Grinder wheels?

N

Nobudy

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Nov 1, 2015
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I am a lead machinist at a company that gave me the approval to make 2-2x72 KMG clone grinders, one for the company and one for myself. I need some dimensions on the drive wheel and tracking wheels, like the radius across the diameter (X axis) of the tracking wheel and does the drive wheel also have the radius or is it just flat? I'm going to buy the contact wheels but I can make everything else and have my electrical guy wire up a variable speed motor.
 
While the KMG grinder is a good base to start from, the ONLY KMG I'd copy exact is the new KMG-TX I think it's called. The diameter of the drive wheel is based on what you wish the max belt speed to be - this is to be a direct drive variable speed grinder?

I've used 3 to 4⁰ or so for the tracking wheel with the drive wheel flat.
 
The EERF plans have nothing on the contact wheels, that I saw anyway. I have access to 2 CNC mills, a Bridgeport, 5 manual lathes ect... a whole machine shop at my disposal, but sadly, no water jet or laser cutters.
 
That's what I was wondering. Thank you! I should post pictures as I work on this. I'm shooting for a direct, variable speed drive if I can get the $$$ allocated. If not, I'll use whatever motor we have in shop and do a pulley drive. We usually have some smaller motors floating around. I haven't talked with my electrical guy yet, I just got approval on this Friday before we left for Christmas holiday. He might be able to do the variable speed drive with what we have in house.
 
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If you can snag a 3ph motor, it's only $75 shipped for a decent Chinese VFD drive. Just put filters over the air inlets and not worry about the metal dust. Perhaps a 3ph motor for your grinder, and let shop have whatever they want for a motor.
 
If your going for a KMG make it a double (two tool arm slots) or send me a PM and I’ll send you plans for a better grinder.
 
Nobudy said:
I am a lead machinist at a company that gave me the approval to make 2-2x72 KMG clone grinders, one for the company and one for myself. I need some dimensions on the drive wheel and tracking wheels, like the radius across the diameter (X axis) of the tracking wheel and does the drive wheel also have the radius or is it just flat? I'm going to buy the contact wheels but I can make everything else and have my electrical guy wire up a variable speed motor.
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If I ever build 2x72 belt grinder this is what I would do . . .Of course with ratchet tension .Dimension on drive wheel depends on motor RPM and what max speed you want .Grinder without at least 6000 SFPM max. belt speed is no grinder if you ask me if you intend to use ceramic belts .Big /4inch dia./ rubber coated idler wheel on bottom is something that you will find very , very useful ...+ speed is slower and bearing will last much longer .Rubber on drive wheel will drastically improve belt slipping . 1degree crown on tracking wheel is more then enough if grinder is build right ,width of tracking wheel 70mm or 2.7 Inch is enough .
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The above style is often called a "four wheel" or a "square wheel" grinder. It saves workbench space as the contact wheel arm does not need to stick out so far. It also has better tracking.
It does limit the size of the contact wheel, so if you plan on running a large diameter (14") wheel, go with a three wheel setup, or use 2X132 belts.

If I was machining a copy of an existing grinder, I would take a good look at the TW-90 and copy many of their features. The tracking is done by moving the whole motor/drive wheel mount a tad. This eliminates the need for a tracking wheel, and lets the tension wheel be rock solid ( because it is not also the tracking wheel). Ratchet tension is by far the best method I have used, too. As sujested by bjansen, two arm slots is very wise.
 
I am in the process of making bjansen's design, with a few modifications, like steel plates instead of aluminum and a different motor mount arrangement so we can use a motor we have in house. I was thinking about using different drive wheel sizes ( 2", 4", and 6') to make it a 3 speed as opposed to a true variable speed machine.
 
This in house motor is an 1800 rpm motor? If so, with the 2" drive you'd have around 900 or so SFPM, 4" drive would be around 1850 ro so SFPM, and a 6" wheel would be around 2800 SFPM. "IF" you could get an 8" wheel instead of 6" you'd have around 3700 SFPM belt speed which would be good for grinding profiles.
 
You are going to find changing drive wheel sizes every time you need to change belt speed a pain in the ass!!! The purpose of Variable Speed Drives(VFD) is to improve efficiency not slow down productivity....You should consider your pitch to the Boss about new 3ph motor and VFD as being part of the tools efficiency.
 
I agree. If your going to have one grinder you should get a variable speed set up. It will be worth every penny!

You will not change those drive wheels as it will feel so inconvenient you will not even mess with it more than a few times.
 
I have free rein to do almost anything I want once I get the approval for my "pet projects", as long as I stay on budget. So far this has cost us $0.00 since I am using left over materials. That should leave me enough to get the motor I want for the company's machine. I will be spending my own money on the one I get to bring home.
 
Stacy E. Apelt - Bladesmith said:
The above style is often called a "four wheel" or a "square wheel" grinder. It saves workbench space as the contact wheel arm does not need to stick out so far. It also has better tracking.
It does limit the size of the contact wheel, so if you plan on running a large diameter (14") wheel, go with a three wheel setup, or use 2X132 belts.
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@stacy , that drawing was there only to show size of wheel I would use in basic setup . Chassis can be classic as most 2 x 72 grinders you build in USA ....so he can use any size of contact wheel ....I will add that it is good idea to use rubber on upper idler wheel to .
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