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clive 05-08-2021 01:32 AM

belt sander
 
I’m in the early stage of building a belt sander, I’m wondering what grit is the most useful? Any help appreciated.

LKeithR 05-08-2021 02:19 AM

If you're working with steel there's no point in using anything finer than 36 grit. That's what I use 99 per cent of the time. Once in a while if I've got something extra heavy to sand I'll throw on a 24 grit belt but the 36 works fine for most stuff. Anything finer takes too long to cut. The 36 grit actually only stays sharp for a while and then you've got a finer belt anyway.

I guess if you were trying to do some finish sanding--like prep for polishing before plating--a finer grit might be useful but for welding prep and general fabrication shaping 36 grit works great...

The nice thing is that it's easy to experiment with different grits and find what works for you.

And by the way, the blue Zirconia belts will give you the longest life...

Lew Hartswick 05-08-2021 08:14 AM

Quote:

Originally Posted by LKeithR (Post 770469)

And by the way, the blue Zirconia belts will give you the longest life...

Boy and How!!! My first use of one of them was about 20 years ago when I started to volunteer at the high school shop. there was one on the 2" belt sander there and that was a "revelation". I was use to the red-brown ones.
...lew...

dubby 05-08-2021 08:39 AM

It really does depend on what you're sanding. Most all of my work is done in plastic and aluminum, so I run much finer grits on my belt/disc combo machine. I run a 50 grit on the little HF 1" belt grinder though to really hog material off quick, then follow it up with 150 on the 4x36 belt, and 220 on the disc to debur and make fine tweaks to the edges.

Matt Shade 05-08-2021 11:37 AM

What size belt are you planning to run?

Is this actually a belt sander, or is this a belt grinder?

What do you intend to do with it the most?

I have a 2x72 inch grinder and it mainly has a 36 grit belt on it, but I keep ceramic belts in 36, 80, 120, and 220, and usually have aluminum oxide belts in 320 and 400 grit as well.

For general fabricating a 36 grit belt is perfect for weld prep, radiusing corners and general grinding.

If you want to dress up points on cold chisels, wood working tools and stuff like that and you can do that with a 36 grit belt at 6000sfpm you are a better man than me. I like 80 or 120 for more intricate tasks. The ceramic belts still cut extremely fast. The 220 to 400 range is mainly for polishing knife blades.

If you are worried about finish quality it is worth noting that even though a dull belt cuts slower, its still leaves scratches in whatever its grit is. A worn 36 grit belt may cut as slow as a 120 grit belt, but the scratches it leaves behind are still 36 grit ugly.

I also have a 4x36 inch sander that runs much slower than the big grinder. I keep 36 grit belts for it for flatting things, or hogging out the basic shape on knife handles, but most of the time it has an 80 grit belt on it for more finish type work.

I buy ceramic belts whenever I can. In 2x72 the 3M cubitron belts have unbelievable life. Its hard to find ceramic in 4x36 but they do outperform aluminum oxide when you can find them.

clive 05-10-2021 01:29 AM

Thank for the replies, it will just be for steel, as we are metric I plan on using a 50 x 2000 belt.

LKeithR 05-10-2021 01:37 AM

Quote:

Originally Posted by clive (Post 770534)
...I plan on using a 50 x 2000 belt...

Approximately 2" x 78 3/4" for those who are metric challenged...:D

Lew Hartswick 05-10-2021 07:18 AM

Quote:

Originally Posted by LKeithR (Post 770535)
Approximately 2" x 78 3/4" for those who are metric challenged...:D

Thank you Keith. :-) When the numbers get over 50 (which was the focal length of my camera lens) I need help .
...lew...

ShawnR 05-10-2021 09:17 PM

Any photos of your sander so far? Are you using plans or winging it on your own? Going variable speed?

I am getting close to finishing one up too. Curious what you are doing.

Regards,

digr 05-11-2021 01:46 PM

Quote:

Originally Posted by ShawnR (Post 770558)
Any photos of your sander so far? Are you using plans or winging it on your own? Going variable speed?

I am getting close to finishing one up too. Curious what you are doing.

Regards,

Lets see the build:D


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