# Tool Post Grinder



## Rick In VA (Mar 13, 2014)

Hi All!
I have been trying to use a South Bend tool post grinder and have had no luck getting it to work correctly and am looking for help.  I have trued the grinding wheel with the tail stock mounted tool.  I have tried running the lathe in forward and reverse, fast and slow, fast feed and slow feed, from right to left and left to right, and I have failed to get a smooth finish.  It looks like a million facets around the metal I am trying to grind.  It looks like it might be a harmonic vibration but I would think trying different speeds and feeds would have broken the pattern.  Are there any simple rules that I could have overlooked?  I have tried taking .002 "cuts" and .010 "cuts" and nothing changes.  I would like to get this worked out so I can grind and polish shafts.  Any help would be appreciated.
Rick


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## RandyM (Mar 14, 2014)

What grade of wheel are you using?


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## Ray C (Mar 14, 2014)

0.002" cut is ten times deeper than what a TPG was intended to remove.  Anyhow, please show some pictures of the TPG so we can see the setup.  We'll also need to know the type of wheel and RPM.

I use a different version of a TPG and generally speaking, try to take off material no deeper than 0.0002" with a finish pass of 0.0001".


Ray


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## Bill Gruby (Mar 14, 2014)

With a .002 cut I speculate your finish looks like hamburger. That is way too much. Ray is taking the opposite but is much better off, .0005 will do the job. As Ray requested, pictures will help.

 "Billy G"


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## GK1918 (Mar 14, 2014)

Bill Gruby said:


> With a .002 cut I speculate your finish looks like hamburger. That is way too much. Ray is taking the opposite but is much better off, .0005 will do the job. As Ray requested, pictures will help.
> 
> "Billy G"




Oh yes, I think your best freind is your ears.  sip - nothing - sip a little more until there is no more ziping just a nice spark flying sound.
would you shave with a .002 cut?  not disrepectfull,  its looking like you are using the tool p. grinder as a 4 inch grinder for grinding welds.

Its only old school


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## Rick In VA (Mar 14, 2014)

Well there seems to be a theme here!  I am taking way to much off.  I do suspect that some of you are applying your knowledge of surface grinding to a tool post grinder however.  To say remove .0002 of an inch implies that one can move the cross slide of a South Bend lathe with a 15 pound grinder .0002 with reasonable accuracy.  In my world that is not possible.  I do however get your point, lighten up.  I like the advice of engaging until the is a light circle of sparks and go with it.  So now we have depth covered.  How about advice on feed speeds and spindle speeds, as well as the rotation of both the object and the wheel?
Thanks for the previous information and I hope you help me further!
Rick


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## xalky (Mar 14, 2014)

Rick In VA said:


> Well there seems to be a theme here!  I am taking way to much off.  I do suspect that some of you are applying your knowledge of surface grinding to a tool post grinder however.  To say remove .0002 of an inch implies that one can move the cross slide of a South Bend lathe with a 15 pound grinder .0002 with reasonable accuracy.  In my world that is not possible.  I do however get your point, lighten up.  I like the advice of engaging until the is a light circle of sparks and go with it.  So now we have depth covered.  How about advice on feed speeds and spindle speeds, as well as the rotation of both the object and the wheel?
> Thanks for the previous information and I hope you help me further!
> Rick


 If you set your compound to a 5-6 degree angle to the work, each .001" advancement on the compound correlates to about .0001" advancement to the work. That'll give you the fine adjustment that you're looking for.


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## DMS (Mar 14, 2014)

Marcel has hit the nail on the head. It's an old trick to get better resolution than your dials can give you.


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## Rick In VA (Mar 15, 2014)

Thanks Marcel!  That is a new one for me.  I will use it and remember it.
Thanks everyone for working this through with me.
Rick


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