# Mounting 3-axis DRO to my RF-30 clone



## Gravydog (Oct 21, 2019)

After getting my mill set up, the first thing I wanted to do was install a DRO so I wouldn't have to deal with the runout on the X and Y axes and the inaccuracy of the dial on the Z axis (dial marked in thousandths but a full turn is actually only 0.084" instead of 0.100"). Also, they are just cool! I looked all around and I was really intrigued by the ones I found on AliExpress with an actual screen instead of just numerical displays. $250 with free shipping (but plus tax). After a few days the DHL tracking showed it was in Hong Kong and the next morning it was on my porch near Seattle!

First I tackled the X scale. I put it on the back of the table because of my power feed with its stops and switch. Yes, I lose some Y travel but I don't think I personally will ever miss it. My career was as a Honda tech and whenever I would make any modifications I always felt more satisfaction when I could leave things as stock as possible so that things could be put back to original without leaving any telltale signs, even though that was unlikely, just the fact that it could. I was frustrated by the many videos I watched about mounting the X scale because no one I saw addressed what they ended up doing with the chip guard. Here is what I did:

I replaced the bolts for the chip guard with studs and made a bracket to function as a mount for the read head and a stop for the cross slide to keep from crushing anything by over-travelling the Y feed, no new holes for that.




Then I mounted the X scale to the rear of the table, did have to drill and tap holes, OK of course when needed. I mounted the read head to my bracket with screws that didn't protrude past the bracket. The read heads came with red plastic spacers between them and the scales that I assumed provided proper spacing and alignment so I decided to just keep them on there. The plastic spacers had two tiny holes on the end and two threaded holes in the read head, so I put in some tiny screws left over from working on laptops that fit correctly.




Next, I put nuts on the studs even with the outside of the scale plus a hair. Then I made a plate to back up the rubber chip guard and placed it over the studs.




Then I mounted the chip guard to the studs and put on the final nuts.




Lastly I installed the guard over the scale and cranked the Y travel all the way to the stop. Nothing crushed, my evil plan worked!




On all 3 scales I wanted to mount them so the read heads were stationary and the scales moving so the cables basically don't move or wear. True, the Y cable moves a little as the cross slide moves front to back but that doesn't amount to much. Next I moved on to mounting the Y head and scale. I took the power feed out of the way and made a bracket to mount the scale. Had to drill and tap more holes, oh well.




Then I mounted the scale to the bracket. I mounted the head to the only angle bracket that I used from the kit, it worked well. More drilling and tapping, where will it end? Since the side of the machine base isn't perfectly vertical I bent the bracket to less than 90 degrees to make the top of the bracket level.




Put the chip guard on and remounted the power feed motor.




On to the Z scale! I did lots of reading online and watched videos on YouTube before ordering the kit. I was pretty clear how I would mount it for X and Y but I was up in the air on how to mount the Z scale. It seemed so bulky to mount it right out front with everything else that's in the area, I just wasn't satisfied. Then I saw a photo (on here, I think) showing someone who had mounted the scale on the side of the head near the column with a bracket going to the clamp around the quill that holds the depth stop screw. That was the idea that gave me inspiration. There is a big opening in the bottom of the head between the quill and the column just the right size to make a home for the scale and read head. I made a little mount to attach to the quill clamp and mounted the scale to it. I had to use a little shim from the kit to make the scale end up plumb. The secret here is that the upper end of the scale is just floating free but since nothing can touch it, it doesn't get disturbed. I made a couple small brackets to mount the read head and it's all set.




Last, I mounted the arm for the display. It's a little crowded back there but I wanted it on the right side and far enough back to clear the handles for the downfeed. The kit comes with a bracket and arm but when you put the bolt through it there is no provision for tensioning the pivot, it just swings freely. To solve this I drilled the lower bracket hole larger and made a slip-fit bushing for it. I put nylon washers under the bolt head and between the bracket and the arm so now when you tighten the bolt the arm is pushed against the washer so there is tension to hold the arm wherever you push it to.




I did find that the soft aluminum arm was being deformed by the pressure before I was satisfied with the tension, so I made an insert for the end of the arm and now I can tighten it as much as needed.




I used some snap-in cable ties to route the cables along the arm and some clamps with rubber inserts to corral the cables here and there. The one on the back of the column is a little oversized so that when you lower the head the cables just slide through it.








Well, I think that's about it. I hope someone in the future will gain some inspiration from this just as I do from reading posts from others.

Rob


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## MontanaLon (Oct 21, 2019)

Nice work. I have been looking to add a DRO to my mill and would be interested in a review of that model if you get time.


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## pontiac428 (Oct 22, 2019)

Great job on the bracketry, especially the rear- mounted, protected, tucked in back, and fitted under the chip guard cleanly!


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## Norseman C.B. (Oct 22, 2019)

I did a similar set up on my RF clone but you have done some refinement on yours
which has got me looking at mine in another light.  I modified the stock Z axis assembly to incorporate the reader on
mine which may be one that you saw here, and your inside the head mount is intriguing.
Nicely done, and Thank you for sharing your set up.................................


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## RJSakowski (Oct 22, 2019)

You have an interesting location for the z axis.  I had previously installed a work light in that space and it never occurred to me to put the scale there.  I  modified the depth stop to install mine.


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## mikey (Oct 22, 2019)

Really nice job you did there, Rob. Thank you for sharing!


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## mattthemuppet2 (Oct 23, 2019)

fantastic install, thanks for sharing.

Do you have a link for that DRO? Displays with screens  don't come up that often and that sounds like a great price.


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## Gravydog (Oct 23, 2019)

mattthemuppet2 said:


> Do you have a link for that DRO? Displays with screens  don't come up that often and that sounds like a great price.



This is where I bought mine:









						223.56US $ 8% OFF|Complete 3 Axis Dro Kit Set Big LCD Display Digital Readout Controller with 3pcs 5U Linear Scale Linear Optical Ruler 50 to 1000|Level Measuring Instruments|   - AliExpress
					

Smarter Shopping, Better Living!  Aliexpress.com




					www.aliexpress.com
				




In installing it and using it a little, I am satisfied with the quality and functioning. For my machine I ordered scales of 150mm, 250mm and 650mm although with losing some Y travel I could maybe have gone shorter than 250mm but it didn't bother anything.

Rob


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## Gravydog (Oct 23, 2019)

MontanaLon said:


> Nice work. I have been looking to add a DRO to my mill and would be interested in a review of that model if you get time.



Well, I can't give much of a review because this is the only DRO I have ever used! I wanted the screen because it can display full characters and graphics. The bolt circle function, for instance, shows the entire circle and which hole you are currently on. You can move to any hole at any time with the arrow keys. I will show this in my next post where I made a spindle wrench, soon.

Rob


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## mattthemuppet2 (Oct 23, 2019)

awesome, thanks! THose must be pretty new - I've been looking on and off for a couple of years and it was either the standard 3 sets of numbers or the fancier and more expensive Easson LCD display versions. Just have to make my riser block, save my pennies then I'll be ready to order


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## DavidR8 (Feb 20, 2020)

Thanks for your excellent write up @Gravydog. I just purchased an RF-30 clone and there will be a DRO in its future.


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## pontiac428 (Mar 4, 2020)

@Gravydog, where did you source those extrusions for your chip guards?


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## DavidR8 (Mar 4, 2020)

pontiac428 said:


> @Gravydog, where did you source those extrusions for your chip guards?


I've ordered the same DRO and it looks like the guards are included.


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## DavidR8 (Mar 4, 2020)




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## Gravydog (Mar 29, 2020)

DavidR8 said:


> Thanks for your excellent write up @Gravydog. I just purchased an RF-30 clone and there will be a DRO in its future.


I have made a small change which I think is an improvement. I moved the mounting point for the display arm up to the bottom of the belt guard/cover. Now the arm mounting is higher and farther back so it allows more room for your fingers to pull the top rear downfeed handle. Be sure to use large washers above and below the sheet metal for less sagging of the arm.




I'll be making another post about the stuff you see on the left.







Hope this helps someone sometime.

Rob


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