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Converting a bench grinder to a buffer.

Hi,

I have a 6" bench grinder and I want to convert it to a buffer. So would a 4" buffing wheel work on my bench grinder? Also i have questions about those arbor motor extensions - not the spindel type but the regular extensions. I was reading online and some people say you need to buy a left threaded extension for the left shaft and a right one for the right. They said because the threads on the left shaft turn clock wise, and on the right counter clock wise - if you get two rights then the wheel will not stay tight. Some say it doesn't matter - that one kind will work on either side. I dunno?
 

ajkel64

Moderator
Great question, I have no idea but hopefully someone will know. I want to to the same thing with my bench grinder as I want to start buffing up my old golf clubs.
 
Hi,

I have a 6" bench grinder and I want to convert it to a buffer. So would a 4" buffing wheel work on my bench grinder? Also i have questions about those arbor motor extensions - not the spindel type but the regular extensions. I was reading online and some people say you need to buy a left threaded extension for the left shaft and a right one for the right. They said because the threads on the left shaft turn clock wise, and on the right counter clock wise - if you get two rights then the wheel will not stay tight. Some say it doesn't matter - that one kind will work on either side. I dunno?
It helps if the are right/left threaded but not the end of the world.....if your worried a drop of Loctite 242 will prevent it from moving.
Word of caution though....a 6" grinder with 4" wheels is going to spin really fast so if your using it for razors be really really careful about heat and edge damage....you adsolutely do not want to hook the edge in that setup.
 
You can run the power cord into a variable speed control if you wanted to slow it down, but that may affect the lifespan of the engine.
 
Many bench grinders have motors that do not do well when you attach a speed control for a different type of motor. There are a ton of threads about this on the internet. As an aside, using a smaller wheel will 'slow it down' - not 'speed it up'; spindle speed stays the same, but there is less surface feet per min across the working surface. When I was using greaseless compounds, I had 6" sewn cotton wheels on a 6" grinder. Worked fine, but I had to pay very close attention. I was going to get 4" wheels at some point, but I stopped using greasless so that was that.
 
Many bench grinders have motors that do not do well when you attach a speed control for a different type of motor. There are a ton of threads about this on the internet. As an aside, using a smaller wheel will 'slow it down' - not 'speed it up'; spindle speed stays the same, but there is less surface feet per min across the working surface. When I was using greaseless compounds, I had 6" sewn cotton wheels on a 6" grinder. Worked fine, but I had to pay very close attention. I was going to get 4" wheels at some point, but I stopped using greasless so that was that.
Yeah the smaller the wheel - the lower gear the rpm.
 
I have read that a sewn spiral wheel will suit most of your need when polishing metal/steel. I'm curious about compunds. Grease based vs greasless? I think the greasless has a shelf life but a grease based is infinite. So which of these 2 compounds are the easiest to work with? I read that certain compunds don't want to stick, and some require drying time after the wheel is charged?? I want the less finicky type.
 
Greaseless has a shelf life because it dries out. If you can stop it from drying out, I think it lasts well but I don't know that for sure. I don't know if 'grease based' (rouges) come in low grits like greaseless does. I always let greasless 'set' after applying, like maybe 2 minutes.
 
Greaseless has a shelf life because it dries out. If you can stop it from drying out, I think it lasts well but I don't know that for sure. I don't know if 'grease based' (rouges) come in low grits like greaseless does. I always let greasless 'set' after applying, like maybe 2 minutes.
I thought about trying this its cheap and readily available at Lowes. Not sure if its dry or oil based though.
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crayons like that are usually like rouge polishing compounds. Usually a stearic acid/olefin base - not aggressive stuff. Sears used to sell a similar set of 3-4 large blocks, black tripoli, Chromox, Red Rouge and white something.... I use the black and red for finish polish on scales sometimes.
 
crayons like that are usually like rouge polishing compounds. Usually a stearic acid/olefin base - not aggressive stuff. Sears used to sell a similar set of 3-4 large blocks, black tripoli, Chromox, Red Rouge and white something.... I use the black and red for finish polish on scales sometimes.
If greasless has a shelflife then greasy based it is - I will never use large quantities of this stuff. Lol, its probably a one time buy. I was searching and the brown rouge ain't made for steel -its typically used on softer metals. So what do you buy?
 
Oof. Lots of stuff to address here. First, your grinder can probably NOT be slowed down with something like a router speed control. Single phase grinders have two armature windings, one for high torque to get the wheel going from a stop and one to run it at high speed. When you start your grinder, after a second or so you'll hear a *click* which is the grinder "switching gears" so to speak. It's actually switching from the start winding to the run winding. This can be done in a couple different ways but usually it means that the grinder can't be slowed down or it will switch back to the start winding and may burn it out.

Left hand/right hand is actually a very good idea. Most bench grinders are set up this way from the factory. If you add extensions, you should do the same. It isn't a big problem with very light pressure, but if you ever bear down into the wheel or buff, it is possible that they can unscrew pretty quickly at high RPM. Then your wheel will zip off the machine and across the floor.

For a good compound, try Zam. I like that one a lot. It has a mix of grit sizes, and if you use heavy pressure it will cut relatively fast but with very light pressure it will also polish up very nicely.

A stiff tightly sewn buff is good if you want to maintain flatness or do some heavy material removal. A soft spiral buff is good for finish polishing. You should use separate buffs for each compound you use. And yes, the smaller the buff, the lower the surface speed for a given RPM.
 
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