DRO

[Darren]

I really want to get myself a DRO set-up....like many cost is a real problem though. It's the one thing that's really holding me back with my mill as the imperial dials put me off using it.

I have been searching around and this seems to be a good price? But is it any good, any reason I should avoid it?

My problem is I don't know what to look for and what features are really needed and what are gimics that'll never be used..

The one I'm looking at is £150 and some go up to £450 or more....my question is why?


Another thing, my lathe and mill are side by side, could I use one display for both machines? I could plug/unplug each machine as required or make a splitter switch.

Thanks in advance for any feedback, I'm struggling with this one.......

http://cgi.ebay.co.uk/3-Axis-Mill-Budget-DRO-Digital-Readout-Display-Console_W0QQitemZ290346232987QQcmdZViewItemQQptZLH_DefaultDomain_3?hash=item4399fbec9b&_trksid=p3286.c0.m14

[No1_sonuk]

That one you linked to needs the quadrature output from glass scales, and the data output from "chinese" scales (I know, I asked them).
Price difference could be because of extra functions, build quality, etc.

Note also that those prices are just for the readout, they don't usually include the scales which need to be fitted to the machine, without which the display is useless.

[Darren]

Thanks, what's "quadrature output"....

I realise scales would need to be added, that's the next step to study, ........

[No1_sonuk]

Quadrature signals give direction and step pulses.

Next study would be searching for people who have fitted DROs to the same, or similar machine to yours.

The type of scales you can fit, will have the most influence on the display you can use.  If you decide on a display too soon, you could limit what type of scale you need.  Glass scales are more expensive than the "Chinese" type, and you'd need to make sure that the display you choose can operate using the scales you fit.

[bogstandard]

Darren,

The one you linked to was the readout only, and it is the readout which gives you the bells and whistles. Depending on how much you pay, depends on what you get on the readout. The cheaper the readout, the less features you will get. A basic one will only handle two axis, say X & Y, then the next step up would be a 3 axis one, X, Y & Z. Then after that comes the features that the box of tricks holds. Things like auto off memory, where if you leave a job half way thru, you can turn the whole system off and come back to it at a later date, and when you turn back on, it is as though you had left it turned on all that time, zero point memory, where you can (on mine 200) store individual datum points that can be recalled at any time. PCD calculations, taper calculations, points along an angled line and the list goes on and on. It all depends what you want it to be able to do. Every function has a specific and very handy use to help make machining and measuring a lot easier. It can only be up to yourself if ever you are going to need or use that function.

Going by my more expensive version. At the press of a couple of buttons, my scale readout will convert to be used on almost any machine, be it mill, lathe or even grinding machine, or the accuracy of the readout, on mine, in imperial, up to five decimal points, or I could have it at two decimal points if it is a roughie job.

Everything depends on what you want to pay and what features you want fully automated.

For each axis you want to display, you will required a read head.

These start from about 100 squid each, but it all depends on the length and size plus quality of the read head. You can get big beefy ones where room is no problem, down to mini sized ones where you need to squeeze them into tight places. The normal size is the cheapest, larger and smaller work out more expensive.
If buying the read heads and displays as seperate items, you must ensure that the two are compatible with each other, both in signal type and plug fitting.

I searched all over the world for what I wanted, and also to match what my machines already came fitted with. I found a lot of cheapie types from the far east, and I think Cedge went that route and had very good dealings with one company, and the one in the UK who I dealt with was

http://www.machine-dro.co.uk/index.php?target=categories&category_id=3

And I found them to be very speedy and efficient in dealing with orders and problems.

I hope this has helped you on your quest.

John

[sbwhart]

Darren

I've just ordered a DRO from the firm John linked to, they do a deal for collection from the Midland Model Exhibition in October give them a ring for a quote for your machine, you'll need to be armed with table travel X, Y and Z if your going to three axis and gap between table and column to get the size of scale that will fit in between.

I'll be fitting the power feed at the same time I fit the DRO.

Cheers

Stew

[28ten]

When I had the ML7 it was fitted with a DRO from the machine-dro.co.uk and as Bogs says they were most helpful. I found the simple display sufficient for my limited needs/skills. one thing is for sure, when you have one you won't know how you managed without it

[bogstandard]

If anyone is interested in fitting a DRO's to their machines, I don't mind taking a few pictures of mine to show how things are done and where they fit.

I don't have a great deal of experience of fitting them, but I have done a fair amount of work with them, and mine are still working just fine. It is the setting up that is the trick, get it wrong, and you can get into a nightmare scenario.

They are a rather expensive bit of kit initially, even a budget system, and will most probably cost as much as your lathe or mill cost you originally. But in all honesty, like Cynric said, you will wonder how you ever managed without it.

I originally went down the much cheaper? digivern route, but in the long term, it worked out almost the same price as a glass scale setup, and it was continually breaking down, especially half way thru a critical machining schedule. Both systems have their followers, and because I have been down both routes, I will now only recommend the one type.

Bogs

[Darren]

Thanks for all the tips chaps, I'll do some more studying ..... and saving.....

I will get there, but not right now...just need to become familiar with what I really want....

[kvom]

I don't think you would be happy with a single DRO for two separate machines (even it it'd possible).

If you can afford only one, it will be much more useful on the mill than the lathe (IMO).

My doesn't have a scale on the Z-axis, and I don't miss it.  The main features on my mill's DRO that I use frequently are:

1) Separate zeroes for abs and incr positions.  Having multiples like Bogs' unit would be useful as well.  I normally set the abs coords  for either the rotab center or for the vise fixed jaw and stop, if any.  The incr gets used for everything else (e.g., centering, edges).

2) The 1/2 button for centers.  Use an edge finder for one edge, zero the axis readout, find the opposite edge, and press the zero to divide in two.  The center will be at zero.

3) My DRO shows feed rate when the table is moving in either x or y.  I use it to set the traversal speed when using the table drive, and also to get an idea when manually milling in y.

4) I might use the bolt circle feature if it weren't out of order on my readout.

On the lathe, the feature I used the most is the preset.  For example, take a test cut and measure the diameter without moving the cross slide.  Use the preset to set the y-axis to the measured diameter.  Then for subsequent passes the DRO will tell you the current diameter.

The lathe DRO will also measure a taper.  I don't think it's any faster than computing it with a calculator, but it's there.  However, it is useful when setting the taper attachment.

[Darren]

Thanks for that Kirk, you have brought up a few interesting points I was unaware of. Exactly the helpful response I was looking for....you have given me much to consider....

[Jonny]

I have one of those budget 3 axis readouts on the larger mill and was my preference regardless of price.
Now they are Sino scale units but have different plugs fitted so it plugs straight in to the budget readout.

Order everything from same place and make sure you fit the covers as well.
Must warn you, if you turn up at the exhibition, there may be a discount of x% Got mine two years ago at Nuneaton inc the 3 axis display at £120, all in covers etc delivered £440.

The B covers are very easy to fit, no messing about. It will come with a supply of aluminium bracketry but if you want a top job make your own, certainly on the quill mine doubles up as coolant output 1/4"bsp.

Bought mine for the mill but worst case could use two of the scales on the bigger lathe without impairing any travel.
Just make sure the Sino units are tight else they shake to bits.

[John Hill]

I know the idea is not popular but my cable operated DROs are very useful and are at least as accurate and repeatable as the graduations on the feed screws.


http://madmodder.net/index.php?topic=781.0

I have since managed to hide the cross slide cables under the slide which is much better and more accurate than the original method of running a cable right under the lathe.  I have also done away with springs and now use screw adjusters to tension the cable to a nice 'note'.


Scheesh!  didnt my lathe look clean in those days!