Ball mold

[Maineshops]

Anybody using a Cnc to make a ball mold? I built a Cnc router awhile back and I am fiddling around with it. I cut a prototype in wood and it looks good. Any words of wisdom would be appreciated. Dan

[Metalshaper]

Just curious?? What kind of wood\metal did you use on your prototype?  And are you just making mold blocks with your machine??
I'd assume if you are doing CNC work, then  you know of shrink rates and metal expansion rates and can coordinate for accurate final products...

Would love to see it run!! Any machinery operations just strike a real chord with me!!!

Respect Always
Metalshaper\Jonathan

My mold making was in aluminum blocks, with had turned\cut cherries, and milled using a bench top drill press ( as I had no mill at that time ) a .295 for my Bud's gun n a .340 for a barrel I had..

[Clark Badgett]

I'd assume if you are doing CNC work, then  you know of shrink rates and metal expansion rates and can coordinate for accurate final products...

I've never heard of shrink and expansion rates in CNC work.

[Metalshaper]

Clark,

My bad, in making the assumption that someone doing cnc work ( specifically for ball\bullet molds ) would be aware of the expansion factors of the materials used for the mold blocks and the associated shrink rates of the materials being cast.. with lead it's not much

In my case the 6061 Al blocks I made my molds from has an expansion rate of +/- .006 at the casting temperature of lead. ( Machinery's handbook btw ) so to cast a .340 ball my Cherry needed to cut a .334 cavity.. my blocks, when up to temp throws a .3405 ball.
Marlow's .295 ball... The cherry should have cut a .289 cavity... I mic'd his as throwing something like 0.2949 ball at temp??

Now admittedly, I'm just a self taught and probably not the world best machinist by a long shot???  I am open to learn anything that you or anyone else can teach me!!! Or help point me in the right direction from where I veered off n screwed up??

Respect Always
Metalshaper\Jonathan

[Clark Badgett]

Ah I got ya Jonathan. I was thinking you were meaning expansion and shrinkage while machining.

[Metalshaper]

Clark,

No worries!  Like I said,  I'm just trying to learn and get better at the work!!

Respect Always
Metalshaper\Jonathan

[Greg Pennell]

As an example of what can be done with CNC, check out this guy in Slovenia. I have several of his molds in different calibers, and they are absolute jewels of precision, and the best casting bullet molds I’ve used in over 40 years of casting.

https://www.mp-molds.com/

Greg

[Maineshops]

Prototype blocks were maple. I’ll be using 7075 t6 for the mold. At an expansion rate of .006 per inch I consider it a non factor on a .310 ball. Patch thickness will take care of that issue, and I do understand that is a moot point.
The little Cnc was built to support Ma’s quilting machine and my rose engine cams but I fiddle around with other things like the lids on my shaker boxes.

[Greg Pennell]

Very nice!  I think I might be able to pick up a CNC router pretty cheap. What software ore you using?

Greg

[Maineshops]

Control software is Mach3 and art work is done with vectric vcarve and bobcad mostly. Fun toy go for it  ...Dan