Barrel Lapping question for Don

[keweenaw]

Don,

I figure I'll get a faster answer from you than trying to call John.  If I want to lap one of John's barrels what grit lapping compound do I use?  What's best, grit in water, like valve grinding compound, or silicon carbide in grease?


Tom

[Dphariss]

Why do you need to lap it?
Depending on the reason and purpose cast a lead lap in the bore on a suitable rod make sure its a decent casting and index it for reinsertion before removing. For a polish use 400 grit or finer. For material removal you need something like 280 grit.
Rod should have a free turning handle, I.E bearings, so the lap does not have to over come handle friction to turn.
Dan

[ironwolf]

  Don would say:  Use some scotch-brite.

[don getz]

Tom.......we have several grits that basically suspended in grease,  320, 400, 600,  this old mind will not recall the name
of the stuff....comes in a green can.  320 will remove rough spots, 400 and 600 are more polishes that anything.  What
are you planning to lap?     Don

[Sam Everly]

Don i think the green cans are Clover Brand . MSC, J&L, and some local auto parts stores have it as valve laping compound . I have a couple of cans that are 50+ years old and still good . A little will go a long way . If it drys up add some motor oil and it will re "juvinate" it . Pure lead is a little to soft but wheel weights will work fine .   

[don getz]

Thanks Sam, that the name...."clover"...just coudn't think of it.  Been a long time since I have lapped a barrel, dirty job.........Don

[keweenaw]

Don,

I have one of John's 54 cal round bottom groove barrels. I charcoal blued it and the first 6 inches or so are a bit tight which makes it hard to load.  It's not scaled or anything, looks as smooth as the rest of the barrel, but it's tight so I thought I'd lap it a bit to see if it would help the loading.  I had the barrel packed with fine charcoal and had a chunk stuck in the muzzle which usually prevents much happening in the bore but I guess my plug wasn't quite tight enough.


I have some 320 clover as well as some 600 so I should be good to go.

Tom

[Sam Everly]

Tom stop everything !!! Hey you did a good thing you put a choke in the barrel . If you lap it and get it bigger than the bore you will kill the thing . Just a few tenths bigger will screw it up . I would leave it like it is, and not take a chance on trashing the barrel. Heck that is why most people lap a barrel to put the choke in.     

[rick landes]

I like to polish out a barrel with a bit of 0000 steel wool, well oiled with a tight jag. I feel it smooths any cut/machine marks w/o adverse effects to the barrel. I think cutting compounds and the like are too aggressive and tend to embedded themselves into the barrel metal.

I have also used JB bore cleaner for a final polish.

[Daryl]

Rick - Flitz and Autosol chrome polish do a much better job than JB, being more agressive. they won't change the dimensions unless you polish for a week or two, but bring a much better shine than JB.  I've used a number of different 'polishes' and Flitz is in the middle of the 3 listed.

[keweenaw]

Sam,

Not to worry, the entire bore will be lapped not just the "choke" with the abrasive going on the lap at the breech end of the barrel.  It's the having to pound the third load down the first 6 inches of the barrel that I'm not liking.  I might try some flitz on a really tight patch first. 

Tom