Hardchroming To Tighten Slide/frame Fit

[EricW]

Benny, Pat, Bob (Brazos), others...,

I'm thinking about buying an older STI that has 20K+ rounds through it.

If the slide/frame fit isn't all that I hoped for, what's the feasibility of Hard chroming up an older gun to take up any slack that may exist between the slide and frame? I'm just talking a couple thou (i.e. not turning a Auto Ordnance into a bullseye gun or anything goofy like that). Unless someone recommends otherwise, I have no plans on plating the barrel or any other internals.

BTW, what are typical hard chrome layer thicknesses that are applied to handguns? Any pitfalls I should be aware of? Special prep?

[Brazos Custom]

Eric,

I would not do it. Normal chrome plating depth is about 0.0002 to 0.0003 so coat two objects and you take up about 1/2 a thousandth play. They can coat thicker but what happens is you get a thicker coat everywhere especially edges and it is a pain to get everything back together - pins don't fit, sights don't go in the dovetail, hammer and sear drag, etc. I tried it once and was cussing the entire time I was putting the gun back together, would not ever do it again.

[ORCA]

When your building a new gun do you need to leave additional clearance for the slide to frame fit when you are going to have it hard chromed? How much? I'm building a limited gun I want to get hard chromed and I'm surface grinding the mating surfaces and the people at Accurate Plating and Weaponry suggested I might wish to leave an additional .001" of clearance. I know I can grind a little after the plating if nescessary, but it kind of defeats the purpose of having it chromed. The plating guys are hard to pin down for the final thickness of thier coating, I understand it is as much art as science. I guess .001" isn't a bad answer, if you have 2 mating surfaces coated .0003" thick when mated will have .0004" slip fit. I did get the impression that APW coats a little thicker than usual, but it just may have been a miscomunication.

I'm glad you answered Bob, the guns I've seen form your shop always have some of the nicest chrome finishes. Is their any other people you would suggest sending a gun to to be chromed?

[Patrick Sweeney]

Yea, chroming is under a thousandth, so you aren't going to take up much slack with it. You'll have to consider the traditional methods of tightening, or the Accurail method. Then again, how bad can it be at the 20K mark?

If it is really inaccurate, there might be something going on besides a loose fit. And if it is accurate but not tight, what's the problem?

You might be able to find a specilaized machinists plating shop who can build up just the area you want, but the corners won't be square, you'll be re-fitting things, and halfway through you'll wish you had just left well enough alone.

[BSeevers]

Now that the pros have chimed in, except Benny. I have to. I agree, Loose at 20K is a bad fit. My hard chromed gun is approaching 100K, major PF, maybe already there. Still shoots very accurate and is tight. Hard chrome, not other designer finishes, is a proven way to protect your gun. I have seen some "finish of the day" flake off or rust. Many of those finish process are probably as good or better as HC but I digress. I would NOT use HC to tighten a gun. BUT I would buy it if its cheap and if you have a good smith, he could tighten it and fix it, and then you can HC it.

PS Refitting a over HC gun is like using a tool that is 1/2 inch too short, to loosen a bolt. You can do it but you will be frustrated. Gun work is taking the gun apart and reassembling many many times. Imagine that and dealing with a thousandths of 70 rockwell. If you gave it to a smith, he will never build you a gun again.

[Larry White]

If done right to start with 20k is not a worry on a s-i, but hc it to take care of the next 200k. Larry

[EricW]

Thanks Bob and all! We have comprehension now.

Can I assume that plating a barrel is generally a *bad* idea? Or is it not?

[Patrick Sweeney]

Bad idea. You gain nothing, and risk making things brittle. I did it once....never again.

[stryfox]

I am new here but I had my para Accurailed and I like it more than my other factory 1911's

It was done by cylinder and slide. Nice work.

Just my .02

[Joe D]

Eric, I would not worry about a little lateral play. Some vertical is OK as long as it goes away when the gun is in battery. One of my old Kimbers has .005"-.006" of lateral play and .002"-.003" of vertical. The vertical goes away at lockup. There is positive contact between the slide stop pin, bottom barrel lugs, upper barrel lug recess and slide lug. If you do not have this contact then there will be a chance of vertical stringing.

My old Kimber still shoots under 1" @ 25 yds.

[joshua]

I was a stubborn tyro way back and I was given advice not to chrome my Caspians and Para. I did not listen and went ahead and had my Caspians chromed. Result was one of them cracking by the trigger bow area of the frame and thank god JV Dynamics fixed it. No one else in the west coast would touch it except for them. It's still shooting major loads, I was adviced not to over do it. Hmmmm... maybe I should listen this time. josh