grinding belt speeds ?

[bill2455]

Hello all

Just joined the forum. I recently started making a few knives for fun and have found it very addicting. I'm putting together a grinder mostly based on the KMG and have a few questions. I've looked around some and have not been able to find a chart with recommended speeds for different grits. If anyone knows of chart or a tutorial to help me with my grinder that would be great.

If I made my grinder only one speed what would be a good compromise for belt speed for grits between 50 and 400.

If it was a 3 or 4 speed grinder what would be my optimal speeds be from lowest to highest.

Thanks in advance.

 

[cdent]

I think you can check on the KMG site for their recommendation of using step pulleys on the grinder and motor. Chances are the three speeds will cover you well.

Good luck with it, Craig

 

[loneronin]

the suggested speeds for KMG are:

3500 ft/min
1750 ft/min
800 ft/min

look here: http://beaumontmetalworks.com/motors.html

 

[balibalistic]

I prefere 1750 over any other speed!!

 

[Nathan the Machinist]

I like:
1000-5000 SFM

 

[John R. Fraps]

It is worth delaying implementation to save up for a variable speed motor/ controller.
If you are going to have one grinder for everthing, almost 0 to top speed is worth the extra front-end cost......
I have run 36-80 grit at full speed...around 2500 rpm on a 10 inch. ....
and 800 to 800 plus grit as slow as around 60 rpm or slower..... the flexibility is so worth the extra cost..
You got my opinion....all 2 cents worth

 

[Fred.Rowe]

I run 5400 sfm when using 36 50 and 80 grit ceramics.

The higher grit belts have such a wide variety of usable speeds; depending on what you are grinding on.
Bone is one speed while steel is a different one.

Variable speed is the most useful setup to have.

Fred

 

[JTknives]

i love a fast belt speed with blaze belts

 

[J-siah]

I like:
1000-5000 SFM

I run 5400 sfm when using 36 50 and 80 grit ceramics.

The higher grit belts have such a wide variety of usable speeds; depending on what you are grinding on.
Bone is one speed while steel is a different one.

Variable speed is the most useful setup to have.

Fred

i love a fast belt speed with blaze belts

I with you guys, I like the speed, especially with my blaze belts. I have my grinder set up for 3400sfpm and 5600sfpm but I would like to add a 1700sfpm when I pick up knife making again. at 5600sfpm a 50g blaze belt hogs steel like AO hogs aluminum.

-Josiah

 

[bill2455]

Thanks for the help guys. I'm an industrial electrician and will have no trouble gearing up variable speed ac or dc when i find the right stuff for the right cost. Right now i have to gear up with 3 or 4 speeds with step pulley.

Thanks again. I'll post pics of grinder when complete

 

[JTknives]

I with you guys, I like the speed, especially with my blaze belts. I have my grinder set up for 3400sfpm and 5600sfpm but I would like to add a 1700sfpm when I pick up knife making again. at 5600sfpm a 50g blaze belt hogs steel like AO hogs aluminum.

-Josiah

ya i havea bunch of the 50 blaze and i have wanted to try them at around like 7000 fpm . that should do the trick. i seem to get better belt life out of belts at a faster speed, it seams to strip of less grint and does not heal like a sand storm with a new belt.

 

[J-siah]

be careful with you knuckles at 7000sfpm .

I agree that they last longer at higher speeds, but I would ruin to many knives at 7000. then again you work that crazy 10v stuff.

 

[Barkes Knife Shop]

I also like using Variable speed on my grinders. I like being able to slow it down when needed or speeding it up when necessary. If you can get variable for your grinder it will be one of the best things you can add to the machine.:thumbup:

Terry

 

[ddavelarsen]

Agreed on the variable speed; I would also add that the more power the better - 2 hp at a minimum. You may not think you need it now, but when you start tapering tangs you'll sing a different tune. That's when speed and power will make for more accurate work. Just my .02.

One thing about variable speed that isn't obvious - it let me learn to grind with much less wasted steel. You can speed it up to hellacious speeds like JT when you know what you're doing!

 

[Bufford]

I made the upgrade to variable speed long ago, and there is no way I would want to go back to a single speed. Your work will come up better, belts and bearings last longer, less overheating of steel and handle materials, and safer too.

 

[marekz]

i have a variable speed motor--2hp i cant get above 2900. i wonder why?!-marekz

 

[marekz]

repeat-sorry

 

[Fred.Rowe]

i have a variable speed motor--2hp i cant get above 2900. i wonder why?!-marekz

Change your drive pulley, make it larger.