Looking for imput on making ouw mold.

[rmatchell]

I have been playing with the idea of making a mold, I have gathered some aluminum blocks and drill rod to make a cutter. I was wondering if anybody has any tips or advice. I am thinking about starting out with a simple .32 wad cutter. Also how do you figure out out large oversize to account for shrinkage.

[theperfessor]

I wrote this a while back. It might be of interest. Best quick and dirty size suggestion: Get a Lee aluminum mold in the same caliber you want to make a mold for. Cast some of your alloy in it and measure the cavity and the resulting bullet. Make your mold with the same size allowance. Consider the $20 the cost of an education in thermal expansion.

http://www.usi.edu/science/engineering/moldfixture/MakingBulletMolds.doc

[rmatchell]

Thanks, I know it would be easier to just buy the mold, but I want to try new things. I'll see if I can measure the cavity with my calipers.

[NoZombies]

For 20-1 with a resulting size of .314 cut the cavity to .3162

[deltaenterprizes]

I have cut a couple molds with cherries I bought one at and a couple that I made the cherry.
The problem I have is sharpening the cherries to cut a known size, it is hit or miss because I am sharpening them on a jig that is shown in The Machinist's Bedside Reader #3.
It is slow and I don't know how to measure the chrerries in the jig with a test indicator or dial indicator.
I bought a "universal" tool & cutter grinder from Northern Tool but have not done any experimenting yet with it.

[Buckshot]

I have been playing with the idea of making a mold, I have gathered some aluminum blocks and drill rod to make a cutter. I was wondering if anybody has any tips or advice. I am thinking about starting out with a simple .32 wad cutter. Also how do you figure out out large oversize to account for shrinkage.

Do you have a Lathe? A Mill?

...............Buckshot

[deltaenterprizes]

You will need a "centering vise" also

[theperfessor]

Not necessarily, lathe boring using a form tool is also a viable option.

Not to cause thread drift, but I just got a Gromax Universal cutter grinder, when I get it set up I'll post a thread on it. Hoping to use it to grind some special tools to help speed up production on a couple of items, and also make form tools for making molds on a lathe.

[Buckshot]

Not necessarily, lathe boring using a form tool is also a viable option.

Not to cause thread drift, but I just got a Gromax Universal cutter grinder, when I get it set up I'll post a thread on it. Hoping to use it to grind some special tools to help speed up production on a couple of items, and also make form tools for making molds on a lathe.

..............Pretty nice piece of equipment to be able to buy. A capital investment, eh? :-)

.............Buckshot

[.22-10-45]

Back when I was in H.S., I needed a .40gr. heeled bullet for my .22 rimfire re-loading..In shop class, I turned up a tool steel "bullet" of desired shape I think I went .002" or .003" oversize for shrinkage.
Made up aluminum blocks with mating pins, & drilled small pilot hole on center of parting line (1/2 hole in each block face)
I set up in 2 1/2 ton hyd. press & pressed blocks together..giving some 'dwell time" for metal to flow. I must admit I got the idea form the then new Lee moulds just coming out..it was part of their advertisement.
Anyway..it worked!..a mirror smooth cavity resulted. I spent many a snowy winter Saterday casting bullets on an old cast-iron wood range in barn "kitchen" with the heady aroma of sulpher waifing out of the oven as the strike-anywhere priming was drying in the case rims.

[theperfessor]

Buckshot, it was a deal I couldn't turn down. Unused machine six years old, never even hooked up to power. Long story made short, I got it for ten cents on the dollar, total cost to me was around 3K for the machine and another 1K to have it moved into my shop.

Moral of story: sometimes people with money buy things they don't know how to use and then later need the space and will sell things cheap to a guy with cash on hand!