to get all of the compound off again. Thereafter the parts will wear to match each other with use. You'll find a rubber mallet to be very useful to move the slide forward and backward on the frame, and should notice a difference in just a few cycles. When you smack the rear of the slide forward be sure that it doesn't sail off the frame and onto the floor!

[pietro]

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I'd run a box or two of hardball through it first.

An automotive parts store should have a two-sided can of fine/coarse valve grinding compound you can use as a last resort.

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[Jkrem]

On country gent’s suggestion I used a sharpie on the top and side of the frame rails, and worked the slide a couple times. Put a couple dabs of the Clover 180 grit on the bare spots, and worked the slide full cycle 10 times. After cleaning three times with hot water and Dawn, acetone and qtips, then hoppes #9 and qtips, I relubed with gun grease and the slide now works smooth as silk. Assembled the slide, and the recoil spring operates the slide perfectly with no catching or binding. Happy happy.

I’m now waiting to borrow a roll pin starter from a buddy to install the ejector. Assembled the rest of the frame, and it looks like I have some binding between the grip safety and the hammer spring housing. I’m going to focus on that while I wait for some grip screw bushings. Thanks for all the suggestions!!!

[Der Gebirgsjager]

Great! I didn't think it would take much. Building 1911s is great fun, and educational. I remember way back when I did my first one I was having some frustration, and I phoned Brownell's and chatted with David Kaiser seeking a little advice. He remarked, "Now you know what riding on the space shuttle must be like, a million parts all supplied by the lowest bidder." The point being that if you assemble a 1911 from parts supplied by different manufacturers something is bound not to fit properly. Fitting, filing, polishing, and once in awhile a part that just won't work.

DG

[Gtek]

Over the years I have done a few and if you are sure those two parts are going to live together, using them to act on each other is the best coarse IMHO. Using files and stones it will be extremely difficult to remove in exact location desired. Using the two parts to clearance each other makes perfect fit. I used fine grit with frame mounted in vise, rubber mallet and block of wood if needed. Quit before you think its perfect due to thickness of abrasive, fatter than you think. When I reached the point of barely being able to move it by hand, cleaned it and was there.

[country gent]

Its a fine line between to loose and just right. Having hand scrapped machine members for several years I tend to go with the fitting thru thru removing the high spots. With practice and small fine files of riffles just the spot can be touched or a small scraper blade to do the job. This has the added benefit of small "hills and valleys" to hold lubricant.

One trick to lapping the frame in is not to add more compound once you start. Just a few drops of oil or water ( depending on the compound). As you lapp the compound breaks down into finer and finer particles improving finish and fit. I have a set of vise jaws for my heavy vise for squeezing slides long enough or the whole slide and an .001 indicator on each end to measure squeeze. These work great for refitting slides.

I usually start with the finer grits and work slower.
Last 1911 I built was a 38 spl wadcutter gun from a Springfield govt model. I put 600 rds of 45 thru it to prove it out before starting. This is the basic budget military model. I then disassembled and cleaned 100%. the slide fit was on the loose side so squeezed it down to just snug. Spotted in with ink and then a very light lapp. Made the barrel bushing to be fitted not only on barrel but in the slide. Takes a wrench to turn its a nice snug fit. barrel to bushing was honesd to a light snug fit. with oil the bushing stays in place. Cylinder and slide shop trigger sear and hammer. this dropped in a 3 1/2 lbs very crisp and clean. Gun shoots very well usually 10 shots inside a 50 cent piece at 25 yds. 6lb recoil spring I shoot HB wadcutters over 2.6 grns of bullseye in it.

[DougGuy]

180 is WAY too coarse. Working the slide with nothing more than oil will greatly free up the fit. I put the frame in a vise and lap the slide by hand. You will be surprised just how much it will free up using nothing but oil. If it will come all the way back, and you need to bump the slide by hand for the recoil spring to push it into battery, you are already TOO close to use any grit at all. I would lap it in this manner first.

If you need grit, go on ebay and find some 500 grit lapping compound and order it.