[KKamel]

I want to try to cast a headstock for a lathe in epoxy granite. I havent done alot of work in eg so i thought i get your input on a few things.

The headstock i want to cast is basicly just a big slab with cast in flanges back and front for a cartridge spindle and a rear bearing, no gears or anything like that on the inside.

Like this only bigger, http://www.toolsandmods.com/images/m...spindles-5.jpg

What wall thickness would you go for at the narrowest point, that will be the sides where the bearing houseing for the spindle sits? And what max aggregate size would you chose?

[KKamel]

I should have mentioned that I haven't decided on a final chucksize but let's say a 200mm for now. Spindelbearings outer diameter will be 110mm and bearing housing around 130mm outside diameter.

[rybov]

Hi,

I am not answering your question fully here, but there is a rule of thumb that your thinnest wall should not be thinner than 5 times the biggest particle size you use. So if the biggest gravel is 8mm, then the thinnest wall should 40mm. In general walls need to be thicker with polymer concrete than metal. So make it as massive as possible with the space avaiable.

If you don't have a lot of experience with polymer concrete mixture design, I think the easiest way to go is to buy the DIY offering from Epucret. They have three different mixtures. The biggest partice size is 8mm if I remember correct. I comes in 30kg bucket ready to use. You can find more info on their website.

I also seem to remember an article I wound on the web. It was a study of replacing the headstock of a commercial design lathe, with a polymer concrete design. Try serching for polymer concrete lathe headstock.

Best regards
Jacob

[rowbare]

Someone did an E/G head for a mill: http://www.cnczone.com/forums/genera...head_hm45.html

There might be some insight in that thread.

bob

[cnccnc222]

I'm very interested in this project as well. My wood router table is nearly finished, and I wonder if it could be used to mill pieces of wood that could be assembled to make the casting forms.

If you continue with this I'd be greatly interested in the dimensions you chose, and any other info. Perhaps I could join in later and upload file for cutting the forms.

Actually I'd like to build a table-top 4th axis for the wood router, made is as much epoxy-granite as possible.

[asuratman]

Its better if you start up with sketching or cad. So that from there you can design wall thickness, bearing size, etc.

[KKamel]

Sketching is "complete" i have made a wooden model of the headstock that i will attach my bearing housings, drive motor, spindle etc to before its finaly cast. The current design makes the epoxy-granite slab about 260mm x 150mm x 330mm and the thinnest section should be 50mm. Im missing the drive motor and some w