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+-- Thread: Which Bench Grinder? (/showthread.php?tid=7349313)
RE: Which Bench Grinder? - omark - 07-19-2019
(07-19-2019, 07:39 AM)Derek Cohen Wrote: Bill, whatever grinder you get, make sure you end up with a 180 grit CBN wheel. Flat, not crowned.
Regards from Perth
Derek
Derek, in order to clarify: by 'crowned' do you mean 'rounded edges and slightly concave' wheel mentioned on your website or sharp edged crowned wheel -- like for example sold by TFWW?
RE: Which Bench Grinder? - Greg Jones - 07-19-2019
(07-19-2019, 04:10 PM)omark Wrote: Derek, in order to clarify: by 'crowned' do you mean 'rounded edges and slightly concave' wheel mentioned on your website or sharp edged crowned wheel -- like for example sold by TFWW?He means avoid the radius wheels. I’ve got along fine with the radius wheels myself, but if I had to buy them again I too would go with the flat wheels.
http://www.inthewoodshop.com/WoodworkTechniques/UltimateGrindingSharpeningSetUp.html
RE: Which Bench Grinder? - Derek Cohen - 07-20-2019
No, I mean the crowned wheels as sold by TFWW. When Joel first wrote up the technique for using a crowned white or blue wheel in FWW magazine many years ago now, it was a brilliant strategy (still is) for those particular wheels. The friable grinder wheels wear quickly, and grinding is less certain than on a square CBN wheel. The CBN does not wear, and one can push a blade, such as a chisel, straight into it and the hollow is created without much difficulty. Crowning a wheel continues to have a place to play with friable wheels. It is simply no longer needed with CBN wheels.
Regards from Perth
Derek
RE: Which Bench Grinder? - bandit571 - 07-20-2019
Was in Lowes this morning ( bandsaw blade and some paint brushes..) and saw 3 different grinders sitting on the shelf...
Plain Jane Delta single speed 6" dual wheel....$59
fancier Delta, variable speed 6" dual wheel....$99
Even fancier Delta 8" variable speed dual wheel....$149
Lowes does not have much in grinder wheels....just the blue/gray ones...
I may check on what Menard's has..next week, when I am over that way...
RE: Which Bench Grinder? - Tony Z - 07-20-2019
(07-17-2019, 03:05 PM)Timberwolf Wrote: ..................
I have three six inch Baldors..one sitting on the floor of the shop...all flea market finds...two are pretty old but they will coast for a couple minutes even now when you turn them off......They use precision bearings...Paid $25 bucks for one......less than $50 for the newest one. Heavy grinders
Jack,
Have you ever disassembled on of the import grinders? When bored, I just might do that: this past week, I learned of the significant diference in premium and precision bearings on a vertical double disc grinder I have in my plant-one of the motors is out for rebuild and I had this explained to me (bear in mind this motor is 35 HP). Regardless, the bearings on grinders have a different sort of load placed on the shaft and this why the Baldors cost so much more. I would be curious if they may even be a sort of roller bearing.
RE: Which Bench Grinder? - Timberwolf - 07-21-2019
(07-20-2019, 03:29 PM)Tony Z Wrote: Jack,
Have you ever disassembled on of the import grinders? When bored, I just might do that: this past week, I learned of the significant diference in premium and precision bearings on a vertical double disc grinder I have in my plant-one of the motors is out for rebuild and I had this explained to me (bear in mind this motor is 35 HP). Regardless, the bearings on grinders have a different sort of load placed on the shaft and this why the Baldors cost so much more. I would be curious if they may even be a sort of roller bearing.
.........
Tony, I have never disassembled one so I don't have any experience with them..But I have known for many years that all bearings are not created equal!.Like so many other things, there's always somebody that will build it cheaper..Harbor Fright comes to mind...Not knocking them because they do serve a purpose and fill a need...but I once bought a HF bench grinder to use with wire brushes, and it vibrated so badly that I had to return it and I exchanged it for their 1/2hp buffer...I put two muslin buffs on it and it shook the bench it was sitting on, so back it went!!!!....What surprised me was the fact that, with that much vibration, they could even keep running!!!!!!!!
...A miracle in itself!!...I have to give those Chinese engineers credit for that!!!!!!!!! 
RE: Which Bench Grinder? - bandit571 - 07-21-2019
(07-21-2019, 08:14 AM)Timberwolf Wrote: .........
Tony, I have never disassembled one so I don't have any experience with them..But I have known for many years that all bearings are not created equal!.Like so many other things, there's always somebody that will build it cheaper..Harbor Fright comes to mind...Not knocking them because they do serve a purpose and fill a need...but I once bought a HF bench grinder to use with wire brushes, and it vibrated so badly that I had to return it and I exchanged it for their 1/2hp buffer...I put two muslin buffs on it and it shook the bench it was sitting on, so back it went!!!!....What surprised me was the fact that, with that much vibration, they could even keep running!!!!!!!!
So....how did those 2 run without the un-balanced loads on them? Did you try without the wheels?
RE: Which Bench Grinder? - Timberwolf - 07-22-2019
(07-21-2019, 01:49 PM)bandit571 Wrote: So....how did those 2 run without the un-balanced loads on them? Did you try without the wheels?...................
I didn't try them without the wheels but I did rotate the brushes and buffs on the shafts for the least amount of vibration, which was still excessive..IMO, the bearings were the cause of the excessive vibration.,.The buff and wire wheels are on the Baldor right now and have been for a long time...Most muslin buffs, because they weigh so little, are pretty evenly balanced and good quality wire wheels can be also if they are bored on center with the correct hole size. I use buffs and deburring wheels a lot in knife making, along with belt grinders.
RE: Which Bench Grinder? - AHill - 07-22-2019
The quality of a good grinder, in addition to the motor and bearings, is the precision of the shaft and how the wheels are mounted to the shaft. The most precise bearings in the world can't resolve a misaligned arbor and mounting flange.
RE: Which Bench Grinder? - Bill Lyman - 07-22-2019
(07-19-2019, 07:39 AM)Derek Cohen Wrote: Bill, whatever grinder you get, make sure you end up with a 180 grit CBN wheel. Flat, not crowned.
Regards from Perth
Derek
(07-20-2019, 01:24 AM)Derek Cohen Wrote: No, I mean the crowned wheels as sold by TFWW. When Joel first wrote up the technique for using a crowned white or blue wheel in FWW magazine many years ago now, it was a brilliant strategy (still is) for those particular wheels. The friable grinder wheels wear quickly, and grinding is less certain than on a square CBN wheel. The CBN does not wear, and one can push a blade, such as a chisel, straight into it and the hollow is created without much difficulty. Crowning a wheel continues to have a place to play with friable wheels. It is simply no longer needed with CBN wheels.Derek:
Regards from Perth
Derek
You said flat not crowned, but you mean the crowned wheels as sold by TFWW. That is a little confusing. Also confusing is that TFWW sells 60 and 80 grit in the 6" wheels and 80 grit in the 8" wheels, but not 180 grit.
Still shopping.
Thank you in advance.
Bill