# What is a good speed for a belt grinder?



## 29palms

I'm finding slow speed (1725 rpm) bench grinders and there are 2" x 48" belt attachments for them. I have an variable speed grinder (2000 - 3450 rpm) now. I know 3450 is way too fast and slower is better and how slow are we talking?


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## JMJones

What are you using it for?


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## zitangy

JMJones said:


> What are you using it for?



so true..

I am still using my Palmgren 2x42 inch belt sander though I have been using 1 inch wide belts primarily for sharpening and the speed is 1750rpm which is a little too fast for my liking for the thin edge on most knives. A few more strokes does not make much of a difference to me. As too fast it will really get real hot which is not too good for the blade esp the tip of knife as it is really too thin.

IF I need to remove more steel, I go to a coarser belt. A slower speed gives you more time to move the blade on the belt without heating it up fast.

I just found out that most sand belt makers will make to any length and width you may desire with a very reasonable qty of 10 belts per order at least in Malaysia. Same for Klingspore.( US brand). OF course.. if it is the standard common belt size.. there are so many options readily available without waiting time...

rgds
d


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## 29palms

JMJones said:


> What are you using it for?



Thinning, profiling, stock removal, repairs, etc.


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## Delbert Ealy

Yeah, slower is better for you, mine is slightly slower than the speed of sound, but I'm used to it. I was demonstrating grinding to a new maker nearby, and he was astonished.
Del


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## TB_London

Different belts work efficiently at different speeds, ceramic likes to go fast so if you're going to run at a low speed save the extra money and go for alox belts.
Belt speed is measured in surface feet per minute (sfm) whic you can calculate using the diameter of the drive wheel and the motor rpm. There are tables on the Internet, I'll try and find one


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## Dave Jacobson

New belts and variable speed motors are always nice but it's all about how much pressure you apply.


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## 29palms

Pressure + agregrate + speed = heat - how do you deal with it besides constant quenching? Which is why I'm looking for a slower motor.


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## Delbert Ealy

29palms said:


> Pressure + agregrate + speed = heat - how do you deal with it besides constant quenching? Which is why I'm looking for a slower motor.



I generally quench every three passes, at that point the blade is warm but not hot enough to burn skin. Its part of how I measure how sharp the belt still is. If I cant make those 3 passes, then its time for a new belt. With a new bely some of the heat is dissipated in the material removed. 
Del


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## jai

Thanks for the great advice del.


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## 29palms

Yes Del thanks for that tip.


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