Making a milling vice

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vtsteam:
Forgive my opinion here, too Norman, and take with a grain of salt.... I like the horizontal layout okay, and the bed is important to preserve clean compared to the ends -- keeping that part low in the mold helps.

I think gating the sprue high up will wash sand down the ends during the pour, so I like the low gating as well.

You just basically need to feed metal into the inside corners during solidification so I'd try a bigger riser off the edge at that corner, and thicker than the upright is --maybe even a blind riser -- like a ball of styrofoam. The riser has to solidify last, so needs to be thick.

Sharp Inside corners in massive casts tend to tear like that since they solidify last, and the leg and main base tend to pull metal away from it while soft.

It helps if there's a radiuus there instead of a sharp corner, even if you machine it off afterwards.

Also a bevel on the outside corner can help.

Also the present sprue and riser look small. They should normally be larger in cross section than the largest thickness you are feeding -- which looks like the bottom of the uprights. That way they hopefully won't solidify before the corner does and can keep feeding iliquid metal.

I know just a bunch of suggestions, but some or one of them might help.

Your base does look good!

NormanV:
Thank you Andrew and Steve for your suggestions. I think that I will keep it horizontal for the next try. I'll add fillets to the corners and make the header and riser bigger. Funnily enough I did not have any problems like this with the much larger castings for the milling machine and I used the same size header and riser for those as I have here. I am sure that the gates between these and the body of the casting are too small as I was trying to keep the metal section small so as to reduce the hacksawing needed, my angle grinder is bust!

awemawson:
I kept a pile of baked bean tins with both ends removed in my foundry. Ram them up tight with floor sand, then press a piece of 1.5" copper pipe through them, and hey-presto you have a taller riser. I used to sculpt them at the upper end to a funnel shape with one of my moulding tools, and place them on the cope over the existing pour and riser, putting a little sand round them to seat nicely.

It also had the side effect of producing useful bars of the alloy for either machining or testing

NormanV:
I have already prepared some cans for tomorrow!

NormanV:
Here is the reworked pattern. I've done it quite crudely but I am sure that it will be OK as I intend to machine it all over. I've put in quite large fillets where I had the splits and added a block at each end for the gates. I have made patterns for the header and riser to mould in situ. I normally cut them with a piece of steel tube about
1 1/4" diameter. I will also raise the height with two cans as suggested by Andrew.

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