Graziano 12S

There are a number of spindle grinding services available. They come to you and grind your spindle in place. While I thankfully have never had to engage one of these companies, I would if I were in your place. Replacement is not an option and trying to ream it and hope to retain tenths accuracy is going to be iffy. If that was my lathe, I would have someone come out and grind it for me.

Try a Google search for "spindle grinding, California".
 
mikey said:
There are a number of spindle grinding services available. They come to you and grind your spindle in place. While I thankfully have never had to engage one of these companies, I would if I were in your place. Replacement is not an option and trying to ream it and hope to retain tenths accuracy is going to be iffy. If that was my lathe, I would have someone come out and grind it for me.

Try a Google search for "spindle grinding, California".
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Mike,
A quick Google search turned up a place in SoCal and a 1-800 number that claims they can service anywhere in NA. Appreciate the lead--I never knew such a service existed.

Seems like it will be expensive regardless.

Evan
 
Yes, expensive but given the importance of the spindle taper, especially if you turn between centers or use collets in the taper, then it would be worth it.
 
I've reached out to a couple in-situ spindle grinding services with no response yet. They seem to specialize in CNC spindles, but we'll see.

I'm questioning how good is good enough? I checked run out again this morning with a 1/2" collet and drill and was getting what I consider unacceptable runout of 0.001", but I really think that is a result of a couple dings I see with closer inspection of the collet lip. After checking the drill, I again checked the roughness and runout of the inside of the collet adapter and it is <0.0001", which seems on par of what was measured when the lathe shipped new. Of course if roughness aligns to push the collet off center it wouldn't take much to be out of spec a few inches from the nose.

Another question is along the lines of Ulma Doctor's point. The fact that I'm not picking up a lot of deviation with the 0.0001" indicator suggests that that scratches are "innies" not "outies", thus will have much less impact on precision (and also be easier to clean up well with a reamer)?
 
Such a pity that the spindle taper is all gnarled up. I hope the grinding service gets back to you and can help.

Still, all is not lost. Luckily, you have a camlock spindle so you can still use an ER or 5C chuck if you need to use collets. The only real capability you've lost is the use of a dead center for between centers turning and you probably won't be doing a whole lot of that.

Hope you get this cleared up, though.
 
mikey said:
Such a pity that the spindle taper is all gnarled up. I hope the grinding service gets back to you and can help.

Still, all is not lost. Luckily, you have a camlock spindle so you can still use an ER or 5C chuck if you need to use collets. The only real capability you've lost is the use of a dead center for between centers turning and you probably won't be doing a whole lot of that.

Hope you get this cleared up, though.
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Mike,
While it looks bad, it doesn't measure bad. What's the determining factor for needing regrinding? Am I just in denial?

From a cost perspective, putting a new 5C collet chuck on the D1-4 is probably a whole lot cheaper than regrinding the spindle?

Evan
 
ACHiPo said:
Mike,
While it looks bad, it doesn't measure bad. What's the determining factor for needing regrinding? Am I just in denial?

From a cost perspective, putting a new 5C collet chuck on the D1-4 is probably a whole lot cheaper than regrinding the spindle?

Evan
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To be honest, the spindle taper is not that critical in terms of how functional the lathe will be. It is useful to assess the accuracy of the spindle; you must be able to directly measure on the spindle surface in order to evaluate the accuracy of the spindle so if it is all gnarled up then you cannot do that. It is also used to house a dead center and other MT accessories. I use a 5C collet adapter from time to time if I have a run of nominal parts to make but this isn't very often and I could easily get by with a 5C chuck if I had to. I also do not turn between centers very often so I could live without it. Even if I had to turn between centers I could chuck some stock in a jawed chuck and make it, then leave it in place to turn between centers.

So, other than being able to assess spindle accuracy, you can live without a nice spindle surface. It's just that for myself, I would want that thing re-ground if it was possible because I am OCD about my lathes.

You are probably right about a direct mount collet chuck being cheaper than grinding the spindle but as I do not know what such a service costs, I'm not sure about that. If you do get it re-ground you will also need another 5C collet adapter to go inside of it and you have to evaluate the collet closer that allowed the original adapter to be loose enough to spin.
 
I'm wondering if I should get a MT5 test bar, as direct measurement of the 5MT taper seems pretty good? Seems like it would be good to have to dial things in anyway, in addition to making a test bar to dial in leveling?
 
I would try emery paper, or even a small file, and see if you can get the high spots cleaned up. As said already, the low spots will not matter. Then try with several collets, and drills to see how consistent the measurements are. Even remove and reinstall the collet adapter. If it is bad enough, I would invest in a tool post grinder, and lightly take cuts to get it in shape. Reamers are for big cuts, compared to the grinder.
 
Superburban said:
I would try emery paper, or even a small file, and see if you can get the high spots cleaned up. As said already, the low spots will not matter. Then try with several collets, and drills to see how consistent the measurements are. Even remove and reinstall the collet adapter. If it is bad enough, I would invest in a tool post grinder, and lightly take cuts to get it in shape. Reamers are for big cuts, compared to the grinder.
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Not sure why the thought of a grinder is so much more terrifying than a reamer? Well, there is the difficulty in dialing in the precise angle. And the abrasive dust.

Thanks for the suggestion--the people I have a lot of respect for think grinding is the way to go so I'm definitely noodling on it seriously.
 
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