Official Luthiers Forum!

I bought a Delta drum sander yesterday as a complement to the Hausmann(Grizzly) I have. Seems to be a much better unit. Larger drum (more paper), easier paper changes, and very quiet, which surprised me. I think I'll use it as the finish sander, and the Grizzly as the rough stock machine. So, to my question...

What grit do you usually start with for knocking down rough back and side sets? I have a roll of 36, but that seems pretty brutal. I was wondering if 60 grit rough thicknesses on Machine A followed by 120 on Machine B seems reasonable. What do you folks use?

Thanks

Ed

60 is great for anything that might gum up the paper Ed. It does leave pretty deep marks though. Make sure you leave enough meat to get rid of them. 80 is good for woods that are easier to sand and I use 120 of final machine thicknessing of top once the rosette is in.

Good to see you're out of the closet and using your real name now. I guess I missed my chance for a tour eh? I need to get out more. I might be around during Christmas. Grad dress shopping.......... not for me. I think I may have some free time. In fact probably most of the time we're there. I'll let you know. We can go kick some tires at PJ White or something.

Cheerio,
Danny

I don't use over 80 in fact I use 36 to rough , 60 to .010 to size and then 80. The finer the grit the more heat. This is a thickness sander not a finish sander. Once you start getting heat you will glaze the paper and thus glaze the paper with the resin and sap.

_________________
John Hall
blues creek guitars
Authorized CF Martin Repair
Co President of ASIA
You Don't know what you don't know until you know it

I stick with cloth-backed 80 grit. I am using Klingspor now and liking it.

Bob

I'm an 80 grit guy too, but 60 wouldn't scare me, just don't have it laying around.

We tried out 36 grit, and it seemed pretty ok. Barbaric for certain though. I'm going to look into some decent 50 grit, if such thing exists. We did manage to bust a set of over thick sides (1/4") to final thickness in about a half hour. I can live with that, I guess. Sure miss the TimeSaver....
But with one machine loaded with 50 and another with 120, we'll just have to limp along til we can afford our own 80,000$ machine.

I use 80 grit to "rough plane". Then 150 or 220. Go slow.

I use 36 and 80. I've got some 120, but haven't tried it -next top probably. I have ruined some things by not leaving enough thickness to get the marks from the 36 out.

_________________
Mike Lindstrom

I've used only 80 grit on my drum sander. If I had two to work with, I think I would go as you suggested - 80 to begin with and 120 to finish. Right now, I follow my thickness sanding with 120 and 220 on my random orbital sander.

I use 80 to rough almost everything, then clean up the 80 scratches with some 150. After that it is random orbit or hand sanding with a block. You should look around until you find a paper you like and then try and stick with it. Right now I've got 80 grit from 2 different suppliers and there is a huge difference in how corse the paper is. I usually keep a little 60 around in case I need to thin out something that is really thick, but if that is the case I try and plane or saw of the excess rather than take it off with the sander. Right now I've only got a 16-32 Performax, but it works good.

Josh

_________________
Josh House

Canadian Luthier Supply
http://www.canadianluthiersupply.com
https://www.facebook.com/canadianluthiersupply?ref=hl
House Guitars - Custom Built Acoustic Instruments.
http://www.houseguitars.com

60 grit 16-32 performax 80 grit 38n woodmaster followed by flat scraping Finish sanding on the instrument to 320 before finishing

Thanks folks...

60 grit on a Performax 16-32 works best for me. 36 leaves some deep scratches and doesn't seem to take much more wood per pass than 60.

on a drum sander anything over 100 is going to build up too much heat. As a machinist and toolmaker , the goal is heat control. when you machine something , you create heat. How that heat is controlled is the key. The finer the abrasive ,the more heat . You can feel the work warming up. To control heat , you learn to "read the chip"
The finer the grit the faster you want to feed , the slower you go the more heat and that can ruin the work and glaze a belt. A thickness sander is not a finish tool. If you do want to use if that way take very fine cuts of just a few thousandths and feed fast. Most posters seem to have found that 80 is about as fine as you need. 36 and 60 grit are good for roughing down 80 is the final for me.

_________________
John Hall
blues creek guitars
Authorized CF Martin Repair
Co President of ASIA
You Don't know what you don't know until you know it

I use to use 120 grit all the time. I switch to 80 and realized that was much better.

_________________
Another day, another dollar.

I think it depends on the individual. I am the opposite of Shaw above. I used 80 and now use 120 exclusively. I see he is a pro, and I am an amateur. He needs to optimize shop time, and I can afford to take small incremental passes. After the drum sander, it is all hand sanding for me, so I appreciate the smaller scratches. I'd advise trying several grits and see what works best for your style of working,
Mike

I use 100 grit most of time. My sander came with several rolls of 220 from the previous owner. 220 worked well on cherry sides and backs. Not really worth the trouble of changing papers for occasional use.

On my current build, I thicknessed the rosewood with 80 and the spruce with 80 till the last 0.3 or so, when I switched to 120.

Supermax 19-38 here. I usually use 80 grit if there isn't much material to remove, or I would use 60 grit. Usually taking about 5-10 thousands per pass feeding at a medium speed. I finish up with a few light passes of 120 to remove the 60 or 80 grit marks. I like to finish with 120 because it saves some time hand sanding before finishing and I get closer to the final thickness I want to achieve.

Never having used a thickness sander what happens to any loose grit? Does some of it become embedded in the wood?

I've never had any issues with loose grit. An adequate dust collection system (which is absolutely necessary) would suck up any loose grit. I do on occasion get scratches deeper than the grit being used which shows up as a single deep straight line. This is another reason why I like to finish with 120. I want to have as little removal of wood as possible when final sanding.

Have a look with magnification. You are unlikely to see it with the naked eye, that's if it does embed.