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Improving frame to slide fit. Wow.

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I finally picked the pistol to start my custom project on. I was going to do the Tisas Service Special I bought a couple months ago, but it shoots so well and the fit is pretty darn good...I decided to leave it alone.
So I picked my latest Tisas Tank Commander. It has a looser frame/slide fit and I carry commanders more often. If you shake the pistol it rattles pretty good. I know, I know, the original 1911's rattled, but this is my project in 2023, we have the technology, and I want to improve every aspect of this pistol. So I want a custom, no rattle fit.

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Anyways here we go. I measured the frame and slide and ordered the appropriate thickness frame plate. I suppose you could do this with no plate but this keeps you from going overboard with the hammer. I did not use a vice (edit 1-25-23 VISE haha got me!) to hold the frame, electing to go old school and hold it. Using the workbench as a base I was able to quite easily keep the plate in the frame groove/hold the frame and get to work with the hammer. I used a new stainless claw hammer.

Apparently this is called swaging and @Oldpistol convinced me to tackle it. I tap-tap-tapped (which became bang bang bang) each part of the 4 rail "corners" - avoiding the open middle where the magwell is. Then you see how the slide goes on, then tap bang tap bang some more. Rinse and repeat. Now I feel the fit getting tight. I flip the slide backwards and attempt to start it at the rear of the frame once it gets too hard to slide it all the way from the front.

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At this point I have reduced the clearance so much that I have to lightly tap the slide with a deadblow hammer to get the slide on very far. I figure this is enough to start with.

Now I get the perma marker out and mark the rails and start the slide. It's very tight and I have to tap with the deadblow hammer. It leaves witness marks where the high spots are. Oil up a 240gr stone and lightly/carefully start hitting the high spots. Wipe off and test fit. Repeat.

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Now the slide starts to fit and working it back and forth by hand, it leaves more witness marks and you file those again, repeat as necessary. Go easy. Remove a little at a time, clean the grit off, and test. After a few cycles it is almost there! Sliding it back and forth there are a couple of spots where you can feel a bit of drag, even though the slide will "fall" through the full range of motion under gravity. So now I switch to a 600 grit stone and carefully work across those 2 areas. Still using marker to check. Clean everything off and now the slide is butter smooth through the entire travel. The fit is noticeably tighter than when I started and instead of a rattle, it has the tiniest wiggle of play. There has to be some play, necessarily, as nearly identical dimensions will have high friction and gall/stick. So let's see what happens with the pistol assembled and lubed properly.

Holy crap. Is this the same pistol? There is no rattle, and I mean NONE. It cycles smoothly. I am SO impressed with the end result. I can't believe I was hesitant to take a hammer to 1911 frame rails 馃槂 I had fit a spare EGW angle bore bushing a couple weeks ago to tighten up the front end, now along with the frame/slide job, this pistol feels ready to run. Shooting tomorrow!

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take a "rough" Caspian frame and slide, and by using:
1. Borepaste (liberally and frequently replaced) on the rails,
2. a strong vise holding the protected frame,
3. a rubber, weighted mallet to "pound" the slide,
4. patience and many hours,
swage the frame and rails to a very nice fit.
FLG and I apparently got lucky on new Caspian parts.
He was able to get the slides moving smoothly with only oil and a mallet.

Anecdote alert:

He found on another gun that just because JB Bore Paste is safe to put down a barrel on a patch does not mean it will not cut fast when trapped between two pieces of steel as a rail lapping compound. It did not take many strokes to loosen the fit. He went back and rehit the rails and polished a very little. He used a rail swaging punch rather than the hammer face, the rectangular whack marks are visible.

He got one very tight and smooth, so tight that when the bluing shop hit the slide and frame with a bead blast, it roughened the rails and the gun would not function. More lapping.

A customer wanted his Springfield slide squeezed. It was too hard for that and the little hangy down part behind the safety notch cracked. His son was a good welder with access to agency equipment for lunch hour jobs; so it was soon replaced, remachined, and refinished. But the hourly income rate for the job became very small.
 

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Why? Perhaps personal pride after a job well done and significant improvement over the factory work??
It's your money, but an honest 'smith would tell you like this:

Larry Vickers said the slide fit really doesn't have that much to do with accuracy, but shooters have the impression that slide to frame fit is important, mainly because it's something that can easily be checked by a nimrod. "It's something the average guy can check, so he thinks it's important, but it's really not."

Too much mythology surrounds the 1911 and it's far more difficult to make people "unlearn" the BS they have been fed/read over the years.
 

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Discussion Starter · #25 ·
Well. The results are in. Between the well fitted bushing and the slide tightening the pistol shoots excellent. Initially it shot low left when new. I drifted the sight to cure the left bias, but it was still low.

Not any more. Dead on poa/poi at 10-15 yards . Ringing 5" steel plates like church bells. I am sure the bushing cured the low issue but hey, I'll take the extra 5%. The pistol just shoots damn well and the trigger is awesome. Caught a couple unintentional double taps when I was riding the reset LOL.

This is going to be a killer fun project pistol.
 

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I've seen many different methods of 'tightening' the slide to frame rail fit. Peening, bending, raising, lowering, etc. Ya might create a few high spots in places to remove a bit of movement. But the truth is once ya machine a piece of metal, ya cannot put metal back where it wasn't.
 

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Discussion Starter · #28 ·
Sometimes the reason to to something is because you want it. Another reason is because you can. I consider both reasons to be valid. It doesn鈥檛 have to make sense to anyone else.

I like very nice slide to frame fit. I doubt that it improves my shooting measurably. But I am happy.
Bingo. In motocross racing, I replaced brake and clutch levers often. Not because they broke, but because the repeated motion creates slack and that rattle trap lever felt like ****. Tight crisp lever action felt awesome and when you feel awesome, you often ride awesome.

Maybe a bad analogy. But damn! The pistol felt great today. And it shot great.
 

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An interesting thing about a loose slide to frame fit, is that the gun may perform more poorly in a machine rest. Firing by hand from a bench rest consistantly aligns the slide with the target, and also the barrel with the target if it is fit well to the slide. The machine rest only aligns the frame consistantly; the slide and barrel may be free to move around a bit.

A good barrel fit will take up any vertical play in the slide to frame fit, and restrict most of any lateral play. This is why the contribution to accuracy of the slide to frame fit is so low.

I have settled on machining the frame rails to fit the slide rather than lapping. I may get .0010" to .0015" of free play, but that is only without barrel installed. When fully assembled, there is no free play. The perfectly square rail surfaces also provide the most durable fit.

Nicely built guns all exhibit well fitted parts that have no impact on accuracy or reliability. Why not the slide to frame fit also?

-
 

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I see nothing wrong for people who have the capability of doing this correctly FOR THEMSELVES. However, for those who cannot by the time you ship the gun to & fro a gunsmith you'll be looking at circa $200 total (work & shipping) cost if not a bit more. Your money, your choice.
 

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An interesting thing about a loose slide to frame fit, is that the gun may perform more poorly in a machine rest. Firing by hand from a bench rest consistantly aligns the slide with the target, and also the barrel with the target if it is fit well to the slide. The machine rest only aligns the frame consistantly; the slide and barrel may be free to move around a bit...
I saw pistol champ and Colt sales rep Bill Blankenship do that very thing one day at a little range I helped build next door to a gunshop.
 

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I would disagree that squeezed slides and peened/swaged frame rails lose the fit. Because of the directions of distortion and the manner of resultant finished fit I would agree some of the fit may be lost. My experience has been the loss of fit will reach a point then maintain for many, many rounds. Of course, this would be contingent on the quality of fit and nature of the metallurgy.

My first full build was a 90鈥檚 vintage Springer Mil-Spec. I spent hours and hours on that slide frame fit. Peening, swaging. I used glancing blows from the hammer to swage the frame rail metal outward to reduce lateral clearance. Not much pinching of the slide was required. When I got close, I used the Dave Sample method, before I had read of Mr. Sample.. Repeat process. I shot that pistol for a long time, won some club level matches with it. I wanted to get away from the extended slide stop I originally built the pistol with. The loss of fit was so minimal I could not substitute an EGW .0006鈥 thicker slide stop for the one I hard fit the barrel to. I would suggest the refitting methods and good steel and temper Springfield uses for their guns wete factors.

The peening/swaging, squeezing, peening/swaging, squeezing cycles was suggested to me by none other than Al Marvel. His observation was the important achievement in the fit is getting the rail system parallel. This is something I strive for 20+ years later. I just start with oversized components now, and use smoother files for probably 90% of the fitting with lotsa measurements along the way.

Through the slide/frame and subsequent barrel fits is the pistol ran smoother and was highly reliable. We all encounter road bumps in our endeavors. But when you fit a good assembly鈥ts a rush.
 

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Discussion Starter · #34 ·
I believe I will probably need to go through another cycle of this. I did a quick and "safe" process for my first attempt. I believe I can go further and get a better, longer lasting fit. But I will shoot this pistol as is until/if it gets loose. Very good learning process.
 

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I just purchased a Tisas 1911 Carry SS45 and I'm very impressed with the slide to frame fit. Sounds like you're learning some very valuable skills when it comes to working on 1911's. I've spent 30+ years in the engineering and QA department of a CNC/Manual machine shop and I've had the good fortune of working with someone outstanding machinists.

I've seen some of the older machinists use the swaging technique and salvage parts I thought were surely scrapped. I believe metalworking is as much an art as it is science and those who possess those skills are getting fewer and fewer. Hearing stories like yours is very encouraging especially when you pass along the technique so others can learn.
 

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20 ppi has a point to depth of about .030鈥 . Finer checkering will be shallower. I have read that the minimum thickness under checkering should be .030鈥 also. Considering any thinning of the front strap to true it, I鈥檇 shoot for .070- .080鈥 initially. The forum in the past has had reports of sections breaking out when straps got too thin. Frames have had to be machined out and an EGW frame patch welded in to save the frame. Not sure a Tisas would be worth the save cost. Measuring the strap thickness provides a challenge. I use a brake rotor mic repurposed from my auto tech days. Like this:
Joe
 

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Discussion Starter · #38 ·
Well Joe, I may have that tool covered, I am in the auto repair biz myself. On the other side, I've been a parts dept. mgr for almost 30 years. With a part time fill in as svc mgr (yuck 馃槅) and asst body shop mgr.
 

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^^^ You鈥檙e wearing many hats鈥udos
 
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Well Joe, I may have that tool covered, I am in the auto repair biz myself. On the other side, I've been a parts dept. mgr for almost 30 years. With a part time fill in as svc mgr (yuck 馃槅) and asst body shop mgr.
Ahhh! A reason for the metalwork fearlessness! I was 40+ years in GM shops. Last 4 as shop foreman. Never aspired to higher management posts, I get the yuck part鈥
Joe
 
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