Surface grinder advice

Atlas Knife Company

Atlas Knife Company

Joined
Feb 16, 2010
Messages
3,668
Here's a grinder nearby for $300. Can I use it with residential 220 or will I need a VFD to use it? I figure for $300, if it runs it can't be that bad of a deal.

Ceramax permanent magnetic chuck. 1 hp, 220/440 vts, 3 ph, 3" spindle diameter. Included are 4 grinding wheels (12" x 3/4" x 3") and original operating and parts manual. Call with inquiries.

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Grab it, NOW!
you need a vfd or you can replace the motor with a single phase. Either way it a great deal.
 
That is a GREAT deal! You would need either a VFD or a single phase motor - I would probably go for a VFD, though.
 
1 hp, 220/440 vts, 3 ph,

The 3PH is 3 Phase,
You could have easily put an inexpensive VFD on a 1 HP motor.

There is a thread around here where Nathan the Machinist recommends not swapping motors as the originals are especially well balanced.


just so you know next time, a new magnetic chuck alone is in the $1,000 range
 
While I don't disagree that they motor is balanced, I wonder how much impact a motor swap would actually have on people like us. What is the balancing going to do? I think it will affect the final finish of the grind.

I don't think any knifemaker out there is going to leave a surface ground finish on their blades, so it may add a small bit of hand sanding to the product. There are a lot of home-built surface grinders in knife makers shops. I doubt many (or any) of them have balanced motors and in addition, they are using inherently less accurate belts. The stuff that we do with this equipment just isn't as demanding as some other applications.

Somewhere years back I read one knifemaker's reply to the assertion that his home built wasn't good enough. It went something like "It can keep 1/2 a thou across a bar of steel. I'm not making heart machines or rocket ships, I'm just making knives." Wish I could remember who said it.


-Edit-
Didn't take long to find it:
"I can generally hold a 1/2 of thousand with my conversion and I finish all my flats to 400 grit. I'm not building heart pumps or rocket ships, just knives."
Michael Vagnino
 
The chuck alone is worth nearly double that. Mine has been running on
110 for like 8 years no problems
Ken.
 
AcridSaint said:
While I don't disagree that they motor is balanced, I wonder how much impact a motor swap would actually have on people like us. What is the balancing going to do? I think it will affect the final finish of the grind.

I don't think any knifemaker out there is going to leave a surface ground finish on their blades, so it may add a small bit of hand sanding to the product. There are a lot of home-built surface grinders in knife makers shops. I doubt many (or any) of them have balanced motors and in addition, they are using inherently less accurate belts. The stuff that we do with this equipment just isn't as demanding as some other applications.

Somewhere years back I read one knifemaker's reply to the assertion that his home built wasn't good enough. It went something like "It can keep 1/2 a thou across a bar of steel. I'm not making heart machines or rocket ships, I'm just making knives." Wish I could remember who said it.


-Edit-
Didn't take long to find it:
"I can generally hold a 1/2 of thousand with my conversion and I finish all my flats to 400 grit. I'm not building heart pumps or rocket ships, just knives."
Michael Vagnino
Click to expand...




I'm speaking from first hand experience. I have owned a surface grinder where the motor went bad and a few replacement motors later (high quality "balanced" motors) I learned the hard way that surface grinders are fickle things. Hell, just removing and reinstalling the pulley is a no-no because the motor and pulley are dynamically balanced as a unit. I learned this after-the-fact. I ended up cannibalizing a motor and pulley from another grinder.

A conversion grinder isn't using a stone wheel, so it absorbs some of the vibration. Otherwise the ripple can be pretty bad. Not to say that it would have no use to a knifemaker, but it would represent a fairly significant reduction in the quality of the grind, and most likely considerably more work to bench out.
 
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