Lathe Disk Sander
A variable speed lathe makes a great disk sander. You can adjust the speed of the sanding disk
to control how fast you remove wood and to avoid burning the end grain on woods like Cherry.
Home made 12" disk sander mounted on my Powermatic 3520B lathe.
Notice the dust hood behind the sander. I have a big powerful dust collector so the hood is close enough.
Notice that corners of the table are rounded. I like to round over the corners on all of my
jigs, etc for safety.
Sand to left of center if the lathe is running in forward. With the tool rest table at or a little above center.
The tool rest table is just 2 chucks of 3/4" plywood. A 1" wooden dowl and a 1" shaft collar.
The shaft collar is important! It allows me to just use a dowel rather than a steel shaft or pipe. 1" wooden dowels are easy to find at local hardware store.
The shaft collar holds the table up. So, I DO NOT need to really tighen up to much on the dowel and crush it.
More about the table latter.
I expand the chuck into a grove in the sanding disk.
Note: This sanding disk has 2 sets of grooves. The groove you see in photos is not being used. It is for larger #3 size jaws. The disk is mounted in smaller #2 jaw size groove you can not see in photo.
I recommend you go with JUST ONE groove. More about this latter.
3 disks. One for each grit. I use 60, 100, and 180 grits.
The sand paper is attached to plywood disk with adhesive. So changing grits destroys the sand papper.
I buy my sand paper already coated with adhesive. i.e. PSA disks. You need to use a good tough cloth backed sand paper.
You can buy 12" disks from Klingspor, etc. But, you probably only need one of each grit and they last almost forever. So, I would just buy 3 12" disks from McMaster-Carr ($5 each). Shipping from McMaster-Carr is always reasonable if not cheap. www.mcmaster.com item #4675A491 and #4675A492. See last photo for shopping list.
You are probably thinking 60 grit is to course? Wrong! It may be to fine. You need course sand paper to avoid burning woods like cherry. You need coarse sand paper for fast lathe speeds. I rarely use the 180 grit.
You may be able to get 12" disks from your local hardware store. They were used for sanding floors. However, square floor sanders are now in vogue.
I make my sanding disks out of good FLAT 3/4" plywood.
I rough cut the disk on bandsaw and then make it look pretty on the lathe. All edges are rounded for safety.
You could use MDF rather than plywood. But, if MDF gets wet it expands. If MDF gets damp it may warp. The disk needs to start out dead FLAT and stay dead FLAT. Thus in my studio, plywood is the better choice in the long run.
This disk has 2 grooves. The inner groove matches #2 jaws on Oneway chuck. The outer groove
matches #3 jaws on Oneway chuck.
If I had it to do over, there DEFINITELY would be ONLY ONE groove. Probably the inner #2 size groove.
Why? Because you can see where the plywood cracked when I expanded the chuck jaws to much into inner groove. Plywood is just not strong enough to support 2 grooves that are close together. MDF is weaker than plywood.
I use 2 layers of 3/4" plywood to create a secure mounting hole for a 1" wooden dowel.
Glue and screw the plywood togather. Round over the corners for safety.
Glue the dowel into the hole and run a drywall screw down from the top into the dowel. (Not shown in photo).
Notice how the dowel has been deformed by tighetening it in lathe banjo. That is why I use a 1" shaft collar to support the table. Then I don't need to tighten the banjo to much. The 1" shaft collar also allows quick set up.
Using a 1" steel rod or pipe is not worth the trouble. 1" OD pipe is hard to find and often not cheap. You have to purchase 1" steel tubing. 1" steel tubing or rod is hard to fasten to the plywood. And then you still need a 1" shaft collar for quick set up.
Note: I use this plywood table for all kinds of things. It was just sitting around one day when I got tired of just holding things up to the sanding disk. Using the table is a lot safer.
I prefer 2 piece shaft collars rather than 1 piece or solid collars with set screws.
Low cost shafts and dowels often are not dead on 1". They often are a little small. 2 piece shaft collars come from the factory with more play in them. So they will tighten up on under sized shafts. You can also open them up and grid in more play. Grind the flats pointed to by pencils in photo.
If you can't find a 2 piece shaft collar locally you can order from McMaster-Carr. www.mcmaster.com item #6436K18