Motor arbor, sanding discs, etc.

[d6monk]

Hi everyone, I have a baldor motor in the mail that I'm going to use for sanding (so I can stop abusing my lathe), but I have a couple of questions. First, I have been using 3" wave discs chucked in a drill chuck in my lathes headstock, but I definitely want to go for something larger this time. I have seen 7" 3m sanding discs (with a 7/8" arbor hole) that look like they may be good, but they don't go to very high grits (120 is the max I've seen).

This brings me to my questions: If I did get the discs how would I go about attaching them to the motor? I would probably want to extend the shaft a more than the regular motor arbors I've seen for sale do (not to mention none of them have 7/8" arbors). Also, what would I use for a backup pad? How are you guys doing this?

Second, what grits do you guys go through on sanding discs etc. before you start hand sanding?

Thanks again.

[SimeonTurner]

Kurt sells a nice sanding disc and arbor set up through his site. I would start there.

[d6monk]

Yeah I've seen that--not quite what I am looking for however.

I guess I could buy some aluminum rod, bore out one end to 5/8" for the motor shaft, and internal thread the other end on the metal lathe I am getting to accept a 7/8" hex bolt and then attach the discs with the bolt and a washer. It would be good practice in figuring out how to use a metal lathe. Still not sure what I would use as a backup pad though (I want something very thin).

It looks like I may end up making as many tools as pipes in the upcoming weeks!

[KurtHuhn]

Backup pads are tough (as in very tough) to come by in anything thinner than what I've got available. If you really need something thinner, you're probably going to have to make it yourself. You could use 1/4" aluminum disks, lightly crown them, and figure out how you're going to attach them to the arbor. Personally I would probably use a 5/16" or 3/8" stainless bolt with a extra wide low profile head or a recessed flat head. Then drill and tap the other side of the arbor to match. But then you've pretty much got what I make, and without the flexibility of the backup pad.

If you have a link to the sanding discs you're thinking about using, I'm sure I could suggest something.

[d6monk]

Something like such kurt: http://www.shop3m.com/3m-fibre-281c-dis ... jzbzh.html.

[KurtHuhn]

Ah yes. Those are great for rough shaping. You'll want a "work arbor" as sold at almost any hardware store. They come in sizes to fit 1/2" and 5/8" shaft motors. They're sold primarily to hold buffing wheels, but also will hold resin fiber grinding discs. The shaft on these is threaded 1/2"-20tpi. You will want to make a small bushing to hold the fiber disc centered on the shaft.

BUT... These are generally unacceptable for anything but rough shaping of anything. For finer sanding you will want to use sandpaper designed for finishing wood or plastic, with a much finer abrasive, much more consistency, more flexibility, and less aggressiveness.

[ToddJohnson]

Something like such kurt: http://www.shop3m.com/3m-fibre-281c-dis ... jzbzh.html.

Yes, these are the right sanding discs to use--36 grit is what you want--but the actual backing disc is the most important part. I will try to post some photos of mine later today. It can be made very inexpensively and this is the setup most all of us use. It works best in tandem with the Beall arbors. That way, everything is "quick change."

TJ

[d6monk]

Thanks all of you.

Todd, photos and an explanation would be wonderful! I have been spending more and more time pipe making and I really need to get a better setup and better procedures going.

[sethile]

Very timely thread for me! I'm in the process of upgrading my disk sanding and have been pouring over photos of disk sanders.

Yes, these are the right sanding discs to use--36 grit is what you want--but the actual backing disc is the most important part. I will try to post some photos of mine later today. It can be made very inexpensively and this is the setup most all of us use. It works best in tandem with the Beall arbors. That way, everything is "quick change."...

I'm very interested in hearing about this backing plate. I've got the Beall arbors on the way...

On many of the shop photos I've been pouring over (Todd's, Tom Eltang's, Jeff's, Love's, and several others) I've seen this set up in combination with a french wheel on a separate motor under the same bench. Is the French wheel more for finish sanding after shaping or is that used for shaping too? Since the Beall arbors are quick change, is there a significant advantage to having these two set ups on separate motors?

Great thread--thanks!

[d6monk]

So here is what I came up with:

I found some hard plastic backing pads at Enco that were pretty thin, so I used those along with the 3M sanding discs and some 2" long 3/8x16 bolts. I turned some pieces of aluminum that the bolts go through and that hold the sanding discs and backing pads (that have 7/8" holes in them) centered. I put them all together, secured them each with a nut and washer, and the final products can just be screwed and unscrewed from the beall arbor--quick change style.

Thanks again for the help everyone.

[KurtHuhn]

Very ingenious! I like it! Do the discs have a tendency to go concave on the abrasive side at all?

[d6monk]

Hi Kurt, I haven't noticed anything like that, but I will keep you updated.