# PM935 - the Best & Jacobs Full Custom Edition



## davidpbest (Aug 28, 2019)

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

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
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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
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​Custom Mitutoyo DRO scale on quill with integral proximity sensor for auto-reverse with quick-position depth stop



​Maxi Torque-rite Power Drawbar
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​Upgraded single-shot oiler ports in the machine casting to eliminate oil leaks
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​Replaced all J-head lever-selector handles
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​Added a stainless steel quadrant-style quill handle
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​Added a Fogbuster MQL Coolant system
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​Added a custom pneumatic distribution system for power drawbar, Fogbuster, and spray wand
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​Added fused accessory AC outlets for feeders, DRO,  and low voltage accessory LED lighting on the head
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​And a simplified Leveling Feet solution
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​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.
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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.


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## carmad (Aug 28, 2019)

David, your skill and attention to detail are truly inspirational, hell of a project.

Julian


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## rwm (Aug 28, 2019)

Really beautiful machine! What is the finish on the  J-head lever-selector handles? Are they painted?
Robert


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## Janderso (Aug 28, 2019)

You sir, are incredible!
Absolutely beautiful, meticulous work.


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## mksj (Aug 28, 2019)

As usual, over the top perfection from David. Been a long bumpy road working through everything, but beautiful work as expected.
Mark


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## davidpbest (Aug 28, 2019)

rwm said:


> Really beautiful machine! What is the finish on the  J-head lever-selector handles? Are they painted?
> Robert


Thanks.   The handles, and all the aluminum brackets for DRO's and other bits were glass bead blasted, then hard anodized grey.   Have a look at this short video:   


__
		https://flic.kr/p/2h77GHW


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## davidpbest (Aug 28, 2019)

mksj said:


> As usual, over the top perfection from David. Been a long bumpy road working through everything, but beautiful work as expected.
> Mark


Thanks Mark, I couldn't have done this without your help and support.


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## petertha (Aug 31, 2019)

The machine looks awesome from every angle, David. Congrats on the huge effort & especially your perseverance overcoming challenges along the way.

The anodized grey is badass, but mostly I was shocked by the reasonable price. Did you do the pre-blasting yourself or just handed over the parts & they took it from there? Is it OK to state the company name or PM if you prefer not for whatever reason.


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## davidpbest (Aug 31, 2019)

petertha said:


> The machine looks awesome from every angle, David. Congrats on the huge effort & especially your perseverance overcoming challenges along the way.
> 
> The anodized grey is badass, but mostly I was shocked by the reasonable price. Did you do the pre-blasting yourself or just handed over the parts & they took it from there? Is it OK to state the company name or PM if you prefer not for whatever reason.



Thanks Peter.   I use this Advanced Precision Anodizing service a few times/year.   They are about 30 minute drive down the river from me, just past Portland International airport, so nice scenery along the way.  It's an interesting place for sure.   About 25 employees, and they put through a tremendous amount of product - literally thousands of parts per day.   The minimum charge for normal anodizing is $45, and for hard anodizing it's $90.   Glass bead blasting, or blasting with aluminum oxide media (more aggressive, rougher finish) is $45/hour.   I think they charged me two hours for the bead blasting, and minimum for the hard anodizing.    The hard anodizing is significantly harder than the normal process, but the color choices are minimal and at least two shades darker than regular anodizing.   What you saw is "medium grey" whereas "clear hard" is more like light grey.   Based on what I've seen, this outfit does a tremendous amount of work for machinists and manufacturers outside of the area - they have 4 full time employees dedicated to packing and shipping for instance.   Check 'em out:






						Home | APA OFFICIAL
					






					www.apanodizing.com


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## StevSmar (Oct 7, 2019)

Wonderful! Thanks for sharing your inspirational build!


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## wrmiller (Oct 7, 2019)

Amazing what time, dedication, and money will do.


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## StevSmar (Oct 8, 2019)

wrmiller said:


> ... and money will do.


Unfortunately not having enough money to provide a sound basis to start from will always be “like trying to make a silk purse out of a sow’s ear”, regardless of how much time and dedication is available.


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