Just upgraded to direct drive

Stromberg Knives

Stromberg Knives

strombergknives.com
Joined
Jan 3, 2015
Messages
856
I just finished my upgrade from pulleys to direct drive on my grinder.

It's marvellous and something I should have done earlier. It's a lot less vibration, it's more quiet and finally I can go real slow.

At the same time I went from a 1,5 HP to a 3 HP motor.

I use a cheap Huanyang VFD, we'll have to see how long it will last. The main unit is hidden from dust.

ImageUploadedByTapatalk1455434406.455572.jpg

ImageUploadedByTapatalk1455434434.776014.jpg

ImageUploadedByTapatalk1455434456.694422.jpg
 
The 3 HP motor will put a smile on your face. I grind all bevels on my 3 horse KMG and it cannot be stalled.

Enjoy, Fred
 
I'd been singing praises of a good 3 speed pulley drive until I changed to direct drive - THEN I had to eat crow. Direct drive with VFD is the ONLY way to go. Add up cost of a "good" pulley arrangement and you'll exceed cost of the Chinese VFD which works just fine - keep dust out. You'll be VERY happy.
 
Wasn't that many years ago everyone was praising the belt drive and saying it was smoother. I wasn't sold... lol
 
Last edited:
It's a 2910/50Hz/2 pole motor and a 5 inch drive wheel.

I run my VFD between 10 - 75 Hz which gives me the following speeds:

10 Hz = 582 rpm = 762 SFM
75 Hz = 4365 rpm = 5714 SFM
 
Last edited:
I guess I'm the oddball here because I still use a belt drive variable speed KMG and I am very happy with the grinder now that I added a second tool arm slot and a gas piston tensioner. I have never had belt wobble problems or lack of power with a 2 hp 1725 3 phase motor. It makes a little more noise than my direct drive grinder but who cares? If I ever have any problems then I will convert but I won't be able to make a better knife than I do now. If the contact wheel has no runout problems then the grinder will make a fine bevel whether its a direct drive or a belt drive. That being said I really like the direct drive conversion that Currenthill and Matthew Gregory have done. They both look like first class grinders. It was a real good move for Matthew because he had so many problems with his KMG. Good work! Larry
 
Fred.Rowe said:
The 3 HP motor will put a smile on your face. I grind all bevels on my 3 horse KMG and it cannot be stalled.

Enjoy, Fred
Click to expand...

Yes, I definitely see what you mean. I can now put an insane amount of pressure when hogging out blanks. Earlier my belt would slip and my motor would stall. It's nice to use the 36 grit belts more like they're intended to - high pressure and speed.

Looking forward to grinding some bevels soon.
 
My nephew is a beginning knife maker and uses a belt drive KMG. Lately, he's been over in my garage using the direct drive variable speed grinder I built and he can't believe how much better and more efficient he is with the variable speed.
 
Last edited:
javajaws said:
My nephew is a beginning knife maker and uses a direct drive KMG. Lately, he's been over in my garage using the variable speed grinder I built and he can't believe how much better and more efficient he is with the variable speed.
Click to expand...

Hey javajaws, I think you're confusing 'direct drive' with single speed motor. Currenthill is talking about eliminating the pulley system and driving his drive wheel directly with the motor, using a variable speed motor. No belts, no belt slipping, so loss of power, no additional vibration!
 
Matthew Gregory said:
Hey javajaws, I think you're confusing 'direct drive' with single speed motor. Currenthill is talking about eliminating the pulley system and driving his drive wheel directly with the motor, using a variable speed motor. No belts, no belt slipping, so loss of power, no additional vibration!
Click to expand...

LOL, I meant to type "belt drive" not "direct drive". I'll edit my post accordingly!
 
You must log in or register to reply here.
Back
Top