DRO On the Lathe?

[Ray C]

Because of another thread going on now, I noticed that DROs are in the $200 price range. Pretty sure I paid about $650 on my mill many years ago. At these new prices, it's tempting to put DRO on the lathe but, I've been doing fine without it and don't know if it's worth rocking the boat. I have an iGaging "DRO" on the Z axis which gets me in the ballpark then, calipers & mics for fine-tuning.

For me anyhow, it seems that operating the lathe and mill is half art and half science. When it gets right down to those last couple cuts and the grande-finale finish pass, it's all art at that point. Does a DRO really help that part of things?

Does anyone out there have any convincing thoughts/opinions why I should try DRO on the lathe?

Ray

 

[T. J.]

I can't really answer your question, since I don't have one either. But since you already have an iGaging scale, you could consider adding another one on the cross slide and incorporating the two of them with this:

http://blu-dro.com/

That would add the functionality of a "real" DRO. Like I said, I don't have any experience, but I have been looking at this setup for my Logan lathe.

 

[wrmiller]

When I'm doing stuff that can be plus or minus a thou or two, I take a cut, measure the diameter of the part, input that number in the DRO and never measure again. And the part comes out fine. Surprisingly, I hit the number dead on about 3 out of 5 times, but that has come with practice and learning how much off the actual cut will be based on how heavy or how light the cut is.

When I'm trying to stay within a thou or less I'll do the above until I'm close and then start measuring the part. The DRO then just allows me to really 'dial in' the DOC as I have .0001" diameter resolution on the cross slide. Takes 'skim pass' to a whole new level.

In the end, I agree that much of this still requires art or skill, but the DRO definitely helps speed/simplify things for me.

 

[Bob Korves]

I recently bought a 3 axis glass scale Chinese DRO for my mill. $228 delivered. It came as promised, no issues, and everything works. Have not installed it yet, too cold out there and I am still planning the installation. I get along just fine with dials on my machines, so it is no big deal. I know how to work with backlash. In my mind, the DRO usually just helps you remember where you are, which dials do as well with some counting and memory work. The DRO is no doubt easier on the old eyes, and is easy to reset to zero. It probably makes for more backlash problems with many users. I am not so interested in the "gee whiz" stuff like bolt circles, but may use them once in a great while. If it was not that my eyes are getting worse, I would not have even considered getting one. I am probably the exception here, however...

It will no doubt be a learning experience for a while using the DRO. The few times I have used one, the numbers on the screen were just rolling by and not telling me much. I found myself having to pay very close attention to not overrun my numbers. That will no doubt improve with time.

 

[tjb]

The first piece of machining equipment I bought was a used Smithy 3-in-1. The guy I bought it from worked in a factory that had commercial machinery, but he wanted something small in his basement to piddle with. He had installed remote readouts on all three axes, and I was pleasantly surprised at how accurate they were. Here's a link to one similar, but not quite the same that's on eBay (if you can't connect to it, just do a search on 'digital readout'):

https://www.ebay.com/sch/Manufactur...=15&_nkw=digital+readout&_pgn=2&_skc=50&rt=nc

Here are a few photos of the Smithy that show the location of the sensors. Since that is not the main focus of the various photos, you'll need to locate them visually. It's particularly convenient that with these remote units, you can mount the magnetic readouts just about anywhere you want. I've included a photo that shows them on the front panel of the Smithy. (Note that none of the sensor wires are plugged in to the readouts. I had cleaned up the unit for sale and taken it out of service, so I left them unplugged. Turned out the sensors were a pretty good selling point for the buyer.)

Clearly not the best option for precision measurements, but as you and others have observed, when you get to that point, it's safer to pretty much rely on 'art and science' anyway. Given that your need is for a lathe, you would only need two, so cost would be minimal. Not necessarily the best option but certainly a good low-cost one to consider.

Regards,
Terry

 

[mikey]

Ray, I do not own a DRO for my lathe but that will be my next big purchase. I've been thinking about it for some time, and while a lot of folks seem to think a lathe DRO is not necessary, it is for me. I use an Emco Super 11CD lathe with very accurate cross slide and compound handwheels and lead screws. There is zero backlash on both of these handwheels. However, for some stupid reason, the Z-axis/saddle rack is calibrated in metric - just shy of 19mm per revolution. This is a major pain for me when precision boring so, for me, a DRO makes sense. Of course, this is my excuse; the truth is that I'm tired of pulling out an indicator.

The other reason for wanting a DRO is that I occasionally use carbide insert tooling and as we know, what you dial in is not what you get with small depths of cut. I have several nose radii on the inserts I use and it would be good to know how the depth of cut correlates with changes in OD with different nose radii so I can more accurately dial in a cut to accommodate those pesky radial cutting forces. For the life of me, I cannot see how it is possible to dial in a sub-0.001" depth of cut with an insert but I've seen enough posts that say it is possible and most of the posters own a DRO. Color me curious.

 

[Reddinr]

I bought a DRO kit from DRO Pros more than a year ago. I recently got the cross-slide "DRO'd" but have not mounted the Z axis yet. I procrastinated drilling holes in the cast iron for a while ... I got along OK without it but I really like being able to easily dial-in to make deep enough cuts that work well with inserts and still be confident about the final diameter. Taking too light a cut with inserts often messes up the finish. I just need to find the time to to do the "Z" now. With my novice level of experience and using inserts, I find the DRO useful and recommend one, especially at today's prices. Be sure to understand the accuracy and resolution figures. They can vary from supplier to supplier. My cross-slide DRO sensor has 2X the resolution of the one for the Z axis. This helps (according to the sales literature anyway) as 1 mil of cross feed travel = 2 mils of diameter.

It does not replace knowing your machine by using it a lot but it is very convenient sometimes.

 

[f350ca]

I've had a DRO on the mill for the last 15 years, recently upgraded from a Shooting Star that used rack and pinion to a 3 axis glass scale. On the mill, in my opinion they are a must, don't worry about backlash or table movement during a cut, they negate or monitor it.
I've have one on my 16 x 80 Summit lathe, wouldn't be without it but could get by. It has three scales, the one on the compound is summed with the carriage feed. (it will read either separately if you want). I keep the compound dialled in parallel to the bed. The carriage probably weighs 5 or 600 pounds, if I'm machining to a shoulder I can kick the power feed out 20 or 30 thou shy and dial the last bit in on the compound. The carriage has a rotary dial with a vernier to measure travel but bumping the carriage a thou or less on that size a machine would be hit or miss. With the DRO you hit it every time.
Also nice on long cuts where I might be zeroing the tool off the end of the shaft and cutting 30 inches to a shoulder.
You can store setups for tools on most lathe DRO's. Set up say tool 1 for a turning tool, finish with it and set tool 2 for a boring bar or what ever, then switch back to tool one and your settings are good to the repeatability of your quick change tool post. Usually 2 or 3 thou.
Making multiple parts its nice,
I've never bothered on the Hardinge, the dials are deadly and parts are small so it really doesn't need one.
The old DRO off the mill went on the shaper where the dials are less than adequate.

Greg

 

[Groundhog]

Just a FYI:
I just got a quote from DRO Pros that includes new magnetic scales that are 1/2 the width and height of their normal S1 scales.

I have a fitment issue with my lathe where the carriage ball oilers and the carriage lock are very close to the cross slide, causing problems with standard glass and magnetic scales. Looks like these scales will eliminate this problem.

 

[Ray C]

Well everybody, thanks for your thoughts. As far as DRO on the lathe... I'm not feeling the love and burning desire. When I work on a part, I measure it and calculate how many passes are needed for the bulk removal. When I get to that point, I have a method of closing-in for the kill. On those last few passes, I toss a dial-face indicator against the compound or cross-slide and I usually snug the jibs just a tad. The indicator helps me determine exactly how much was dialed in; a micrometer tells me how much came off... Do that little rain dance 2-3 times in a row and bingo -all done.

When I'm making shoulders, the iGaging thing helps get really close and calipers & mics tell me the rest of the story.

Last year, I got rid of most of my digital calipers and switched-over to dial calipers. ...Troglodyte, I guess.

Ray