DRO recommendation for Mill

[SirJohn]

I have a new Craftex CX600 mill/drill and would like to install a 3 axis DRO. A couple question:s;
1. Any recommendations on sourcing a suitable DRO.
2. I am baffled on how the scales are attached to the mill. Does this require drilling and tapping the mill frame or is is some other method of attaching the scales as I am not too anxious to drill holes into my new mill.

 

[ShopShoe]

SirJohn,

If you include your location we will be better able to link you with a source.

Taking Your Questions:

2. Most likely you will have to drill and tap some holes, but the DRO will help your work in so many ways it is well worth it. You have a new machine, so you are not modifying a priceless classic. Measure lots of times before drilling and take your time. I strongly recommend you get some new top-quality drills and taps before you start, once you know the sizes you need. I also recommend that you use the same thread standard as your machine, most probably metric on a new machine: Even if you are more comfortable with inches.

1. If you are in the U.S. you should visit: DRO PROS Digital Readout beats Heidenhain Newall Acurite Sargon Fagor I have no ties to them, but I bought a system from them last year and I was very happy with the product and their help. In advance of purchase I called them and they spent some time on the phone answering my questions and were able to quote a system specifically for my mill. Their website is very helpful even if you can't use them as a source. I also suggest you read some of the posts on this forum from those who have installed DROs.

I wanted a GOOD system as I tried one of the small scales and readers that sold for around $100.00 and I was very disappointed with that. What I got was a 3-axis system with a mid-range mill-specific display and that uses magnetic scales: It cost around $1200.00. With only two axes, or with glass scales, it would have been $800.00. The ability to cut the magnetic scales and their smaller size made installation easier and made the installation less "clunky." See the DRO PROS website to understand the terminology and the rationale I followed to make my decisions.

I'm wishing you the best of luck with this and I'd like to see you post your process when you do it.

--ShopShoe

 

[SmithDoor]

I have a new Craftex CX600 mill/drill and would like to install a 3 axis DRO. A couple question:s;
1. Any recommendations on sourcing a suitable DRO.
2. I am baffled on how the scales are attached to the mill. Does this require drilling and tapping the mill frame or is is some other method of attaching the scales as I am not too anxious to drill holes into my new mill.

Most time you will need to drill and tap.
Depending on you budget on what you buy. I have in past use the LED display works great but cost a lot. The mill have today installed a low cost LCD display and single display a lot lower in cost from Shars they are also on Amazon too. For under $200.00 great for retirement budget.

Dave

 

[SirJohn]

SirJohn,

If you include your location we will be better able to link you with a source.

Taking Your Questions:

2. Most likely you will have to drill and tap some holes, but the DRO will help your work in so many ways it is well worth it. You have a new machine, so you are not modifying a priceless classic. Measure lots of times before drilling and take your time. I strongly recommend you get some new top-quality drills and taps before you start, once you know the sizes you need. I also recommend that you use the same thread standard as your machine, most probably metric on a new machine: Even if you are more comfortable with inches.

1. If you are in the U.S. you should visit: DRO PROS Digital Readout beats Heidenhain Newall Acurite Sargon Fagor I have no ties to them, but I bought a system from them last year and I was very happy with the product and their help. In advance of purchase I called them and they spent some time on the phone answering my questions and were able to quote a system specifically for my mill. Their website is very helpful even if you can't use them as a source. I also suggest you read some of the posts on this forum from those who have installed DROs.

I wanted a GOOD system as I tried one of the small scales and readers that sold for around $100.00 and I was very disappointed with that. What I got was a 3-axis system with a mid-range mill-specific display and that uses magnetic scales: It cost around $1200.00. With only two axes, or with glass scales, it would have been $800.00. The ability to cut the magnetic scales and their smaller size made installation easier and made the installation less "clunky." See the DRO PROS website to understand the terminology and the rationale I followed to make my decisions.

I'm wishing you the best of luck with this and I'd like to see you post your process when you do it.

--ShopShoe

Thanks for the detailed reply SHOPSHOE . Still don’t like the idea of drilling and tapping. Has anyone tried holding the scales on with JB Epoxy? A Canadian in Calgary.

 

[Mike Ginn]

SirJohn
The key to a successful DRO is the quality of the product. Cheap systems are based on the digital Vernier. There are useless and have far too much lag in their reading. You should use either glass scales or preferably magnetic scales which are smaller and a 2 or 3 axis readout unit. For a mill I would always use a 3 axis system even if I install the Z axis some time latter when I have worked out how to install. You don't state your location but have a look at www.machine-dro.co.uk for info about their systems. Their readouts are generic and available in other parts of the world.
Magnetic scales are smaller than glass and, for a lathe, allow you to insert them into a machined slot in the cross-slide. Both glass and magnetic give the same performance and I have had no issues with either. You do need to drill some holes - as I recall they were M4 size - 2 per scale. My DRO kit came with various brackets which were only partly useful. Make sure you purchase the correct length of scale for your machine!
Best of luck
Mike

 

[Mike Ginn]

When I purchased my Warco Minor/Grizzly G1005Z mill I found that there was excessive backlash on all axis. Having tolerated this for several months I decided to fit a 3 axis DRO. This was a "Wow" moment. Suddenly I had control of the axis with the ability to swap between mm and imperial, zero where I liked and use many other useful features. I can't emphasis how much this changed my ability to machine with accuracy. Clearly it is possible to work with backlash and badly made index wheels but it just makes simple jobs difficult. I quickly installed a 2 axis DRO onto my Myford which had very little backlash. Again machining became so much simpler especially with the added features.

I would always recommend modelers to fit DROs to their machines - yes there is a cost but it is worth every penny!

 

[vederstein]

Any recommendations on sourcing a suitable DRO.

I recently installed a Grizzly T33081 head unit and slides on our Alliant milling machine at work to replace an ancient Accu-Rite that finally died over 40+ years of service.

Considering the Grizzly head unit with the 5 micron 1000mm & 600mm slides was under $700, I was quite pleased with the quality (it's Taiwanese) and its capabilities.

...Ved.

 

[trlvn]

A Canadian in Calgary.

Have you looked at the Canadian Hobby Metalworkers forum? Example threads:

https://canadianhobbymetalworkers.com/threads/need-a-dro-what-one-to-get.2193/
https://canadianhobbymetalworkers.com/threads/milling-machine-dro.3352/
Craig

 

[bluejets]

Still don’t like the idea of drilling and tapping. Has anyone tried holding the scales on with JB Epoxy?

Joking right......???

Any glass scale DRO will do just fine.

Made my first DRO on the old mill using software originally written by bloke Lindsay (DRO40 through to DRO54)and used an old PC with bare bones Windows 95 operating system.
The optical sensors from old PC mouse were used to track the screw on the table X and Y and fed ito the pc via a small interface to the LPT.
Only drawback was one had to remember to take backlash into account as final programming for this feature was abandoned.
Use was simple, run in to the job from the same direction each time.
Dead accurate. Had to re-fit some previous work a couple of times for additions.

Mill with the program etc. still in use today.

 

[clockworkcheval]

Where space permits I would advice glass. Magnetic sometimes looks preferable because it builds in tight places, and easily, but you run the risk of destroying your magnetic unit if you com too close with a magnet. Like a magnetic base or a magnet to pick up hidden chips.

 

[AndrewW]

Hi sirjohn
To be honest I had exactly the same concerns regarding drilling and tapping my new mill, but they were totally unfounded.
Epoxy or any other type of adhesive will not work as you need to be able to introduce some fine adjustment in order to get the scale to run exactly parallel to the axis. Also, adhesive is too permanent and will introduce further problems if you ever need to replace the scales. If you are entering the world of model engineering you will be drilling and tapping holes in all sorts of material, large and small. Treat it as part if your learning experience.
Drilling and tapping one hole in your mill will probably take 2-3 minutes. In the unlikely event that you mess up you can just drill and tap in a different location.
Get a piece of scrap cast iron and practice in order to gain confidence. Also, the factory drilled and tapped numerous holes when manufacturing your mill, so a few extra won't hurt.
Hope that helps.
Good luck.
Andrew

 

[Mike Ginn]

In a word - or two - Don't even consider using adhesives. The design of an adhesive joint is complex and would require the removal all all paint in the area. Cast iron is very easy to drill and if you are concerned about breaking the tap then just dill oversize - there is very little strength needed to hold a scale in place. AndrewW is completely correct. My experience with magnetic scales is that they are robust and not damages by magnets - I carried out some experiments! It's obviously sensible to keep strong magnets away from the scales but in normal use with mag bases I have never had a problem.

Oh and use a good quality drill - ideally a new drill - I always use Dormer brand which I find drills holes to size.

Mike

 

[djc]

Epoxy or any other type of adhesive will not work as you need to be able to introduce some fine adjustment in order to get the scale to run exactly parallel to the axis.

Epoxy can have a useful role to play in mounting a DRO as a filler material between the mounting plate and the unmachined castings of the machine.

Very often you will mount a sub-plate to which the DRO scale itself bolts. Rather than trying to shape this plate such that one side is intimate with the casting and the other is parallel with the axis, hang it in place so that one face (the 'front', to which the DRO scale attaches) is correct and use a conformable material (epoxy) to fill the gap on the other side.

You can set the sub plate correctly planar and hold it in position using a rigid but temporary fixture attached to the mill table such as a piece of plate drilled to the same hole pattern as the DRO scale.

You would have to make your own judgement over the reliability and longevity of any strictly non-mechanical fixing.

If I were to pursue this, I would use two securing screws and tighten them only when the epoxy is dry so there is a small compressive load on the sub-plate-epoxy sandwich.

Drill the sub plate tapping drill size. Fill the hole with blu-tack to stop the epoxy coming out. Once the epoxy is set, drill through this hole and into the casting. Open out to nominal size only to the bottom of the epoxy. Tap the casting, open out to clearance size, countersink the hole and install the screw.

 

[raveney]

Sirjohn,
Your Craftex looks very similar to my Grizzly vertical mill. I am very pleased with a 3 axis glass scale digital readout with LCD display that was purchased in 2021. Model YIHAOGD YH80-3. I found it on Bangood for about $350 as I recall. I cannot find my receipt, but measured the scales and took some pictures that may help you. It improved my machining skills alot. The circle pattern is easy to figure out and use, and the global and local readings help with groups of features located on the same part, or performing the same operations on two parts clamped in the vice.

https://usa.banggood.com/YIHAOGD-YH...html?cur_warehouse=CN&ID=6281039&rmmds=search
X axis 620 mm
Y axis 270 mm
Z axis 370 mm

I was able to drill the holes into the mill without disassembly, just center punch and drill and tap by hand. The shipment did take a very long time (3 months) but there was a lot going on affecting China trade/shipping.

 

[SmithDoor]

Thanks for the detailed reply SHOPSHOE . Still don’t like the idea of drilling and tapping. Has anyone tried holding the scales on with JB Epoxy? A Canadian in Calgary.

JB weld at best for most work a temp fix.
When I work in Machine shops you see JB weld on parts where JB weld failed.

Dave

 

[L98fiero]

I have a new Craftex CX600 mill/drill and would like to install a 3 axis DRO. A couple question:s;
1. Any recommendations on sourcing a suitable DRO.
2. I am baffled on how the scales are attached to the mill. Does this require drilling and tapping the mill frame or is is some other method of attaching the scales as I am not too anxious to drill holes into my new mill.

Not all glass scales are equal, that said, I bought a 3 axis system off Aliexpress, it works pretty much the same as any of the others and was half the price of a locally purchased Chinese DRO, the trade off is waiting time for delivery. As for reliability/longevity, the first Chinese DRO I have is over a decade old and still 100% reliable. The only issue I have with any of the Chinese DROs is that, I believe, they are metric based and they have rounding errors in the ten thousandths in Imperial, i.e., if you are working in Imperial the number you preset may be 0.0001 off position, not something that's a problem in 99.999999% of our work or even industrially.

As for using adhesives to attach the scales, screws are a better bet, even if just from the standpoint of the adhesive possibly failing and the scale being damaged when they fall off and your machine won't be bothered by having a few holes drilled for the scales and you'll probably never take the scales off so everyone will understand the screws will have been required anyway.

 

[Mike Ginn]

I suspect we have all come to the end of this thread! My view, and that of most of the postings, is that epoxy is not suitable for holding scales to a mill. It just doesn't work. Please use small screws in (probably) newly tapped holes. M4/6 size is fine. You can use JBWeld as a packing/levelling material but it probably isn't necessary.

Get you drill and taps out and enjoy the DRO experience!!!

Mike

 

[william_b_noble]

I installed a SINO brand 2 axis DRO on my logan lathe - it took a few hours because I had to take some things apart, but the installation went exactly as instructed, and the unit is quite accurate - I replaced a Trav-a-dial that I had on the carriage that would slip from time to time. my lathe is quite a bit larger than your little mill but the installation is basically the same, you install stuff, you do some careful alignment using an indicator, and it works. make sure you have a indicator you trust and a stand to hold it, and make sure you dress the cables properly and all will be well.

 

[gsg]

I installed a 4 axis DRO on my XC 45, because there was only a 3 axis DRO installed and I missed the spindel heights gauge. So i used the 3 axis DRO for my CJM250 lathe and installed 3 magnetic scales due to the smaler size of the puckup and the scale. I used a magnetic scale also for the mill Spindle, the 3 installed glas scales had an TTL Output, which did not work with the RS242 input of the new DRO is RS422, so I needed a converter TTL to RS422 for the glas scales. For the converter i used a AM26C31 IC for the old glas scales and made a PCB to fit the converter beewtwenn the output of the scales and the input of the DRO. The two systems are workin fine for some years now.

Regards Guenter

 

[firebird]

Hi
For many years I have had this type fitted to my lathe and milling machines

I have no connection to the above company just a satisfied customer

They can be used with the supplied readouts which are ok but I have used a programme called TouchDRO which is a free download and works on any Android phone or tablet. The DRO's are connected to the tablet via Bluetooth.

Cheers

Rich