My first question is "can your lathe produce sufficient speed for

a sanding disc to work well?". It looks as though your maximum RPM is

2200. Normally, the speeds are significantly higher. Is that 12 inch

diameter?


Good points. The machine is 750 watts, and yes, 2200 rpm max. I can turn a max of 14.5cm radius, so the disc could be up to 11.4 in. I have a guy nearby with a small shop and a bigger lathe, however. The standard disc size here is 300mm, or 11.8 in.

Second -- how are you going to keep the sanding dust from

rapidly abrading the ways of the lathe? I would put a disc sander as

far as possible away from the lathe or any other precision machine

tools. The grit from the sanding disc is *very* bad for the ways.

I agree that having the disc on the chuck side is a bad idea, but if I mount it to the back, I don't see so much dust hitting the weighs.


And -- another safety point brought on by your photo of the

lathe itself. *Never* leave the chuck key in the chuck -

Yeah, I have a bad habit of doing this. Thanks!




Anyway -- I would turn a plug which would just barely fit into

the open end of the spindle, then drill most of the way through and tap

for a large setscrew (say 1/2 inch or so (or 13 mm or so), with a cone

point), and then using a hacksaw or bandsaw if you don't have a milling

machine, cut through the diameter on the inside end twice -- the second

at 90 degrees to the first. At this point, when you run the setscrew

into the center it will eventually hit the bottom of the drill hole and

expand the plug to grip it firmly into the spindle.

Good Idea!




If you punch a hole in the center of the sanding disc (which is

moving too slowly to be of use sanding anyway) you can reach through

there with the Allen (hex) key to loosen the setscrew and pull off the disc.



The cover is fairly beefy, so

I think with some reinforcement bars I can mount a table which would

work well enough.



Again -- I would not put sanding operations this close to the

precision machine surfaces.



Better to go ahead and make the disc and hub (without the

expanding split grip I described above) and get a used electric motor of

adequate size and bore the hub to slip on the end of the motor shaft.

Get at least a 3600 RPM (really marked something like 3450 RPM or so)

and I think at least a 1/2 HP motor for that large a disc -- and more

likely a 1 HP motor. (In Germany, probably marked in KW instead of HP,

figure about 0.750 KW is about one HP.) Sorry for the inch figures, but

I *think* you used inches for the diameter of the sanding disc, anyway,

even though the ID of the spindle is just slightly over 1" (25.4 mm).

At this point I would just break down and buy a sander. Now that I think about it, by the time I add up the hours and Euros to do any of this it seems to not pay off. I can get a lower end machine for about $240. It's just that it would be so cool to have one sticking off of the back of the lathe, saving a lot of space.

Thanks Don, I used to post as Robobass when I had a shop in Brooklyn back in the '90's. Not many of the old guard seem to still be around! I've been without toys since I went overseas 12 years ago, and am now putting together a proper shop once again.