Hitting dimensions when turning

[Munkul]

I thought that but I just cut some awful mild steel that ripped when taking large cuts but at 0.2 produced a reasonable finish

Thats the material though, some steel is just awful
Also some inserts and shapes produce weird results.
VCMT has a very narrow sweet spot for chip breaking, for example, on cheap or expensive inserts. Push it too hard or deep and you end up with a mess.

 

[mike os]

This technique and practice is the real key ... don't expect to jump on a lathe once a year and hit close tolerance off the bat... unless your dro is dialled in

 

[Guineafowl]

This technique and practice is the real key ... don't expect to jump on a lathe once a year and hit close tolerance off the bat... unless your dro is dialled in

No DRO! Might get one one day, but the mill has priority for that.

It seems to be a good idea to go for good surface finish and precise dimensions, even if the part doesn’t need it (eg tractor pin); that way you’ll stand a chance of getting it right when it is needed.

 

[Munkul]

You don't need a DRO, it just speeds the process up. A calculator and a paper and pen achieve the same thing, and you use the zero points on your handwheels.

 

[fizzy]

I regretted fitting a DRO to my Triumph. It is VERY handy on the bed but the cross slide one makes me less accurate. so I ignore that one. They should sell a single axis DRO!
Would be lost without one on my Bridgeport though - Backlash? What is backlash

 

[Seadog]

It is VERY handy on the bed but the cross slide one makes me less accurate. so I ignore that one.

I find the opposite. Wear in the feed screw and nut entail more measurements. With the DRO I can hit finished dimension with ease.

 

[ukracer]

I regretted fitting a DRO to my Triumph. It is VERY handy on the bed but the cross slide one makes me less accurate. so I ignore that one. They should sell a single axis DRO!
Would be lost without one on my Bridgeport though - Backlash? What is backlash

That's strange. I find the same myself.
If I use the cross slide on my colchester I can get close but using the DRO I never seem to get as accurate and thus I do more creeping up if I use the DRO.

 

[tigdlo]

I regretted fitting a DRO to my Triumph. It is VERY handy on the bed but the cross slide one makes me less accurate. so I ignore that on

If the scale is the oposite side of the cross slide to the tool, when the tool is loaded it will deflect more then the slide, balancing the final cuts and setting the DRO to the corrected diameter before the final cut should still work as the deflection should be equal.

 

[fizzy]

If the scale is the oposite side of the cross slide to the tool, when the tool is loaded it will deflect more then the slide, balancing the final cuts and setting the DRO to the corrected diameter before the final cut should still work as the deflection should be equal.

I just need practice with it really. No time as always

 

[Guineafowl]

Backlash? What is backlash

In my limited experience, you might rediscover it when climb milling too deep

 

[RichardM]

Lock cross and top slides off for the finishing cuts. Removes a couple more variants.