Disc sander grit

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Forum topic by deadherring posted 09-28-2016 02:05 AM 889 views 0 times favorited 13 replies Add to Favorites Watch
View deadherring's profile


68 posts in 1793 days

09-28-2016 02:05 AM


I recently purchased my first disc sander, the “12 from harbor freight

In all of the videos involving a disc sander I’ve seen on youtube, the material seems to be removed very quickly/aggressively, which is why I got it, however on mine it seems to be the opposite—it seems like very little material is removed even if I push with some force on the workpiece into the sander.

I’m wondering if it might be because the grit on the sandpaper is much higher than what most people use so it doesnt remove much material? I’ve never changed the sandpaper on a disc sander before and in looking at it, I don’t see a way to tell what grit is on it.

What grit is recommended if I’m looking for the aggressive material removal you see on youtube videos? Is that likely the issue? And what’s recommended to remove it? I’ve seen some people use a heat gun?



13 replies so far

View DirtyMike's profile


637 posts in 1051 days

#1 posted 09-28-2016 02:08 AM

Ae you using harbor freight sanding disc? If so there could be your problem. I like 100 grit on a big disc sander, the powertec brand on amazon is really swell.

View bigblockyeti's profile


5230 posts in 1870 days

#2 posted 09-28-2016 02:36 AM

I have a 12” JET combination machine that runs at ~1800rpm and I typically have either 80 or more frequently 120 grit on it. I can’t remember the brand name of the discs off hand, but either will remove stock very quickly with the 80 being faster and leaving a slightly rougher finish. Even a well worn 120 grit disc will still go through quite a bit of stock fairly quickly. One of the keys to making any abrasive last a long time is keeping it clean. I keep a big eraser by the machine made specifically for cleaning belts/discs/drums on powered sanding machines and it works great. Another key to long abrasive life is to avoid overheating, too much pressure on a dirty disc can burn the junk that’s already stuck to the disc to the point that it’s almost guaranteed to never come off.

-- "Lack of effort will result in failure with amazing predictability" - Me

View deadherring's profile


68 posts in 1793 days

#3 posted 09-28-2016 02:50 AM


Yes, I’m using the stock sanding disc that came on the unit from harbor freight. I’m going to order the powertec brand.

Any advice on how to remove the old disc? Heat gun?


View jumbojack's profile


1685 posts in 2774 days

#4 posted 09-28-2016 03:25 AM

I have a Shopsmith for sanding. I also have three discs. One is 80 grit, one 120 and one 180 that I use to sharpen chisels.

-- Made in America, with American made tools....Shopsmith

View distrbd's profile


2252 posts in 2596 days

#5 posted 09-28-2016 03:26 AM

I have a similar 12” disc sander, tried both 80 grit and 120 Grit( hook and loop kit) which is on it right now but when the time comes to replace it I’ll go back to 80 Grit, as others mentioned, the sandpaper quality is also very important, Klingspor is what I use and highly recommend.
Don’t forget to order a cleaning stick.

-- Ken from Ontario, Canada

View patron's profile


13630 posts in 3490 days

#6 posted 09-28-2016 03:31 AM

take off the table
dribble some lacquer thinner down between
the paper and the disk
as you peel the old disk off

wash the gummed up glue from disk
add new disk
replace table and square up again

i use 80grit paper

don’t force the work
let the sander work the job as it does

pushing to much only burns the work
and clogs the paper

-- david - only thru kindness can this world be whole . If we don't succeed we run the risk of failure. Dan Quayle

View Planeman40's profile


1257 posts in 2910 days

#7 posted 09-28-2016 03:03 PM

For years I have used floor mounted belt and disk sanders. I generally install a relatively rough sanding belt or disk and I am careful in using it for a while until it gets somewhat worn. By then it’s just right for most applications and stays that way for a good while. Works for me.


-- Always remember: It is a mathematical certainty that half the people in this country are below average in intelligence!

View greenacres2's profile


328 posts in 2317 days

#8 posted 09-28-2016 06:16 PM

I go between 80 and 100 on my 9” combo. No matter what I have on the disc, the aggressiveness of stock removal is reverse-related to the amount I need to remove!!

View MrUnix's profile (online now)


6951 posts in 2348 days

#9 posted 09-28-2016 06:23 PM

80 on the disc (10”), 120 for the belt. Just using the cheap HF belts and PSA discs, and haven’t had any problems with them yet… they actually have held up as well as the much more expensive brand name stuff. Keeping it clean with an eraser (or old tennis shoe) will prolong its useful life considerably.


-- Brad in FL - In Dog I trust... everything else is questionable

View OggieOglethorpe's profile


1276 posts in 2260 days

#10 posted 09-28-2016 06:25 PM

I also prefer 100 on my 12” disc. I find it a good balance between stock removal and cleanup time.

View jimintx's profile


840 posts in 1734 days

#11 posted 09-30-2016 05:15 AM

Removal: begin to pull the disc off, using fingers or even pliers but being gentle to get it started. Dribble solvent between the sanding disc and the metal plate.

Once it is pulled off, use more solvent and clean it off.
Rub the solvent off with a sacrificial rag or try the heavy blue paper towels.
Spread some more solvent and scare with a putty knife as needed.
Once the metal surface is reasonably clean, good to go with the next one.

that is what i do, and I am happy with results.

-- Jim, Houston, TX

View Julian's profile


1369 posts in 2840 days

#12 posted 09-30-2016 02:25 PM

I have two disc sanders and I found that cheap sand paper wears out very quickly. Buying a good brand of sand paper is worth the money to me because it just lasts longer and works better. As others have said; clean the disc with a rubber type stick. I clean my discs after every use. To remove the old sanding disc I start with a heat gun and then use mineral spirits or similar solvent to remove the adhesive residue. I typically use 100 grit.

-- Julian

View jimintx's profile


840 posts in 1734 days

#13 posted 09-30-2016 02:52 PM

In post #11, I intended to mention using a heat gun, also.
If you don’t have one, the cheap one from Harbor Freight seems to work just fine.

I also tend to leave an 80 grit disc in place, and 120 on the belt. I change to a different belt on occasion as warranted, but not often. Changing the belt is fairly easy.

My belt/disc sanding machine is an old Craftsman on a stand (model 113.225931), that I bought new a long time back.

FWIW, I also have the 1×30 upright belt sander from HF, by Central Machinery. I got that a year or so back with a handful of coupons that made it less than dinner out. I can’t imagine not having it now – very useful and easy to use.

-- Jim, Houston, TX

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