Drum sander grits

[Kansas City Fireslayer]

Tell me your drum sander grit preferences for different types of work you do. I recently purchased a lightly used, 6 y/o, Supermax 37x2 dual drum and dual post sander. It has 80/120 on it and boy will it leave some scratches. Nonetheless, it’s a beast with the true 5 HP Lesson.

[cvillewood]

I’m still figuring out my drum sander, but I just switched from 80 to 120 and it’s made a huge difference is the depth of scratches (which of course it should). No big difference in the amount of material it will take off either, but I also discovered the feed rate adjustment which makes the biggest difference. I smacked myself when I finally started adjust the feed rate! Makes a huge difference.

I’ve got a craftsman version of the Grizzly G0458.

[CARYinWA]

Tell me your drum sander grit preferences for different types of work you do.  I recently purchased a lightly used, 6 y/o, Supermax 37x2 dual drum and dual post sander.  It has 80/120 on it and boy will it leave some scratches.  Nonetheless, it’s a beast with the true 5 HP Lesson.

I just leave 120 on mine all the time.

[ez-duzit]

...boy will it leave some scratches...

Gotta expect a few losses in a big operation.

[jteneyck]

Tell me your drum sander grit preferences for different types of work you do.  I recently purchased a lightly used, 6 y/o, Supermax 37x2 dual drum and dual post sander.  It has 80/120 on it and boy will it leave some scratches.  Nonetheless, it’s a beast with the true 5 HP Lesson.

When I had a single drum sander I settled on 120 grit as best for my needs.  150 grit burned too easily and 80 or 100 grit left scratches too deep.  Last year I moved up to a dual drum sander and the guy I bought it from had 100 on the front and 150 on the back drum, and a roll of both, too.  I thought it was great, but I'm finding (again) that the 150 grit burns too easily so I'm going to 80 grit on the front and 120 on the back.  I also changed to alumina zirconia sanding media from pure alumina to get longer life, hopefully.  

Interestingly, the scratches left by the new dual drum sander are much less noticeable than from the old single drum unit, even when running the same grit.  I don't know why that is, but your comment got me thinking about it.  As others mentioned, try adjusting the speed, if you can, to see if that has an effect.  Another thing I've noticed is both machines leave almost invisible scallops in the finished surface, as if the drum is slightly out of round or out of balance.  You can see them when you hold the board up to raking light.  Fortunately, they are easily removed by the ROS.  Overall, my drum sander is a huge time saver but, like most everything, you have to recognize its limitations and adapt to them to get the most out of it.

John

[Kansas City Fireslayer]

Thanks for the comments so far. I am still learning about this machine to say the least. I am probably feeding the stock slower than what I need. Most likely because all the reading I’ve done on feeding too fast. I’m sure I can speed it up some but I’m also shy of trying to remove too much on one pass.

I used the DS with the 80/120 on the backside of a FF last week to flatten any twist it may of had. There was no way I was going to run the nearly perfect and already relatively smooth front of the FF through it. The ROS starting with 150 made very quick and easy work of it. If I was doing multiples I’d guess I wouldn’t want anything lower than 100-120 on the front drum. I’m curious if I’ll get the same burning as others running 150 on the back. I know burning is caused by the excessive heat. Won’t an increased feed rate, lighter pass, and skewed feed help remedy this? I’m hoping the bigger motor will help make 150 grit on the rear drum a possibility for anything not needing much thickness removed.

Also, any recommendations on where to buy the paper? I’ve used 2sand.com in the past and really like their Rhyno brand for the money. I have two boxes of Jet paper now but I can’t imagine it’s the best value paper out there given their brand is on it.

[WaterlooMarc]

I pretty new to the game with my Supermax but so far have kept 80 on it and it’s too coarse. It takes way too long to sand out the lines left by the DS. But I’m cheap so I’m using the rest of what I have. I’m surprised at how quickly it will remove stock. I think 120 with me a happy landing point for me personally.

I bought strips from Supergrit and cut my own.

[jteneyck]

Also, any recommendations on where to buy the paper?  I’ve used 2sand.com in the past and really like their Rhyno brand for the money.  I have two boxes of Jet paper now but I can’t imagine it’s the best value paper out there given their brand is on it.

I'm using Klingspore sanding media now, but the Al-Zr stuff I just bought I got on Amazon from Red Label Abrasives.  No clue yet if it's good, but it was substantially cheaper than Klingspore's version.  

John

[HawkeyeStoob]

I recently picked up a new to me Supermax 25X2 and also have been playing with the grits on the drums. I grabbed an assortment of papers from http://www.industrialabrasives.com/ and now have 60, 80, 100 and 120. The prices are very good even with shipping and the paper seems to be as good as anything I have run on my 16/32.

[Ken Vick]

I think that 80 and 120 are just about perfect.  150 is too prone to burning especially with maple and cherry.  If you are careful, you can get several months use between changing the sanding belts.  And if you are anything like me, you hate changing the belts.  I am curious about the scratches.  While, my sanded surfaces are not perfect, the scratches from the drum sander come out easily with a normal progression of grits with a ROS--150-180-220 for me.  Ken