Cost effective DROs for mills

[Benedict WhiteParticipant @benedictwhite51126]

I have a Naerok mill drill, quite pleased with it. Have read the discussion on DROs and am looking for recommendations for a 3 axis DRO for my mill that is cost effective from people who have fitted them to their own machines.

All sources including Banggood considered.

[Benedict WhiteParticipant @benedictwhite51126]

Advice sought for cost effective DROs for my Naerok Mill/Drill

[Clive Brown 1Participant @clivebrown1]

Just over a year ago, I purchased a 3-axis DRO for my Warco 16B from eBay, (Fast-to-buy). Items arrived well packed and quickly. Total cost was ~£270.

So far the kit has worked as expected. The most taxing part of the exercise, apart from paying the money, is making up bespoke brackets to attach the scales. The pieces of aluminium angle suppled with each scale were of little use in my case.

I think that I'd use the same supplier again.

Edited By Clive Brown 1 on 27/09/2023 14:22:14

[Benedict WhiteParticipant @benedictwhite51126]

Many thanks Clive. Can you post a link?

[john halfpennyParticipant @johnhalfpenny52803]

I used the Arc Euro scales for my Naerok. Left and rear sides of the table, and on the quill. Quite straightforward fitment.

[Benedict WhiteParticipant @benedictwhite51126]

Many thanks John. I see you have a separate readout for each scale.

[Clive Brown 1Participant @clivebrown1]

Posted by Benedict White on 27/09/2023 15:18:49:

Many thanks Clive. Can you post a link?

PM sent

[PeteParticipant @pete41194]

If you've never bought or owned a dro before Benedict it's easy to make a mistake when choosing your scale length to match your machines travels. There not the same thing. The reader head has a length of its own, and depending on where the pick up sensor is located within it, the lengths from each end of the head to where that pick up point is has to be added to your total scale length at each end.The read sensors on mine are in the middle, but I can't say the same would be true for all dro brands and types. In general most of the manufacturers will have line drawings of the scale and reader head dimensions. Checking those before you buy would be time well spent. Crashing a reader head into the fixed end of the scale due to inadequate length usually destroys at least the head.

How you mount the scales and hold them in place may also add a bit more length that might be needed as well. At the professional level of dro's, Newall is regarded as one of the easiest to mount because of the universal kit of mounting brackets and screws that are included. Studying what they use on there website might be very helpful if you have to design and build anything to mount yours to whatever machine you have. Newall dro's use fairly small round magnetic scales , so the rectangular shaped bar scales are of course different. How to mount them in the easiest way possible has still about the same requirements except for that difference in scale profiles. Even then and just to be sure, I'd probably want about 1/4" / 6 mm of spare length at the ends of each scale just to be 100% sure.

[not done it yetParticipant @notdoneityet]

All sources including Banggood considered.

You are on your own if you are buying from them – or vevor and a few other suppliers of possibly substandard items.

[Nicholas FarrParticipant @nicholasfarr14254]

Hi Benedict, I too used Arc Euro scales Digital Readout Bars on my mini mill almost eight years ago, and they are still working fine, and like John used a standard vertical readout bar for the quill, which is similar to these from Arc Euro Standard Vertical Readout Bar

You can see how I fitted mine DRO's for a Mini Mill

Regards Nick.

[Benedict WhiteParticipant @benedictwhite51126]

Thank you Pete and Nicolas.

Not Done It Yet, no, plenty of people use both Banggood and Vevor.

[Clive SteerParticipant @clivesteer55943]

My experience is that the generic Chinese readout head products are of good quality and value for money. However the accuracy and repeatability of a DRO system is mainly down to the quality of the scales and the rigidity of their fixing to the machine. Devising and making a suitable mounting arrangement may be difficult for a beginner especially fitting one to an old machine not designed for a DRO.

Where long scales are needed I use glass scales as they are in aluminium cases but for short scales and certainly where space is restricted I use the magnetic scales. Also magnetic scales are good if you are uncertain about the amount of travel needed as the magnetic scale "tape" can be cut to any length required and if cut too short the tape is quite cheap.

Glass scales lengths are usually quoted as being overall length rather than movement range which is less so allowance must be made plus 20mm extra margin.

As has already been mentioned the fixing brackets supplied with most Chinese scales are inadequate but suitable brackets/clamps/shafts etc can be purchased from say PlanetCNC to build a suitable fixing arrangement.

It is difficult to be specific as each machine has its own challenges so it might pay to use the Blue Peter method of using wood, cardboard and glue to make a mock up before final purchase. It is even quite cheap to purchase lengths of 20×30 mm extruded Ali tube to mimic glass scales.

Although the readout bars are quite good they don't provide the extra functions often needed on mills.

CS

[Dave HalfordParticipant @davehalford22513]

Posted by Benedict White on 29/09/2023 08:02:36:

Thank you Pete and Nicolas.

Not Done It Yet, no, plenty of people use both Banggood and Vevor.

Yes they do, however if you buy direct from China and you have a failure the return postage is interesting. Buy from Vevor UK and you are covered by UK rules which means you can't buy an inverter drive for a motor any more as they aren't legal, but if you could it would be covered for failure. Their dro were also removed from UK sale for some reason.

It just depends on how big a gambler you are.

[Gary WoodingParticipant @garywooding25363]

Posted by Pete on 29/09/2023 00:01:44:

……..

Newall is regarded as one of the easiest to mount because of the universal kit of mounting brackets and screws that are included. Studying what they use on there website might be very helpful if you have to design and build anything to mount yours to whatever machine you have. Newall dro's use fairly small round magnetic scales , so the rectangular shaped bar scales are of course different.

The Newall scales are not magnetic, they are a chain of accurately sized ball bearings enclosed in a carbon fibre tube. The reader detects changes of magnetic flux induced as the balls pass along inside it. The system is unique and totally incompatible with all other systems, glass or magnetic.

I had to make my own mounting brackets when I installed a Newall system on my Centec.

[Benedict WhiteParticipant @benedictwhite51126]

Many thanks Clive, Dave and Gary. Helpful advice.

I do have both a mill and 2 lathes to make mounts though.

[PeteParticipant @pete41194]

Yes your quite correct Gary, and I do know how they work, but while it's technically incorrect, that's the almost universal term most seem to use to differentiate between glass scales and the ball bearing type. Newall does offer actual magnetic tapes now which are designated as magnetic. But my real point was that the Newalls are one of the easiest to mount. So to reiterate, studying what they use should be helpful for anyone who has never mounted dro scales before. My knee scale still required additions just to correct for the column taper, but the rest of it was quite easy.

[Colin HeseltineParticipant @colinheseltine48622]

If you want to keep costs down take a look at the Yuristoys website. If you are handy with electronics then you can make the interface between the scales and the display. The display is an android tablet. I have used Machine-dro magnetic scales and read heads. Have fitted them to a range of machines including Cowells ME90 lathe and Cowells vertical mill.
colin

[Benedict WhiteParticipant @benedictwhite51126]

Many thanks Colin, I will have a look.

[Stuart Smith 5Participant @stuartsmith5]

I fitted the digital readout bars from Arceurotrade to my Warco mill, but found the display a bit small. I made a circuit on veroboard with an Arduino nano and Bluetooth module to use the TouchDRO app by yuri as mentioned by Colin above. The app runs on a very cheap tablet ( I think it was £35). I fitted a 3rd readout bar to replace the existing quill dro.

There are photos in my Mill DRO album : **LINK**

If you happy with programming the Arduino and a bit of soldering, it is a cheap alternative to a ‘proper’ DRO.

Stuart

[Benedict WhiteParticipant @benedictwhite51126]

Very interesting Stuart. I have a few Arduinos about and a rubbish tablet. I take it Yuri has information about building and the app for the DRO on his website?

[Stuart Smith 5Participant @stuartsmith5]

Have a look at the TouchDRO website for info. If you decide to build a diy one, I can send you the Arduino sketch I used and a drawing of the circuit I made.

Stuart

Edited By Stuart Smith 5 on 29/09/2023 16:17:47

[Clive SteerParticipant @clivesteer55943]

I'm not absolutely certain but I believe the latest Newall scales have the electronics that drives the inductive position sensing circuit incorporated into the scale head so they now output the more common quadrature signal that is used by glass and magnetic scales.

Earlier Newall DRO's had analogue electronics in the scale and the digital conversion was performed in the readout head which resulted in a complex and unique interface.

The Newall method of position sensing is similar in some respects to a Linear Voltage Displacement Transducer (LVDT).

CS

[Benedict WhiteParticipant @benedictwhite51126]

Many thanks Steve. How did you connect your board to the Andriod tablet?

Many thanks Clive.

[John HaineParticipant @johnhaine32865]

LVDT = linear variable displacement transformer

[Stuart Smith 5Participant @stuartsmith5]

Micro usb sockets to connect scales to Arduino and Bluetooth module to connect Arduino circuit to Android tablet

**LINK**

for more photos see my album ‘Mill DRO’

Stuart

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