Granite surface plate lathe

[will gilmore]

I've been thinking about this and collecting parts for at least a couple of years. Thanks to everyone on CNCzone and elsewhere that has posted pictures and info of their CNC machine builds. Especially: 5bears, Bob Warfield, Guldberg, JH-Q, S_J_H, The Blight. (edit: how could i forget mackeym !)

I started with a 18x24x3 Granite surface plate. I drilled half way through from the top and then half from the bottom. All the components will be bolted down rather than using epoxied inserts.

[tootalew]

I will be watching this with great interest. I have drilled and epoxied tapped inserts into a 18 24 4 surface plate and bolted up the ballscrew and rails. I am currently laid off, and cannot go further until I find steady work. Did you drill dry, or did you use a water swivel?
I used a (leaky) water swivel, that i had to put a bag over with zip ties, but it was still a messy job. I could not believe how easy it is to drill granite. What will you be using as a headstock? Will this be a gang lathe?

[jalessi]

Will,

What type of drill bits did you use?

Jeff...

[will gilmore]

tootalew - we talked about sharing a granite plate at one point. lets see some pictures of your project.

i did use a water swivel. you can see it in the 3rd and 4th pictures. i drilled one hole trying to stop the spray with rags and wood blocks. after that i made the spray shields shown the in the picture. there are two types of spray that i found. when you first bring the drill down to the surface of the granite with the water flowing the water sprays out horizontally. the two "C" shaped pieces fit around the water swivel to stop this. the second spray happens when you have the hole started. the water sprays out of the hole vertically and hits the bottom of the water swivel and gets every where. i put the cylindrical piece of sheet metal around the water swivel to contain this spray. after i had these pieces in place i could drill with next to no water spray.

jeff - i used a 3/8 sintered diamond drill from ukam http://ukam.com/webcatalog_drills_ordering.htm

[tootalew]

Will, I will get some pictures posted soon. I did not see all the photos before my response. I used a short section of pvc pipe for my "moat" but that vertical spray is hard to control. I used a 5/8" core bit, going down about an 1 1/2" then took a thin screw driver wedging it in and a quick slap from hand the granite slugs broke out very easy.

[Guldberg]

Interesting project (hurray, I was mentioned :-). Looking forward to more pictures of the beast. Any drawings/conceptual art to show us the goal?

[will gilmore]

Not a lot of progress. Other stuff going on and waiting for materials and hardware.



the second image should give you an idea what is going to happen. headstock will go on the left.

[underthetire]

Very cool. We just pulled a "granite lathe" out of service and threw it away. Had full laser feedback for position/tilt/ya/and temperature. It was built back in the late 70's. About 100 ton of granite total. Accuracy .000005, flatness.000001. Yes, nano-inch resolution. Pretty impressive in its day. Room temp control was .5 deg, machine temp control was .001 deg. It actually made the lens for the Hubble telescope. I love watching the machine builds here.

[will gilmore]

Finally some progress. Got some tube for the stand and have that tacked together. Started machining the spacer that holds the headstock off the granite and will hold the Z stepper and ball screw.

[will gilmore]

More progress. Have the Z screw mounted. Pretty soon I'm going to need to start thinking about electronics.

[student1616]

nice project.
please continue the updates.iam very much interested to a lathe built on granite

[john huijben]

That is looking great!
The granite makes it look like it's going to be a very accurate machine

What sort of travels are you aiming for? And are you going to mount a tailstock?