What is the max speed that you run a belt.

BrianThie

BrianThie

Joined
Jun 18, 2007
Messages
382
Hi all

I recently got an email from a abrasive supplier and they had the following table for belt speeds.

Belt Speed 6000-10000sfpm 24-40 Grit
Belt Speed 5000- 6500 sfpm 50-80 Grit
Belt Speed 4500- 5500 sfpm 100-120 Grit
Belt Speed 2500- 3500 sfpm 150-220 Grit
Belt Speed 800- 3000 sfpm 240-600 Grit

I am running a KMG and I have my VFD set to max out at around 5000 sfpm. The numbers above have me wondering how fast is fast enough. I cannot imagine getting slapped by a broken belt running at 10000 sfpm.

So what is everyone else running.

Thanks
Brian
 
Don't know what my variable speed KMG maxes out at, but I run 60 grit 3-M Ceramics at full-bore when I am roughing in the bevels.

After that, I slow down a tad.

Robert
 
I never hit 3000 sfpm...even on the heavy grits belts! The thought occurred to me..... I wonder who came up with those speeds???....probably somebody with an engineering degree who has never seen a belt grinder, much less used one.....or maybe they just want us to tear up belts quickly, so we can purchase more from them? :confused:

Run a 600 grit belt at 3000?? About the only thing you'd accomplish is to smoke whatever touched it!:eek:
 
Judging by the sound it made when I caught the belt wrong, I think my runs at Mach 1. Sounded like it broke the sound barrier.
I honestly don't know fast it runs. I have step pullies and never taken the time to find out.
 
Do those numbers makes sense for woodworking?

When I'm hogging steel off with a Blaze belt I turn my KMG VFD all the way up. I've got the optional larger drive wheel that increases the speed 50% over the standard drive wheel. I don't know how many SFPM that is. It's real fast :D
 
RUGUR said:
Do those numbers makes sense for woodworking?
Click to expand...

I don't think so. My little Craftsman runs pretty quick (4400fpm according to the Sears website) and scorches wood and stuff easily. :mad: I don't know why you'd need anything faster; I hope one day to upgrade to a proper variable speed 2x72.
 
I have a 4 speed grinder:
I dont know exactly what is the speed but I name them, rabbit, koala, turtle and sloth. I use most of the time the sloth :D...
 
I measured my KMG at 1000-5000 SFM, four speeds.
 
Any belt grinder I have ever used or seen used was plenty fast enough for me. What I want to know is how slow will it go? I want one that I can use between the splices in the belt. I like drill presses that will go slooooooow too. Seems that salesmen of both grinders and drills like to talk about how fast they go when the other end of the spectrum is often where you need more control.
 
Hello:"

I have my grinder running at 7200 SFM on a 14" wheel...I hate grinding and it cuts so niiiiiice....and 5 HP I do not even slow it down when I lean into it...

NVHammerHead
 
Thanks for the replys. I know these numbers are probably intended for industry applications, but I wanted to get a feel for what everyone else was doing.

Brian
 
A 2" x 72" grizzley with a 8" wheel will run 7,226 SFM. Reckon where I can buy a 4" or 5" wheel?
 
Brian, I've got a laser/digital tach.
I use a variable Bader BIII.
On the larger wheels, which also have the larger bearings, I run at about 75%. This reads about 800 rpms on the belt X 6 feet = 4800 sfpm.
On the flat platen and the smaller contact wheels with smaller bearings and usually with finer grit belts I run at top speed of about 50%.
This reads about 550 rpms on the belt X 6 feet = 3300 sfpm.
Of course it will vary from task to task.
 
i just think it would be easier to do with a good cheap sander like the 2X42 craftsman than spend more for variable speeds...dont ya think?..or is it just plain too hard to go that rout?

me again
 
i just think it would be easier to do with a good cheap sander like the 2X42 craftsman than spend more for variable speeds...dont ya think?..or is it just plain too hard to go that rout?

me again
 
andrewfinnie13 said:
i just think it would be easier to do with a good cheap sander like the 2X42 craftsman than spend more for variable speeds...dont ya think?
Click to expand...

No. There are all kinds of issues with trying to put a pot on the motor. Besides, there are many other reasons to upgrade to a proper knife-making grinder that will pay for themselves.
 
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