KMG 3 speed or variable

[John Wilson]

same here. I have an Ironhorse on my KMG and a duplicate of it on my disc grinder. I did that to have a backup for my belt grinder. Never had any trouble with either of them. I run them off the same VFD using cords / plugs.

 

[MTBob]

It just occurred to me.... you might not be aware of the very practical reason(s) for variable speed..... because different grits of belts cut more efficiently, and last longer at different speeds, a variable speed grinder can save you money on belts.

Heavy grits, 34-60 grits, work best a top speeds, as grits become finer, speed should be reduced for efficiency, longevity, and heat reduction. Exact settings depend on drive wheels on the grinder, but roughly.....
24-60 grits FULL SPEED, whatever the drive wheel size.
80-120 grits 50-60% on the speed control dial for a 4" drive wheel (KBAC 2X series VFDs)/30-40% for 6" drive wheel
220-400 grits 40-50% on the speed control dial for a 4" drive wheel (KBAC 2X series VFDs)/ 20-40% for 6" drive wheel
600 and finer grits..... varies based on material being ground and belt type, but I rarely run these grits higher then 25% for either drive wheel size.

Of course, those are the speeds that work best FOR ME. I'd consider them as BEGINNING points for you, with the exception of what you use for heavy grit belts (24-60 grits) which are almost always best used at highest speed, then adjust to your liking.

Thanks Ed, that is REALLY helpful!

 

[Gliden07]

Definitely go the VFD if you can afford it. If I was to buy again I think I would get the KBAC29. It's rated up to a 3HP motor and from what I've seen is 15-20 dollars mor than the 27! So if you ever feel the need for a 3HP motor you'll be all set. Also there is a saying on here "BUY ONCE CRY ONCE!!". Good luck whatever you decide!!

 

[Jon Buescher]

I don't know if I can describe it or not, but I have noticed that there are times when I'm grinding that the combination of belt speed, grit, angle, etc. will almost start an oscillation. The blade seems unstable and I feel like it's moving all over the place. Like I can't hold it still. I can reach over to the VFD and bump the speed up or down just a few rpm and it goes away. Smooth sailing then. Ya'll ever notice that? That's a life saver on the VFD for me.

so its not just me! seems like when I go from 120 to 220 grit I notice the biggest increase in that