- Joined
- Dec 26, 2015
- Messages
- 2,080
It’s been almost a year since I received my PM935 mill, and I thought it was finally time post here about the process of upgrading and accessorizing the machine. Some of you may recall that I embarked on a similar project with my PM1340GT lathe a few years back, and documented here. The mill project was similar in scope in many regards.
The new mill was to be an upgrade from an 18 year old original Rong Fu 45 that had served me very well as a workhorse over the years, performing well beyond what I thought was possible from a “bench top” mill/drill unit. But I wanted a slightly larger machine, and I especially wanted power feeders on all three axis, a power draw bar, variable speed controls, and more rigidity. I faced serious constraints in ceiling height and available floor space in my basement shop, so the PM935 seemed like an ideal platform for the move to a knee mill.
Mark Jacobs developed the electronics to convert it to full VFD controls, and at the same time provide several convenience features I was after. The result has thus been christened The Best & Jacobs Full Custom Edition – just like my 1340 lathe project. Many thanks go out to Mark for his thoughtful and diligent work on the controls, and all his advice and support during this project.
What follows is a summary of the various improvements and additions, along with some photos. The base machine is the pulley-drive TS version, and I retained the original motor. If anyone is interested in going through the entire build log, you can find that here.
New electronic control system by Mark Jacobs
MachTach tachometer with custom quill sensor mount including LED ring light.
And of course, as I did with the 1340 lathe, I stripped the entire mill (with the exception of the J-head) back to bare castings, got rid of the chalky body filler that facilitates the paint chipping. Re-fairing the casting with proper Bondo filler, upgrading a lot of the fasteners on the machine, spray painting with DTM alkyd enamel. Unlike my lathe project, I decided to keep the same color as the original.
The project has not been without tribulations. The original J-head supplied with this mill was defective. Working with Matt at PM, I made several attempts to fix the problems I was having with the head unit, employing spare parts sent from the factory in Taiwan. The original power quill feed had issues necessitating the replacement of the drive gear assembly inside the head. Several weeks were spent diagnosing the source of broken carbide end mills and terrible surface finish, which led to the replacement of the upper drive housing and the quill/spindle assembly. In the end, none of the extensive corrections resolved the problems, and I was sent a complete new J-head from PM which resolved a myriad of issues. Hearty thanks go out to Matt and his team for supporting me through this effort.
It’s been a rewarding effort. I can’t say I’m am fond of the J-head itself. In contrast to the gear-driven head on my RF45, I regard it as positively crude - full of design compromises that at times take my breath away. Having 3-axis power feed and a power drawbar have certainly increased productivity and the enjoyment of the craft.
As I mentioned above, for those interested, the complete build log is here. Fully six pages of photos and videos with descriptions below.
Questions and comments welcomed.
The new mill was to be an upgrade from an 18 year old original Rong Fu 45 that had served me very well as a workhorse over the years, performing well beyond what I thought was possible from a “bench top” mill/drill unit. But I wanted a slightly larger machine, and I especially wanted power feeders on all three axis, a power draw bar, variable speed controls, and more rigidity. I faced serious constraints in ceiling height and available floor space in my basement shop, so the PM935 seemed like an ideal platform for the move to a knee mill.
Mark Jacobs developed the electronics to convert it to full VFD controls, and at the same time provide several convenience features I was after. The result has thus been christened The Best & Jacobs Full Custom Edition – just like my 1340 lathe project. Many thanks go out to Mark for his thoughtful and diligent work on the controls, and all his advice and support during this project.
What follows is a summary of the various improvements and additions, along with some photos. The base machine is the pulley-drive TS version, and I retained the original motor. If anyone is interested in going through the entire build log, you can find that here.
New electronic control system by Mark Jacobs
- NEMA enclosure
- Hitachi VFD with electronic breaking
- Heads-up display with speed control, tachometer, E-stop, momentary down/up tapping controls, LED spindle lighting
- Knee mounted controls for Start/Stop, spindle direction, auto-reverse proximity stop, and coolant control
MachTach tachometer with custom quill sensor mount including LED ring light.
Align Power Feeders on X, Y and Knee
Newall DRO with 5 micron scales on X, Y and Knee including all custom brackets integrating power feeder limit stops
Custom Mitutoyo DRO scale on quill with integral proximity sensor for auto-reverse with quick-position depth stop
Maxi Torque-rite Power Drawbar
Upgraded single-shot oiler ports in the machine casting to eliminate oil leaks
Replaced all J-head lever-selector handles
Added a stainless steel quadrant-style quill handle
Added a Fogbuster MQL Coolant system
Added a custom pneumatic distribution system for power drawbar, Fogbuster, and spray wand
Added fused accessory AC outlets for feeders, DRO, and low voltage accessory LED lighting on the head
And a simplified Leveling Feet solution
Self-tramming head (joking)And of course, as I did with the 1340 lathe, I stripped the entire mill (with the exception of the J-head) back to bare castings, got rid of the chalky body filler that facilitates the paint chipping. Re-fairing the casting with proper Bondo filler, upgrading a lot of the fasteners on the machine, spray painting with DTM alkyd enamel. Unlike my lathe project, I decided to keep the same color as the original.
The project has not been without tribulations. The original J-head supplied with this mill was defective. Working with Matt at PM, I made several attempts to fix the problems I was having with the head unit, employing spare parts sent from the factory in Taiwan. The original power quill feed had issues necessitating the replacement of the drive gear assembly inside the head. Several weeks were spent diagnosing the source of broken carbide end mills and terrible surface finish, which led to the replacement of the upper drive housing and the quill/spindle assembly. In the end, none of the extensive corrections resolved the problems, and I was sent a complete new J-head from PM which resolved a myriad of issues. Hearty thanks go out to Matt and his team for supporting me through this effort.
It’s been a rewarding effort. I can’t say I’m am fond of the J-head itself. In contrast to the gear-driven head on my RF45, I regard it as positively crude - full of design compromises that at times take my breath away. Having 3-axis power feed and a power drawbar have certainly increased productivity and the enjoyment of the craft.
As I mentioned above, for those interested, the complete build log is here. Fully six pages of photos and videos with descriptions below.
Questions and comments welcomed.