I hope this is going to turn into a 9" wide thickness sander
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Author:  MaineGeezer [ Fri Apr 08, 2016 11:31 pm ]
Post subject:  I hope this is going to turn into a 9" wide thickness sander

I decided a thickness sander would be a handy thing to have. Ideally, one about 18" wide that can do an entire guitar top or back would be the way to go. Unfortunately, sanders that big cost over a thousand dollars, a bit too much for me. I looked at the Byrnes miniature thickness sander. It costs $350 and can handle stock up to 6" wide. It would do for a lot of things, but it's small. After looking at the Byrnes and at online plans for building a thickness sander, I decided it was feasible. I'm going to build one that can sand up to 9" wide. That capacity will handle guitar sides, half a guitar top or back, or an entire dulcimer top or back.

"Cheap" is a major requirement, which is one reason I'm not building one 18" wide. After digging through my 40 years accumulation of jun.... er, "surplus raw materials," I've manged to come up with a design that should get me a 9" wide sander for about $150.

The sander will sit on top of my table saw and driven by the table saw motor. I'll replace the blade with a pulley and a belt coming up to the sanding drum shaft. That will save the cost of a motor. It will also slightly decrease the materials requirements.

Here's a photo of the base. The two sort-of-I-beam aluminum extrusions were shipping brackets of some kind for one of Digital Equipment Corp's VAX computers, I think. I've hauled them around for at least 25 years. I'm glad I finally found something I can use them for. The milky white plastic plate attached to them is left over from some other project I had, now forgotten. The rest of the sander will sit on top of that. The slab of aluminum sitting on top will become the uprights and hold the shaft bearings. I bought that a couple of years ago for a project that never happened.

I sure hope it works.

Author:  Diane Kauffmds [ Sat Apr 09, 2016 6:23 am ]
Post subject:  Re: I hope this is going to turn into a 9" wide thickness sa

I hope it works well. Thickness sanders are very expensive.

Author:  MaineGeezer [ Sun Apr 10, 2016 6:12 am ]
Post subject:  Uprights in place.

The uprights need to get bored out 1.625" diameter to accept the shaft bearings.

The sanding drum will be 3" in diameter, with a circumference of 9.42". The Plan is to use a standard sheet of 9" x 11' sandpaper on the surface of the drum. I probably could have made the drum 3.25" diameter (10.21" circumference) but the cost of materials would have gone up significantly for the increased diameter, with little gain in performance.

Or I may wind a narrow strip around the drum in a helix, as is done with commercial sanders. I haven't made a final decision yet.

Author:  MaineGeezer [ Sun Apr 17, 2016 3:17 pm ]
Post subject:  It works, mostly

I've got to the point that it's usable. It works fairly well. The biggest problem is uneven thickness. Since the stock is fed through by hand, rate of feed is variable, and that produces variation in how much gets sanded off at any one spot. Multiple passes help reduce the unevenness. A power feed may be in the works, if I get sufficiently inspired.

Here's a photo of the assembled unit with one of the covers removed to show the drum. I didn't cut the angle on the end of the strip of sandpaper quite right, so there are gaps. I have since made a pattern that I think is correct, so I ought to be able to cut the next strip and get more complete coverage of the drum.

A belt guard, and a proper-sized belt, are on the list.

I made this so it runs off the motor on my table saw, but now that I've confirmed that it works I may see about building a base and giving it its own motor.

Author:  MaineGeezer [ Tue Apr 19, 2016 6:21 am ]
Post subject:  Difficult to get a truly flat surface

I'm finding that it is very difficult to get a uniformly flat surface. Because it's hand fed, there is some amount of variation in the feed rate, and that produces variation in sanding depth. With really coarse sandpaper (e.g. #80) it's quite pronounced.

I may see about coming up with some sort of power feed, but some of the design aspects of the sander interfere. We'll see.

Author:  tippie53 [ Tue Apr 19, 2016 6:42 am ]
Post subject:  Re: I hope this is going to turn into a 9" wide thickness sa

what grit are you using.
May I suggest 2 rollers to help hold the work down. A spring mounted rolling pin may work

Author:  MaineGeezer [ Tue Apr 19, 2016 8:27 am ]
Post subject:  Re: I hope this is going to turn into a 9" wide thickness sa

I've tried #80 and #120. The 80 was quite aggressive.

I was wondering about some pressure rollers. As you suggest, something spring loaded.

One problem that I need to fix is that the part the work slides on tends to flex a bit. (The black slab in the photos.) It's some variety of plastic, 1/2" thick. I thought it would stiff enough, but it's not. I may add something to stiffen it up, like a piece of aluminum angle across its width, or replace the whole thing with a piece of aluminum plate.

Author:  tippie53 [ Tue Apr 19, 2016 8:44 am ]
Post subject:  Re: I hope this is going to turn into a 9" wide thickness sa

You can make a lot of ways to do this.
having something to help hold it down is key also you can try making a sled. that way the sled pulls it through rather than getting pushed and having it bind up.

Author:  MaineGeezer [ Fri Nov 08, 2019 8:59 pm ]
Post subject:  Re: I hope this is going to turn into a 9" wide thickness sa

Update, a couple of years later.

I gave up on the idea of drivng it with the table saw motror. A friend of mine was happy to give me a suitable motor as a way of getting rid of some of his collection of STUFF, and I built a simple wooden stand for the sander.

I've gotten a lot better at feeding at a uniform speed so I get a uniform thickness. A piece can still end up a bit wavy, but generally I do well enough so it's not noticeable, or hand sanding with a sanding block takes care of it.

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