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For those of you with thickness sanders, and especially for those who have a variable rate of feed speed, what speed do you use for general sanding tasks (back & sides, tops, etc.)?

I notice that Delta and Performax both have adjustable rates for the feed, between 0 and 12 SFPM. Maybe a better question is: If you had to choose a single feed speed and live with it for everything from Western Red Cedar to Koa to curly Maple to resinous Cocobolo, what single speed would you choose?

I am making a thickness sander, and I am trying to decide on the pulley configuration to achieve the "ideal/compromise" feed speed, if only I knew what to shoot for...

Thanks in advance!

Dennis

{edit} If it would affect your decision, the sanding drum will be spinning at about 2200 SFPM (about the same as the Performax 16-32, and about the same as the slower of the 2 drum speeds of the Delta X5.)DennisLeahy38666.9581597222

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Dennis Leahy
Duluth, MN, USA
7th Sense Multimedia

Dennis, just to get your discussion going, I'll way in. I have a General International double drum sander, for top sets I was running 80 and 120 grit but have just recently switched to 60 and 80 grit to do the rosewood I just got in. My speed rate stays at about 11 to 12 sfpm. My machine adjusts up to 16 I think. I adjust the thickness of the passes. Drum sanders are better classed as "finishing" sanders rather than "thickness" sanders although we all use them to thickness. You really do want to keep the feed rate up to reduce over heating on the wood surface that will transfer to the drum. Cumpiano took a plan for a drum sander and added another roller higher up and made it a widebelt sander. If I was building one that is also what I do, much better results me thinks!

Shane

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Canada

Thanks, Shane. That helps.

I have heard the same things for resinous woods: lower grits, thinner passes, and faster feed rates. I know you sand plenty of Spruce/Lutzii, so knowing that you keep the feed rate the same for softwoods is helpful.

As for your good suggestion to go wide belt rather than drum, I am convinced that the belts would last longer, but I have already exceeded my budget, and the additional drum (initial cost) plus the wide-belt sanding belts higher cost are too much over budget for this hobbyist-level, wannabee luthier.

I'll try light passes, running at a slight angle for the initial passes on resinous woods, and I'm going to use hook-and-loop on the drum and sandpaper to try to keep the surface friction heat down.

Dennis

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Dennis Leahy
Duluth, MN, USA
7th Sense Multimedia

Dennis,
I have the Delta and light passes at full throttle work best for me. Also sanding across the grain helps. I usually use 60-80 grit then scrape to remove the sanding marks.

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Jim Watts
http://jameswattsguitars.com

Dennis, I also keep the feed belt set at max speed on my Delta sander. I usually use an 80 grit belt foe everything, cause I'm too lazy to change it very often.

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Dave Rector
Rector Guitars

Thanks, Jim and Dave. Sounds like a consensus to build my drum sander with feed rollers that spin at around 12 SFPM.

I have been exposed to more than I wanted to know about pulley OD vs. pulley pitch, belt geometry and characteristics, minimum pulley pitches for each belt type, jackshafts, idlers, and pulley speed reduction. Whew! It does deepen my respect for mechanical engineers!

Dennis

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Dennis Leahy
Duluth, MN, USA
7th Sense Multimedia

Just to add to this, I have a Performax 16-32, and I almost always run my wood through with the feed rate cranked all the way up. Seldom do I ever take any more than a quarter turn of the crank (about 0.016") off at a time, and usually, especially with hard woods, I do only an eighth turn at a time once the drum is making even contact across the board.

I have also found that a coarser paper on the drum handles the more resinous woods better because it doesn't load up as easily. Right now I'm using 80 grit. Of course, the drawback to using a coarser paper is that it leaves deeper scratch lines in the wood, which then have to be sanded or scraped out.

Best,

Michael

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