Laps for swage dies

[Methuselah3]

Looking for info on making laps for homemade dies. I bought some brass adjustable laps from Mold Shop Tools that wear out much faster than the steel I used for straight dies for core swaging .I have info on American Lap dies who use cast iron rather than brass for straight laps . What I want to know about is making laps for bullets with ogives and making your own laps for straight bore work in making my own swage dies for pistol or rifle. It seems the topic arises in the posts by folks making dies for resale but never a picture or additional discussion. Any one care to kick start me on an approach?
Also need info on silicone oxides vs aluminum oxides for polishing said dies.Can find silicone oxide in powder form but no source for alum oxide in less than barrel(large) quantities.Any suggestion there?

[martin]

Methuselah3,

Greetings. I think if you were to look through the posts associated with the bookmarked "making home made dies" from KTN (at the top of the listings), you will find discussion on laps, lap materials, and lapping compounds along with a few pictures.

My experience is that alumininum oxides and silicon carbides break down quickly into smaller paertical sizes when lapping. They may be ok when doing rough lapping but for final finish lapping dimond paste is preferred as it comes in finer partical size for polishing. Any of these can be purchased through machine tool catalogs (MSC, Enco, McMaster etc).

Good luck,
Martin

[GerryM]

Clover brand grinding compound should work pretty well.
It comes in cans ready to use in a variety of grits. You can also final polish with diamond dust as suggested. A fanous die maker used brass laps with diamond dust.
In a article years ago in one of the shooting magazines he stated he used 35 different laps to finish his dies. The name of the die maker was Roschack. I think the magazine was precision shooting.

[Methuselah3]

Thanks for the inputs Martin and Gerry. I read KTN 10 pages of posts/replies and gleaned very little info except from making laps using the reamer to make mirror image cutter and then use that to make brass or aluminum laps to match the reamer.Never have seen any pics or videos which are helpful to folks who watch and learn.And I don't have reamers....yet.Got a better clue from BT Sniper on a link which spoke of the whole die making using homemade expanding laps for straight work.That will be easy enough with taper pins and a taper reamer.. Also saw a comment on alum vs brass and copper with no definitive best.As to compounds, you'd think Brownells would be a good source but they carry more for gunsmiths and have garnet and alum oxide, Clover is silicon carbide. Silicone eats the laps I bought 10/1 over the die.I have some aluminum ox which is 800 grit and does a fair job of shining. I think speed is where I have become disillusioned. Can't imagine it taking days to polish a die when you can buy a set from Lee for $20 in shiny carbide.LOL.Gerry, I can imagine 35 laps of varying configurations for bore and ogive lapping considering mentions in other threads of making 6 laps for a core die only. Must just be too boring a work for a video production. I can only hope.

[GerryM]

A lot of the lapping is done by hand. slugs are swaged into the die to check for mesurement. Detsch is edms the dies and it leaves a pretty good finish,
From what ive been told you get a better finish with carbide, I guess tool steel is quite a bit more stickey. Ive read about ted smith and his dies years ago. Roschack did similar things in the die makeing process along with Sherman. Ross was quite a man. Tenths men are Rare. clover is ok for rough lapping then I guess you go to the diamond dust.
They used Brass laps and diamond dust in 1/10 thousand increments. That was for carbide. B&A used the same process at RIT from what I have also read years ago.
I have a set of those dies and from what i was told they were shop prodjects for students.
They are really really nice dies fit and finish is excellent.

[Reload3006]

If I were going to make laps I would use either cast iron or Oil-lite bronze. both are relatively porous and reasonably tough. for medium duty I would use clover aluminum oxide lapping paste when it got it pretty well polished I would switch to Diamond lapping compound. that would be for a point form die. For core swage and core seat (dies with straight through holes) I would use a honing machine.

[Methuselah3]

Thanks for the responses. All the internet searching I have done shows Clover brand and I quote from an ad "Grease-based silicon carbide compound. Most economical for polishing cavities and other areas where compound loss is excessive. Best for use on 50Rc and softer steels.

Available grits: 180, 200, 320, 400, 600, and 1200

Packaged in convenient 1 lb. cans." at $25.00 and up in price. If anyone supplies an aluminum oxide powder or paste in small quantities, I would like to know the source. Yes a honing machine would be nice.I'll look for some oilite and cast iron rod stock at McMaster -Carr or similar. I have some diamond polishing compound to try when I get closer on the laps.Again thanks.


If I were going to make laps I would use either cast iron or Oil-lite bronze. both are relatively porous and reasonably tough. for medium duty I would use clover aluminum oxide lapping paste when it got it pretty well polished I would switch to Diamond lapping compound. that would be for a point form die. For core swage and core seat (dies with straight through holes) I would use a honing machine.