grinder question

L

lukek655

Joined
Jan 4, 2007
Messages
26
when would a variable speed motor be needed for your grinder. Read about it a lot but at a loss right now. OH YEAH found a source for pretty good motors check out QC Supply. They provide farm supplies and have pretty good prices.
 
If you are ham fisted like me and tend to screw up things, the VS motor gives you more control so you can catch the mistakes before they are beyond repair:D With that said, check out Harvey Dean's flat grinding video to see how a real pro uses a VS grinder to maximum advantage.
 
There are many reasons VS is good. One is control for certain tight jobs, but don't forget that when you're running those really small wheels, they can't handle full speed, so it's nice to be able to just turn a knob when you switch to the small wheel adapter rather than having to mess with belts or drive wheels every time you change the tool arm.
It's one of those things that just makes the job more efficient. It's hard to convey to someone just how valuable that aspect of it is all by itself.
 
If it the price of VFD setup that makes you uneasy about it, you
can try going the DC way: 2.5HP "treadmill duty" motor and a minarik
DC control, from surpluscenter.com, will set you back about $110.

You will have to find a way to mount the motor (which happens to be
open frame) away from the flying grit & sparks. KMG-design grinders
allow you to do just that.


If later you decide to upgrade to VFD, you can always reuse the
DC motor and controller on another piece of machinery: drill press,
lathe, etc.

The 3Phase TEFC motor + good VFD _is_ the way to go. VFD is the most
expensive piece of this setup. If money is tight, see if you can score one
@ an auction, etc. Ebay. But, it will be in unknown condition, w/o support
etc. So it better be a very good deal :) - like $20 or so.
 
I use a Bader 3 in my shop and it has variable speed controls. It come in handy when doing finishing work and cleanup unwanted scratches. You will love utilizing one of these features. Great upgrade to grinders. Some people may speak against this but it is because they don't have one or do not want to invest in one. But believe me it is nice to have it when you need it. And you will. feel free to check out my setup using mine in the Knife Shop at the following address below. When you get there just click on Barkes Knife Shop and enjoy your visit.

Barkes
http://my.hsonline.net/wizard
:thumbup:
 
In over30 years of knife making, I've never had a variable. Other than pulley and belt change set-ups. A couple of weeks ago I got a killer deal on a Vari, Burr-King. You can bet I bought it on the spot. I haven't had the chance to go pick it up, but just as soon as I get back from Riverside, I'll make the trip. Looking forward to it! A long time coming! Mike
 
mlovett said:
In over30 years of knife making, I've never had a variable. Other than pulley and belt change set-ups. A couple of weeks ago I got a killer deal on a Vari, Burr-King. You can bet I bought it on the spot. I haven't had the chance to go pick it up, but just as soon as I get back from Riverside, I'll make the trip. Looking forward to it! A long time coming! Mike
Click to expand...


The Bader and the Burr-King is the TOP OF THE LINE in grinders. You will be one happy Knife Maker.

Barkes
http://my.hsonline.net/wizard
:thumbup:
 
Hi Mike, Your proof that no one needs variable speed, but after you try it out you'll probably wonder why everone doesn't want it. Best of luck with the new set up, and hope ole Brock is not too aggravating lately.
Take care, Craig
 
Haa! Brock is always aggravating!! Heehee! I have both a 960 Burr-King, and a Bader BMIII in the shop. I love them, but the Bader is a bit too loud. I think a vari would help it out a lot. The old Wilton Square Wheel would run you out of the shop after a few hours. The worst for noise was a Blade Master the I had custom built years ago, and set up to turn at 8500 sfpm. It souded like an F-4 ready for take off. The Burr-King is so Smoooooooth!!! Mike
 
When Variable Speed?
My first grinder was a Burr-King w/full speed motor...2nd was a wilton Sq Wheel with single speed. The day I caught a blade on the wheel of the Sq Wheel and threw it over my shoulder close enoug to my right ear to feel it go past, traveled anothe 5-8 feet and shattered a 2 bulb florescent light fixture....all in less than a blink of an eye, I bought 2 variable speed motors and controls.
I run seldom over 1500 sfpm on either grinder now....and the conversion wasn't as much from the almost accident, but I grind my steel after HT so i thelps to keep the temp down as well.
My 3rd grinder is a Bader that they built for me in horizontal configuration...I learned its better to start with variable, so it is.....if I ran it full speed, it could throw a pieces of steel to or toward, my right pretty quickly, if the piece got loose...and in part for temp control and in part just for "feel" control, I always have a finger on the piece or hold it with fingers....so heat isn't a factor to the steel....fingers get "warm" much sooner than steel temp. could damage the HT of the steel.

Mike, I'll bet unless you ar hogging outlines of knives, once you use the Burr King much slower that high speed almost always...

Also, it is possible to virtually avoid almost all the sparks when grinding Titanium if you run slow enough and just compensate by using a heavier grit belt.....yes, I have had a few flames from Ti ....that is one of the reasons the dipping bucket is right next to each grinder....
My disc grinder is variable speed and reversable.....highly recommend....I use it to square up ends of handle material, steel, etc. It seldom goes fast at all, even to be turned by hand to final fit handles on a double bolster integral bolsters/liner folder.....
 
I really can't think of any situation where a VS unit wouldn't be an asset.
Personally, I would not use a non-VS grinder. There are too many times when full speed is too much speed.
Stacy
 
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