2x72 grinder question

T

Trauma

Joined
May 26, 2019
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I have found a 2x72 grinder, new, with tool rest, base plate and a TEFC single phase motor (3350 rpm) for $750. Since it is a single phase motor it has no VFD. I can find the same grinder with a VFD for $400 more. As a new knife maker, is it worth it to get a single speed grinder?
 
As you start using finer grits, the heat input into the blade increases greatly so the ability to slow it down it a huge benefit. Also, some woods needs slow speed or you'll keep burning them as well so a VFD will say you a lot of time and aggravation.

I often have my grinder (home built treadmill motor) running at a crawl.
 
I built my own grinder on the cheap and went with single phase. While its a whole lot better than no grinder, id shell out the extra for a vfd.
 
I had a 2x72 for almost a year before putting a VFD on it. If you can at all afford it, get one. Your grinder will be an entirely different machine with one. I've had mine for several months now and the greater control still amazes me.
 
Back in the prehistoric days, knifemakers like Bob Loveless, Buster Warenski, etc., didn't have variable speed grinders.
We learned to use what we had.
Variable speed is wonderful-but certainly not necessary for making quality knives.
 
Each type of grind, steel type and finish you want to achieve is made much easier with a VFD. Yes, as Bill stated, these things can be done with a single speed, but VFD makes the grinder more versatile for the user. Also, I wouldn't want to run a leather belt at the same speed as a grinding belt.
 
Drew Riley said:
If I had to go with a single speed, I'd rather have a 1750 RPM motor than 3600. I got by for years with a 1750RPM motor and a 3 step pulley.

That said, spend extra and get the VFD. :D
Click to expand...

Bam ^^^


I agree that a variable speed isn't "needed" to make nice knives, as many guys start out with a relatively fast single-speed Grizzly. I'm still using three-step pulleys with a 1HP 1725rpm motor from Harbor freight (actually a decent motor). The slow speed is actually pretty slow and the high speed is fast enough for the way I personally work, although it seems faster than it is because of how loud it gets with the vibration of the drive belt lol. Even Master Smith, Kyle Royer is still using his original KMG set up with step pulleys and look at the work he has and is putting out.

That said, I definitely would go the direct drive route with a VFD knowing what I know now, and probably will set one up sometime unless I just build or buy a new grinder that already has in it the design, although a porta-band with a Swag table is probably next in line and actually has been for years (went with a reversible VDF disc grinder first), but just as with most things you can get by without it, but somethings make the process much more pleasant to do and may also allow for a shorter learning curve (i.e. less screw ups).



~Paul
My Youtube Channel
... (Just some older videos of some knives I've made in the past)
 
I also used a three step pulley set up to have a adjustable on my www.cootebeltgrinder.com. On his site he will show you how to set one up. Or one of the ways.,... I have my Coote machine with a VDF and use it as a potable I can roll out onto the tailgate of my truck for sharpening work, and light knife making demos also own two other grinders, both purchased with VDF set up. Only cry once! Buy the best you can afford!
 
I am a new knife maker and I have a vfd. It's wonderful. I made my own 2x72 and I bought a second hand 3phase motor for about $75 (Can't remember exact price but it was under $100. I think it is 2hp...but I can't remember that either). Then I bought a cheap chinese vfd and made my own enclosure for it. Works like a charm for about $200 cdn.
 
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