Re: Head stock alignment


sblatheman
 


"PS He more or less managed to twist the bed in a way that would practically eliminate the taper. Therefore, the lathe could have passed inspection that way."

NO WAY !
The first thing the tester did was level the bed, then perform the geometry tests. The cutting tests were next(chatter test and 2 collar test)

Ted

On Mar 11, 2014, at 2:57 PM, Paolo Amedeo <machineshop@...> wrote:

 

It is more likely that, instead of cutting a nice taper you'd end up more or less with a two diameters piece, with an abrupt change in diameter when the carbide tool starts to bite into the piece (cutting from tailstock to headstock) or starts gliding over the surface (cutting the opposite way).
I don't think Mark has mentioned anywhere that he has used a carbide tool.
Anyhow, hopefully we haven't been very successful in scaring Mark away and I hope that he will intervene in the discussion by filling in with missing details.

Paolo

PS He more or less managed to twist the bed in a way that would practically eliminate the taper. Therefore, the lathe could have passed inspection that way.
 

On 03/11/2014 02:48 PM, Jim B. wrote:
 

I do know that, (from my sad experience) trying to cut an unsupported 6”, or even a 4” length, with a carbide tool, using a light cut will result in a taper.

Carbide, unless you take the time to hone/polish it, should not be used for light cuts. It just skims over the surface.

A nice sharp, polished HSS tool, with a rounded point might be OK.

 

Jim B.


From

 

Jim,
I agree that we miss a few details (e.g. material of the bar, etc.), but by the overall description that Mark gave in his original post, I have the impression that he knows at least the basics (light cuts, not a really skinny test piece, etc.).
Moreover, at least for me it would be quite challenging to be able to remove such a strong taper and cutting true the whole 5-6" if the taper were mostly caused by a lousy cutting setup.


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