Advice on DROs for a mill

My first mill was a Warco VMC to which I had fitted a Mitutoyo 3 axis 0.001mm DRO system. It never gave an ounce of trouble, or even a gram, but it did cost more than the mill. You could say that I was a bit spoilt by that.

My new Warco WM40 mill is equipped as standard with only a Sino 2 axis 0.005 system, and it drives me mad. It was supposed to be upgraded to a 3 axis but that never happened, neither did the 0.001 scales.

The new DRO I have bought is an Easson with 0.001 scales. I have just completed a new mounting system for the readout unit as the old one was combined with the machine push-buttons. This also did not prove very easy to use, as the DRO never seemed to be in the right place. Warco are still advertising the WM40 with two separate units, viz DRO and push buttons, which would be a doddle to modify.

The only downside so far, with the Easson, is that I had to open up the case to change the voltage to 110v, but Machine DRO said it would not invalidate the guarantee.

Pete

I have machine-dro hardware on both by Colchester Student, ML7 lathes and Chester Mill complete with their digital readouts. No connection other than being a satisfied customer.

When I wished to fit DRO to a Cowells Mill and a Cowells Lathe I again used their Magnetic scales as they can be fitted very neatly and do not take up much space. I could not justify the cost of the readout to go with them.. I saw a posting re the Touch-DRO Android app from **LINK** This site has all the information required to build your own controller to use with whatever scales you desire. The Touch-DRO app is then downloaded from his site and loaded onto an Android tablet. I had a suitable Android tablet doing nothing and the components to build the controller cost me less than £20 (possibly around £15). The controller could be shared between several devices if required. I in fact built two one for mill and one for the lathe. Android tablets can be had quite cheaply if you do not have a suitable device available.

Colin

The posts talking about Touch-DRO have opened up a bit of a Pandora's box for me, hence I have been doing some research on Yuri's site and others. Santa brought me an Arduino kit, much lighter on his sleigh than a complete milling machine!! This makes a very interesting option to a conventional DRO and really does put DRO in the realms of the home engineer.

However from all that I have read, it seems Yuri concentrates only on his TI Launchpad design now for most types of scales. The Arduino work seems to be only supported now by his friend at rysium.com and this seems to be only for the IGaging scales. This is an interesting option for a DRO but will take a hit on accuracy due to the IGaging spec compared to glass/magnetic.

So, Colin, I am very interested to know the Arduino code you used for your magnetic scales from machine-dro as it would provide the ease of sourcing Arduino parts here as opposed to the Launchpad with Yuri's proprietary code.

Paul

Paul,

I'm sorry but I did not mention using an Arduino anywhere in my posting. I am using the TI Launchpad. These can easily be purchased direct from Texas Instruments web site in the States. I paid $9.99 for the Launchpad and $14 for shipping, so total of $23.99.

I used a case and resistors from Maplins, 9 pin 'D' connectors, Veroboard and wire from IT spares box, Power supply from old mobile phone, Bluetooth modules are anything from around £4.50 to £6.50. You should be able to build the whole thing for less than £30.

Regards,

Colin

My machines have good resettable dials so I found my self using the DRO to just get within one turn then I would use the dial which was great for my jig borer but on my Cowells mill I found magnetic tape works really well you do have to understand about backlash but then you should understand about backlash

if you go to **LINK**

you will find out how I and my mate Paul did DRO with Arduino, but if I'd wanted 3 axes I'd just have bought the ready made stuff from Mdro

Sorry Colin, a bit of confusion on my part. I feel I have to pass on the Launchpad as at this stage I am just getting back into electronics and have a lot to learn and relearn so as has been discussed on various threads sometimes I am sticking to one microcontroller first, in my case Arduino.

I don't have any problems dealing with backlash, it was drilled into us apprentices in the first months in the training school. For a very cheap DRO, Stephen's technique would work well with the IGaging type scales; get approximately there with the IGage and then use the dials.

I have to take my hat off to Duncan's system, a simple and elegant solution. It has got me thinking!

Touch DRO using the TI launchpad is a complete working solution, why re-invent the wheel just because you have bought an Arduino. All the hard work has been done for you. You either want a working solution oir you want to design your own, one route is simple, the other can lead to a lot of frustration.

I do not know why people think the Arduino is the best/easiest solution, it is like saying I will only use a particular make of end mill rather than ones that suite my particular use.

The solution is already out there, save yourself a lot of hard work/frustration and cost, Yuri has put a lot of work into the proiject, it's cheap and it works.

The Arduino IS NOT the solution to everything.

Horses for courses.

The Arduino is popular amongst folk who want to learn a microcontroller because it's development environment is friendlier than most - it hides a mass of complexity providing beginners access to C/C++ efficiency, without swamping them with complicated details. The relatively electrically robust chipset reduces the chance of wiring mistakes causing magic smoke. And Arduino's success as a hobby platform has created a large community offering help, cheap peripherals of all sorts, and hundreds of off-the-shelf software libraries.

In terms of capability Arduino sits above microcontrollers running BASIC or Python (both useful and easier to learn but too slow when performance matters), but below a professional development toolset. The latter are hard to learn, probably over the top for most amateur purposes. Arduino provides a good balance between power, functionality, ease of use, and cost. It's a good choice for starter and more advanced projects.

When I wanted a DRO I bought one. But - out of interest and to understand how scales work - I've also experimented reading them with an Arduino. In a clean room with an oscilloscope and other tools that have no place in a mechanical workshop! Different hobby.

Although TI Launchpad is an excellent platform, the steep learning curve and relative lack of support make it unattractive to me. So far I haven't needed any of it's particular virtues. When I need more oomph than Arduino can provide, the Nucleo family does the job.

Lots of choice out there.

Dave

I stumbled upon Yuri's site in about 2013, when I was looking to replace the caliper-style scales on my mini-mill. Back then he was using an Arduino board. I never pursued it any further than the initial research and reading through Yuri's site. Not been back there for ages, so I assume, without re-reading all the bumph, that the use of a TI board is relatively recent.

John

Spelling edit!

Edited By John Hinkley on 19/05/2022 10:30:22

I fitted a 3-axis "Machine-DRO" set specified for my mill, a Myford VMC, and although I indulged in a heck of a lot of elaborate bracketry to both support and protect the sensors and magnetic strips on a machine not designed for DRO scales, I have never regretted it.

The instruction advise protecting the armoured sensor cables from coolant. I don't use flood-coolants, nevertheless I ran them through flexible conduit, actually spiral-wound polythene sink-waste hose from a camping & caravanning shop. (You'd be surprised where you can find engineering materials!) The standard electrical flexible conduit is too small to allow the sensors or connectors, passage.

One thing I did do, when setting the specified gap between sensor and strip, was use a plastic (soft and non-magnetic) feeler-gauge. I measured a few old plastic bank and club cards, which make very good shim material, and cut a strip from the appropriate one.

'

It was joy on first use to drill several holes in two bits of metal to be screwed together, and find all the screws fitted through all of them first time!

The one drawback is that fitting the long axis strip and sensor lost the use of the table-stops. Some would argue that a DRO avoids their need, but as with the 3-phase conversion sets I put on this and other machine-tools, I prefer to enhance the machine as it exists, not simply replace bits. Also, once a positive stop has been set by the numbers, you don't need keep sidling up to digits or dials.

So from time to time I look at the mill to work out how to make and fit new table-stops. In any case, sometimes I do use the handwheel dials alone, on short, simple tasks. If nothing else it keeps my hand in!

'

The fitting and operating instructions are nice and clear, and though I have not so far used the more advanced features like generating radii and pitch-circles, I have no qualms about doing so. Though I might practice on a bit of scrap material first!

Incidentally, I don't keep this or any of my machine-tool manuals in the workshop. To protect them, they normally stay in the house where I write the salient details from them on a notepad. If I do need the document in the shed, I put it open at the relevant page in a polythene bag or a walker's map-case.

Edited By Nigel Graham 2 on 20/05/2022 15:35:53

For what it's worth, when I fitted the 3-axis DRO system to my Warco VMC mill.decided to re-instate the table stops by fitting a slotted strip on stand-offs from the front of the mill table, like this:

This arrangement also allowed the x-axis power feed stops to be mounted on the same plate. It wasn't long however, before I found that neither were being used, so it was removed and has languished on a shelf in the workshop for 5+ years.

John

For what it is worth…

This thread was started in 2016 by Paul H 1 and, until the 18th of this month, the thread appeared to be completed on the 6th Jan 2017.

None of the recent posts appear relevant to the ‘non-reply’ posted on the 18th of this month.

This is just for info - in case others want to waste their time replying in the same way.

Hi

I too use arduino devices in a lot of projects, I also use ESP8266, ESP32 etc as and when,

Yes! I agree the Arduino is a great learning tool with lots of info BUT my suggestion to go with Yuri's solution i.e the TI board was to save having tyo re-invent the wheel, Yuri has done all the hard work on youre behalf.

The board is cheap and easy to program so why noit use it. I have biult it and it works great. This post reminds me of someone who wanted an electronic rotary table and was insistant in using an arduino board, when again there is already a solution out there (a number of solutions as it happens but one is much cheaper than the others).

Circuit boards and kits of parts were available when I built mine and again it works poerfectly.

I look at it this way, do you want a working solution or do you want to start from scratch, all the effort going into programming the arduino and learning all about C++, then if and when you have successfully created your program you have to implement it mechanically.

It is wrong to think anyone can program the arduino with little effort as they soon find out.

The scale options that I have looked at, the stick on magnetic strip ones, rate them to -20C. It is not the DRO, it is the scales that have the problems with the cold temp. The Glass scale ones I looked at were only rated to 0C. Not what I would have expected. The magnetic ones are down to 1um resolution, but commonly are 5um is about 20% cheaper than the 1um magnetic reader head. The tape is specific to the reader heads resolution. The advantage of the magnetic is that they are basically touchless systems, apart from rubber wipers. There are 2 types of magnetic scales, the ones where the tape is applied by the installer. The other system has the tape already mounted to an extrusion with the protective strip in place. It is installed like a traditional scale is set up. The reader heads have differing working gap limits, specific to the system brands etc. Some need to be within 0.5mm of the tape, others can be as far as 3mm from the tape.