About a year ago I bought a TPAC Tools 3-Axis DRO for my PM-833T. PM was out of their DROs at the time. It took me a year because I knew it was going to be a long job with a bunch of stuff to figure out and fabricate. While I can chamber a barrel that will shoot sub 2" groups at 1000 yds, I have only moderate fabricating skills and tools. So I didn't even start until I had thought enough about it to figure it out.
The best option is to buy the DRO from PM when you buy the mill and have them install it. If you are installing it yourself after you already have the mill, buy the PM DRO kit since it has brackets that need minimal modifications. If you have to buy a universal DRO, have a tig welder, know how to use it, and have lots of aluminum around, then install it like FL 420 ( @7milesup ) did. https://www.hobby-machinist.com/threads/pm-833t-dro-install.76240/#post-640049
@RIMSPOKE also did a nice job: https://www.hobby-machinist.com/threads/easson-es-12-b-dro-install-on-a-pm-833t-mill.56329/
If you are a hack like me with a universal DRO, here is the magic. This only requires mediocre welding skills, the ability to drill a reasonably square hole, and the ability to successfully tap those holes.
The X-Axis is very easy. Just attach the scale to the back of the table and attach the reader head to the stationary part. I didn't even take a pic of that.
The Z Axis is easy as well, though I did have to move my previously installed Z-Axis powerfeed stop to the other side of the column.
The Y-Axis is the hard part, and this little bracket made it all happen. It is made of 3/16" x 1.5" mild steel bar.
Here it is attached to the universal bracket that came with the DRO:
Here it is in place. And painted:
Knowing what I know now, I wouldn't have tried to correct the slope of the milling machine base. I would have just bent the bracket to align it. I wound up having to do that anyway. I don't like how the cover fits and I'll need to make a different one or at least a new front cover. I also don't like the stacked washers and I did find some spacers I may use instead.
Final Pics. Everything works and each scale is aligned to withing about .002". I don't know if i need to calibrate it further.
The best option is to buy the DRO from PM when you buy the mill and have them install it. If you are installing it yourself after you already have the mill, buy the PM DRO kit since it has brackets that need minimal modifications. If you have to buy a universal DRO, have a tig welder, know how to use it, and have lots of aluminum around, then install it like FL 420 ( @7milesup ) did. https://www.hobby-machinist.com/threads/pm-833t-dro-install.76240/#post-640049
@RIMSPOKE also did a nice job: https://www.hobby-machinist.com/threads/easson-es-12-b-dro-install-on-a-pm-833t-mill.56329/
If you are a hack like me with a universal DRO, here is the magic. This only requires mediocre welding skills, the ability to drill a reasonably square hole, and the ability to successfully tap those holes.
The X-Axis is very easy. Just attach the scale to the back of the table and attach the reader head to the stationary part. I didn't even take a pic of that.
The Z Axis is easy as well, though I did have to move my previously installed Z-Axis powerfeed stop to the other side of the column.
The Y-Axis is the hard part, and this little bracket made it all happen. It is made of 3/16" x 1.5" mild steel bar.
Here it is attached to the universal bracket that came with the DRO:
Here it is in place. And painted:
Knowing what I know now, I wouldn't have tried to correct the slope of the milling machine base. I would have just bent the bracket to align it. I wound up having to do that anyway. I don't like how the cover fits and I'll need to make a different one or at least a new front cover. I also don't like the stacked washers and I did find some spacers I may use instead.
Final Pics. Everything works and each scale is aligned to withing about .002". I don't know if i need to calibrate it further.
Last edited:
