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Fitting 2011 / 1911 slide to frame


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I have been collecting all the bits for building 2011's for a while and I was about to order a set to do the first one completely on a mill. What are peoples opinions on clearance to start the slide onto the frame. Then do people have a target clearance other than slides without friction? I have seen a top gunsmith say he shoots for 0.002 in clearance for reliability and others swear by misc other numbers. Just trying to get a feel for the starting clearance ex: 0.0002 clearance to start? I know I will have to remove the slight scalping of the mill cutter to get a long lasting fit. Will probably end up using super fine stones to accomplish that. Not in a hurry to finish it, just want the best possible outcome. To the point where my final "polish" if there is a tight spot will be flitz.

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The ones I have done needed around .005" to .009" removed from the bottom of the slide before it would start on the rails. Then about .003" to .006" off of the outside edges of the frame rails before it would slide on completely. I would tap it on with a plastic/nylon hammer, you wat it pretty tight at first. Then I would use lapping compound to smooth everything out. Use a new endmill as it will leave the best finish so you don't have too much work left to do by hand.

 

Sent from my SAMSUNG-SM-G935A using Tapatalk

 

 

 

 

 

 

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Caspian slides will work on an STI 1911 frame, but generally not vice versa.

 

PP, IMO, the starting clearance should be an interference fit.  That is, the slide will go on, but it is tight enough that the pistol will not function.  Then use lapping compound to cut, or motor oil to burnish.

 

The clearances you end up with will be determined by what finish you plan on using.  If blued or something like black nitride, you need no more clearance than burnishing gets you.  You will need a little more if Ceracoating, and more yet if hard chroming or nickel finishing.

 

As far as leaving "extra" clearance for reliability, you don't have to.  I fit my slides tight and have zero malfunctions.  The only caveat is if you shoot USPSA or SC matches in Winter at 22 degrees.  Since your pistol is exposed for 5 hours and shrinks, I'd leave an extra 0.0005" clearance. 

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d_, Caspian slides generally come through with .752" ways.  Call CK Arms and ask what their frame rail width typically measures, and go from there.  There are sometimes wide variances from the same manufacturer, so you could get Murphy'd.  The good news is if you buy a Caspian slide from anyone and it turns out not to be right, send it to Caspian and they will make it right.

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6 hours ago, d_striker said:

Anyone ever fit a Caspian slide to a CK frame?

 

Yep, I've done 2.  Both required removing around .008" off the bottom and a few thousandths off the frame rails.  Great combo IMO.

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1 hour ago, zzt said:

d_, Caspian slides generally come through with .752" ways.  Call CK Arms and ask what their frame rail width typically measures, and go from there.  There are sometimes wide variances from the same manufacturer, so you could get Murphy'd.  The good news is if you buy a Caspian slide from anyone and it turns out not to be right, send it to Caspian and they will make it right.

 

21 minutes ago, tyler2you said:

 

Yep, I've done 2.  Both required removing around .008" off the bottom and a few thousandths off the frame rails.  Great combo IMO.

 

Awesome!  Thanks a lot for the info guys.

 

 

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On 3/24/2017 at 1:41 AM, jcc7x7 said:

Depends on your frame and slide.

Mix and match can require more work

All sti, all CK my choice, etc USUALLY results in less /simplified fitting

I meant AFTER you cut the slide and frame. Cut it for say 0.005 interference and then stone down to 0.000 clearance? Just trying to get a feel for how other people do it. 

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.005" is  not an interference fit.  It's too much.  It would take you a long time to stone down that much.  Stone the ways of the slide until they are smooth.  Machine the slide rails with the side of a sharp end mill until they are .0005" to .001" oversized.  Then do the same for the bottom of the slide.  Stone out the machining marks and you should be at an interference fit.  The lap or burnish or complete as you see fit.

 

I prefer to do the final finishing on a good surface plate with sandpaper down to 6000 grit.  Make sure to use the plastic film backed stuff with a microscopically thin layer of adhesive on the back.  I can get a mirror finish that is dead flat to less than .0001" variance.  I'm going to try fine diamond lapping compound on the next build, just because Mr. Postman says it works well.

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On 3/25/2017 at 3:17 PM, zzt said:

.005" is  not an interference fit.  It's too much.  It would take you a long time to stone down that much.  Stone the ways of the slide until they are smooth.  Machine the slide rails with the side of a sharp end mill until they are .0005" to .001" oversized.  Then do the same for the bottom of the slide.  Stone out the machining marks and you should be at an interference fit.  The lap or burnish or complete as you see fit.

 

THAT is what I was looking for lol. 

Would that be 3m 6000?

Edited by PaladinPrecision
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PP, Yes, I prefer a good lapping/surface plate and I am anal enough to go to 6000 for side rail and bottom of slide finishes.  I like 3M materials.

 

I'd now rather burnish the works.  If your machining is very good and the tooling marks are not deep, you don't have a lot of stoning to do to remove the marks.  Keep everything straight and parallel and go for an interference fit.  Then clean EVERYTHING and lube with motor oil.  Put the slide on and move it back and forth on the frame until everything is butter smooth.  It may take 100-200 cycles.

 

It would definitely go faster with fine diamond lapping compound or rouge.  MR Postman swears by it.  The reason I don't lap is because my friends who tried it did not end up removing material evenly.  It may have been due to the way they fit the slide.  Both used the "old" gunsmith trick of opening up the back of the slide, working it on, then opening up a little farther up, etc.  The tool and die maker in me rebels at that approach.  I want everything straight and square

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  • 3 weeks later...

I'm just wondering how do you guys take these measurements? I mean are you useing indicators? Micrometers, or calipers as I assume.   Because every brand of caliper I've seen the manufacturers state there reliable tolerance is.002, measurements tighter than that should be taken with other instruments.  

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6 hours ago, Can said:

I'm just wondering how do you guys take these measurements? I mean are you useing indicators? Micrometers, or calipers as I assume.   Because every brand of caliper I've seen the manufacturers state there reliable tolerance is.002, measurements tighter than that should be taken with other instruments.  

they require 0.0001 resoluton. I use a mitutoyo 0-1 inch outside micrometer, everglades ammo slide measuring block, and micrometer similar to the marvel customs slide rail thickness mic you can find at brownells. Since I am measuring between 0.002-0.0002 inches, The differences in clearance are critcial... 0.001 uncertainty will not work when I am shooting for 0.0015 clearance.

Edited by PaladinPrecision
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Tbh as a tool and die maker i would expect such from you ^^ I actually ment everyone else.   I do similar, but every youtube Smith I see only owns a digital caliper  and they trust it to that.0005 resolution  which makes me wonder how they could make good parts. 

 

I also love people measuring telescoping gauges with micrometers. 

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I have a couple builds to my credit, but I am always looking for a better way to do things. If I get the fit perfectly tight, sometimes it takes some rounds to break in and shoot 100% reliable. The most I will do is use flitz as a lapping compound. The reason I don't have a final method is because most of the youtube vids have knuckleheads or they are advertizing their own class. I want to take the Bruce Piatt class :)

 

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On 18/04/2017 at 1:07 AM, Can said:

, but every youtube Smith I see only owns a digital caliper  and they trust it to that.0005 resolution  which makes me wonder how they could make good parts. 

 

The simple answer is they can't. They may get lucky sometimes but cheap shit digital calipers don't have the accuracy or resolution to measure what they are measuring. 

 

Just as bad is half the people with a micrometer don't know how to read it properly. 

 

I really enjoy people measuring bullet diameter with cheap calipers. When the difference between say 0.354 and 0.355 has a massive effect on performance they are using a device that in reality can probably only hold to around 0.002 or worse. Even better they go to 4 digits and tell me their caliper says their bullet is 0.3555. Lol. So accurate. 

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Well, I used to be a tool & die maker.  I still have the measuring tools I did not give away.  The name brands are Starrett and Mitutoyo.  I needed a vernier caliber a couple of years ago.  I didn't want to spend $225 for a good one, so I picked up a dial version for $30.  I only wanted it for OAL measurements, so it wouldn't matter if it was off by a thou or two.  As it turns out, it was accurate to .0004", at least in the 0 to 1" range.  I know this because I checked it with my Starrett mic, known to be accurate to .0001".  I guess I was lucky.

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On 4/17/2017 at 3:15 PM, PaladinPrecision said:

I have a couple builds to my credit, but I am always looking for a better way to do things. If I get the fit perfectly tight, sometimes it takes some rounds to break in and shoot 100% reliable. The most I will do is use flitz as a lapping compound. The reason I don't have a final method is because most of the youtube vids have knuckleheads or they are advertizing their own class. I want to take the Bruce Piatt class :)

 

Bruce might be setting up another class in Kansas City this fall.

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