# So...tell me; Why use a DRO????



## Tony Wells (Sep 4, 2011)

I find them particularly useful in the Z axis of the lathe, instead of using the dial or indicators.


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## Blogwitch (Sep 4, 2011)

I set my machinery up to carry out precision machining for small contract work. Four readouts each on both lathe and mill.

I can machine to 0.0002" accuracy with relative ease, once the machines have warmed up, and that is repeatable over a batch of components.

One of the main advantages is that you don't rely on having all backlash taken out of the feedscrews and nuts, as they do direct measurement of machine slides, in fact I haven't looked at the dials on my screw handles since I installed the machinery.

In all honesty, now that my working days are over, they are a bit of an overkill, but knowing that I can drill on my lathe to an exact depth or coordinate drill on my mill to dimensions previously undoable, gives me great confidence in what I am doing, plus it lets me work much faster as I am not continually measuring things. 

Getting just basic ones (NOT the vernier scale types, too temperamental and inaccurate) makes life so much easier.


John


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## Zigeuner (Sep 4, 2011)

It's interesting hearing about folks who can mill and turn to .0002. Most machines are not that accurate but I guess some people are. 

As to DRO's, they are a valuable device on a mill and somewhat less so on a lathe. On a mill with an edge finder, they are very useful in determining the center of a piece, say to drill a hole. Also spotting a hole from the edge of a workpiece. I have a two axis Mitutoyo on my Mill with an add-on digital scale on the Z (spindle) axis. It will give me a depth to .0005. Bolt circle patterns are easily done as well, that is if you can decipher your manual. LOL. 

On a lathe, with the cross slide set properly for lathe where each .001 reading gives an actual .0005 movement, it's fairly easy to turn a correct finished diameter. I also like the ability to measure lengths on the Z (long Axis on the lathe). 

I don't use the DRO on the lathe as often as I do on the mill. I actually prefer my micrometers. 

All in all, if you have a DRO, you will use it part of the time and it will come in handy. 

I'm still getting used to the different letter names for the axes on a lathe. It's nice but somewhat counter-intuitive. On each of my DRO's (Mitutoyo and SINO) I got some stick-on letters to change to lathe usage, although I find it easier not to worry about it since I'm a hobby machinist and seldom have any visitors.


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## Tony Wells (Sep 4, 2011)

I'll admit to being spoiled, and having become lazy because of DRO's, but also I must credit them for helping eliminate errors and speeding work up immensely. I was well into my career before being exposed to DRO's and immediately felt that they were more efficient.

On the X axis of a lathe for example, when I rough in a piece, I simply establish the largest OD for the part, by measurement of course, then enter the numerical value of the size I cut. Let's use 4.000" for example. I can set the Z off the face at 0.000, then turn all the steps for features on the part, starting at 3.8750 (or whatever), then down to the next size, and so on. It is accurate also accurate in Z, and leaving appropriate stock for finishing. Same drill for finishing. Once I am satisfied the DRO is "calibrated", it is a simple matter to turn all the finish diameters and lengths by reading the DRO. I don't have to even glance at the dials. As a nod to CNC training, I often leave 0.015 for a finish pass, and after checking that it is indeed 0.015 oversize, take my finish cuts. Or adjust as necessary if it is 0.014 or 0.016.

On the mill, it saves a lot of math finding centers of parts, or moving incrementally versus absolute in either axis. I presently do not have a digital for the Z on the bp clone, but have used them, and they do work.

I don't claim to be able to cut repeatedly to within 0.0002 on any machine, but on an as needed basis, I have one lathe that will do it readily when needed. Just have to pay attention to detail. The DRO on that lathe reads only in 0.002 increments, on diameter, so if I need to get close than that, I do hang a tenths reading indicator on it for those cuts.

Overall, DRO's make a machinists life much easier, and less prone to making simple mistakes.


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## Blogwitch (Sep 5, 2011)

> It's interesting hearing about folks who can mill and turn to .0002. Most machines are not that accurate but I guess some people are.



Actually, once your machines are lubed up correctly and warmed up, you would find that it is relatively easy to get within that tolerance repeatably. The Sino units that I use do in fact read to 0.00005", but they are rather difficult to follow at such a setting, so I just leave it on 0.0001" and it is rock solid.

This is the sort of thing where DRO's assist greatly




When you have a lot of them to do




Do your schedule first, then just sing along with the music




You need the high accuracy when you are asked to make nearly a hundred of these small steam valves, and they have to be guaranteed not to leak. All the work is on the internal surfaces of the valve, and on the tip of the needle which was ground up using a toolpost grinder to tenths accuracy.




The finished article





With regards to axis layout on the lathe, I don't bother, it is just too complicated. I just remember which head does what.




The left one is reading in metric, the right in Imperial.


John


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## Ed. (Sep 5, 2011)

For me, as a newby to machining I find it is much easier to read the DRO then to work out how turns of the wheel the carriage or cross slide has travelled. I wouldn't be without one now! ;0


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## Zigeuner (Sep 5, 2011)

The SINO is an excellent DRO for the money. Unfortunately it has five digits to the right of the decimal point. When I set mine up and discovered that this "feaure" is not adjustable, I was not happy. I called the seller and asked him what I could do about it. He suggested that I "put some tape over the digits I don't want to see". That really warmed my heart. 

I made a piece out of aluminum, painted black, that covers the last one or two digits, depending upon how many I want to see. 

Good luck to all those hobbiests who work to .00001.


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## randyjaco (Sep 6, 2011)

The best thing about DROs is that the make machining so easy. No need to count how many turns you have made. You don't have to worry about where zero is. So what if you accidentally spun the wrong handle. Who cares if your old American Iron has .147"slop in the X axis. To boot, the newer systems have capabilities that can virtually turn your worn out machine into a manual CNC. Try out a DRO on someone's machine and you will be immediately converted unless you are just a true Luddite.

Randy


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## joesmith (Sep 6, 2011)

I have a sargon dro on my 9x42 mill(xy). The display stopped working after I left the machine idle for 3 months. I have a new 3 axis Sinpo kit to replace it. Any references for better instructions fo mounting than came with the kit? The old dro was quite useful on the mill. I had never felt a need for a dro on my lathes. After reading the replies I may have to try one. I noticed 1 machine had 2 dros providing a 4 axis setup. Is this typical?

Joe


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## Zigeuner (Sep 6, 2011)

> author=joesmith link=topic=3387.msg24641#msg24641 date=1315329714
> I have a sargon dro on my 9x42 mill(xy). The display stopped working after I left the machine idle for 3 months. I have a new 3 axis Sinpo kit to replace it. Any references for better instructions fo mounting than came with the kit? The old dro was quite useful on the mill. I had never felt a need for a dro on my lathes. After reading the replies I may have to try one. I noticed 1 machine had 2 dros providing a 4 axis setup. Is this typical?
> 
> Joe



It's not typical to use two DRO's per machine. A DRO is nice on a lathe but I still enjoy doing the work without one from time to time. I like micrometers. 

The SINO manual is not very good. The only pages that are useful are the ones on setup since the unit will have to be set up for lathe, mill or grinder, etc. Additionally, what SINO calls "resolution" must be changed for the radius-diameter issue on a lathe. This is done in the setup. 

Other than that, getting the scales parallel to the axes is the main thing and little is said in the manual about that. There is a short page on changing the cable from left to right on the scales which is difficult to understand for someone such as myself who used English as a first language. 

Good luck.


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## Blogwitch (Sep 7, 2011)

Actually, I found my Sino manual very instructive, and once you get used to the jargon used, is very easy to follow for all operations.

Most operations, once set up for what type of machine you are using can be done while the units are in general use, say changing from four decimal point imperial to five decimal points (3 and 4 in metric).

The read heads do require setting up correctly if you want them to give consistent results. Time spent setting them up to thou accuracy will be repaid with a trouble free installation. Mine have been in use now for 3 years, and have never missed a beat. Whereas when I used to use the vernier scales type, something was going wrong all the time. 

With reference to the two read heads on my lathe. This was done purely for precision production work, when normally you would just use a 2 axis, or maybe 3 even if you use your compound a lot, as I do, but really for a mill you need a 3 axis unit.
On my mill I have a 3 axis Sino unit, for X, Y and Z1 (knee), but I also use a standard vernier scale for the quill (Z2, which is only used for drilling, not for putting a cut on). The most useful setup on the mill unit is the PCD function, you can drill a perfect set of holes around the PCD without having to break out the rotary table. But there are usually a lot more functions available, just by pressing a few button


John


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## Zigeuner (Sep 7, 2011)

> author=Blogwitch link=topic=3387.msg24772#msg24772 date=1315381760
> Actually, I found my Sino manual very instructive, and once you get used to the jargon used, is very easy to follow for all operations.




And exactly how does one get used to unintelligible jibberish? LOL. 

Whenever I see a statement that is in respnse to something I have said and that statement starts with "Actually", I know I'm about to be contradicted. I acrtually like being contradicted. After using computers since 1983 starting with Bulletin Boards and a Commodire 64, I understand that the highest use of intermet fora is contradiction. 

"Actually",  the manual on the SINO DRO is crap. You may understand it, but no one else does.


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## randyjaco (Sep 7, 2011)

Please tell us how you really feel about the Sino manual . I think you are holding back on us 8^)


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## Zigeuner (Sep 7, 2011)

> author=randyjaco link=topic=3387.msg24855#msg24855 date=1315420854
> Please tell us how you really feel about the Sino manual . I think you are holding back on us 8^)



I would do so but modesty won't permit. Those who like the SINO Manual, will be charmed by their website. It has many of the qualities of their manuals.


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## Blogwitch (Sep 8, 2011)

Zigeuner,

No need to get uppity.

This is not a boast, just another little skill I have tucked into my belt.

ACTUALLY, all my working life I have been used to reading technical manuals, from ones that are just a few pages to others that run to hundreds of mighty tomes, I did a basic month long course on how to read and write technical manuals, so the Sino one presented no problems to me, and that is all I stated, no one upmanship, just the truth!

There is a knack to it, and if you take the time to study what you are after in the manual, and get used to the colloquialism and Chinglish methods of referring to an item contained therein, things do become a lot clearer.

Where people do go wrong, rather than taking their time to study what is written, they just look at the manual, can't make head nor tail of it because they never really try, because they don't understand straight away what is in front of them, then just offhandedly say it is crap. 

I know it can be difficult for the run of the mill Joe to understand it, but everything you need to know about how to set up and run the Sino units is in their manual. It is up to the person reading it to extract the correct information.


John


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## HMF (Sep 8, 2011)

John and Zig,

Two smart guys, but you are locking horns, maybe time to agree to disagree and have a beer.

 ;0

Hey, I figure if the advice is good enough for the Mayor of New York, it's good enough for me.  ##

I appreciate the depth of the discussions that you both bring to our forum. John, we're a bit softer bunch than you are used to, so go easy on us.  ######

In the meantime, I am merging some sub-boards together as was suggested to me, so f you see some strange things happening on here, it's just me working. &lt;&gt;

Nelson


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## joesmith (Sep 9, 2011)

I'm more concerned about positioning the scales than operation of the unit. I would hate to damage a read head. As soon as i complete the reverse tumbler project for my 2 9x20's I will install the Sino. I have tested the scales and left the project for 6 months. It's time


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## Blogwitch (Sep 9, 2011)

Joe,

Don't get too scared, the units are in fact fairly robust.

The best bet is to leave the little plastic transit pieces in position for all your setup work. They can be slid up and down the unit with the small read head without too much trouble. That will ensure the spacings are correct inside for the unit to work. One of the last jobs to be done before turning any handles will be to take out the transit spacers.

Do ensure, if you can, to have the long split seals facing downwards, and if you haven't already got them, buy some dedicated protective covers for the units. What you are trying to achieve is stopping any liquids or debris from getting inside. Also, try to get a small hanging down bit or a full loop on the armoured cable just before it enters the unit, that will ensure any liquid will drop off before it can get to the sealing fittings on the small read head.

The only precision instrument you will need is a dial gauge or DTI on a mag base so that you can sweep along the unit to make sure it is perfectly parallel to the fixed part of the machine you will be using to mount either the small read head or the outer casing.

It is really a matter of using your common sense, doing things in a logical order, check and double check as you go along, and if you can do that, when you have got it all up and running, you will wonder why you worried over it at all.

John


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## joesmith (Sep 9, 2011)

John Thanks for the tips. That is what I was looking for Joel


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