Quirky Turn Mill Build

[vtcnc]

Btw that casting is supposed to house skate bearings, it's not meant to be a sliding fit, as it is now -- don't know if that was the reason cast iron was considered?

I think lost foam casting of the type I did wouldn't be possible with iron -- I can imagine big problems there from mold fragility and flammable gas. And considerable danger. I'd want to stay with regular greensand castings. Maybe others have done it, I don't know. But it doesn't appeal to me.

Also, I plan on keeping the traveling parts as light as I can, so aluminum is first choice for this part. The steel is in the base.

[vtcnc]

I cut 6 foam patterns out today so I have spares in case I get some that don't pour well I've also decided to pour them as 2" sections instead of 4" -- and that should make filling the molds easier. I'm also re-considering how to orient them in the sand and where to put the sprue. I'm going to try the first one with the flat base uppermost, and maybe a 1" diameter sprue instead of the four smaller 1/4" square sprues. I think the metal will fill well, but I do wonder whether I will get a shrink cavity on the flat base. Guess we'll find out.

I've been very influenced by the vertical orientation threads, so I'm going to try that on this one. I've also decided that this is going to be a pure turn mill, rather than a convertible flat bed/turn mill. So I will only use two linear axes and one rotary, rather than the 4 axes I first envisioned.

Because of these changes, I'm considering a cantilevered carriage, rather then a gantry, like a conventional lathe. But since the mill's X axis will be flipped vertically, the carriage (Z axis) will be on top, rather than extending in the direction of the operator, as it is on a lathe.

I was going to box the gantry from pieces in the original configuration, but now I'm thinking about making a single casting -- probably from a regular pattern in greensand (not a lost foam process casting) I'm not sure yet. Just some ideas floating around in my head.