Casting gear blanks from scrap aluminium

[Russ Hanscom]

Have you checked Boston and Browning? As I recall, they have standard change gears in your DP and pressure angle. I bought a 127 tooth gear for my lathe a few years ago. The gears are not cheap but cheaper than a custom shop.

[Ike Turner]

Have you checked Boston and Browning? As I recall, they have standard change gears in your DP and pressure angle. I bought a 127 tooth gear for my lathe a few years ago. The gears are not cheap but cheaper than a custom shop.

Thanks, I have just emailed them both and requested a quote. I'll see how it adds up, unfortunately the international shipping on heavy bits & pieces is often the deal breaker. The quote I got from a local gear making company was more than I paid for the machine and there was nothing available here off-the-shelf.

[Ike Turner]

Thsi is a good chance to carve a Wax master, sink it in plaster and cast the result for light cleanup. It could ease the tricky machining by many hours.

Good luck.

That sounds like it might add an even more interesting aspect to the project. Now I'll have to add another leg to the research for this project- what wax to use, where to get it, etc!

I have another question regarding what I can use for a makeshift crucible, but I'll do some searching before I post a question on that.

[RCW]

Is the 127-tooth gear to allow cutting both Imperial and Metric threads?

[Ike Turner]

Is the 127-tooth gear to allow cutting both Imperial and Metric threads?

Yep that's correct, 127 being the first whole multiple of 25.4. So it's a bit of a bummer having this one missing, especially considering I live in a metric nation.

[ctwo]

The way I understand it, the 127/100 compound gear set converts the imperial threading to metric, so it is an additional capacity and will not do both (except for some off multiples).

[Ike Turner]

I figured that RCW meant that having the 127 tooth gear enables the machine to be used for cutting both metric and imperial threads; i.e. the 127-tooth gear must be included in the gear train in order to cut metric threads, but is not included in the gear train when cutting imperial threads....hope that's not too confusing....

[Pipescs]

you haven't mentioned what you are going to use to melt the aluminum to make the blanks.

[ctwo]

Do we think a cast iron cooking pot will hold up on a bed of coals with the hair dryer trick?

[steamin10]

A cook pot of iron will hold the aluminum alright, but it would be better if you put a thin wash of powdered chalk, or talcum powder carried by some sodium silicate to coat the surface and prevent iron contact and absorbtion. This coating is fragile and wont hold up well, but is most desirous for melting clean aluminum without iron contaminants, that disolve from the pot itself.

Melt fast, pour strong, and be safe.

Good luck.

[Ike Turner]

A cook pot of iron will hold the aluminum alright, but it would be better if you put a thin wash of powdered chalk, or talcum powder carried by some sodium silicate to coat the surface and prevent iron contact and absorbtion. This coating is fragile and wont hold up well, but is most desirous for melting clean aluminum without iron contaminants, that disolve from the pot itself.

Melt fast, pour strong, and be safe.

Good luck.

This is the sort of thing that I had in mind, I have a small makeshift forge that is powered by barbecue heat-beads and my leaf-blower on idle; this has been used for some light blacksmithing, with some modification I should be able to produce enough heat for this task. I'll look out for a suitable cast-iron cookpot.
Can you explain the chalk wash a bit? Do I just crush up some chalk, make a slurry with water and smear it on the inside of the pot with a paintbrush?

Also, can anyone advise how to calculate what weight of material will be required to fill a given volume in a mold? I'm planning on pouring simple disc shapes into open molds such as an earthenware pot or similar, then mounting the rough disc in the lathe and cutting away all the parts that don't look like a gear blank. I'm very open to input, even if it's just 'that won't work you idiot' or similar. I'm also not really wanting to go so far as setting up a complete home foundry to accomplish this one project.

[ctwo]

Ike, I just bought a 1/2" plate of 6061 aluminum for under $20, enough to make five 4" gears.

Try this calculator for the weight/volume

http://www.custompartnet.com/quick-tool ... calculator