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Old May 26, 2012, 12:35 PM   #1
HiBC
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1911 timing/linkdown/slide-bbl clearance

Bought a ATI Philipine 1911 clone for darn good son-in-law.
Its pretty OK,I have replaced most internal parts.Its unfired.

Drawing the slide back till the bbl lug contacts the frame bridge,I see no clearance barrel to slide.There are light drag marks on the barrel as seen in the ejection port.On other 1911's I have seen what happens when the locking lugs do not fully disengage in firing.We don't want that.

I tried a new GI barrel just to see how it would act.Same problem,but a little more so.

My conclusion,some steel needs to come off the bridge,rather than the barrel lug.

IIRC,the spec per Kunhausen/Scheuman is a .012 feeler gage to pass at the forward lug with spring preload up on the bbl.

My plan:

Measure actual linkdown travel with depth mic,from there figure the unlocked angle of the barrel.My eyeball tells me it will be about one degree. As the barrel underlug is square to the barrel,it makes sense to me the face of the bridge where the lug contacts can be drafted (angled) some,so I should get full prussian blue transfer.I understand the hard contact needs to be close to the barrel or the lug may break off.

There is a mill technique of making a single tooth broach,you put it in the Bridgeport collet and just stroke the quill up and down,no motor.You cut one chip per stroke.I have made square corners,keyways,etc this way.I think that is how I will cut the bridge face back,initially.I can get square corners that way,no cutter radius.
I should be able to take about .008 off and still have my chips cut free as the draft angle runs out.

I do not think taking .008 will get me the full .012 spec,but if I have some running clearance,it beats no running clearance.

As I am a 1911 rookie,I would just like feedback as to if my plan seems sound.Thanks.
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Old May 26, 2012, 09:18 PM   #2
HiBC
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I hit the book and studied some.Using the frame,slide stop,and bbl,I ended up just stoning the radius at the base of the barrel lug,slightly improving the corner break on the frame bridge.The barrel sits down in the frame bed.

So,I have abandoned my initial plan.I stoned about a .002 or .003 corner break on all the locking lug edges,just a minimal corner break.

Back togetherI now have a slight bbl to slide clearance visible.Its probably only .003 to .005,but at least no drag.

Now I think I can shoot it a bit,see what happens.
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Old May 28, 2012, 12:58 PM   #3
Hawg
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Just wondering why you replaced all those parts and never fired it?
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Old May 28, 2012, 01:12 PM   #4
Sarge
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I think you came to a good resolution, HiBC. I've had a number of 1911's exhibit a wee bit of wear on the top of the barrel at the ejection port; no harm ever came of it. I have done exactly what you described in cases where the radius interfered with barrel/frame bedding.
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Old May 28, 2012, 04:39 PM   #5
HiBC
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Hawg:On replacing the parts;

Partly because I'm crazy,I guess.I do have a good impression of the ATI 1911 for the most part.

The edges of the spur are sharp enough to cut,as is the wide spur hammer and square thumb safety.Yes,I could dehorn them,but then the parkerizing is messed up.

With my hand,an arched mainspring housing plus no speed bump ,if I was in a hurry,got less than perfect grip,grip safety would be a problem.

I also was real disappointed in how the slide stop fit,and how it was made.Its a Harbor Freight part.

I decided to not alter any original parts.This gun can be put back to original config by just pulling the new parts.

I used the semi-drop in Wilson beavertail,but it requires a commander hammer.

I just decided to get a Cyl and Slide kit.The spring and pin rebuild kits are cheap,and CYA for the dropped pin,or whatever.

So,yeah,I could have bought a Springfield Armory for what I have spent.Might have been a better plan,

But,now I know what I have,I know all the parts inside are Wilson or Ed Brown or Cyl and Slide and I am giving my son in law a handgun I can trust.

Once I shoot a couple hundred rounds through it.
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Old May 28, 2012, 05:30 PM   #6
Harry Bonar
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1911

Sir;
The 1911 Metro Arms 1911s are fine out of the box as I've had several and have never had your problems! You spent lots of money on a good pistol!
Harry B.
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Old May 28, 2012, 06:23 PM   #7
HiBC
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Sarge,thank you for your feedback!

Harry,thank you,too.As I understand it,there are three outfits in the Philipines making 1911s.One makes the Rock Islands,one makes the ATI's,and one makes the one you mention,Metro

I get the impression the Metro is a little more high end,competition tuned

I do think this will be a good handgun.Slide frame fit,etc is good.Minimal hood clearance....

But that slide stop...not good.

This is my third 1911 project.I'm learning.

Son in law is a good man.I want him to have some good iron for his hand.

I'm happy.
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Old May 28, 2012, 06:50 PM   #8
Hawg
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That's cool Hi. I was just wondering. I usually like to shoot a gun before I start spending money on it.
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