KMG opinions

J. Neilson

J. Neilson

Joined
Feb 6, 2001
Messages
3,621
I'm thinking about getting a 3rd grinder in the upcoming months and will most likely make it a KMG to suppliment my two Grizzlies. It's basically going to be for flat grind bevels (HC & damascus) whereas I'll use one Griz for profiling and slack grinding and the other for handles. My questions to this point are 1- is the rotary platen worth the $390.00 if I can already flat grind and 2- should I get one of Rob's motors or do some looking around. A 1.5 HP motor is what I was thinking of and it runs about $220.00 on his web site. Thanks. The whole deal seems like the best bang for the buck.
 
No doubt about it, Rob makes a great grinder. As far as the rotary platen goes, it gives you a somewhat convex grind. So if you are used to getting "flat" bevels................???

You can get an AC variable setup here for not much more than $220.00.
http://www.dealerselectric.com/

$290.00 for a 1HP, $385.00 for a 2HP. Hard to beat that. :eek: :D
 
For flat grinding, get the KMG-PL. Ready to go right out of the box.
 
J. -- I've been seriously thinking about taking the leap myself. Rob says he's bringing a truckload of stuff to Blade, so I might be in trouble. Not sure if I'm going to sell the grizzly though.
 
J. if you have the $$ for a rotary platen, I'd use that on a VS motor setup first. Buy the rorary later.

Steve
 
Sando said:
J. if you have the $$ for a rotary platen, I'd use that on a VS motor setup first. Buy the rorary later.
Steve
Click to expand...

I agree with Steve. The rotary platen is a specialized tool. See Caffrey's, Steve's, and my replies on this CKD thread:

http://www.ckdforums.com/showthread.php?s=&threadid=22285

Go for the variable speed, J. You won't be unhappy you did. It can really make a difference at times. I have DC VS. In retrospect, I should have chosen a variable frequency AC. Those suckers can make a grinder crawl at just a few RPM and maintain full torque. I was most impressed with Darren Ellis's KMG/ACVF setup at Bowie's last fall.
 
The rotary platen is a SUPER piece of equipment. It makes like so much easier. However, in using it you might have to adjust the way you do your shoulders.

For the style of grind that I do...I could not live without it.
 
OK, no rotory platen now. I can flat grind no problem...really. So no sweat there. But,....what's the big deal about variable speed? I've never used it and have never seen the need to slow a belt down, hell I usually wish it would go faster. I was planning on 1.5-2 HP since I've only always had 1 HP. I push real hard when I'm grinding, always have, so I think I can slow down the belt speed enough that way. ;) Still don't get the VS though.
 
I just went to Rob's site and ordered a McCaffrey platen. He said it would after the blade show probably. Ok by me.

I never used a VS either, but for finish grinding they tell me it's better sex.

I'm getting a motor setup like Daniel's :D :D :D
 
Variable speed is great. Goes like this:

I'm slack belt grinding a few blades last night. I'm up to 240 grit. I give the blade some good pressure against the belt to clean up scratches in general. When it comes time to get closer to the edge, I reach over and dial the speed down, do the edge and tip, dial it back up and start the next one.

At the rough grits, I just put it at the highest speed I can tolerate...:eek:

I'm getting pretty amazing hogging at around 180 Hz, which on my 1750 rpm motor is around 5250 rpm.

The fine finishing I referred to was done at about 1300 rpm.

I have yet to have the motor "stall" on me.

I have also noticed that different belts behave differently at different speeds. Sometimes I have to fiddle a bit to get the most desirable speed on a belt....and you can only do that with variable speed.

It might not be for everybody, but it fits what I do nicely.


Now, if I could only talk Rob into making me a custom rotary platen.....with a flat section on it, a convex platen ;), and a small wheel arm on the third side....:eek:

I'm definitely dreamin'....

:o
 
yeah for finish work its pretty nice... especially for hollow grinding. i use the same 1 hp leeson that rob sells and i like it.... pretty good torque, slower speed but i like that too. J if you need a motor i have a nice "mostly new" ac 1 hp GE. let me know
 
J., I ground on a 1.5HP Bader for twenty years. If I had never put together a VS KMG, I probably would never have known what I was missing for the way I like to grind. However, I am not one of those who leans into a blade with all my weight. I learned on stainless hollow-grinding and don't like to heat steel that much in grinding: it can cause problems. That said, I've heard of enough people grinding at a red heat, I feel, for them, "go for it."

There are, IMO, the advantages Daniel has mentioned. One thing I would amplify that he said is about the belts: modern "engineered" abrasives like Norax and Trizac are intended to operate at high speed-high feed in order to refracture the abrasive and expose sharp cutting edges. Slow speeds dull these belts.

For me, the slow speed offers a lot more control when finishing, and generates a lot less heat. Yes, it is slower. If you are not the most patient person at the grinder, then perhaps VS is not for you. :) There are several makers I know who have 3HP singlespeeds on their grinders, and one I know has a 5HP. Different strokes... one of the things that makes knifemaking so much fun for me.
 
Yes....you said it much better than I could.
 
pendentive said:
Yes....you said it much better than I could.
Click to expand...


Daniel, I'm with you. I LOVE my VS. That poor-old poor-tracking Bader essentially sits relegated to the dust with a Scotchbrite belt on it to knock the rust off of garden tools. If only I had known about the variable frequency AC when I spent $700 for the DCVS....live and learn, eh?

BTW, I didn't say it better than you...your post allowed me to think further and post a couple secondary thoughts is all. Good Lord, but I love the way we help one another here! Have a good one!
 
J: Fitzo brough up the most important point so far..... look through pops knife supply catalog he lists the belts that run better at different speeds.... the newere belts that last longer, give better result, all that depends on the speed. and the same that dan and fitzo said with the AC is true.... way more torque at slower speeds. though i know the motor IG has is GE DCVS, and he had rob frink tweek out all his trim pots so you can it at a crawl and you still can lean right into it without slowing it down much. its all in the motor and speed control. you can get a basic speed control, or one with all the trimpot settings, or one that can control more than one motor etc. what am i talking about i don't know $hit! other than the VS is worth having....
 
You must log in or register to reply here.
Back
Top