Group Project: Dividing Head - Organization and Design

[rwm]

I have a ton of yellow mystery brass for casting that I will likely never use. Would a cast brass worm gear blank be good? Most of the brass is probably 60-70% zinc. I could add copper. Cast blanks would likely have small casting defects that we would have to accept.
Robert

 

[ErichKeane]

I have a ton of yellow mystery brass for casting that I will likely never use. Would a cast brass worm gear blank be good? Most of the brass is probably 60-70% zinc. I could add copper. Cast blanks would likely have small casting defects that we would have to accept.
Robert

I'd imagine that would be alright, what do you think guys? I was actually thinking that if I got my heat-treat-kiln together, maybe I could also put together a mold and cast brass (apparently 1900 degree pour temperature?) and just do that instead. But I'm probably a few months from being able to do that.

 

[ttabbal]

I'd imagine that would be alright, what do you think guys? I was actually thinking that if I got my heat-treat-kiln together, maybe I could also put together a mold and cast brass (apparently 1900 degree pour temperature?) and just do that instead. But I'm probably a few months from being able to do that.

Sounds good to me!

 

[rwm]

I think it will be hard to do brass in a heat treat kiln although you could try it. My casting equipment is in storage at the moment or I would jump on this. One thing I noticed is the large size of the gear. It is .750 thick x 3.6". I would probably consider a 1 x 4" blank so you could machine off the cast surface. That is a big chunk of brass. I wonder if casting a brass cylinder and using that as the stock would be easier?
Robert

 

[ErichKeane]

I think it will be hard to do brass in a heat treat kiln although you could try it. My casting equipment is in storage at the moment or I would jump on this. One thing I noticed is the large size of the gear. It is .750 thick x 3.6". I would probably consider a 1 x 4" blank so you could machine off the cast surface. That is a big chunk of brass. I wonder if casting a brass cylinder and using that as the stock would be easier?
Robert

Either would work for me! I can always toss it on the bandsaw to make them smaller. The 1x4 blanks would likely be great too! I think we're currently at making 7 of these, so that plus a couple of "oopsies" might be nice

 

[Flyinfool]

There is a lot of metal in this project, and a number of heavy parts that will not be cheap just for the stock to make it.

I looked at dropping the OD of the gear to 3.475 to allow 3.50 stock instead of 3.75 stock. This change would cut about $30 off the cost of the bar, it would also reduce the tooth contact area by almost half. This would still include 3/8 of an inch down the center of the gear with full tooth contact. I think It will still work but will be right on the edge of clean engagement.

 

[ErichKeane]

There is a lot of metal in this project, and a number of heavy parts that will not be cheap just for the stock to make it.

I looked at dropping the OD of the gear to 3.475 to allow 3.50 stock instead of 3.75 stock. This change would cut about $30 off the cost of the bar, it would also reduce the tooth contact area by almost half. This would still include 3/8 of an inch down the center of the gear with full tooth contact. I think It will still work but will be right on the edge of clean engagement.

Ouch... Not sure that is worth it.

 

[Shotgun]

You wouldn't need to cast a cylinder as much as a REALLY thick walled tube. There is a lot of material coming out of the middle there. Could almost use a piece of pool noodle if doing lost wax casting.

If your kiln won't do it, might someone on the forum lend a hand?

 

[rwm]

Let me check my brass inventory firsthand. I am sot setup for lost wax. I would use sand casting. The process would probably involve making a match plate with mahogany patterns. Perhaps 3 or 4 patterns per plate which would end up being a very large casting flask. I have an example somewhere.
R

 

[Weldingrod1]

Btw, 7075 machines very nicely! Frankly easier to work with than 6061.

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