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Gunsmithing Lapping compounds

LRI

Lance Criminal
Full Member
Minuteman
  • Mar 14, 2010
    6,305
    7,351
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    Sturgis, S. Dakota
    www.longriflesinc.com
    For my fellow plumbers:

    Years ago I had a conversation with Boots Obermeyer about lapping compounds.

    He turned me onto a company that he's used for years. I bought several grits of the stuff. They have sat in a drawer of my tool box for almost 8 years now unopened.

    I ran out of clover last week and Sturgis is an industrial vacuum so I decided to crack one open and try it.

    WHOLLY CRAP! I feel like an "idjit" for not using it sooner!

    The company is United States Products in Pittsburg, Pa
    412.621.2130 is the phone #

    PN: 38-100-ECG

    I've never "scrubbed in" a bolt/receiver so fast ever. Literally a few strokes and I'm done. Plus its much cleaner to work with than clover.

    Cool stuff!

    C
     
    Re: Lapping compounds

    Chad- checked USP site and did not find that exact product #. Maybe you missed a # in there somewhere?
     
    Re: Lapping compounds

    Chad,

    Thanks, I gave them a call. The reason why that exact product number is not on the site is because it's a special item. They handle mostly oil and soap based products. The ECG is a different base that was developed for barrels according to them. The "ECG" is what sets it apart. Don't know what base it is, because the lady that was helping me didn't know, but I'm sure if someone needed to know she could track it down.

    I ordered some in 100 grit like you posted and some in 180 grit. It was $19.30 for an 8 ounce can for each grit. Really nice folks to deal with. The next size up was 1 gallon.

    She did say that they can add just about any grit you want to the "ECG" base.
     
    Re: Lapping compounds

    Barrels yes.

    Stands to reason since Boots is a maker.
    smile.gif


    I think you'll dig it man. I've been running receivers off/on all week it seems. Everyone of them laps in lickity split with this stuff. Pretty crazy how well it works. Literally takes a dab from a qtip and about 20 strokes on the bolt. I took an old screw driver and clamped the shaft in the vise. I push the bolt face against the plastic handle and lean into it as I work the receiver/bolt back and forth.

    Goes really quick.

    Good luck.

    C.

    I'm using the 100 btw.
     
    Re: Lapping compounds

    Chad,

    USP is good stuff. One compound you might try is AC-280. They'll send you a sample, lasts a while. Looks like chocolatey mousse, and not an unpleasant smell. MADE for the hardnesses of steels we're using for barrels and actions. I too use the ECG's, as you said the medium is a bit different and if you get the 38White it's a type of alox that does actually break down and polish.

    my .02

    later
     
    Re: Lapping compounds

    What are you pros using grinding compound FOR?
    I am using it, but probably on the wrong things.