I was able to get my hands on a 3 axis DRO (digital read out) for the RF-45 clone mill. I have never had any experience with these units however I have only ever heard good things about DROs on mills. I currently have some milling jobs in the brainstorm and early design queue so I figured I would take the time now to get the mill in peak running state.

The DRO system I obtained is a Chinabuilt SINO SDS6-3V 3 axis unit. I was able to obtain the user manual for the system before I decided to buy and had spent time determining if I would be capable of using the system. The manual translation is a bit rough and it takes some mental work to decifier what is being explained however I figured once I could get my hands on the system and work with it I was going to achieve success. The manual contains no installation instructions as these systems are a universal fit and therefore it relies on the ingenuity of the installer to ensure it is going to fit.

So this blog posting is nothing more then a documentation of pictures showing my installation. I had attempted to find pictures and information on how others have done the install however I had no luck. I decided that with nothing to go on I was going to wing it and see what I could come up with. I was very pleased with the install and I am not sure I would have done it any differently. I am sure there are other ways of doing it, and perhaps better ways, however at this point I will plead ignorance. I decided I would post some pictures in hopes that it will help others who are planning to perform an install. Perhaps the information found here will either show others what to, or not to, do.

The basic concept is that there are 3 linear scales that need to be mounted to the mill. One scale for each axis X, Y, and Z. The criteria for the mounting is as follows; 1. The scales cannot affect the operation of the machine in any way. They cannot be mounted in such a way that it limits adjustment knobs or travel. They also cannot impede machine maintenance such as lubrication points of the ways or gearbox oil changes. 2. They need to be mounted rigidly as to maintain the accuracy of the readout. The biggest challenge was the Z axis. 3. The scales need to be as protected as possible from any oil, coolant, or metal contamination.

So off I went to start drilling and tapping holes into the mills castings. The DRO came with a few universal aluminum brackets; I was only able to use one for the Y axis. I ended up having to fabricate a total of three other adapters to get all the scales mounted.

I’ll let the pictures tell the story. It took me approximately 4 evenings to do the complete install and in the end I think it was 4 evenings well spent. I am happy with the rigidity of all the scales. The Z axis scale, the one that gets exposed to the worst vibrations, seems to be holding fairly accurate. Since the install I have spent a few hours educating myself with all the math functions. The DRO is more then just a readout as it can also help to perform accurate machining functions such as circle drilling, radiusing corners, center finding, drilling evenly space holes along an oblique line, plus a whole range of other functions. I was able to successfully get my way through many of the functions. Perhaps I’ll save my new found knowledge for another posting.

The Y axis needed a bracket made to connect the scale to the supplied aluminum adapter. Using a chunk of scrap channel I milled a bracket to attach to the Y table.

These are the three completed brackets that I built for both the X and Z axis. I left the quill clamp in the picture to show how the aluminum adapter fastens. The rigidity of the Z axis bracket was a concern however the use of 3/8" aluminum plate seemed to do the trick.

I was able to neatly bolt the X scale onto the back of the compound table. The scale is out of the way and protected.

A complete picture of the Y axis was difficult to take. This is the top view of the Y scale bracket mounted to the Y table on the right side of the mill.

Here you can see the mounting of the Y scale on the left side of the machine. The factory aluminum bracket goes up and connects to my fabricated steel bracket. Rigidity is not a problem with the Y scale.

The 3/8" aluminum plate bolted to the quill clamp was the right choice. It looks clean and is out of the way. The angle cut towards the left rear of the bracket allows me to still drain the gearbox oil.

The Z scale was tucked in behind the vertical feed controls. It's mounting still allows me to access the nut required to angle the machines head.

The final picture is of the plate I built in order to mount the control panel arm to a wall stud.

  1. Jason Garber says:

    Hey Gord,

    Do you experience any backlash issues when using the DRO, or does it accurately represent the position of the cutting head 100% of the time?

    Awesome pictures, by the way.


    • gordsgarage says:

      Hey Jason, the DRO is accurate to the tables 100% since the scale is mounted solid to all 3 axis. There are no backlash issues like when you are manually reading the dials on the lead screws. This is the beauty of the DRO set up in that accuracy can be maintained. The one area that would affect the digital readings would be any play that is present in the gibs. As long as the tables are adjusted and maintained the unit is good to go. I giddy with excitment with this one.


  2. Don C says:

    Hey Gord, what size of scales did you purchase? Any problems with the scales limiting the full length of travel in any direction?


    • gordsgarage says:

      Hi Don, the scales that I bought for the RF-45 clone were as follows; X=570mm, Y=470mm, X=270mm. There are 2 issues with the set up I did. First the length of the X scale is too short. I loose approximately 1 inch on both ends of the travel. I have a power feed on my X table so all I did was adjust the cut out switch stops to match the scale travel that way I won’t damage the scale. If I ever need to use full travel of the X table I will need to disconnect the scale, not hard to do, and run the machine without the DRO. The 2nd issue is that my Y travel is limited by where I mounted my X scale. Since I mounted the X scale on the backside of the table the scale will get crushed between the table and the square column should I ever run my Y axis all the way in. I only loose about an inch of travel on one end. I am not sure if you can decifer what I am trying to describe. Anyway…both the issues, in my mind, are minor. The Z scale has plenty of travel and works 100%. Hope this helps.

      • Don C says:

        Gord – that s exaplina it all clearly. My scales have arrived and I will be mounting them similar to your setup. Thanks for leading the way…


      • gordsgarage says:

        Hey Don, glad the info helps out. Good luck with the install. The addition of the scales are a fantastic feature to have.


  3. Dan says:

    I am adding a DRO to my mill and have a question. On the x-axis scale did you bolt the reader head directly to the cross slide carriage? On mine the reader head holes are tapped 5mm so i was thinking of drilling them out so I could use through bolts that thread into the carriage. Or did you use a bracket bolted to the reader head?

    Any help would be great.


    • gordsgarage says:

      Hey Dan, I couldn’t remeber how I did it so I took a quick look. The reader head is some what hidden on the back side but it appears that I used through bolts and secured it right into the carriage. I may have had to shim it a bit with a couple of washers. The x-axis is the only axis I didn’t have to built a bracket for. Hope this helps, good luck!


  4. Dan says:

    Thanks Gord. I appreciate you documenting your work as it has helped me in improving my mill


  5. Andy M says:

    Thanks Gord. This posting has helped to confirm my ideas for mounting the DRO scales on my own machine. I have the same mill as you, except mine is badged as a Titan Machinery TM45FG. I’m still in the process of setting it up as it has only just arrived.

    I was wondering if you had the dimensions of the Z-Axis Aluminium plate handy?

    Another question for you, assuming you’ve had this mill since new, what break in procedure, if any did you use for the spindle?

    My spindle gets quite hot after approx. 5 mins at full speed (H-3). So far, I have been running it for approx 10mins then letting it cool off completely, then repeat. Does that sound OK to you?

    • gordsgarage says:

      Hi Andy, sounds like you have a cool new toy. The challenge, for me, is getting all the tooling set up. The collenction is never complete.

      The aluminunm stock that I cut my Z-axis plate from was a section of 6″ x 3/8″ flat bar. I made the template on the fly.

      It has been awhile since I broke in the spindle. If memory serves correctly I believe I ran the machine, no load, on each speed for 20 – 30 minutes. Also the oil they ship in the gear boxes is junk and should be changed. I have never had any excessive heat issues with mine. I am unsure if you saw my post in regards to the X and Y table rebuilds, you can see it here. It was a well worth modification as the smoothness of the tables are now great to use.

      I highly recommend a DRO retrofit. Good Luck!


      • Andy M says:

        Gord, assembling all the tooling needed will probably take me eons, but I have the machine at least 🙂 It came with quite a few accessories, like a stand, a good vice, collet chuck & collets (endmill holding), hold down clamp set, 2 drill chucks and arbors (R8) and various spanners, allen keys etc.

        I just ordered my DRO, it’s a Meister BOLTS3 (I already have a Meister ARC2 on the lathe so I thought I would stay with what I know) and it will be mounted in a similar fashion to yours, although I will probably use all mild steel components and brackets.

        I may have to check the spindle bearings, they do seem tight. Maybe they need greasing? My mill came with an empty gearbox so I filled it with 80w90 Hypoid (Differential) gear oil. It makes the gearbox almost silent 🙂

        I may do a similar treatment to you regarding the X&Y axis. My X-axis seems fine, but the Y-Axis is a little tight and as you noted, there are no means of lubricating the critical areas at all. I don’t have any clear plans for adding the oiling system yet, I may do a poor man’s one shot system … that’s one shot per oiling point with an oilcan … lol

        It would be nice to get the oil where it needs to go though. I may at the very least add some oil cups. It will all depend on what parts I can source here (Australia) as a lot of suppliers have gone to ‘trade only’ supply which leaves me out in the cold 😦

        Anyhow, thanks for posting all this info here. It has made things a little easier for me as it has at least given me some direction in which to travel.


      • gordsgarage says:

        Hey Andy, sounds like you at least have a bit of a running start with the tooling. It’s always a work in progress.

        You will have no regrets installing a DRO on the mill, it’s fantastic. Sounds like you’ll have the set up that I want, a DRO on both my lathe and my mill. Someday I may order up some scales for the lathe and then just share the DRO display between the 2 machines. It won’t happen for awhile.

        Finding suppliers can be tough, it’s not easy for the DIY crowd to get quality tooling, especially when we have to fund the entire operation ourselves.

        Post pics of you install if you get a chance.


      • Andy M says:

        I have quite a few tools for the lathe and for my Sherline CNC machines, but still I find I need more tooling … sound familiar? … lol

        The DRO should arrive sometime next week. I will take some happy snaps when it arrives and when I bolt it on.

        I have also acquired a used garage door opener that hopefully will see duty as an automated head raiser/lowerer. I don’t have forearms like Popeye anymore so this will help I’m sure 🙂

  6. Andy M says:

    I just got confirmation that my DRO is on it’s way. It should arrive Wednesday 06/Feb/2013. Now I’m getting excited!!! 🙂

  7. Andy M says:

    I’m in the process of fitting my DRO to my TM45FG (same as yours) but I hit a bit of a snag while cutting some 6mm Mild Steel flat bar. I made what was supposed to be a straight cut using a 3/8″ 4 flute endmill but the results were anything but straight. It looked more like a dog’s hind leg actually. I didn’t think it would be that badly setup from the factory. Time to follow your strip and rebuild for the X&Y axis I think … lol … Anyhow, I have some pics at http://www.trumpy.net if you care to take a look. I have a pic of the piece I cut out of that flat bar, it’s not on my site, If you’d like to see it and comment on it, email me, I would sure appreciate it.

    • gordsgarage says:

      Hey Andy, you have a nice looking set up. I agree with your mounting of the x scale on the front of the table in order to maximize your y travel. I did mine the other way so my y travel is slightly limited however it has not caused me an issue yet. I am sure that someday I will be kicking myself for it.

      It sounds like you may have a work holding or a table adjustment issue with your flat bar milling. I would consider my mill 100% un-usable out of the crate. Cleaning and adjusting was absolutely required before use. Anyway…I would be interested to see your picture. PM sent.


      • Andy M says:

        Thanks Gord, check your inbox. Another advantage of mounting the scale to the front of the table was that I didn’t have to drill any holes in the table. I used the T-Slot for the travel stops to mount the scale.

        The center stop was then replaced with the read head bracket, although I will have to remake that bracket and place it underneath so that I can fit a cover on the scale. The few cuts I have made on the mill showed that there may be some ingress of chips/fluid etc. into the scale. I’d rather play it safe.

        Thanks Gord.

      • gordsgarage says:

        Thanks for sending the pictures Andy. To help those of you following comments to catch up here is what Andy had to say.

        “GDay Gordon,
        Thanks for the email. I’ve attached some photos of the offcut. It looks a lot worse than the opposite side of the cut but still it is a little alarming.
        Needless to say that this is the first cut I have made on this machine and I wasn’t looking for perfect results, just better ones than I got … lol
        I had a piece of 50x6x400mm Mild Steel laying on top of a piece 10x25mm BMS and then toe clamped to the table with the long edge adjacent to the t-slot. I indicated the long edge to make it parallel with the X-Axis. RPM was approx. 465. 3/8″ 4 Flute center cutting HSS endmill.
        There was another small notch that I put in the piece first and that went nicely, at least as well as I expected.
        I would appreciate any comments you may have even if they are negative in nature.
        I sure would appreciate any tips on removing the table also. Like how heavy is it, should I use lifting gear or would I be able to lift it on my own (I used to be able to bench press 300lbs but I’ve lost a lot of condition since then).”

        You can view the picture that Andy sent here.

        I would agree with you Andy that there is obviously a problem. It is always hard for me to diagnose situations when I can’t actually be present however I will try and help. I admit, though, that the finished cut looks very odd. It looks as though the cuts were made by feeding in the y axis in instead of running the mill with the x axis. Rigidity is the key when it comes to machining. I noticed that you have your milling vise mounted to a degree table. I have the same set up however I always ensure that I have my vise bolted directly to my x table when the degree adapter is not requires. Based on your description it sounds as though the vise was not used therefore my point may be irrelevant. I also ensure that I do not feed my z feed down any further than is required. Rigidity is vital. Taking note of the direction of table movement is important as I always cut into the blade of the clockwise rotating mill, in other words, if the work piece is between you and the and the cutter then the x table should be fed from right to left. Another factor to consider is the SFM (Surface feet per minute) of your 3/8″ 4 Flute center cutting HSS end mill, Manufacturers publish suggested SFM charts that help you determine proper machine RPM. Your 465 RPM sounds low; I typically cut in the 1000 RPM+ range however it is always best to consult the manufacturer for the specs.

        Ultimately I question how secure everything is clamped. It sure looks as though there was a lot of movement in something. If I could see it as it occurred I suspect the problem would be more evident. Perhaps someone else that follows the comments section on my blog may be able to chime in; perhaps they have experienced what you did and know exactly what happened. Can you shoot and post a YouTube video? Seeing it real time would help.

        I’ll keep pondering.


  8. Andy M says:

    It would appear that I found the problem that created that horrible cut. The gibs are loose and not adjusted.

    I finished installing the Y-Axis scale so I thought I would switch on and check my handy work. With the DRO powered up and a few movements in X & Y, feeling rather pleased with myself, I leaned on a corner of the mill table and lo and behold both X & Y Axis DRO’s jumped.

    I grabbed the corner of the table and proceeded to push and pull on it and I was quite surprised at how much play there is. Strangely though, after twisting the table around, I now find that both axis are free and easy to move. I guess I must have dislodged a burr, or more likely some casting grit and everything has freed up tremendously.

    I still plan to disassemble both axis though, so that I can clean everything, re-lube and adjust the gibs correctly before I put this machine into service again.

    Thanks for the help Gord.

    • gordsgarage says:

      Hey Andy, glad to hear that you got it figured out. Loose gibs would certainly contribute to the poor cuts. Disassembly, cleaning, lubing, and adjusting of the tables wil be certain to bring much more joy when using the machine. Good luck!


      • Andy M says:

        Thanks Gord. To be honest I thought your complete strip down etc… was a bit of overkill. How wrong could I be? Very wrong as it turns out … lol

        The DRO installation is complete now, I finished off the Z-Axis this morning so it’s time to strip and clean … the machine that is … lol


      • gordsgarage says:

        Hey Andy, glad to hear you got the DRO set up, you’ll love it! Stripping down, cleaning, and adjusting the tables doesn’t take much time (a few hours) but is sooooo worth it, you’ll thanks yourself 10 times over for doing it.


      • Andy M says:

        NO Gord, I’ll thank YOU 10 times over … lol

  9. nixieguy says:

    Awesome install!
    Can I ask where to get the manual? (also, does it have any serial or USB connection capability for a future CNC mod with servomotors?)

    • gordsgarage says:

      Hi nixieguy, sorry for the late reply, I was out of country for awhile. I have a PDF copy of the SINO SDS6 DRO operation manual, if you are interested in a copy please request. It does not have a serial port or USB capability as it is designed primarily for readouts only. For a CNC application you would have to go to a system like Tom, from CandCNC, builds. He offers just one of many available systems. You can link to CandCNC here.


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