Buckmark Trigger Job puzzle

[TMan]

Since buying the Buckmark "Target" rifle, and finding out it didn't have the good target trigger that two of my Buckmark's have, I decided to dig out the two Buckmark's with crappy triggers and do a trigger job on all three.

I used the Power Custom I jig with the Buckmark adapter for the sear. Each sear was stoned the same way at 4 clicks from the baseline, which I verified with Dykem. I did everything the same on all three guns. When I got all done, I tested them with the Lyman digital gauge. Two of them were within 1/10th of a pound of each other. The third one was 7/10th's of a pound heavier.

Why the difference has bugged me for several days. Then it finally dawned on me. Anyone want to take a guess.

Hint: while out buying curtains on Saturday, we stopped at Sears and I bought a new 4"x36" sanding belt.

[MLB]

Variance in the local gravitational field? ;D

I don't imagine that you're using sandpaper to "stone" a sear, but I suppose the stone could get clogged like a belt would. Is the heavier one the last you did?

I'd love to see pictures of the work or equipment. I haven't yet attempted any sear work and am annoyingly ignorant of what a Dykem is. The "four clicks from baseline" reference is lost on me. Hopefully I'm not bringing the curve down here and others might benefit from the lesson as well.

[5ontarget]

Around here, Dykem is a brand name of markers used a lot by construction and machinists. I use a marker on the edges of my knives when sharpening them so I know I have the angle of the stone set to the angle that the facotry (or I) ground on the knife. I've forgotten, but a machinist friend of mine told me about how much material had to be removed to remove permanent marker from a metal surface. .003" seems to stick in my mind, but not sure.

[TMan]

Unfortunately, I put the stuff back into storage when I finished. If I can remember, the next time I'll take some pictures. I find that I use the Power Custom Series I more than I do the Power Custom Series II for doing the stoning work.

As 5OT stated, Dykem is used for marking. It provides a very thin coating of dye on the part. Then while stoning, you can see the dye being removed and know you are being successful.
From their web-site, here is a picture of the Custom I fixture:



I thought I'd talked about this before - guess not. The elevation wheel has detents and raises or lowers the angle of the stone, which changes the angle on the sear, hammer, or trigger depending on the type of adapter they provide for the gun. This entails buying adapters for whatever gun you are going to do a trigger job on. So 4 clicks on the elevation wheel was a far as I went. You don't want to get too aggressive on a semi-auto.

If you get too carried away, you can end up with a neutral or even worse, a negative engagement, which is unsafe.

Yes, the heavier one is the last one that I did, and that was when I noticed that I wasn't getting any sparks off the belt. What I do is to take a punch and put the hammer spring over the punch. I then hold this at approximately a 45 degree angle to the belt sander. When the spring engages the belt, it spins and material is removed. If you remove too much a couple of things can happen: 1) You get light primer strikes and the gun doesn't fire or 2) even worse the spring breaks. This is the Robert Dunlop method and I prefer it to cutting coils off the springs.

The Power Custom Series II works a bit differently, and requires different stones. It as a Universal adapter that fits many different guns. What you do with it is rather than going the initial 20 clicks to establish the base line for that adapter, you use dykem on the part and adjust the tool up or down in order to remove all the dykem evenly. That establishes your factory setting for the sear/hammer and then you count the clicks to either lighten or make heavier the engagement.

[MLB]

I learn something every day TMan. Thanks.