A few years ago I built a rim sander ala Proulx and McKnight. It is essentially a shaft that protrudes above the surface and had a set of "dogs" that spun a radius dish which sat on a lazy susan bearing. I use my rim sander a lot as I make radius dishes on the cnc and use the rim sander to finish sand the dishes. So I didn't really like the lazy susan bearing, it was load and they wear out fairly quickly in the high dust environment I was exposing them to. So I removed the lazy susan bearing and had the 5/8" shaft welded to an 18" diametre 1/2" steel plate and then placed 4 cup bearings to support the edge. I felt better about that but the machinist couldn't really get my centre hole bang on and that bothered me. Also, I felt that the cup bearings were only marginally better than the lazy susan bearing. Then Brad Way posted the nice sander he made and I have been lusting after it ever since! So I finally bit the bullet and just started all over again and now have something I think that will last me some time! Now this is not your inexpensive version by a long shot, but as I said I use it a lot and I wanted it accurate. So the heart of the project was the plate that I had made up in a machine shop. It cost me $675 to have this made
, but it is robust and true! Here it is:Attachment:
the disc.jpg
The centre pops out if I ever want to remove the pin (I can't see needing to do that but just in case.....)
This heavy steel disc just sits on the shaft of 15:1 reduction gear powered by a 1/2 hp 1750 rpm washing machine motor.
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the inards.jpg
The reduction gear and motor are inside an mdf box which is on wheels so I can move the unit around very easily.
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overview.jpg
The top of the box is a double laminated piece of mdf, 24" by 32".
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tops on.jpg
The steel disc fits on the reduction gear shaft through the hole in the mdf top and just sits there by gravity.
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disc on.jpg
The last picture is with one of my laminated radius dishes (without sandpaper) and shows the area of the top of the box around the dish.
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dish on.jpg
So I still have to mount the door in the front of the motor cover and I will also be moving my go bar deck right on to the rim sander. That is the reason the top is the size it is. I have also begun making guitar moulds and forms and this rim sander will be outfitted with posts that will limit how far I can lower a set of sides onto a dish while they are still in the mould. This will make getting side width for each guitar a thoughtless and accurate process. I will post on that part later when I get it done. So this sander turns at 117 rpm, just about right! The "A" type belt is sitting on 3" pulleys with a one to one power ratio. I can't stop this sander by hand, it is very smooth and much quieter than my other sander. Not only that but it has a smaller footprint and is much more maneuverable with the larger wheels. I was concerned that it would try and roll around on it's own but it is pretty heavy and just feels solid! Total cost is probably about $1000. But that is what you would pay for any other good tool.
Anyway, just more ideas for the 'ole library in case anyone else is thinking about something like this. It could be done for a fair bit cheaper using ebay and if you know a good machinist with a large lathe.
Thanks
Shane
). When I am finish sanding radius dishes there is indeed more dust but it is not easily collected and it is MDF so it is heavy and usually says on the dish as well. I have tried dust ports on my last sander and none were that effective. The steel disc is steel.....It weighs probably 40 pounds or so. That just makes the unit nice and stable. A person could build these indeed for a fraction of the cost. My first one still works fine (and will be living at friends house now) and it was probably less than 1/2 the cost of this and still has a steel plate rather than dogs. The dogged version was probably in the $200 range to build.![[clap]](./images/smilies/smiley32.gif "adulations")