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Wishful thinking - wanted 8" 1hp low speed grinder

VicHobbyGuy said:
How much pressure are you putting on the tool? Is the wheel a good quality one? I got Norton white wheels for the 8" and I can touch up the metal lathe .040" parting blade in pretty controlled way. But those white wheels are soft and I don't think they would last long for 'general grinding' - odd jobs around the shop shaping cold-rolled steel. I kept my 6" grinder for that.
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I've got Norton wheels on it, both K hardness

VicHobbyGuy said:
Don't diamond wheels need water? My flat diamond sharpening plates need water lubrication or they will load up quickly. Or are the coarser diamond wheels OK run dry?
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That grinder has CBN wheel which are not diamond wheels. CBN is cubic boron nitride and is the standard among turners.
 
David_R8 said:
I've read reports that a 1/2hp grinder struggles to get the CBN wheels up to speed which makes me wonder how long it would last.
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Really? 1/2 HP is quite a lot . Both my 6" and 8" grinders take a few seconds to get up to speed, but I'm not worried about that. Is a CBN wheel that much heavier than a 1" wide abrasive wheel? Anyway, that's what the start winding on the motor is for, IMO. I wouldn't worry about the power rating as much as the proportions (fat motor? short shafts?) and design. But you may be using the grinder without the shields and stock rests?
 
I have some 1100 grit belts (Buddy of mine located them somewhere in Calgary but I dont know where) for my ordinary 4x24 belt sander that i use when I have to get serious about sharpening HSS bits or the wifes knives very easy to control metal removal rate & heat as well as lots of room for angle control on the knives.
 
VicHobbyGuy said:
Really? 1/2 HP is quite a lot . Both my 6" and 8" grinders take a few seconds to get up to speed, but I'm not worried about that. Is a CBN wheel that much heavier than a 1" wide abrasive wheel? Anyway, that's what the start winding on the motor is for, IMO. I wouldn't worry about the power rating as much as the proportions (fat motor? short shafts?) and design. But you may be using the grinder without the shields and stock rests?
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The steel CBN wheels can be quite heavy, some are up to five lbs each.
Yes ditching the stock rests and using a Wolverine system from Oneway
 
David_R8 said:
The steel CBN wheels can be quite heavy, some are up to five lbs each.
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My Logan 10" lathe has a 1/2 HP 1725 motor and it manages to spin up all those cast iron sheaves and shafts without any problem. A few seconds to wait for a grinder to 'wind up' wouldn't be a problem for me. I like to flip the switch and stand back a bit anyway. :) A grinder for sharpening is a pretty light load the way I use it.
EDIT: Just checked and the 1"x8" wheels that came on that Magnum are 4 lbs each. If a 1/2 HP came with the same wheels, I wouldn't worry about the power rating.
 
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It's interesting how times change. When I first started woodturning (1980s?) I remember the 'turning heroes' in FineWoodworking having 6" grinding wheels mounted on the outboard end of the lathe so they could touch up the (not HSS) tool (freehand) as they worked. I dutifully bought the necessary adapter for my Beaver lathe. The adapter and the wheel don't get used much any more, but they are still in a box under the lathe.
 
VicHobbyGuy said:
My Logan 10" lathe has a 1/2 HP 1725 motor and it manages to spin up all those cast iron sheaves and shafts without any problem. A few seconds to wait for a grinder to 'wind up' wouldn't be a problem for me. I like to flip the switch and stand back a bit anyway. :) A grinder for sharpening is a pretty light load the way I use it.
EDIT: Just checked and the 1"x8" wheels that came on that Magnum are 4 lbs each. If a 1/2 HP came with the same wheels, I wouldn't worry about the power rating.
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This is the video I was thinking about.
 
David_R8 said:
This is the video I was thinking about.
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I know life is short, but I wouldn't worry about the 'wasted' 5 seconds to wait for the lower powered grinder to spin up. :)

It doesn't likely matter for sharpening lathe tools, but for general grinding a 'skinny' motor gives a lot better clearance.
Some pics:
mini-Rikon 8.webpmini-rikon 8 half.webpmini-rikon 1HP size.JPGmini-Baldor size.JPG

If I had my choice, I'd probably opt for the 1/4 HP Baldor (though it is a 6" grinder).

Putting $600 (?) worth of CBN wheels on the grinder would probably change my choices, though.
 
I have that grinder as well. Have not used it much as of yet. I have to figure out how to balance the wheels sometime as there is a vibration in mine during start up.
 
Degen said:
Have you considered a belt grinder (2x72), I built my own, doesn't have VFD or run up to the higher speeds as some do, but I never found it lacking.

Haven't touched my regular grinder since.
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I've thought about it but never needed the capacity that they have, nor do I have the space for one.
 
Degen said:
Have you considered a belt grinder (2x72), I built my own, doesn't have VFD or run up to the higher speeds as some do, but I never found it lacking.

Haven't touched my regular grinder since.
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I have a 1x42 sander, but the belt life isn't great and belts are an on-going expense, so I'm glad I have bench grinder(s). The good aspects of the 1x42 is that it's quick and easy to change grits, and there's an unsupported belt section for working on curved surfaces.
 
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