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Old January 30, 2009, 02:31 PM   #1
cjw3cma
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Okay to lathe barrel to get bushing to fit ?

I recently ordered a barrel bushing from EGW and it came the other day (very nice work and reasonable for a custom made bushing). Before I ordered I measured the OD of the barrel and found that at the crown end it measured .577" but got progressively larger the further down the barrel I measured - .5775" @ 1" from the end / .578" @2" from the end. Thus the new bushing does bind a bit on the barrel but fits into the slide perfectly so I have not installed it until I find out if the barrel can be turned to an even .577".

Specs I gave EGW were - barrel OD - .578" / the bushing starts to bind on the barrel about 2" from the end.

Is this the proper approach to fitting my new busing to the barrel - by having the barrel turned to an even .577" (it sounds right but the voices of experience on this forum is what I'm looking for).
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Old January 30, 2009, 03:57 PM   #2
brickeyee
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The barrel needs to be at least uniform over the range the bushing will move, and being slightly smaller after a short distance eliminate the need for relief cuts in the bushing to allow for tilt down clearance as action operates.

You are very liable to have to re-crown the barrel after you chuck it up and turn it.
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Old January 30, 2009, 04:10 PM   #3
cjw3cma
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Well then, what about manually fitting the barrel by using a marker and finding the higher areas and the by hand smoothing them down to the .577" spec ?

Looking to get it done as inexpensively as possible.
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Old January 30, 2009, 04:43 PM   #4
sadsack
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CJW: It sounds like a lot, but .0005 is nothing to worry about. The bushing is fit to the barrel on the 1911, and there are several web sites that show how it should be done. (I'm assuming that the 1911 is what your working on.)
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Old January 30, 2009, 08:15 PM   #5
James K
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It is more common to fit the bushing to the barrel, the bushing usually being the cheaper part (gunsmith tip: always screw up the cheaper part!), but I see nothing wrong with what you are considering for that small amount of difference. As Brickeyee says, don't forget the tilt-down clearance.

Jim
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Old January 30, 2009, 08:58 PM   #6
Scorch
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I usually leave 1/2" to 3/4" at the muzzle at full diameter, then turn the barrel down .020"-.025" for clearance for the bushing. Tight fit is important at lockup, not during slide travel. And yes, you do it on a lathe.
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Old January 31, 2009, 01:31 PM   #7
brickeyee
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Quote:
Well then, what about manually fitting the barrel by using a marker and finding the higher areas and the by hand smoothing them down to the .577" spec ?
The odds of using a flat file to produce a uniformly round object are very small.
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Old February 2, 2009, 02:51 PM   #8
hunter11
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Tight sleeve

From a Toolmaker with 60 years experience do not use a Lathe under any circumstances. You would be much better off with a piece of Crocus clothe and twisting it in your hand. .0005 is very easily removed by hand. Dan
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Old February 2, 2009, 08:36 PM   #9
drail
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Unless you are real fond of that barrel due to its amazing accuracy I would just get a new match grade barrel. I have never seen a barrel dimensioned like that. There's something really weird about that, like somebody tried to fit it to something else. What kind of barrel do you think it is?
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Old February 3, 2009, 01:52 AM   #10
cjw3cma
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Quote:
What kind of barrel do you think it is?
Well, that's a good question. Like so many the only markings on it are .45acp. I do know that it was a new barrel - as the gun was a project build for a student in a 1911 gunsmithing class (the gun and he got a B+ from the instructor. I asked the instructor why a B+ and he said the final fit of this gun was a bit loose for his liking so the instructor tighten up the slide to frame fit and set the trigger pull to 4-1/2 lbs. before he allowed the gun to be sold. I think that the student messed up on the barrel as it was polished up to look good and probably got too heavy against the wheel - as the high spots were .0005" to .00125".

Anyway, tonight I got into town and picked up a sheet of each: 320 / 600 / 1000 grit wet / dry paper and after dinner proceeded to get rid of the high spots with the help of some REM-OIL on the paper. Once I got the barrel evened out I polished it up and then did the final bushing fitting. It is extremely smooth with probably just the amount of clearance to allow the slide to cycle completely and smoothly.

Have to wait until the weekend to shoot. Thanks for the comments (Hunter11 - I did as you suggested).
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Old February 3, 2009, 08:14 AM   #11
hunter11
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barrel bushing

There is one other thing you should do, Glad to hear the emery cloth worked for you. Most folks have no idea how small .0005 is.
You should get a round hone stone and take the bushing on the inside part toward the frame stone a semi circular area abour 1/4 way into the bushing making the back end eliptical about .005 to allow the tip motion at locking. Dan
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Old February 6, 2009, 04:40 PM   #12
cjw3cma
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hunter11,

I apologize that I did not include that the barrel bushing was purchased with an angle bore. Barrel lock up is crisp and according to what I've read operating per spec.

Thanks again.
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Old February 6, 2009, 08:35 PM   #13
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I'm assuming this is the same barrel and bushing written about on 1911forum? As others have pointed out, .0005" is inconsequential in the fitting and functioning of the bushing. If the pistol cycles properly without binding, and you test for barrel spring and it doesn't, then you're fretting over something that doesn't need to be fretted about.
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Old February 7, 2009, 01:18 AM   #14
Unclenick
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A half thousandth isn't much, but what was described was a taper that was 0.0005" wider at one inch growing to 0.0010" wider at 2", and perhaps wider beyond that? That would take a little more work with the paper, but it is doable.

cjw3cma,

It is standard practice in target barrels not to use the old military straight barrel form, but to have a dog nut in the muzzle region. In other words, the last half inch is full diameter, then behind that going toward the breech, it tapers down a hundredth of an inch over another eighth or quarter of an inch or so then keeps that narrower dimension for the rest of the tube length before the chamber body portion. This ensures free movement in the bushing without binding. If you want something more to do with your paper, that might be the thing.
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