Best grit for belt disc sander?

[Guest]

What do you guys recommend for grits for a 6x48" belt and a 12" disc sander? I was thinking 120 for both but I'm mostly interested in general purpose. Not really sure exactly if I'll be doing more de-burring or finish grinding, etc.

[JRouche]

60-disc
80-belt
Watch yer knuckles, they will disappear.
JR

[Bob Fisher]

120 seems a bit too smoth to me , I like JR's recommendation, although 60 on both would work for me. Bob

[LKeithR]

...Watch yer knuckles, they will disappear...

I can vouch for that. Let the gap between the table and the belt get a little too wide and, in a moment of stupidity,
I let the piece I was sanding flip up and get sucked into the gap. Took my thumb with it. Stalled the sander and blew
the breaker. Took off most of the nail and the flesh off the knuckle--almost to the bone so flesh only. That was in
October and I'm still healing. Sorry, no pics I wasn't thinking of them at that moment.

As to belts, we use nothing but 36 grit blue zirconia. Anything else is a waste of time. Even 50 grit gets flat pretty
quick and 80s or 120s don't do anything even when new--the 36 grit will really remove material. We always keep a couple
of used belts around for those times when we want to put a finer finish on something...

[dian]

36 for shaping. 120 is almost polishing territory. that is if you use correct speed (fast enough).

[Tundra Twin Track]

On my 24"DD Disc grinder I use 60 Zarconia on one side the other is 150 oxide.when I reorder will not get oxide again but will get 60&120 Zarconia

[Paul Alciatore]

Sooner or later you will need several grits, but for starters I would recommend 80 or 100 grit. You will be surprised at how smooth of a finish those will produce on it, not at all like using them by hand. And they will work fast so go light at first.

And a few drops of oil in them will give an even better finish without changing belts or disks.

[projectnut]

60-disc
80-belt
Watch yer knuckles, they will disappear.
JR

Same here. Been using this combination for over 30 years.

[engineerd3d]

I have been looking into this. I am thinking of a 2"x24" belt and am wondering about surface speed. What is fast enough? That would dictate pulley size.

[MattiJ]

I have been looking into this. I am thinking of a 2"x24" belt and am wondering about surface speed. What is fast enough? That would dictate pulley size.

Depends on your goals. Slight deburring or serious material removal.
For serious material removal 6000 to 8000 feet per min and 2 HP.

[epicfail48]

Odd man out, i vote 120. Works fine for general deburring and light shaping, i.e smoothing a curve thats already been rough cut, and still leaves a decent finish

[Wheels17]

It figures this would come up a week late!! I just got a 6x48 belt/ 9" disk 3/4hp belt drive cast iron Craftsman at an on-line auction for $30 two weeks ago, I wasn't sure what belts to get, and ordered 60 grit and 120 grit belts a week ago. I was using the 60 grit today and it seems pretty good.

It was a good auction n for buyers. Jet #3 arbor press for $25.50 as well. Many items didn't get a single offer.

[Joel]

It depends on what you are doing. I run coarse on the disk and fine on the belt. A finer grit can still be reasonably aggressive with a belt sander. The belt isn't hard to swap so it is easy enough to switch it out when the need arises.

[wdtom44]

I usually get 40 or 50 grit and use a worn one if I want a finer finish. But it depends on what you are doing and if you are trying to get a nice finish or just remove material. I am somewhere in the middle.

[platypus2020]

all I use is a 50 grit ceramic grit belt