Tool post grinder

Clock work

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Unsure if this is a lathe or grinder topic... guessing lathe.

I've decided to un-bell-mouth the 3-jaw on my 10k which has caused me to dig out and start to de-crap I believe the last thing that came with the lathe, the tool-post grinder. Since the original owner purchased every single option SB made at the time, I assumed it would itself be SB but no joy. Once the years had been cleaned off the thing, I have this. Anyone recognize it? I haven't determined runout yet due to project overload but in looking at it closely I'm not setting my expectations very high. If it's known junk, I'll just put it back in the box and either get one of the cheapie direct drive units off eBay or one of the Dumore's. Either way, I need more in that it doesn't have the reach to get into the jaws. No plans to make tool post grinding a common thing. Just want my chuck back. Thanks for any input on this thing.

CW

20180508_222922.jpg
 
For dressing chuck jaws I would prefer a larger Dremel type tool or an air die grinder mounted in a custom toolholder. More rigid setup. Also easier and faster to set up. What you have should work, though, if it is not clapped out. The current configuration will probably not have enough RPMs for good I.D. grinding of chuck jaws. Still, it should work.
 
A good, sound TPG with ID spindle will easliy do a fine job. Just remember to block the jaws in a gripping fashion so after grinding and you chuck up a part you have the same clamping as when ground.
 
If you decide to junk it, please throw it in my pile.
 
A good, sound TPG with ID spindle will easliy do a fine job. Just remember to block the jaws in a gripping fashion so after grinding and you chuck up a part you have the same clamping as when ground.

Thank you, Sir. As I'm certain I'll get a different answer at any given point on the scroll, I intended to plot out what the error vs scroll position looks like and select my position from that. See.. like.. I used to be "technical" and I'm struggling to remain boring:)

CW
 
For dressing chuck jaws I would prefer a larger Dremel type tool or an air die grinder mounted in a custom toolholder. More rigid setup. Also easier and faster to set up. What you have should work, though, if it is not clapped out. The current configuration will probably not have enough RPMs for good I.D. grinding of chuck jaws. Still, it should work.

Bob... do you think something direct-drive will hold as nice a finish as something where drive vibration is dampened out by a belt of some kind? I know there are CNC routers and surplus spindles from semiconductor fabs that I was going to look in to if I had to go a different route to mine.

Clapped out... always loved that phrase:)

CW
 
Bob... do you think something direct-drive will hold as nice a finish as something where drive vibration is dampened out by a belt of some kind?
I don't think that with or without a belt makes much difference to the finish, as long as the belt and the bearings are good. Typical surface speeds for internal grinding are around 4000-12000 SFPM (I was going to say 5000-6000 SFPM, but looked it up...)
http://www.abrasiveengineering.com/speeds.htmhttp://www.abrasiveengineering.com/speeds.htm
Unless your TPG motor has a much higher RPM than I guess it does, you will not likely be very close to the numbers above. It will still remove material, but not with as nice of a surface finish.
 
We typically get 25 -34 RMS on ID's with our TPG'S. Belt vs. flexable shaft drive....belt will always win out.
 
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