Thread: A Little Shop Math, Bench Grinder Speed vs Hand Held Grinder Speed

Great post, I like to think about feet per minute of the tool I am using. The surface feet per minute is a lot more relevant and less discussed than RPM. I had never thought about in terms of miles per hour the mph's figures surprised me.

I think the pressure applied and the movement of the tool and the mass/heat dissipating ability of the material is more important the the contact patch size. With all the variables it could get very complicated very fast. It boils down to if it to hot to hold-its to hot.

Charlie

PS my 3" buffs on a 1725 rpm motor, 1354 fpm, slow and safe, just like me

I did a similar less formal look at this on another thread. Thanks for being a lot more exact than I was. As for the safety, I don't want anyone to get hurt. Growing up I watched my Dad sharpen axes with a bench grinder and chainsaw blades with a Dremel. After a while he and I both learned that using files were more effective and didn't pose as much danger. So even now I try to use the Dremel at slow speeds and taking a lot of time because as I said in another post I have ruined blades because they were over heated.
SO be careful folks, I enjoy these razors, but I like my fingers better.
Trey

Originally Posted by gssixgun

Whoa Nelly:
Now you just did open a huge can-o-worms there if that was the presumtion...

You can march out all the math in the world, and never ever prove that a Dremel is near as safe as a bench mounted buffer....
There is one huge glaring difference... the Dremel is handheld!!!!! this one fact alone makes it way, way, way, more unpredictable when being used...

I thought you where just showing that heat generation was similar or less...

Sharp metal + fast spining wheels = Dangerous stuff, period...

Now you guys that are holding the razor in one hand and the Dremel in the other, you should be on TV on one of those extreme sports things.... at least hold the edge of the razor on a surface....

Hey Glennactica,

It is not my can of worms. I see videos by Jockeys with his one handed Dremel operation and I read Bruno's list of bench wheel injuries. Me? I am a safety nut. I teach safety as much as I teach woodworking. All I did was provide a real world comparison of the two types of grinders. I will say that the torque delivered by a bench grinder is way more likely to throw a blade across the room than a hand held Dremel type machine. I also see the potential for a chip to be torn from the edge of a blade by a hand held grinder if the wheel is allowed to spin onto an edge (as opposed to spinning off the edge). That is why I never work on a razor unless It is pressed down onto my leather sandbag so the edge is not lifted off the surface.

B-rad

No matter what one key is to always wear eye protection as well as an apron of some sort and a light set of leather gloves. I know with gloves on it's hard to feel the heat etc but it's worth it to go ahead and wear them.
I know at the Missouri Meet we were talking and Lynn mentioned he uses a leather apron. Mine is much lighter weight and really I need to try and find a leather one.

Kinco Heavy-duty Leather Shop Apron, Aprons, Workwear - GEMPLER'S

http://www.gemplers.com/product/1566...rethane-coated Gloves Cut Resistant