Source for 8" disc sander attachment for mt lathe?

[L6steel]

I'm tired of trying to make a disc sander attachment for my lathe so I figure I'll just buy one. Anyone know where I can find an 8" disc that either comes with or fits onto an mt3 arbor? Man I never thought it would be so hard making something so simple, lol! Thanks up front guys!
Michael

[SGW]

Here's one thought for you: buy yourself a #3 Morse 3/4" collet, make a suitable drawbar, and just put a straight 3/4" shank on the disk.

[Joel]

Or, you could get a MT3 threaded arbor (very cheap). Make a 2" dia adapter to fit it to the disk. I would probably cut the disk out of 1/4" aluminum. Rough it out with a scroll saw, then turn the OD and face it on the lathe. Shouldn't take but an hour or so to do. We can't let you give up too easily!

[L6steel]

I've been trying to make em out of steel. Maybe I should give aluminum a shot before going to the store. Thanks guys!

[CCWKen]

Why MT3?
If you're going to be using it "once in a while", make it easy to swap on and off. Put a straight arbor on it and chuck it up.

If this going to be a common fixture, go buy a stand alone unit to keep the grit out of the lathe.

[Evan]

That is what was bothering me too, but I didn't realize until you mentioned it Ken.

L6steel,

Take a chunk of 1" cold rolled bar stock and cut it off three inches long with a hacksaw. Chuck it in the three jaw chuck and face it off on both ends. Champher the edges slightly. Then center drill or spot drill it to make a starting point for a tap drill. Then drill it with a 13/64 drill 1" deep, use plenty of oil. Use a countersink to remove any burr, don't be shy. Thread it with a 1/4 x 20 tap, use a tapered tap, not a bottoming tap (there is a reason for this). Tap it to the bottom of the hole taking care to feel when it hits bottom. Start the tap by holding it in the tailstock drill chuck (tailstock loose so it can slide) and turn the headstock chuck back and forth by hand with power off. Once you have it in by about three turns then use a tap handle to tap the rest of the hole.

You now have an arbour. Take a suitable sized piece of 1/4" aluminum plate (as mentioned above) and centerpunch it. Scribe an 8" diameter circle with a compass. Cut it by whatever means you have to slightly over the size of the 8" circle. Drill a 1/4" hole in the center. You will need a 1" long by 1/4 x 20 tpi socket head countersunk cap screw. Countersink the hole in the aluminum plate to accept the capscrew head slightly lower than the surface of the plate. You will also need to countersink the end of the arbour a bit as this type of screw in 1/4" plate will project the head through the plate when countersunk. This will help to lock the plate to the arbour. Then clean any lubricant or oil from the tapped hole in the arbour, make sure it is very clean. Apply Locktite and screw on the plate with the cap screw to the arbour. Make sure there is loctite between the disk and the end of the arbour. Wait for the locktite to set. Overnight is good.

Turn off the outside of the disk until it is the right diameter. Champher the edges. You may also wish to face off the front of the plate with a light skim cut. This is where seating the countersunk screw slightly below the surface of the plate is important.

You now will have a nice sanding disk mount, ready to accept peel and stick discs. Before removing the arbour from the chuck mark the arbour with a center punch so you can later align the mark to the same jaw it was aligned to when you machined it in the first place.

The reason for using a tapered tap in a 1" hole is that the screw will encounter undersize threads at the bottom of the hole at just the right depth and so help lock it in place. Trial fit it a couple of times before using the locktite. That will help the threads to form at just the right depth.

One last thing. Sanding on the lathe is not the best way to treat a lathe. If you do then be prepared to do a very thorough cleanup afterwards.


[This message has been edited by Evan (edited 05-01-2004).]

[L6steel]

Hmmm, you guys sure have made me rethink some stuff.
I was wanting to be able to change discs/grits quickly and setting up a disc sander on my lathe would make this possible. After reading what you gents have to say though I'm going to come up with a quick change system for a regular disc sander. I want to keep my lathe in good shape as long as I can. Thanks for setting me right on this one guys! Michael