I'm in the process of fitting my first hard fit barrel. I've just finished using the .186" lug cutter and cut enough that the thumb safety swings positively into the respective cut out in the slide. I have a 3/16" round file on recommendation from Brownells. The question is, what is the proper technique for the final fitting? Do I coat the lower lugs, check for high spots, and file with the barrel out of the assembly, or do I assemble the barrel onto the slide and frame, then file through the SS hole?
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.. do I assemble the barrel onto the slide and frame, then file through the
SS hole?
NO! That would mess up the SS hole in the frame.
Do you have the 0.195" diameter cutter?
Wow, I don't know what I was thinking! Must've been the New Years brain melt down. Anyways, I decided to do final fitting by hand in lieu of getting the 0.195" cutter. I figure I'll have a larger impact on the outcome whether good or bad, and thus I'll get a better learning experience.
In terms of the rest, so far so good. I have full vertical lug contact on the first barrel lug, horizontal contact on the first as well, with the 2nd and 3rd within 0.001" of horizontal contact. The firing pin hole is centered and the hood length and sides each have a 0.001" gap from their respective slide counterparts. I think I may increase the hood sides to 0.003" or 0.004" eventually.
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...Do you have the 0.195" diameter cutter?
In police work we would call that a clue.
I figure it should be pertinent at this point to mention as well that this particular gun has a SS pin of 0.196", so in this case the 0.195" cutter is too close for comfort.
I must be missing something, is the 0.195" essential?
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In police work we would call that a clue.
OK, I give up. I'm clueless. What's the 0.186" cutter for?
Somebody make a little teeny 1911 clone with a skinny SS pin? Or was it meant as a "pre-cutter" so the 0.195" cutter wouldn't have so much metal to remove?
But, I think TopHatJones' idea is a good one: cut the lugs for a 0.002" below spec SS pin so if a little too much gets removed from the lugs it can be corrected with an in-spec or "oversized" SS.
I like to use the .186" just to stay on the tight side, especially with a loose slide to frame fit. If you think about it, in a perfect world it's only .007" under and that's not much. I also like the idea of flattening the top of the slide stop pin where the lug rides this gives a long life and added contingencies. And then some times I just use it as a pre-cutter for the .0195".
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Hi Dave:OK, I give up. I'm clueless. What's the 0.186" cutter for?
I don't know. I've never used mine except as a "roughing" cutter prior to using the larger cutter like you mentioned. My point was that you were giving good advice to use the larger cutter. You can always assemble the pistol and using gauge pins in the slide stop hole, measure exactly how much you need to remove.
Now I use a milling machine and the Weigand fixture
According to Brownell the main purpose is for pre-cutting to save wear and tear on the .0195 and they mention that in some instances the .0195 may actually be too big but I've read that unless your doing a lot of barrels it's not critical to worry too much about the wear and tear. At 50 bucks a pop them cutters ain't exactly cheap. I was hoping to find one on ebay or somewhere but no joy yet. Geez, if I bought every tool that is recommended for a barrel fit I'd be scaring 200 bucks to death. I've got plenty of time these days. I think I'll put my money in good files.
Hey nothing wrong with files I have a friend that builds guns featured on the internet and are sought after and he selects the link first(?) puts a 3/16" file through the link and files the lower lug to fit the link, who'd a thought! They do shoot well and accurately, so I guess somebody will be doing it well with a bench grinder before long or already. LOL
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...he selects the link first(?) puts a 3/16" file through the link and
files the lower lug to fit the link
That sure is a clever idea!
With links available in increments of about 0.002" you could gradually creep up on just the right amount taken off before maybe a few file strokes were taken without the link (all, I'd assume, done by "draw filing").
Not to contradict your friend, but, I do agree with your question mark after the statement. I personally don't know how you can calculate the C/C pin distance of the link until after the lugs are completely fit. You can guess at it or I know a lot of people who think .278 is carved on stone tablets, but I don't find that to be true. Most match grade after market barrels finish some where in the mid to high 80s. After the lugs are finished, the use of a granite surface plate and gage pins to measure the precise C/C distance will give an exact link measurment to fit the particular frame/slide/barrel combination. We use the .186 cutter merely to rough out the cut while in the frame..It gives a very good indication of the lug to slide stop alignment, as Dave Berryhill mentioned; Pickup and maintain that alignment up in the milling machine, and take a few tenths at a time, until the precise fit is acheived. At one time I used a shaped wheel on the surface grinder. It works well also and gives a superior finish. With some of the new helical geometry forms on todays endmills, the same mirrior finish can be obtained.
Sorry to be in opposition of his method. I guess it works for him.
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I personally don't know how you can calculate the C/C pin distance of the
link until after the lugs are completely fit.
I was thinking (perhaps incorrectly) he began with a real long link (just to get the file to take off a little) and worked down through his assortment of shorter links (testing for fit after taking off what each shorter link would allow) until he got real close.
Yeah, he's a real magician if he can somehow start the process with the correct (final) link. Maybe he just wasn't totally sharing his "trade secret" with Log Man, huh?
All are very interesting comments, thank you for sharing your perspectives. I guess fitting barrels is similar to eggs, there are many different preferences.
But, back to my problem. Should I order the 0.195" to finish the job, or is (my current preference) to get a good a fit possible with the 3/16" file? How exactly should I file to fit anyways?
No, you didn't take me at my word because it just doesn't seem right. But he uses a .278" link, yep, no link down problems and doesn't want the barrel to be a hard fit in the slide as most all his guns are open and the comp eats up most the recoil energy and wants it to open easy. So the file goes through the link and back and forth, draw filing can't be done when the file can't even get there yet because the link is holding it down, yeah I was speechless, and we're still friends. It isn't any worse than Colt when they just grind the lower lug out of the way and ride the link, at least his do sit on the pin albiet a little head room. LOL
Yikes, I wouldn't do it this way myself, but if it works for him, more power to him!