# Shop-Built Thickness Sander

Discussion in 'Tele Home Depot' started by Guitarnut, Apr 13, 2012.

1. ### GuitarnutFriend of Leo's

Jun 29, 2009
USA
While I'm working out a few design issues on the feed table, I thought I would tackle the cutting template for the sandpaper roll.

I started with some math. The drum is 18" x 3.5".

d x pi gives me 3.5" * 3.142 = 10.99" or, the distance around the drum. The sandpaper roll is 3" wide so 18/3 = 6. So, 10.99" * 6 = 65.95" This is the area of the drum...I'm sure there's an easier way to get to this number.

Then I put a few cut lines on an 8.5" x 11" Illustrator doc and printed it out. I included a .50" overlap so I could tape them in a straight line more easily. It also gave me an even 8" multiplier. By my math, I needed 8.5 strips.

After cutting the strips and taping them together at the overlap line, I started rolling them onto an 18" piece of PVC pipe. I knew it would be tricky to start on an end, so I started in the middle and got a comfortable angle were the paper wanted to lay side by side and not buckle. Then I worked a few wraps to the end of the pipe and taped it down.

Here's where the math fell apart. I knew it would because some of the area I calculated would be cut away in the tapers. This meant that additional length would be needed. So I had extra paper strips standing by.

I added them one at a time until I got to the end of the roller and taped that end in place. Then I trimmed off the ends with a utility blade.

After carefully peeling the tape off the ends, I have my template

Because of the tapers, the template came out to 76" total length.

Just for grins, I measured the taper. This way I won't have to worry about lining up a template on the curly sandpaper and make sure it's all laying flat and tight. I can just cut a 76" length, mark it 10.25" from each end and use a straight edge to cut from each mark back to the corner. I only have to be concerned with the foot or so that I'm working on. Slide the straight edge down to the other end and cut the same angle.

I just need to remember to mark and cut the back of the paper.

Last edited: Apr 24, 2012
2. ### macaroonieFriend of Leo's

Mar 24, 2009
Loch Lomond Scotland
Don't wish to point out the obvious here Mark but you use rolls of abrasive, Stick it on at one end and work on round to the other and trim the excess. Did you have a diferent plan or am I missin something.

M

3. ### GuitarnutFriend of Leo's

Jun 29, 2009
USA
Yep, rolls but cloth backed. The pieces will clip in at either end. Just easier to cut the taper and length first since I have very little clearance on the ends of the roller for trimming. Pre tapered belts are common and available for most sanders.

Of the drum sanders I've looked at, none of them use adhesive. I have a hand-held dual action disc sander and if I leave a sticky back disc on it for a week or two, it can be hellish getting all the pieces and adhesive off. No sense gumming up the drum.

4. ### src9000Poster Extraordinaire

Jul 3, 2010
Albrightsville, PA
I'm In the middle of a similar project. I hadnt thought about pinch rollers. Here's something I picked up regarding adding sandpaper.

http://www.rockslide.org/drum sander.html

MATTING AND SANDPAPER ANGLE*

"The folks at Woodmaster provided me the information for determining the proper angle needed on the ends of the matting and sandpaper. This process will ensure you get the proper angle for the specific size that your drum ends up being after final shaping. Simply take a piece of string and wrap it around the drum. Mark the string at precisely the location where they intersect. With the matting or paper laying on the bench, place the end of the string on a corner of the material and stretch the string out until the mark is at the opposite edge of the material and mark this point. That is the proper angle for your drum. Use a straightedge and utility knife and cut the angle. Then wrap the material around the drum (before taking off the backing in the case of the matting) and mark the other end where it meets the edge of the drum. Cut the same angle on that end and you are ready to install the material. Take your time with the matting because you can't have any bubbles and once it goes on it pretty much ruins it if you try to remove it."

5. ### GuitarnutFriend of Leo's

Jun 29, 2009
USA
Thanks! The project is looking really good. You're farther down the road than me and I see a few ideas I may borrow. I haven't read the entire build but I plan to. Thanks for sharing.

The Woodmaster info is basically what I discovered in my test with paper. The taper length is equal to the circ of the drum. It's really the only angle that works since the paper buckles either side of that angle for any given drum. It just took me a few extra steps to get there.

Thanks again...

6. ### GuitarnutFriend of Leo's

Jun 29, 2009
USA
I got a little bit done last night. I took everything apart and saw that the pass thru holes for the drum axle had a little bit of scorching so I drilled them out to .75" to give the axle a bit more clearance.

Then, I cut a slot in the top of each side so the roller assembly can be removed without taking the rest of the sander apart. I also added a PVC cap. it doesn't do anything other than cover an open slot.

7. ### GuitarnutFriend of Leo's

Jun 29, 2009
USA
Updated Render

Here's an updated look at the design so far. I'm considering several approaches for the height adjustment and the feed table.

8. ### src9000Poster Extraordinaire

Jul 3, 2010
Albrightsville, PA

I'm not much further than you. That link was something I found in my research. I have tested mine with some adhesive sandpaper, as I haven't picked up any of the hook and loop paper or Velcro mat. I did get some snipe and the paper eventually came off. Now I'm thinking of tearing it apart (again) and using flange instead of pillow block bearings and your pinch roller design.

-Steve

9. ### GuitarnutFriend of Leo's

Jun 29, 2009
USA
Ah, it's a good thread for sure. That hook/loop stuff is expensive and I've read opinions that it can cause inconsistent thickness because of the give in the matte. See my post below for my plan on this.

Best of luck with the build.

10. ### GuitarnutFriend of Leo's

Jun 29, 2009
USA

Since we're on the subject, I thought I would do a quick render to show my plan for attaching the paper to the drum.

It's pretty simple. I plan to make clips by cutting sections from the drum and reattach them using screws. Just loosen off the screws, slip the paper under the clip and tighten back down.

I'll make the cuts at an angle so the back of the clip can rotate like a hinge and the so the front of the roller won't have a sharp corner for the paper to bend over.

11. ### WarnzTele-Meister

Dec 31, 2010
France
Simple and effective, it's looking good Mark

12. ### GuitarnutFriend of Leo's

Jun 29, 2009
USA

Good to hear!

Simple is what I excel at. Effective is a lucky bonus most times.

13. ### GuitarnutFriend of Leo's

Jun 29, 2009
USA
Feed Table

I don't know if folks in other towns have this but last Monday was "large trash pickup day". I had a treadmill in the side yard that was ready for the curb but I decided to strip it first. Aside from a plastic cowling that may end up as part of the dust collection, I salvaged the rollers, fan belt and DC motor. I didn't have much hope for the motor since the treadmill quit "milling" last year.

The rollers are, I believe, what they refer to as "live" rollers. Meaning the axle is fixed and the bearing mounted roller rotates on it. The one with the pulley is coated in rubber for traction. The roller without the pulley is threaded thru the axle for tension adjustment. i couldn't have bought a better combo off the shelf...well not for the price anyway.

The motor has a welded mounting bracket with tension adjustment built in. Just mount it on 2 bolts and it swings to tighten the belt. And, it has a finned fly wheel that cools the motor...they're on the back. It also has an integrated pulley.

There are black and red wires that came from the DC voltage supply and 2 others that I'm guessing were from the speed control. I don't know anything about the control system or if the power supply still works... might put a meter on it and see.

Just for grins, I decided to test the motor with a 9V battery. Surprise!!! It works. And, it's whisper quiet...see if you can hear it running in the video.

Looks like I just landed on a power feed system. The ratio of the pulleys is a good starting place, too. I didn't show it in the video but I tested it again with 2 batteries in parallel and it rotated faster. So, my guess is I need about 12-24VDC with an ample amount of current to get enough horsepower that it won't stall. I can adjust the speed with a voltage regulator of some sort.

14. ### WarnzTele-Meister

Dec 31, 2010
France
Nice find, isn't that what they call "the icing on the cake"

15. ### GuitarnutFriend of Leo's

Jun 29, 2009
USA
Yes, and it's yummy!

16. ### GuitarnutFriend of Leo's

Jun 29, 2009
USA
A little more icing on the cake. I did a little research on the controller and found out it's a very common unit found in a lot of treadmills. I was able to determine the voltages and once I get a pot for testing, I'll give it a try. It's power supply and control all in one. It has LEDs that indicate it's status. It may not work since the treadmill was kaputz.

This little diagram on the cowling I saved, makes it pretty clear. The 120VAC line comes from the plug to the breaker, to a harness...the dead-man switch that stops the treadmill when the key is removed... and then to the thermal switch in the motor. From there it goes to the controller where it's connected beside the neutral.

The terminals marker L, W and H are the Lo, Wiper and Hi from the control pot. The motor connections are marked Red + and Black -. The choke, which I'm not using...it weighs about 5 lbs...would be in series with the DC -. It's supposed to suppress interference. It's likely critical with the bio systems and reed switches being used on the treadmill. Not so much with a sander.

I also found out what the other 2 wires on the motor are for. They connect the thermal switch in line with the mains. If the motor overheats, the switch opens and shuts it down. Apparently, it's normally closed since I was able to run the motor without it.

Last edited: Apr 26, 2012
17. ### GuitarnutFriend of Leo's

Jun 29, 2009
USA
The New Feed table

i also did some design work on the feed table. The rollers are odd sizes and needed some extra width here and there to make them work and it all fits within the earlier design of the frame and drum. And, the smaller diameter rollers give me about 2 more inches of usable table length.

The non-drive roller will have tension adjustment on both ends.

Last edited: Apr 26, 2012
18. ### bbmyersTele-Meister

May 15, 2011
NY
I built a ShopNotes drum sander from their plans. It came out looking like this:

The whole story: and the BT3Central Post

Works great. Runs off my table saw. I have a treadmill track motor and electronics that I might someday adapter to it for auto-feed but for now, the crank handle is fine for me. It's almost 6 yrs old now.. Geeze...

Looks like you're on the right "track".

Bb

19. ### GuitarnutFriend of Leo's

Jun 29, 2009
USA
Looks great, Bill. Running 6 years now. That's the true test. Great job!

I love the red. If I paint mine, I'll probably go Team Ridgid orange...that way it will match my planer and ROSS.

20. ### GuitarnutFriend of Leo's

Jun 29, 2009
USA
I got so carried away with making the rollers fit the design, I didn't give much thought to changing the belt...okay, I didn't give it any thought.

The belt I'm using is 100 grit and looks tougher than leather. Since it's only being used as a friction surface and will never see any sanding action, I doubt I'll have to replace it in my lifetime. But, If i do, I can remove the non-drive side pretty easily. Rollers can be replaced fairly easily, too.

Last edited: Apr 26, 2012
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