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View Full Version : what do you use for "beagling" abrasive, and where do you get it?



samwithacolt
05-10-2013, 07:31 PM
I would like to open my lee mold for .38-55 bt about a thou, and I have a lee .312 that barely makes .310(although it seems to work in my sks!)
I like the idea of making fire lapping style slugs for major metal removal, but what do you use for finer work? What do you use for coarse or fine grit, and where do you get it?
How about valve grinding paste?

Ben
05-10-2013, 07:56 PM
I'm afraid you have two terms confused.
"beagling" is the use of metal adhesive tape in between the mold halves to prevent the mold from fully closing. It is a great technique to gain .001 or .002 on the dia. of your bullets.

You're also making reference to using an abrasive paste on your bullets and lapping the mold cavity using a bullet impregnated with abrasive compound. Some use fine Clovers Paste to accomplish this task.

The 1st technique is reversible. The 2nd one is not.

DeanWinchester
05-10-2013, 08:08 PM
If you've got a lot remove, valve grinding compound can be had at the auto parts store. I use a diamond lapping compound I had from one of the machine shops I used to work in. I finish with Semi-chrome or Flitz which can be had at Autozone.

Google Machine shop supplies for lapping compounds. Try MSC or Grainger, maybe even Carr-Lane.

samwithacolt
05-10-2013, 08:08 PM
ok, got it thanks. I just found the sticky.
Beagling sounds better, as I don't want to open the mold up if the throat won't take it and I'm stuck with a bigger diameter.
I might buy another .312 mold and lap it if neccessary.

oldpara
05-11-2013, 08:17 AM
In a pinch I've used toothpaste, softscrub, etc.
Softscrub is fairly aggressive and scratchy on aluminum and toothpast takes a while to be effective but if you have the time and not much to lap out it will work.

country gent
05-11-2013, 09:34 AM
Clover abrasive lapping compound is available from most manufacturing supply houses. It is availible dry or in an oil base, And several diffrent grits. Diamond comound is good but diamond isnt really needed for aluminum or cast iron. Its for hardened steel or carbide polishing finishing. Simichrome, fllitz, various jewelers rouges white and red, toothpaste all will work. I am getting ready to make a copy of the old Ideal perfection 1 piece paper patched bullet mold, I am planning on getting the nose punch close to form and the bore with in .003-.005 then cast some slugs and lap up to finished size. If you decide to lap a mold do it by hand working the bullet back and forth as you rotate it Forward back forward back forward back 1/4-3/8 turn. rotate 3/8 turn and repeat till a full circle has been made. then check your work. To make the lap drill a hole in the base of the bullet ( nose for a nose pour) and make a small square driverto be able to be driven snuggly into hole. A light taper on the end is a big plus. ( you can then tap the driver deeper to enlarge the base of the slug) Work as mentioned above thru several grits. 600-800 grit will give a very good finish. Load the lap like you would a fire lap bullet roll it with the desired grit between 2 steel plates.Work slowly and have patience remeber you need to leave metal to finish with each finer grit. It is much easier to remove metal than put it back on. Ive never learned to cut a piece "bigger".:-?

Hardcast416taylor
05-11-2013, 10:21 AM
These abrasives work fine on aluminum. I want to open up an RCBS size die from.284" to .287" Would valve grinding compound be appropiate, or should I let a person more qualified than I do it on a mill or lathe?Robert

Cane_man
05-11-2013, 10:57 AM
valve grinding compound is fairly aggressive, its OK to take out the first .002 but be careful with it... then you want something like Flitz to finish the last 0.001

Boolseye
05-11-2013, 12:11 PM
I have lapped a couple molds with permatex valve-grinding compound, and it worked fine.
I cast a few perfect bullets, mark them for the cavity, tap them out at the base and screw in a sheetrock screw. I then lap by hand with a screwdriver–an electric drill is too out-of-control for me. After a few turns the bullet will spin freely in the cavity. I opened up a 6-cavity Lee this way, every cavity, and it worked out great. After the valve-grinding compound, Lap again with a paste made from comet and a little water. Polishes it up nice. I recommend that you go slow and keep notes marking the original diameter of the boolits and the final size. Preparation and precision are key. Also, clean the mold faces regularly.

DLCTEX
05-11-2013, 11:56 PM
Getting .003 from an iron mould will take a while and will probably be out of round by then.IME

MtGun44
05-12-2013, 12:52 AM
Send it to Erik at Hollowpoint Services to have him open it up.

Bill