[Azalin]

I'm seriously considering to build an EG CNC metalworking lathe but I see no one has done it yet. The size I'm planning to build is 1000mm (40") between centers so the total length will be about 1500mm.

Why is EG not a good choice for DIY'ers?

What is the preferred material for such machine?

Note: Cast iron is not an option for me.

[mcphill]

You will find FAR fewer lathe builds than mill builds on this forum in general. Since there are only a handful of completed mill builds, it is only logical there are no (or very few) lathe builds (I seem to recall there was one that was pretty far along).

[Azalin]

I guess mine will be experimental.

[LeeWay]

Just about any home made machine can be considered experimental.
I think a lathe lends itself better to an EG type of base than a mill does. You don't have the added joints off the Z axis. Either can and have been done, but it would be a very nice build I think.
In fact most of the pats off my 80 20 lathe would fit very well on a similar EG base and probably be three times the lathe it was. Add a new spindle system that can be automated and you have something then. It only had 5" of X travel though, so either a turret or longer X axis would have been desirable.
Good luck with it.

[charlieslasher]

Good choice for lathe material. Lots of Gang Tool lathes use polymer concrete bases.

[Azalin]

Hi,

Thanks for the feedback.

So is it recommended that using some steel inside the EG for more rigidity?

Wait, I'll sketch the skeleton that is in my mind so you'll get what I mean.

Sent from my GT-I9300 using Tapatalk

[G59]

Why is EG not a good choice for DIY'ers?

I can't think of a simple answer for that, but surely you realize that it is twice the work, as you have to make the mold first. Maybe that, in and of itself, is enough to discourage most DIY's.
Also the cost of materials and availability can also be a deal breaker.

However, the benefits would certainly payoff if well planned and successfully done .

Have you seen this video? Not quite EG but homemade and precise to 1um. https://www.youtube.com/watch?v=sFrVdoOhu1Q

[Azalin]

Hi,

Yes, I've seen this video couple times. Very nice machine. I wish there'd some build pics.

OK, decision has been made so EG it is.

First question is about the spindle. The lathe will have a tailstock and the distance between centers will be 1 meter long. I'm not very clear about the max size of the spindle chuck but say it is a 150mm chuck. I'll turn some large (up to 150mm round steel) material on it. What type of a spindle do you recommend?

Note that I'm a home hobbyist and didn't see so many lathes so I am not familiar on lathe spindles. I only know the one on my spindle and it is very ordinary one. The guy who runs a project log right now uses a spindle that is capable of auto-change chucks (don't laugh ). I'd like to build something like that.

Anything you wrote will be appreciated.
Thanks

[G59]

So you will be making the tailstock too?

What type of a spindle do you recommend?

Well that really is up to you.
Are you building this machine for production purposes or is it just another lathe, CNC'd with with a bigger work envelope?

You should maybe draw a sketch of what you have in mind.

[mcphill]

Project dead, or is there a new thread somewhere?

[Goemon]

I can't speak specifically about lathes but I am making an epoxy granite base for a CNC router / CNC mill and, as a general point, I find it far easier than working with steel.

I can easily create a perfectly flat and mirror smooth surface with epoxy granite without any special tools (which I could never do with steel).

In terms of making a mold, this part is easy, cheap and quick. Just use wood coated with mold release and bolted together in the desired shape.

The materials are easy to acquire and cheaper than steel. Epoxy off eBay and sand from Home Depot. I add carbon fiber and fiberglass strands too but whatever.

I have read about people using epoxy granite for a lathe bed. It seems like it would be an easy enough project. I doubt I would want to use it for a head or tail stock (or housing for anything with a motor) because it softens when it gets too hot.

The overall benefits over steel should be the same with a lathe as with a CNC router or mill. I.e. Better vibration dampening and greater accuracy.

just remember to adjust the thickness to compensate for differences in stiffness between the EG and steel.

check out this pic - the guy made a diy lathe out of concrete:
https://hackadaycom.files.wordpress....e_wb.png?w=800