Bench grinder. bigger better?

Anonymous-0

Well-known Member
Hey folks, need a bench grinder. Have a little prolly china one with 4" wheels that is pretty worthless for anything other sharpening a shovel or something. Was looking at some on line with 6" wheels and ran across a few used on ebay with 8" wheels. These were pretty old and heavy bosch models. Probably better than anything new but don't want to get an overkill. Use will just be whatever comes up and one wheel will get replaced with a wire wheel.

Thoughts???


Dave
 
I have 3 bench grinders and all have the 6 inch wheels and have yet to find any thing that I need bigger wheels on. I do still need to mount the one and then play with the one wheel which is set up to use emery cloth on
 
The bigger the better. LOL just like life. I have found that with the bigger diameter wheels you have a better grind. The small ones seem to vibrate more than they cut. I have an old Bosch 10" floor mounted grinder. I don"t even know how old it is or where it came from. It has always been in one of our shops. I am sixty years old and I would not bet that it isn"t as old as I am.

The real key is getting the right hardness of grinding wheel for what you usually grind. Too hard and it will not cut and too soft and it will wear too fast. Hard wheels are for soft metal and soft wheels are for hard er steel. I know it sounds backwards but ran a surface grinder for a few months in a factory many years ago.
 
I have the 6 inch in the mold shop for sharpening drill bits and ejector pins mostly. I have a fine stone on one side and a course on the other. I kind get upset when it gets used for anything else. Dressing takes a lot of the wheel down when someone hogs a grove in the center.
I have an 8 inch in my home shop with a wire wheel on one side. I like it as well. It has a larger motor which helps on the wire wheel.

Both will do what they are meant to be used for. Some people try to use them for other than what they were meant to do. If you want to hog weld off you need a body type grinder.
 
The type of grinding wheel makes a big difference. If you buy a cheap grinder it will have almost useless grinding wheels on it. Go to an industrial supply or machine shop supply and get a good name brand grinding wheel and a wheel dresser. It will make a huge difference. Also with grinding wheels, you should wear gloves when ever you handle them. Not so much for general purpose wheels but on specialty wheels for doing precision grinding, the oil on your hands acts like dull spots on the grinding wheel. Dave
 
I have the best results with a 8" - 1/2 Hp double ended shaft with a medium course wheel and a steel wire wheel on the other end. I believe both are 5/8" to 3/4" wide. Presently they are about $60-70 new and $50+ at auction on a metal stand in clean condition.
 
Hi Dave,

That's interesting. In the community college welding shop where I work, there's an ongoing debate about whether to wear gloves when using the pedastal grinders. For a few years the policy has been to prohibit gloves for grinding and wire brushing. The rationale, backed by the experience of a couple of accidents, has been that gloves are more likely to get caught and pull the hand into the grinder. Over the last five years or so, in an environment that is extremely dangerous for people as careless as the current generation of students, the only accidents requiring medical attention have been with people wearing gloves getting their hand snatched into grinders (twice) or rollers (once).

My preference is to wear gloves and be more careful. To do this, I have to make sure that students aren't watching when I use the grinder because I can't tell them that it's okay for me to do something, but not them. Insisting that they be more careful would be about as effective as insisting that they don't drink beer at home with their friends, or have s3x until they are married.

Stan
 
Stan, I believe Dave (135 Fan) was only referring to when you are handling the wheel itself, when mounting it or otherwise touching it, not for when you're actually grinding. I seldom wear gloves for anything except welding, so I'd come down on the side of not wearing them when grinding.
 
I have been using surface grinders and post grinders for close to 50 years and it is good to know that I have been handling my grinder wheels without gloves and causing grinding problems with dull spots. Learn something new every day even at 72 and still using them. Of course dressing a grinder wheel before using it after starting it just might have removed the supposable dull spot. The torque in starting a grinder can cause the stone to not strike even against the work if not dressed and not leave as smooth of a surface. That also causes them to vibrate.

I would never have wanted to catch any of my tool makers waring gloves when using a grinder which is why I never used them. I wanted the magnetic chuck on the surface grinders wiped with a bare hand before a piece was set down on the chuck. Never a glove or towel. Gloves and towels will leave crap on the chuck where the bare hand will pick up that residue. I always dress my post grinders before starting to sharpen a drill bit. Just enough to see a light color surface. It makes a difference if getting the angles and rake correct.

Wire wheel a different story. Heavy thick well fitting leather gloves to keep the skin on the hands in tact. Also keeps the heat blisters away.

If you need gloves to keep the heat blisters away with the post grinder your using the wrong grinder or using it for the wrong purpose. IMHO
I have always concidered my post grinder as a percision tool. Might be the difference. Might be why my 6 inch post grinder in the tool shop is over thirty years old and still looks almost new.
 
Helllo dave2,
My vote is for an 8"unit. The 6' may do just fine, but the 8" will last twice as long and give a better perfomance.
Safety and gloves came up as well. If you are grinding away and the work gets hot you will need gloves. What you should also be using, is safety glasses, and ear protection. Most people will not do all 3............I DO!.
Guido.
 
Dave. We have a $19.00 grinder -6" wheel. Used it on most every piece imaginable /Tractor/crawler,bobcat. yard tractor, trucks etc. Over the years the usage =price couldn't be beat. NOW the best grinder for ruff items comes down to the hand held grinder.Milwaukee/DeWalt/Black & Decker.Works well for us. Hope this helps. VICTOR& LOU
 
I was told when I took machine shop in school to never handle precision grinding wheels with your bare hands because the oil on your hands can have adverse effects. Other machinists have confirmed what I was told. My dad sharpened a lot of reel mowers and there was a warning on the box of the wheel to not handle it with bare hands because there was a difference in the quality of the grinding. I was only taking about handling the wheels, not everything else. They warn about handling halogen bulbs with bare hands too, even if you just washed your hands. I'm not making this up. Dave
 
My neighbor worked on the railroad as a section hand. They had a big grinder with a flex shaft and a Wisconson engine - used it to grind out the frog in track switches. They wear the wheels down to about 6 or 8 inches and pitch them. He brought all the throwaways home to me, and I haven't bought a grinding wheel in 30 years. He's been retired for 10 years. I gave my brother a supply, and still have a lifetime stack under the bench. They're real coarse wheels. Very good quality - long lasting. No good for fine work.

Neighbor knows he can use my grinder anytime he wants.

By the way - my grinder is belt driven, 1/2 HP motor, mounted on a pedistal with the motor below the pillow block.

I like it.

Paul
 

Yes I graduated from a 6" to a 8" and ran across a 10",,, the 10" is sweet,,, 10" wheels are expensive tho but worth it...
 
How did halogen bulbs get in here.

In the 30 some years I have had my own mold and die shop I have bought a few grinding wheels and have yet to see that warning. Some of the time I have had three tool destroyers, Ahh, tool makers which upped the quanity on all machine tools.

Never got into the fancy stuff like reel mowers.

More into the rough stuff that didn't take a lot of skill.

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Just the simple easy stuff to produce things like this.

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And as for the halogen bulbs I agree that you don't handle them with your bare fingers.
 


Dave ,

If you need a big one, I have one that

I'm not using at the moment.

george

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You don't have to believe me but a reel mower is a very high precision cutting tool. The best sharpening machines are accurate to within .001". They refer to it as surgical precision and it eliminates the need for back lapping. Usually only the most precision machined parts need lapping to achieve a precision flatness. No need to make sarcastic comments. I only mentioned halogen bulbs because you wouldn't think if you just washed your hands it would effect the bulb either. I've had some very experienced machinists confirm what I was taught in school. I'm sorry if you can't except that. Dave
 
Grinding wheels vibrate because they are out of balance.You can dress a bad wheel all you want.You cant have any vibration when sharpening saws or planer blades.Dressing wheels gets the metal particles out of the wheel.
 
I have my father in laws reel mower grinder.He taught me how to use it.It sits idle most of the time.He was in the mower business long before the rotary mower can out.
 
Dave,

I started out with a consumer grade 6" grinder. It worked OK, but I was never really satisfied with it. Several years ago, I bought a Baldor 7" industrial grinder at auction for $80. Boy what a difference! The Baldor turns smooth as a whistle and I have never bogged it down. Cuts great and is much less likely to burn the steel than my old grinder.

As wheel size gets bigger the motor needs to turn slower. This is very important, especially if you are sharpening things. Otherwise it is difficult to keep the heat build up in check and it will take the temper out of the edge (turn it blue). Then the edge is too soft to stay sharp.

I would buy an industrial grinder at auction or off ebay over the consumer grade stuff any day. It is one of the best tool purchase I have ever made.

Cliff (VA)
 
The relatively new spin grinders take most of the skill required out of sharpening. They are very similar to a CNC machine tool and very pricey to boot. The old manual sharpeners like Foley's required a great deal of skill to properly sharpen reels. My dad got into commercial mowers in the 50's. He was the factory appointed rep for both Toro and Jacobsen(not at the same time) during his career and set many sales records including selling the most Jacobsen F 20's in the world. The F 20 was the largest self propelled reel mower made with 9 gangs that would cut a swath almost 20' wide. All these reels in addition to greens mowers and other reel mowers, meant there was a lot of sharpening to do. They weren't many people who were really proficient at it. A few hacks that thought they knew what they were doing though. My dad fixed a lot of other peoples mistakes and got more business because of it. He thought about retiring from sales to start a business just to sharpen reels because 95% of his customers didn't trust anyone else to do their sharpening. He also taught sharpening at the turf grass college. Reels are highly precision tools. Dave
 
Not totally true. I never bought a grinding from my supplier that vibrated when put on. When someone misuses the grinder some how or other it will vibrate. Dress the chips away and the vibration is gone.
I suppose you could buy a bad out of balance wheel. I just never have. Might be where it was purchased.
 
I have two bench mounted 6" and find they can handle most of what I need to do. One has two different grade stones and the other has a stone and a wire wheel. Two things not mentioned yet are good light and variable speed. One of mine has speed controll that I find very useful and both have lights mounted on a flexible arm. Being able to select the speed helps a lot when doing fine work.
 
I mostly use my Grizzly 1 hp. 2x72" belt sander for general grinding. I custom order the belts so I get good ones made for steel. A 36 grit zirconia oxide belt out does most grining wheels. It only take a second to change belts, I have a array of belts all the way up to 320 grit.
 
I have an 8" variable speed delta bench grinder. The best grinder I've ever used/owned. I've used bigger industrial ones, but this delta is very user friendly, with plenty of power. That being said, I use the 2 x 42 belt sander way more.
 
I just had to reply to the comment (I know there was sarcasm involved in your post) but if that is an example of the rough stuff that doesn't take a lot of skill I would love to see some of the precision skilled work that you do. Mold and tool making isn't my thing but the work done by skilled machinists looks better to me than most art seen in a fancy gallery.
Keep up the good work
Dan
 

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