Any advantage of three axis DRO on a lathe compared to two axis?

Laverda · Mar 7, 2019

After years of no DRO on my 16 x 40 lathe, I think it's time to put one on. I see both two and three axis units available. I am trying to think of why I would need to know what the compound is doing as unless it's at 90 degrees to the carriage it's a meaningless measurement and I don't use the compound unless I am threading.

I am retired so this will be in my home shop and as I get older, remembering where I was at when I have to stop for something else (the wife) is getting to be a pain. So is a three axis unit of any value? They sure seem to cost a lot more than a two axis.

And finally one last question, my mill has a SONY Magnescale DRO which has worked perfectly for may years and was hoping to put one on the lathe. I don't see Sony DRO's on anything anymore. It appears they are no longer owned by SONY? Are they any good and can't find any info on pricing?

RJT · Mar 7, 2019

No reason I can think of to have a 3 axis DRO on an engine lathe. No idea on Sony DRO availability, haven't seen them advertised lately but I haven't been looking for them either.

ripperj · Mar 7, 2019

You can set the compound angle into the DRO and if you put it in summing mode-it will account for both compound and cross slide movements

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sfriedberg · Mar 7, 2019

2 axis works fine for me, and it is a massive time and headache saver.

The angle scale on my compound is only marked every 5 degrees, and there's no guarantee it's accurate even at that lousy precision. So I wouldn't trust a DRO compound reading unless I spent a bunch of time indicating it in.

Cole2534 · Mar 7, 2019

If your compound never swings, maybe. Otherwise I can't find the value.

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steve-l · Mar 8, 2019

There is no advantage to having a DRO on a lathe. None. If you mount your position scales on your carriage, you have eliminated your ability to mount a travel rest. I see no way to mount a scale on your compound that would not interfere with all lathe operations. DROs belong on table machines, not on lathes.

MilGunsmith · Mar 8, 2019

steve-l said:
There is no advantage to having a DRO on a lathe. None. If you mount your position scales on your carriage, you have eliminated your ability to mount a travel rest. I see no way to mount a scale on your compound that would not interfere with all lathe operations. DROs belong on table machines, not on lathes.

I have DRO's on both lathes in the shop, a Hardinge HLV-BK and a Clausing 1565. I installed the one on the Hardinge and the Clausing was installed by the vendor. Both are Accu-Rites. Both lathes still have full functionality of all parts, taper attachments, steady and follower rests. If the scales are properly installed there is no issue.

RJT · Mar 8, 2019

Steve

I respectfully disagree . Scales can be mounted is such a way so as not to interfere with any function of the lathe. If you were to use one properly mounted you would certainly see why this is a popular time saving option.

MattiJ · Mar 8, 2019

RJT said:
Steve

I respectfully disagree . Scales can be mounted is such a way so as not to interfere with any function of the lathe. If you were to use one properly mounted you would certainly see why this is a popular time saving option.

DRO is huge improvement especially on a old clapped out lathe. No more quesswork or dicking around with dial indicators in an attempt to turn accurate diameters.
Anything better than 0.04mm was huge pain in the ass earlier, installed cheapo 200$ DRO kit and now turning bearing fits to less than 0.01mm is amazingly easy compared to earlier.
Not to mention that I always got lost in count with dial wheels..

GregSY · Mar 8, 2019

No DRO on a lathe? That's crazy talk. Using a lathe without a DRO is like going through a drive-thru window or toll booth in a car with windows that don't roll down. You can do it, just don't let your friends see you.

eKretz · Mar 8, 2019

Yeah, major benefit having the DRO on a lathe. Especially with repeat parts and a quick change tool post. Saves a ridiculous amount of time and trouble if it's used right. I served my apprenticeship in a shop with no DROs on the lathes, and it's not a problem to work around but it costs time. After using DROs on lathes in subsequent shops I would not want to go back to those without.

steve-l · Mar 8, 2019

I have 3 lathes in my shop, big little and middle sizes. All have TA's. I have owned eight other lathes. None have had a DRO. I don't make many of anything. More than 90% of my lathe time is set ups. All my machines use Multi-fix. All my machines are as new. If I dial in a cut, that's what gets cut. How do I benefit from a DRO? On all my machines, there is no way to mount a scale that does not inhibit something. Please educate me. I must be missing something. If the scale is mounted on the left side, it is vulnerable to damage and it interferes with carriage depth of travel to the left. If a cross slide scale is mounted on the right, it prevents mounting the follower rest because it blocks the mounting holes and it inhibits TS quill range as well. What am I missing?

HuFlungDung · Mar 8, 2019

steve-l said:
I have 3 lathes in my shop, big little and middle sizes. All have TA's. I have owned eight other lathes. None have had a DRO. I don't make many of anything. More than 90% of my lathe time is set ups. All my machines use Multi-fix. All my machines are as new. If I dial in a cut, that's what gets cut. How do I benefit from a DRO? On all my machines, there is no way to mount a scale that does not inhibit something. Please educate me. I must be missing something. If the scale is mounted on the left side, it is vulnerable to damage and it interferes with carriage depth of travel to the left. If a cross slide scale is mounted on the right, it prevents mounting the follower rest because it blocks the mounting holes and it inhibits TS quill range as well. What am I missing?

Who the hell needs a follower rest?

I tried one. Once.

A DRO on a lathe improves the precision of moving the cross slide accurately. How is that not a benefit? It is also kind of nice to use to set up a taper attachment quickly and accurately.

You say you don't make much of anything. But so what, it is very common use at least a couple of tools, which you need to know the position of quite accurately. A DRO with a tool offset feature makes this quick and easy because you can calibrate an offset for each tool, just punch in its tool number, which resets the displayed scale position, and off you go. You know exactly where your tools are (especially with a multi-fix). I find it almost CNC like in its usability factor. I had one DRO acting up lately and had to go back to manual dial mode. What a PITA.

I've only ever had a DRO on the cross slide. Never used one on the Z. My excuse was that an 8 foot long Magnescale was $$$$ way back when. I have a tape measure and a dial on the carriage handwheel which gets me close enough for the most part. Now I'm too damn old to spring for the upgrade. It would be nice though, to have dual offset for each tool so I could hit the exact same shoulder positions with different tools.

Nmbmxer · Mar 8, 2019

Don't put the 3rd axis on the compound, put it on the tailstock. I used to have a lathe that had a mits digital caliper on the ram and it was awesome for drilling holes.

DDoug · Mar 8, 2019

This brings up a point to consider....

Why not add an encoder to the lead screw, and program
the display to show the threading dial ?

MattiJ · Mar 8, 2019

digger doug said:
This brings up a point to consider....

Why not add an encoder to the lead screw, and program
the display to show the threading dial ?

Or Renishaw/RLS rotary encoded built inside the top slide:
Rotary magnetic encoders | www.rls.si

620000 pulses per rotation would give plenty of resolution.

BTW for someone who has too much time the RLS magnetic linear tape scales would allow some really slick possibilities to build totally "hidden" system with the scales inside the crossslide or topslide:
Linear magnetic encoders | www.rls.si

Lumberjack · Mar 8, 2019

I have 3 axis on my lathe and I´ll never get anything else.

One big benefit is you Always know where the tip of the tool is even if the compound gets moved. Normally one can select if it should sum with one of the other axis or not.
Vectorising is great.

Ken hosford · Mar 8, 2019

I put digital on all 3 axis of my lathe the thought at the to verify the position of compound after bad chatter or the likes . In retrospect I should have bought 2 2 axis readouts . An the same on my mill bought 3 and I was planning on Mitutoyo ? digital Quill read out , but figured out to late theydo not work in my unheated shop in the winter .

Jim McIntyre · Mar 8, 2019

steve-l said:
... On all my machines, there is no way to mount a scale that does not inhibit something....

...What am I missing?

An open mind?

On my EE, I just made a bracket to mount the cross slide encoder behind the cross slide. I lost exactly zero in Z-axis motion for both the tailstock and carriage. I tucked the Z axis encoder under and behind the back way. Again it had no impact of travel on either the carriage, tailstock, or cross slide.

eKretz · Mar 8, 2019

What you are missing Steve is the experience of trying it both ways to know how much more efficient things can be. I have used both ways extensively and far prefer having the readouts. The "almost CNC-like" comment is very on point. I've said before here that I can make pretty damn good time on a lathe with DRO, to the point that a CNC (needing to be programmed) probably couldn't outrun me on a middling quantity of parts. A hard worker can literally go that quick, no need to do any measuring at all once the DRO is set the first time except for when finishing tight tolerance parts.

I lined more than a few guys up on jobs after doing the setup and dialing in my speeds, feeds and depths of cut and finishing a few parts (I often got pulled off of jobs to get other "hot" jobs dumped in my lap) and would say hey you ought to have about *insert quantity here* parts done by the end of the shift - only to have them comment with some variation of "I can't get that much done in a day, I'm not a machine!"

Any advantage of three axis DRO on a lathe compared to two axis?

Cast Iron

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