DRO Questions.

[armscor 1]

Hi Guys, hope someone can answer my questions.
Just installed a DRO on my 13" lathe, sorry Harold but we have to keep up with the times.
On the LCD screen it has a f display, the faster you move the carriage or cross slide the number increases proportional to the rate of travel ,am I assuming it is feed rate?
The second question is what is Axis Summing?
I can't find it in the manual.
Thanks Guys.

[jwmelvin]

Sure sounds like the feed rate, a feature useful on mills.

Axis summing combines two axes, for example the z-axis and quill of a mill, where both represent movement in the same relative direction.

[whateg0]

I read that as axis summoning! I know making stuff is a spiritual experience for me but I didn't know it was being Incorporated into DROs!

[NP317]

What brand and model number is your DRO?
Axis Summing is not for use on 2-axis lathes.
My 4-axis Mill DRO can Sum the Quill and Table axis (U + Z). Extremely useful for long vertical movements.

My Lathe DRO is 2-axis: Z and X.
RussN

[armscor 1]

Thanks for the response guys.
It is a yhsino 2 axis unit, the reason I went for this is the features, Aluminium housing and LCD display, easy on the eyes and the numerals triple in size when it detects movement, my 69 year old eyes are not as good as they used to be
Can switch from dia to radius machining with the push of a button and can display a graph for diagnosing scale problems.
My back is still sore from bending over the bed to fit the "Z" scale, no access to the rear of the lathe.
Makes sense on the axis summing, it is displaying off as I have selected lathe operation in the menu.

[pete]

Actually Armscor's use of the word summing is correct at least on the dro's I know of and how they use the term. Acu-Rite https://acu-rite.com/news/did-you-know- ... -function/ and for sure my Newall uses that term to come up with the sum total of the two movements combined. Some like in that link use an add on box to do it, and some like mine have it built in to the display. It's also my understanding quite a few dro displays have functions available that may or may not be capable of being completely used depending on the number of and type of scales and reader heads you got with your dro. The displays with some brands are generic and can be used either on a lathe or mill. And with some you have to be specific and go into the display and either reset it for lathe or mill use. So that's something to be careful of and check into Armscor. That axis summing is mostly seen on mill dros, but not always. Afaik some 3 or more axis dro's for lathe use can also use it with a scale on the top slide. You have to input the angle the top slide has been set to into the display and it gives the travel the top slide is moving, as well as the distance in/out in the X axis. As one example, it would be handy when single point threading with the top slide angled to 29-29.5 degrees for your total X axis infeed. It depends on what dro you bought and how many scales and axes your set up to use. As Russ said,if you only have two for Z and X it can't be used even though the display may be showing it. And if you have a 3 axis set up, that axis summing with the top slide won't be absolutely perfect to 10ths for that summing number because it's pretty hard to set the top slide to a known perfect angle. For most purposes it will be close enough to not matter.

Nice mill Russ, how do you like that SB model?

[NP317]

"Nice mill Russ, how do you like that SB model?"

My South Bend Mill SB1027 is meeting my needs very well.
It is more robust than any of the many Bridgeports I have used. The quill bearings are Japanese industrial quality, so 5,000 rpm is quiet and easy to use.
The built in Variable Frequency Drive (5 h.p.) is wonderful, working from my Shop's 220 Vac single phase power.
I added the 4-axis DRO and power feed for the knee. Very useful for serious boring jobs.
I have yet to exceed the rigidity of the machine. But there's always the future...

Anyway, I can recommend this mill for quality and functionality.
RussN

[pete]

I looked the specs up for your mill Russ, very very nice, turcite, hardened and ground table etc. A bit bigger and certainly much better built than mine for sure. Mines pretty quiet as well and I was real surprised the first time I hit the on switch. Probably half decent Taiwanese bearings and not Japanese though. Yeah I'm more than happy I went with a VFD over anything else for 3 ph. power. Having that built in from the factory is a real bonus. I could get 5k rpm out of mine, but since I don't know just what my bearings are rated for I've not pushed it that far.

[John Hasler]

Pete writes:
And if you have a 3 axis set up, that axis summing with the top slide won't be absolutely
perfect to 10ths for that summing number because it's pretty hard to set the top slide to a
known perfect angle. For most purposes it will be close enough to not matter.

Cut a taper and calculate the actual angle (measure the start and end diameters with a micrometer and the length with the DRO). Input that calculated angle to the DRO.

[pete]

Yep that could be done, but probably not many would do a check like that to get almost an exact calculated angle when setting the top slide for single pointing threads. In a home shop I can't think of too much threading that would require better than + - 1/2 a degree in accuracy for the input number and how much inaccuracy that would change the exact result for the in feed distance that the dro would display. Dro's are far more accurate than the flexible machine tools there being used on for the most part. So they get you pretty close on one off parts and obviously a whole lot closer on multiple parts if your cutting to the same numbers and depths of cut each time.