epoxy-granite in the mini lathe bed?

[regcabdak1]

Hello all,

After reading some of the Epoxy-granite thread, I have been thinking about adding some epoxy-granite to the mini lathe bed to try and add some mass to the lathe to maybe inprove its perfromance and take some vibration out of the machine.

Like I show in the crude picture below, I would try to completly fill the "leg" on the tailstock end of the lathe, and then partialy fill the webbing in the bed, leaving oval shaped holes for the metal shavings to fall through. Might be able to put a little bit of material in the headstock end of the bed around the motor, but I dont think it would be very much.


Has anyone else done something similar to thier lathe already?

What do people think?

Thanks!

Tyler

[chalky]

Don't think leaving the oval holes will work too well. I don't get much swarf dropping through the bed on my machine so why not fill up the entire sections? Looks a good idea overall to me though. I've just finished filling the column on my small X1 mill with epoxy granite and it really deadens it - haven't checked the stiffness yet. I think I'll try filling the bed of my minilathe sometime in the not too distant future. Are you definitely going to do yours?

[regcabdak1]

I am still thinking about doing this. since you just worked with the epoxy-granite, I have a few questions, where did you get your supplies from? and how much did they cost? It seems like a pretty straight forward process, did you run into any snags?

Getting rid of the ovals might be a good idea, it would add more epoxy granite to the lathe bed, and would be much easier to "form up". I think you could "fill" the bed with it in its normal upright position, unless the granite is to large to get through the slot that the tailstock clamp bolt passes through. I would make sure to tape off the areas you didnt want to get epoxy, like the ways of the bed.

Tyler

[chalky]

I got the granite chips from a builders merchant in four sizes - dust, 6mm,12mm, and 14mm. I also used sand and glass bubbles. Dried the chips and sand in the oven at 160C for 45min. Then I mixed one 200ml plastic cup of each together in a plastic bucket. Pumped in four shots of resin and four shots of hardener and mixed everything together. Then I pumped in four more shots of resin and four of hardener followed by more mixing. You're supposed to mix the resin and hardener together first and then add the fillers. Done this way the resin/hardener mixture gets very hot very quickly ( the reaction is exothermic ) and will melt a plastic bucket if you don't get the filler in fast. Done my way the mixture only gets gently warm and you don't seem to get any bubbles either. This gave me a gloopy paste which I could spoon into the column of the mill. I tamped it down as best I could as I went along. The epoxy granite begins to set in about 15mins after mixing so you have to be fairly quick. You can get 106 hardener which will give you 30mins pot life but as I remember the epoxy doesn't then set quite as strong. In retrospect I could have made life easier by using one or two more shots of resin and hardener to make the mixture a little more runny. Left it overnight to cure and that was it. The mill column sounds really dead now when you tap it with a hammer. The epoxy granite fills all of the space and doesn't appear to leave any voids - at least it didn't when I test filled a small transparent plastic cup with epoxy granite. The resin and hardener I used were West System 105. I got it from a boat building supply supply house. I got the glass bubbles from them too. Its available in the US because Bob Warfield used the same stuff - see www.cnccookbook.com - thats where I got the idea from. A 1.2kg pack of resin and hardener cost about £20 ($30 ) and I've got loads left over, enough for my minilathe. I would advise you to buy the metering pumps for the resin and hardener because they automatically mix them in the correct ratio They cost around £10 ( $15 ) Hope this helps.