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Project Information

I have been hankering for a 20" disc sander to flatten big segmented bowl rings for glue up. A long continous streak of not winning the lottery (maybe I should buy a ticket) had reduced my options to the home grown version.

Some leftover MDF, a hunk of rock maple, tap the maple and add a 20" sanding disc ($14 on Amazon)

Problem #1: I need to either raise the lathe or make the maple longer to exted over the edge of the table without sliding the lathe all the way to the edge.

Problem #2: I need to make the face of the maple block more carefully, or use something other than MDF, not sure which but it has the slightest wobble.

Wiley Coyote moment: Disc is so big that in order to get the tool rest against the edge to finish the edge of the disc I had to reverse the lathe. Turned the lathe on, it flashed it's warning and instead of turning the disc it simply unscrewed the tapped maple. In what appeared to be slow motion the disc bounced once and karate chopped my shin. No permanent harm to disc or shin.

Jake

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Comments

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Nice disc. I hate it when I throw mine into revers and forget to tighten the setscrew!
 

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Love this idea. A friend of mine uses what he calls a "bump sander" in his guitar shop - which is basically a giant belt sander turned on it's side with a perpendicular table to it. I've coveted this for some time and can use it anytime I want, but I like your solution for some in shop power-sanding. Sometimes that's just the best solution. Perhaps instead of threading a maple block, you could use a lathe chuck meant to hold bowl blanks. Or even a lathe plate with tapped threads for bolts. Just a thought. I'll try this method on my version and see what happens!
 

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Nicely done - just need a table of some sort in front.

Seen others make one just to the limits of the spindle to bed distance (often only 14-16 inches, and have a platform that mounts on the bed rails.
 

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Drbyte, thanks. At least as far as accidents go this one is more funny than scary.

Dinger, yep Agree about the face plate. For my $14 I got two discs so version two is likely to use a face plate into bigger maple cone to increase glue joint and increase distance from lathe. Probably also will give plywood a shot over MDF if that all sounds reasonable.

If you look closely at maple block you can see "Burn" crossed out and "save" scrawled on it. I am in process on a drum sander with the lathe and had made the maple to insert in some pvc but didn't think it through so well. I was happy to reuse the mistake but agree completely that threaded maple isn't the long term solution.

DrDirt, I am thinking the lathe table needs a redo, maybe with a swing out of the way table for the sander? Or something on dowels that can fit in hopefully well located holes? Someone must have already done this?
 

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My experience with large diameter sanders is that the speed at the outside edge tends to burn almost anything it touches also , you will have to decide for yourself whether it is worn the risk to use to after you find out how plain dangerous large discs are.
 

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My experience with large diameter sanders is that the speed at the outside edge tends to burn almost anything it touches also , you will have to decide for yourself whether it is worn the risk to use to after you find out how plain dangerous large discs are.

- exelectrician
There is I think an opportunity here because it is on the lathe, where you can control the speed. So it wont be a 20 inch disk spinning at 3600 RPM.
 

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I did briefly attempt to calculate the speed at edge with the lathe at max 3500 rpm but quickly realized the answer was well into the scary range. I have seen many videos of segments being sanded on a big powermatic or similar and thought "what a mess it is going to make if he slips."

For the limited use so far I have found 400rpm to be nice and comfortable. Now I am going out to the garage to find those oyster shucking gloves ;-)
 

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Excellent disc sander, home built. Thanks for sharing
 
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