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Discussion Starter · #1 ·
I'm working on my first 1911 build, I am working on fitting the lower lugs of the barrel. I bought the Brownells lower lug cutting kit, and I used the .186" cutter until I could swing the thumb safety up, I carefully measured and picked my barrel link, I installed the link, I can put the slide stop in the barrel link and swing it around, it doesn't catch on anything, but when I try to assemble the pistol, I don't get lockup. I am unable to push the slide forward enough for lockup. Do I need to use the larger cutter? Or is there something else I am missing?

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One, I wouldn't ever ride the barrel with link onto a cutter, two, the .186" cutter is to rough the lower lug in, three the .194" may still not be enough. Fitting, required. choosing the link should follow after the lower lug cut will ride on the slide stop pin.

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When I am fitting the lower lugs on a 1911, if the slide stop doesn't allow full lock up and the slide is still not closing, I may use the shank of a drill bit to see how the fit is with a drill bit that is smaller than a .200" diameter slide stop....at one time, slide stops were sold with different diameter shanks. I believe military armorers would fit a smaller diameter slide stop for their members on shooting teams, so when the slide stop would eventually wear and loosen up, they could install a slight larger diameter pin. I don't know if you can currently order slide stops with different diameter shanks.....
 

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When I am fitting the lower lugs on a 1911, if the slide stop doesn't allow full lock up and the slide is still not closing, I may use the shank of a drill bit to see how the fit is with a drill bit that is smaller than a .200" diameter slide stop....at one time, slide stops were sold with different diameter shanks. I believe military armorers would fit a smaller diameter slide stop for their members on shooting teams, so when the slide stop would eventually wear and loosen up, they could install a slight larger diameter pin. I don't know if you can currently order slide stops with different diameter shanks.....

Yes and yes.

You can use drill bit shanks but China made pin gages are cheap and have many uses.

Armorers did use smaller slide stop pins so when your fit wears a bit, you can put in the next size up. Colt Slide stops are .1985, EGW makes .200 and .203, and Greider precision in CA can make you almost anything you want. You can also take a .200 slide stop pin and remove material with a stone or sandpaper at the 12:00 position to get the required fit. I would not remove material at the 3:00 position.
 

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I highly recommend getting a gauge pin set, doesn't have to be anything fancy, there are plenty of cheap Chinese seats on Amazon. After you finish cutting the lugs with the .186 cutter, remove the cutter, and start with, say, .185" pin instead of the slide stop and see if the slide moves forward and the barrel locks in place. If yes, try the next size pin and so on, until the slide won't close freely or will require a lot of force. Then use micrometer (not calipers!) to measure your slide stop pin and subtract the gauge size from the result, this will tell you how much metal you need to remove from your lower lugs. Don't cut it all at once, go slowly and recheck often - math is hard! :) Use sharpie or dykem blue to mark your lugs and see where the pin makes contact.
 

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Discussion Starter · #8 ·
I just measured my slide stop pin, it measured .1960", so it looks like I need to use the bigger cutter. Correct?

The slide stop pin hole in the barrel link measured .2045".

I don't own a pin gauge set, but will look into getting one. I'm using a set of Mitutoyo calipers.

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I just measured my slide stop pin, it measured .1960", so it looks like I need to use the bigger cutter. Correct?

The slide stop pin hole in the barrel link measured .2045".

I don't own a pin gauge set, but will look into getting one. I'm using a set of Mitutoyo calipers.

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Yes. The link pin hole isn't of concern and is larger so the link doesn't interfere with the barrel's position when in battery until the slide has been forced back during recoil approximately .100", this is part of the design. The larger cutter will get it closer, but you must fit the last few thou, for a nice snug lock-up, then pick the link that is hugging the bottom of the slide stop pin when in the battery position. Do not pick, or install a link until the lower lug allows the barrel and slide to go into battery with the slide stop pin.

LOG
 

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Discussion Starter · #10 ·
Yes. The link pin hole isn't of concern and is larger so the link doesn't interfere with the barrel's position when in battery until the slide has been forced back during recoil approximately .100", this is part of the design. The larger cutter will get it closer, but you must fit the last few thou, for a nice snug lock-up, then pick the link that is hugging the bottom of the slide stop pin when in the battery position. Do not pick, or install a link until the lower lug allows the barrel and slide to go into battery with the slide stop pin.

LOG
Makes perfect sense. Thanks for the reply!

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Yes, you do need a bigger cutter, but honestly, I would go slow and just use a chainsaw file (unless you have access to a milling machine and proper size end mill), mark the workpiece often with dykem or sharpie, take a little bit at a time, check and recheck, I know it's a slow and tedious process but the reward is big, there's no greater satisfaction than seeing your build printing 1.5" group at 50 yards :)
 

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Yes, you do need a bigger cutter, but honestly, I would go slow and just use a chainsaw file (unless you have access to a milling machine and proper size end mill), mark the workpiece often with dykem or sharpie, take a little bit at a time, check and recheck, I know it's a slow and tedious process but the reward is big, there's no greater satisfaction than seeing your build printing 1.5" group at 50 yards :)

This.

While the .186 cutter is on the small side, the .195 cutter Brownells sells maybe to big. The reason is due to vertical frame to slide fit slop. Think of it this way: a.195 cutter centered in the frame's slide stop pin hole that measures .201 would require a .198 slide stop pin ONLY if there was 0 slop in the vertical frame to slide fit. Introduce vertical slop and you could feasibly wind up with your lugs over cut.
 

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A 3/16 chainsaw sharpening file is cylindrical. Useful item. As is Dykem blue and patience. If done with great care, you can get pretty close. Proof of the pudding is in the eating. As in perfect reliability coupled with great accuracy.

Enjoy the holidays!
 

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Discussion Starter · #14 ·
Small update. I found another slide stop in my parts draw. The slide stop pin measured .196", and the larger cutter I have measured .195". I checked, and with the smaller slide stop pin, it still won't go into battery, so I went ahead and used the larger cutter. It looks like I'll be have fitting from there to remove at least another thousandth of an inch.

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Discussion Starter · #16 ·
One last question, working on the barrel link. I have a barrel link stamped ".278", and the distance between it's 2 holes measures .0965". I believe this is a #3 link (middle measurement in my set of 5). I believe this is the link I should use. I'm easily confused though, so would like some confirmation.

I have taken the following measurements:
On the barrel - bottom of link pin hole to the bottom of the lower lug: .0955"

Slide stop pin: .1965"

Slide stop pin hole in frame: .2005"

My 5 different barrel link measurements:
.0865"
.0910"
.0965"
.1015"
.1070"

I believe the .0965" is the correct one to use, since it's closest to the measurement of the bottom of the link pin hole to the bottom of the lower lug, while still allowing some clearance.

Is this the correct link to use?

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On the bottom rear of the lower lug are the two small standing lugs. The correct size link will be just long enough to allow the slide stop pin to come to rest against these two small lugs.

Try the #3 (.278") link first. Install the link and insert the slide stop pin. Swing the slide stop pin rearward against the two small standing lugs. The slide stop pin should be in firm contact with the standing lugs, with no freedom to move downward away from the lower lug surface.

In other words, all of the clearance in the link holes will be taken up when the slide stop pin is in contact with the two small standing lugs. If the link is too short, the slide stop pin will not come into firm contact with the two small standing lugs. If the link is too long, the slide stop pin will come into contact with the two small standing lugs, but will be loose due to all the clearance in the link holes not being taken up.

The link holes have this clearance to allow the the link to swing in an arc while the barrel (and lower lug) is simultaneously moving in a straight line.

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