I decided that I wanted to build a Thickness Sander so that I can sand boards that have been glued together for segmented wood turnings. When you have multiple species of wood at different angles, you can't run them through a planner anymore.
I found a set of plans at http://www.shigshop.com/thickness-sander.html for a thickness sander, bought them, and embarked on the task of building this project.
It is a lot of fun -- and a reasonable amount of work. Since I am making this at Tech Shop, I have all of the space and tools necessary to make the job easy.
So far, I have the sanding drum and four conveyor supports done. It has taken me about 20 hours to get this far.
Step 1: Cut Out the MDF Disks
The plans call for 38 5 1/2" MDF disks and 128 2 1/2" MDF disks.
I made these on a CNC shopbot using vCarve Pro. The MDF is 3/4" thick.
Click here to see the ShoBot do it's stuff: http://youtu.be/Febtki81qE0
Step 2: Prepare Blocks for Use As Rams for the Glue-up Process
I purchased 1" cold rolled steel rods and cut them to length using a metal lathe at Tech Shop.
I then cut 2" square blocks of pine and drilled 1 1/8 holes in them. I built a jig to allow me to quickly and safely drill the large holes. I used a forstner bit,
When I was done, I had about 35 blocks.
Step 3: Glue the MDF Disks to 1" Steel Shafts
The steel shafts are 1" in diameter and the ID of the disks is also 1". This makes for a tight fit.
I drilled a hole in a 4x4 and placed the shaft in the hole. I then placed the disks over the rod and used a 10 Ton arbor press to force the MDF disks down the shaft.
I used Original Titebond PVA glue and liberally applied glue to the disks. I then used the wooden squares and the arbor press to ram the disks together on the steel shaft.
This took a while , but I was able to apply pressure. Note the glue squeeze-out.
I used long clamps to apply pressure while the glue dried.
Step 4: Use a Router and a Fixture to Turn the MDF Disks Round
Build this fixture and mount two bearings on it using bolts. Mount a shaft with the MDF disks in the fixture.
Use a 3/4" flat router bit and go back and forth with the router slowly turning the shaft.
This takes about 45 minutes to an hour for each shaft. You need to take your time and use feeler gauges to adjust the height of the router as you measure the diameter of the disks / shafts.
This video shows the process. http://youtu.be/lnMJCr7mGp4
Step 5: Measure and Prepare for Sealing With Polyurethane
Use a caliper to measure the diameter of the drums. I wanted the diameter to be 5 inches. I was a little bit off -- 0.002 is not that bad.
Note the dust from routing one of the drums round.
I sealed the drums with three coats of poly in the Tech Shop finishing room
This was a lot of work -- but it should pay off in the end.
As it stands right now -- I have twenty hours of work. I have the drums for a thickness sander completed.
I made it at Tech Shop!