DRO On the Lathe?

Ray C said:
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
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Ray, I find your last comment to be very interesting. I am on my second pair of digital calipers - good quality - and I am not very happy with them. This second pair is essentially brand new (3 months old, maybe), and its lack of precision is very disappointing. I can close the calipers, set them to zero, turn it off, immediately turn it back on, and it will be off plus or minus .0005 - .0010 (every now and then, .0015). More often than not, when using them, I can set to zero, take a reading, then close back and the closed reading will be something other than zero. I've wondered if maybe it's a little bit of trash on the jaws, but I've had the same result many times under very controlled circumstances. I'm ready to go back to dial calipers myself. Anybody else out there have this kind of problem? (I prefer to not mention a brand name, but it's one everyone will recognize. The calipers (both pair) were a little over $100 each - not the el cheapo's.

Regards,
Terry
 
tjb said:
Ray, I find your last comment to be very interesting. I am on my second pair of digital calipers - good quality - and I am not very happy with them. This second pair is essentially brand new (3 months old, maybe), and its lack of precision is very disappointing. I can close the calipers, set them to zero, turn it off, immediately turn it back on, and it will be off plus or minus .0005 - .0010 (every now and then, .0015). More often than not, when using them, I can set to zero, take a reading, then close back and the closed reading will be something other than zero. I've wondered if maybe it's a little bit of trash on the jaws, but I've had the same result many times under very controlled circumstances. I'm ready to go back to dial calipers myself. Anybody else out there have this kind of problem? (I prefer to not mention a brand name, but it's one everyone will recognize. The calipers (both pair) were a little over $100 each - not the el cheapo's.

Regards,
Terry
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Terry / All...

I've had similar experiences (if not identical). One of the best digital calipers I had was the early version of the "Centronic" brand when digital calipers were first coming out. I had two, 6"ers and they gave me 4+ good years of service before loosening-up and becoming unreliable. I bought another in the $120 range (this was about 5 years ago) and even though I used it for 3 years, it seemed to have phases of being reliable then, not-so-reliable. It was not the battery, they were changed proactively. Around that time, I bought a couple sets of HarborFreight units and they worked OK, but not great, for about 2 years.

I noticed there were about about 4 sets of digital calipers in the shop and each one had a different set of quirks. In all those years, I could probably fill a Hills-Brother's can with those #357 batteries. One day, I started using an old dial type that was in my collection and I liked how you can see the needle move with different pressure. I like being able to dial the face to zero. I like being able to visually interpolate between the half-thou zone...

The dial calipers I'm using regularly now are not all that expensive (about $39 each) but they're doing OK and so far, seem to give me faster and more confident measurements.

What's next; Vinyl and Tube Amps?

Ray
 
mikey said:
I'd say a good vernier caliper but we don't need to get carried away.

Hill's Bros - you have to be of a certain vintage to remember that brand!
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58... And FYI: In my early days, I did fundamental R&D on cell phone technology. I didn't start carrying one till the mid 2000's and only did it begrudgingly for a few years. I've all but given-up on it now. I check it once a day whether I need to or not. I'm going to go shopping for a rotary phone and have just one, in the kitchen.
 
I'm going to o throw this out there but read it with a grain of salt since I am one of the biggest newbies on this forum. I have a lathe, and a mill. 14x48 lathe, 9x49 msc mill. The mill had a 2 axis dro. The lathe had nothing. I wanted a 3 axis dro for the mill because I found myself try to measure depth of cut. Remember I'm a newbie!!! So finally I bought a 3 axis for the mill. I went against experienced advise and instead of installing the third axis on the knee, I cut it and put it on the quill. It works for a newbie, maybe not correct in application, but it suits me well so far. Anyway, my idea was to buy a 3 axis and put the two axis on my lathe, which patting myself on the back I got it installed and working tonight!!! The way I built requires some bushings for the "reader," glass scales by the way, for a reason I may explain in another thread. Anyway I had to remove .155 off spacers to make it fit the way I wanted. I did the first one manually, ballpark cut, remove, measure, repeatedly, etc. Took me about an 30 minutes. If you have forgotten, I'm a newbie at this. After it was done I installed 1 spacer to hold the reader on so I could use the dro to do the second. Took me three passes and probably 3 total minutes to finish the second one. I'm hooked on the dro for the lathe already.
I will say this, I didn't install the dro on the cross slide since it's a glass mill scale and can't be cut. The dial is accurate so I don't mind not having digitally monitored. I hope it helps. Do remember, I'm a newbie so it's possible for a lot of better methods, but after the first cut I used it on, I'm hooked!!
 
Ray and Mikey,

Can't say I'm glad I'm not the only one with issues on digital's, but it is comforting to know that it's more pervasive than local. I think I'm going back to dial's as well, and I'm not opposed to a good set of vernier's either. I recently bought some vintage tooling from a retiring machinist, and a couple 12" vernier's were part of the package. They're very high quality (though a bit large for most applications), and I'm impressed with their accuracy. I suspect I'll end up with some more dial calipers, but you're welcome to all the dial telephones you can find.

Regards,
Terry
 
I guess I am in the other boat, I can't see the dials/lines very well and would need to switch back and forth between glasses to see which mark the needle is sitting on. Not much better reading the macine dials, but I do use them at times. I am also more of the buy once mentality these days, so I have 3 calipers (6", 8" and 12") that I have used for the last couple of years, and I can close the jaws and they will hit "0.0000" every time. Two are absolutes and I have not had to rezero them. I was going over some machining tricks with another person, whipped them out on some 123 blocks and they were all spot on, all within 0.0005". I can still see the digits and I can switch between metric, imperial and fraction on the fly. Since I do a lot of metric, they are really handy. So it is a matter of both the reliability, quality and your preference/visual acuity.

On the DRO's I can hit very close tolerances without working hard at it, and when you do a lot of repeat parts I think it greatly speeds up the process. On the lathe, once I get close to my final dimension, I measure the cut and enter it into the DRO and then take my final cut. I can reliably repeat the process and expect the same results. Since you can setup both increment and absolute DRO readings, I use each to setup different cut parameters. These can be for two different holders or two different turning parameter endpoints. With the electronic lathe stop, I set it off of the DRO position, once set the stop position repeats to 0.0002". I would be challenged to get anywhere near that with say a Travadial. It doesn't make you a better machinist, but it does make your life a lot easier, providing you understand the skill/art of what you are doing. Understanding your lathe, material properties, cutter properties, etc. are still all part of the equation. But as Bill mentioned, I can make 10 sets of parts using the DRO (which I had to do the other day on the lathe and mill), and they all where within the accuracy limits of my measuring calipers (0.0005"). If I had to do every piece manually and creep up on the dimensions, well it would have taken a lot longer. When using inserts, you cannot often creep up on the final dimension because of the insert properties or the material you are working on. This is the art, but I can take a trial pass, read the numbers and know that I can hit the same numbers on the next pass. So I see it as just another tool to increase your productivity and to simplify the process. Do I use analog dial gauges, sure I do. They still have their place, but I would be surprised to see a machine shop that didn't use DRO's.

I have learned a lot from another local machinist with ton's more experience than me, used analog micrometers, dial calipers and the machine dials. I slowly have converted him over to the dark side, and now he is mostly a digital convert. The other day he was remarking that he set up his mill to do a bunch of repeat parts with deep cuts in steel. He put the numbers in the DRO and cut right to his final shoulder dimension on each part. He no longer creeps up on the numbers, he machines by the numbers.
 
Good points, Mark. I can see how a lathe DRO can speed up your work and make inserted tools easier to use. There are also times when I have multiples of a part that need to be made and it is tedious to hit tight tolerances on each one. The last time I had to turn out 8 identical parts I swore I would buy a DRO, and I will.

I'm with Terry and Ray on the dial calipers and indicators. I own one digital caliper, one of the original Starrett's that were very accurate. Still have it but don't use it. I just prefer analog stuff - reliable, easy enough for me to see and I prefer to see the hand swing and interpolate. Sort of like preferring an analog tach instead of a digital one when you need to speed shift your trans - just easier for me to use.
 
I have a US made Starrett dial caliper that I use constantly. I gave away the digital one I bought because I hardly ever used it.

I also have a set of old Starrett mics that I use for when I need a little better accuracy than my caliper offers. But for those times when I need to be really close, I have a digital 0-1 and 1-2.

I just wish the batteries lasted longer in these digitals. :)
 
Interesting to hear the different opinions. I like digitals (calipers or DROs) for the ability to easily zero at any point and to convert between metric and imperial. I have readouts on the XY vise on my drill press, just put them on my 618 (no dial on the carriage wheel) and am waiting to buy a set for the mill. I find it a real hassle to work without them, takes a lot of the mental busy work out of machining and lets me focus on the important stuff and/ or day dreaming. But if you had imperial screws and dials on a lathe I can see how you could manage without one fine.
 
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