DIY Thickness sander addition

[TDMpicker]

A new addition to the luthier's workshop. I built a thickness sander to do my instrument top, backs and sides. I need to add the sandpaper to the roll and it will be ready to use. The "spindle" is made of 3/4" MDF disks glued together. The table adjusts up/down to sand off just a wee bit of wood on each pass. Power is a 1/2hp motor. The grey box is a dust hood that the shopvac hose plugs into. Got the planshere.

[fscotte]

Surely there is something easier to use for the spindle?

[Marty Jacobson]

Easier, maybe.. less expensive, no!

[sunburst]

What could be easier than stacking a bunch of MDF discs? ...and what could be more dimensionally stable and more likely to stay round? ...and what would be easier to get round again if it moves a little?

Looks like a pretty good design. I'd be tempted to add a sheet of plywood to the side of the frame opposite the belt to help hold it square when push/pulling wood through the tool. Also, I see the plans call for laminate flooring material on the table. That seems like a good idea to me because tables wear pretty fast right under the drum, where the wood is forced down against the table by the pressure of the drum, and where bits of dust and loose grit from the sandpaper get dragged along with the wood. The laminate is slick and hard, and could be replaced when it wears enough to cause uneven results.

Good job! What is the width capacity? ...and let us know if the 1/2 HP motor is strong enough for sanding wide stock.

[Pete Jenner]

What could be easier than stacking a bunch of MDF discs? ...and what could be more dimensionally stable and more likely to stay round? ...and what would be easier to get round again if it moves a little?

I hope these questions are rhetorical.

Nice looking machine Terry. Can you send it to me for testing?

[sunburst]

I hope these questions are rhetorical.

Not exactly rhetorical, if there is something cheaper, easier, more stable, and more repairable, I'd like to know about it, because I can't think of anything.

[Pete Jenner]

No there isn't.

[TDMpicker]

The drum is 22" wide. Big enough for guitar tops. I may add a laminate to the table if it starts to wear. Some people use 1/4" ply disks. If a person had a lathe you could turn the drum down out of solid wood. It's easy to turn the drum/true it by using sandpaper on a sheet of 3/4" ply and pushing against the raw disks.

[sunburst]

If a person had a lathe you could turn the drum down out of solid wood.

Yes, but it wouldn't stay round. Actually, stacked plywood doesn't stay particularly round, at least not in my experience, having turned sanding drums from glued-up blocks of solid wood and from stacked plywood. I think MDF is probably the best choice, short of expensive and difficult alternatives.
Take my word for it, the table will start to wear, and if you wait until it wears too much, there will be a "trench" under the added laminate so the support will not be as solid as if would be with the laminate added before the table wears. (The metal table of the shop-built thickness sander at the shop where I once worked had a considerable trench under the drum. I attributed it to people adjusting the table too close to the drum and letting the sandpaper dig into the table, but eventually I figured out that it was simply wear from normal use, mostly making veneers.)

[fscotte]

At first thought I was thinking a PVC pipe of some sort, but then you'd have to have them capped at the end for the bolts. Or you could try metal pipes of various sizes. Not really that expensive. Think like a plumber. Maybe conveyor rollers? And antique shops are loaded with old, well made rollers mounted on various devices.

[Jim Adwell]

At first thought I was thinking a PVC pipe of some sort, but then you'd have to have them capped at the end for the bolts. Or you could try metal pipes of various sizes. Not really that expensive. Think like a plumber. Maybe conveyor rollers? And antique shops are loaded with old, well made rollers mounted on various devices.

I've actually made a sander with an 8" diameter conveyor roller, and yes it works very well. Mine had a 3/4 hp motor driving the sanding drum, and a feed system made with smaller conveyor rollers, with a 1/2 hp motor driving that through a variable speed gear box, also from the same defunct conveyor system. Overkill, but fun to make. It's long gone now, though.

[Master of None]

Looks vaguely familiar, Terry! I built mine a few year back and it works great for me. (Mine has a, way overkill, 2 HP motor -but only because that was the first inexpensive motor that came up on Craigslist.) I'm surprise at the number of unexpected ways I've used this. I even used it thickness a bone nut the other day. And I definitely like the amount of $$ it cost to build.

[pianoman89]

Very nice! I will definitely utilize your planes when I have a shop! But why not use PVC pipe with MDF caps? It could even be filled with something to keep it true to the axle. Did you decide not to use this for any reason? Perhaps distortion due to heat? If you considered PVC and decided against it for some reason, please explain so I dont screw up when I build mine and regret my lack of insight lol.

I love these DIY projects that make thousand dollar pieces of equipment affordable to us broke folk!

[TDMpicker]

Looks vaguely familiar, Terry! I built mine a few year back and it works great for me.

Looks like a nice machine. Where do you get your sandpaper rolls?
I made the roller out of MDF because thats what the plan suggested. Also the original designer used MDF and if it has worked for him I did not see a reason to deviate.

[Master of None]

Where do you get your sandpaper rolls?

I was given a bulk quantity of surplus, large belt sander rolls. The 120 grit is 2" x 32", so conveniently can be cut to make a long strip to tightly spiral around the roller. Somewhat less convenient is the 80 grit. It is about 36" width, so I have a bit more work cutting that into 2" wide strips to wrap around. But again -the price was right.

I also used MDF for the roller and haven't had any problem with that yet. I secure the sand paper ends down by a screw tightening down a wedge. I had made that wedge out of MDF as well, but found that part not holding up well. One of these days will replace with something a bit more robust.

[Fred Young]

I've never found regular PVC pipe to be perfectly round.

[TDMpicker]

Update on the thickness sander. Seems to work great. Have done a rosewood back and sides for a dreadnought guitar.

[Michael Lewis]

Terry, what is the reason there is a gap in the 'popsicle' brace? the reason I ask is that is a stress area, and when it fails is difficult to repair. Much easier to prevent.

[TDMpicker]

Terry, what is the reason there is a gap in the 'popsicle' brace? the reason I ask is that is a stress area, and when it fails is difficult to repair. Much easier to prevent.

The plans I am using show the head block depth of 2" which extends into the area where the popsicle brace would cross. I am going to add add an additional patch between the back of the head block and first cross brace.