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Rotation direction, inside grinding attachment for cylindrical grinder

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Diamond
Joined
Sep 25, 2011
Location
Garbsen, Germany
I want to put together an inside grinding attachment for my cylindrical grinder. One idea is to modify a lathe toolpost grinder. In any case:

- what is the normal rotation direction for an inside grinding spindle on a cylindrical grinder? Is it clockwise or counterclockwise as viewed from the workstock?

- what is the normal rotation direction for a lathe toolpost grinder spindle? Is it clockwise or counterclockwise as viewed from the lathe headstock?
 
Rather than get into the confusion of c, cw, from where, just think conventional cutting, not climb cutting. You do not want to climb cut and force the wheel to re-cut chips.
 
I agree with Red..climb grinding is much avoided for the sake of the grind and take up of the drive for the work head and grinder head. The work or wheel might have a reversing switch. Grinding to the close side or the far side ID can often control the work to wheel direction.
Direction of sparks can be a factor as you don't wish to have up-going sparks or in your face.
One grinder fellow I worked with had a round magnet on a shaft he could put into his motorized grinder head and so would often grind small Id and Od work off one end face or off the stub and part ID. Handy but took a little care not to throw a part...some times he would put an arbor stub on the magnet so to then indicate or grind the stub true.
Often he would ask me to make/grind the arbor stubs for him with making the stubs on the B&S 13 grinder between centers. Yes the big end for setting on his magnet face, and with having centers he could still run between centers for a much slower production..His jobs often ran one or two to a few hundred..so short run work..
Such grinding on a stub required on-going grinding direction because off-going might take the part off the stub arbor. yes with getting heatexpand on-going would push the part onto the stub...not off.
 
Buck: I can't reverse the work rotation direction on my cylindrical grinder. (Yes, I can reverse the work drive motor direction, but I am afraid that the design of the work spindle bearings and retainers only works for one rotation direction.)

Red: OK, let's talk about conventional versus climb cutting.

Assuming conventional cutting as you and Buck say, then I have a choice of (1) a downwards-rotating ID grinding wheel running on the inside-back of the part, or (2) an upwards-rotating ID grinding wheel running on the inside-front of the part. Are both OK? It seems to me that (2) will spray coolant upwards and is not desirable. Is that right?

If I want (1), can I use a lathe toolpost grinder for this? Or does that spin the wrong way?
 
Buck: I can't reverse the work rotation direction on my cylindrical grinder. (Yes, I can reverse the work drive motor direction, but I am afraid that the design of the work spindle bearings and retainers only works for one rotation direction.)

Red: OK, let's talk about conventional versus climb cutting.

Assuming conventional cutting as you and Buck say, then I have a choice of (1) a downwards-rotating ID grinding wheel running on the inside-back of the part, or (2) an upwards-rotating ID grinding wheel running on the inside-front of the part. Are both OK? It seems to me that (2) will spray coolant upwards and is not desirable. Is that right?

If I want (1), can I use a lathe toolpost grinder for this? Or does that spin the wrong way?

I think a toolpost grinder doesnt have the rpm needed for internal grinding.
I have some internal grinding spindles, varying from 18000 to 32000 rpm.

Maybe a dremel like tool would be better?

Greetings Peter


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It seems the work head would go left (up at the wheel) and the grinder turning right so at the far side of the ID all should be fine.
but now I cant remember the direction of my tool post grinder...it should go the way that tightens the wheel nit....
 
Ok, I checked. A normal tool post grinder is right-handed (counter clockwise rotation viewed from the headstock). So it will work fine as an inside grinder on a cylindrical grinder, cutting on the backside of the part. This would be regular cutting not climb cutting.
 
You want them to opose rotation wise at the point of the grind, ie if work moves down at that point wheel wants to go up, not so much for the climb or conventional cut, but to gain surface speed, you can only spin a wheel so fast, but if you spin the part the other direction you can soon gain-some not insignificant surface speed and generally when grinding there’s not a upper limit on cutting speed imposed by the work material, just a safe limit for how fast you can spin a given wheel!
 
Just FYI, a Dumore 57-031 with interchangeable spindles will do 42,500 RPM. Used to use one in place of the original head on an OD grinder for ID work. You can flip the motor and spindle around on the casting so they point in a more sensible direction.
 








 
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