RAMoynihan
Member
Hi Folks,
Some background for this project:
I have a Rongfu round column mill that I purchased on Kijiji some few years. It was in fair condition and there was no motor or control system. The previous owner intended to install a CNC controller but couldn't get it to work and decided to sell the machine as is.
First, I completely stripped it down so that I could repaint it in my preferred machine tool colour: grey! After reassembly everything seemed to work OK save the main table feed screw.
The table would bind when it was moved over to the right side. There was (still is) some kind of misalignment between the lead screw and the handwheel mounts. I'm suspisous that some pieces may have been cobbled from a different machine, because the mounting holes don't line up well, and one of the cap screws goes in at an angle that is noticeably not 90 degrees. The quickest solution for me was to leave one of the handwheel mounting plates off on the left side. Not great, but it works.
I purchased a motor from PA and used a magnetic starter that I had lying around. The lack of a reverse function hasn't bothered me so far - no power tapping on this one.
The draw bolt for the spindle was an absolute embarassment, so I had to remake it.
The column lock was done with a couple of bolts that were so spalled that they were hard to turn with a wrench. I replaced them with new, and made a lock handle to mimick the spindle lock handle. The new handle feels just right.
Next I made a mobile cabinet to mount it all on. My basement shop is fairly small (400 sqft) so most of my machines (save the table saw) are on wheels so that I can get them out of the way when I need to. There's enough space in the drawers to hold all of the tooling, etc.
With those mods done the machine was getting near daily use. But the backlash in the lead screw, and having to count (and keep track of) handwheel revolutions in my head was bothering me. I decided that I needed a DRO to make things easier and I found one with really small sensors that I could fit under the table. I didn't want to mount something in front (blocking the limit stops - which I use a lot) or behind (reducing y-axis travel). I found that I could affix a magnetic scale directly to the underside of the table and that there was just enough headroom under the table for a sensor to sit right next to the main leadscrew nut. With this arrangement, the mill operation wasn’t changed in any way. The ‘y’ axis was dead easy, so ‘nuff said. The ‘z’ axis was handled by mounting the scale inside the machine head behind the spindle. All that has worked really well for a couple of years.
More recently, I mounted a different type of DRO on my lathe. Having used both for a while I really prefer some of its features on the newer DRO, and I now plan to install the newer system on the mill. The main issue is that the new DRO uses sensors that are quite a bit larger than the old one, so I’ll have to do some surgery this time to make it fit the way I want on the x-axis. The y and z axis should fit pretty well with just new mounting plates.
This thread will document this project.
First a pic of the machine in question:
Some background for this project:
I have a Rongfu round column mill that I purchased on Kijiji some few years. It was in fair condition and there was no motor or control system. The previous owner intended to install a CNC controller but couldn't get it to work and decided to sell the machine as is.
First, I completely stripped it down so that I could repaint it in my preferred machine tool colour: grey! After reassembly everything seemed to work OK save the main table feed screw.
The table would bind when it was moved over to the right side. There was (still is) some kind of misalignment between the lead screw and the handwheel mounts. I'm suspisous that some pieces may have been cobbled from a different machine, because the mounting holes don't line up well, and one of the cap screws goes in at an angle that is noticeably not 90 degrees. The quickest solution for me was to leave one of the handwheel mounting plates off on the left side. Not great, but it works.
I purchased a motor from PA and used a magnetic starter that I had lying around. The lack of a reverse function hasn't bothered me so far - no power tapping on this one.
The draw bolt for the spindle was an absolute embarassment, so I had to remake it.
The column lock was done with a couple of bolts that were so spalled that they were hard to turn with a wrench. I replaced them with new, and made a lock handle to mimick the spindle lock handle. The new handle feels just right.
Next I made a mobile cabinet to mount it all on. My basement shop is fairly small (400 sqft) so most of my machines (save the table saw) are on wheels so that I can get them out of the way when I need to. There's enough space in the drawers to hold all of the tooling, etc.
With those mods done the machine was getting near daily use. But the backlash in the lead screw, and having to count (and keep track of) handwheel revolutions in my head was bothering me. I decided that I needed a DRO to make things easier and I found one with really small sensors that I could fit under the table. I didn't want to mount something in front (blocking the limit stops - which I use a lot) or behind (reducing y-axis travel). I found that I could affix a magnetic scale directly to the underside of the table and that there was just enough headroom under the table for a sensor to sit right next to the main leadscrew nut. With this arrangement, the mill operation wasn’t changed in any way. The ‘y’ axis was dead easy, so ‘nuff said. The ‘z’ axis was handled by mounting the scale inside the machine head behind the spindle. All that has worked really well for a couple of years.
More recently, I mounted a different type of DRO on my lathe. Having used both for a while I really prefer some of its features on the newer DRO, and I now plan to install the newer system on the mill. The main issue is that the new DRO uses sensors that are quite a bit larger than the old one, so I’ll have to do some surgery this time to make it fit the way I want on the x-axis. The y and z axis should fit pretty well with just new mounting plates.
This thread will document this project.
First a pic of the machine in question:
