Taiwan lathe spindle runout

I have a VFD on my lathe with dynamic braking. When threading i never disengage the half nuts, i just pull the handle straight up and into reverse, while simultaneously withdrawing the tool. The VFD brings the spindle to a rapid stop and then accelerates into reverse. I have also programmed my DRO to beep when it goes over the Z datum zero. I then set this datum about 1mm short of the shoulder.. I can then watch the thread cut and just listen for the beep.. I found without the beep it was easy get kind of hypnotized by the rhythmic cutting action and get your self distracted and overshoot the mark.
With the beeping DRO i can easily thread to a very consistent 1mm short of the shoulder.
The VFD also allows me to have a separate speed setting for reverse, so i can cut the thread at say 150 RPM, and have it retract in reverse at 1000 RPM.

Cheers
Lee
 
Leeroy said:
I have a VFD on my lathe with dynamic braking. When threading i never disengage the half nuts, i just pull the handle straight up and into reverse, while simultaneously withdrawing the tool. The VFD brings the spindle to a rapid stop and then accelerates into reverse. I have also programmed my DRO to beep when it goes over the Z datum zero. I then set this datum about 1mm short of the shoulder.. I can then watch the thread cut and just listen for the beep.. I found without the beep it was easy get kind of hypnotized by the rhythmic cutting action and get your self distracted and overshoot the mark.
With the beeping DRO i can easily thread to a very consistent 1mm short of the shoulder.
The VFD also allows me to have a separate speed setting for reverse, so i can cut the thread at say 150 RPM, and have it retract in reverse at 1000 RPM.

Cheers
Lee
Click to expand...

Thats a good idea with the beep. It would be nice if you could get it to give you three beeps so you could retract on the third.
 
leeroy
what lathe do you have? I am seriously thinking about a third lathe for the shop. I really like the VFD on my new south bend, and id like to have one on this third machine when I get one.
Ive been looking at that Taiwanese made precision Mathews. Lee
 
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skeetlee said:
leeroy
what lathe do you have? I am seriously thinking about a third lathe for the shop. I really like the VFD on my new south bend, and id like to have one on this third machine when I get one.
Ive been looking at that Taiwanese made precision Mathews. Lee
Click to expand...

I have the Australian version of the precision Mathews lathe. This one.. http://www.machinetoolonline.com/PM1340T.html
The only difference is the saddle controls on mine are mirror reversed (ie Long axis wheel on the right hand side of the saddle).
I've had mine for nearly 10 years and i is still going strong, although i have recently replace the spindle bearings.. I like it because it has a very short headstock and i can work with barrels as short as 18".

Cheers
Leeroy
 
Leeroy said:
I have the Australian version of the precision Mathews lathe. This one.. http://www.machinetoolonline.com/PM1340T.html
The only difference is the saddle controls on mine are mirror reversed (ie Long axis wheel on the right hand side of the saddle).
I've had mine for nearly 10 years and i is still going strong, although i have recently replace the spindle bearings.. I like it because it has a very short headstock and i can work with barrels as short as 18".

Cheers
Leeroy
Click to expand...


That precision Mathews in the link is the same lathe I have . Not a precision Mathews but same lathe.
 
Hlh-v

James Lederer said:
Lee,

Consider a nice used Hardinge HLV-H. Although nice used ones go for $10,000. They are top notch. Or maybe a Harrison M300. Harrison also makes some smaller CNC lathes that are very suitable for barrel work.


Here's one that "appears" to be in nice shape, also happens to be in Illinois:

http://www.ebay.com/itm/Hardinge-HL...178406?hash=item1c6c3f65a6:g:9kUAAOSw3xJXpnjn

Or maybe a Takisawa like this one:

http://www.ebay.com/itm/Takisawa-14...513952?hash=item33bc2ec5a0:g:nb4AAOSwepZXSLBr
Click to expand...

It may be a great lathe. The seller wont answer any questions, offers or return emails. He has no history so i would be wary of him.
Jerry
 
Back to spindle runout. I have a question. Are you turning the spindle by hand, or running the machine with the indicator in place? That may make a difference.
 
jlcprec said:
Back to spindle runout. I have a question. Are you turning the spindle by hand, or running the machine with the indicator in place? That may make a difference.
Click to expand...

I check both ways same results.
running there is more vibration but with many years of dialing in parts you learn what your getting.

I just finished a 7 saum with dialed in muzzle and throat to .0002 then used an expensive floating reamer holder and the chamber was getting belled. couldn't get reamer holder running good so cut chamber off (hate doing) started over with my cheaper one that is much more simple and got less then .0001 tir all through the cut chamber. The tail stock on my lathe is about .001 high in the Y and had it within .0002 in the X.
I'm getting good results. Just trying to remove all the error I can.
 
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