Abandoned: CNC Mill

I don’t know about the rest of you, but I start a lot of projects that don’t reach completion. I’ve become emotionally attached to the parts that I dragged around with me so I’m loathe to part with them, but I thought I would start documenting them.

Back when I lived in San Francisco and had full use of my arms I bought a Rong Fu RF-31 Mill/Drill from Enco:

I was having a blast with it and lusting after making it CNC. But then I got a repetitive strain injury and lost the ability to wrench the bolts that hold the head in place. The mill languished for a long time at my studio at the Cataclysmic Megashear Ranch. When I moved to Seattle I left the mill behind in the care of Jamie Nasiatka. This was back in 2004, I haven’t been a great friend and slowly lost touch with him. But a quick search just showed that he finished what I always intended: converting the mill to CNC.

I’ve since purchased a Mini-Mill that fits my shop and arm capabilities. Due to my CNC lust back in San Francisco, I purchased a number of the parts needed to convert the mill to CNC.

The parts are totally useless for my Mini-Mill.

Mini-Mill, small but easy on the arms.

Here are my parts that I’m still trying to come up with a creative use for:

36V 20A Linear Power Supply for the Motors, also from Dan Mauch

Old Servo motor drives from Gecko

Servo motors with encoders from Dan Mauch
Parallel Port breakout card (sorta useless since I don’t have a computer with a parallel port anymore).
Possible uses:
power drive for the lead screw on the 9×20 lathe. I doubt I’ll cnc it, but it would be an mighty accurate power feed if hooked up to an arduino.

data geekery and tuning

I finally finished my data acquisition for the bike. I used an Arduino with an SD Shield to capture the TTL serial data as output by the Cycle Analyst.

Arduino with SD Shield taped to back of bike.

I actually took the bike out to run some errands. One of the annoying things is that I’m using the current and speed control on the Cycle Analyst. It uses a PID loop to do this, and the defaults are tuned for a bike with less power than mine. That means it oscillates. If you look at the image below, this represents me running on flat ground with the throttle wide open. You’ll see the PID loop cranking the amps up and down and the speed oscillating about 3mph. I’m trying out Tableau so you should be able to play with the data.

Full run coming back from Bartells :

Sheet 1
Sheet 1

eBike construction details

I had a great time giving a talk at dorkbot-sea about my build. Lots of great questions.

A couple of people asked how the motor is attached to the controller. Here’s a close up that shows the torque plate machined out of 1/4″ mild steel along with the motor wires with a drip loop.

Torque plate on left side of axle.

Battery Management System showing fully charged (except for one cranky cell)

Parts Ordered

After an obscene amount of time reading the forum at: http://endless-sphere.com/forums/viewforum.php?f=20 I went ahead and ordered parts.

What do I have enroute?

Direct from Ping Battery (Direct from China):

From ebikes.ca:

From Amazon:

From Recycled Cycles:

  • A set of thumb friction shifters to replace the 8 speed index shifter (which won’t work with my new freewheel)
  • Grease
  • New bearings for my front wheel
  • Cone wrench
  • New cables
  • Lubricant
From Stoneway Hardware:
  • 5mm Fender Washers (first time I’m ever using fender washers on actual fenders)
  • 5mm button head socket head cap screws



The bike has seen better days. It spent much of last winter our in the rain, tucked in the corner of my backyard in some mulch.

I spent some time this weekend cleaning the hubs and repacking the front bearings. I also picked up some nice new tires at REI. I got a pair of Michelin City 26×1.85 tires with reflective sidewalls. Better rolling resistance than the old ones, less mold stained, and have reflective sidewalls. I did not want to tempt a blowout after adding 50+ pounds more of crap to the bike.

I also switched the rear derailleur to use a friction shifter since the new powertrain is going to have a 6 speed freewheel instead of the 8 speed casette that is on there now.

I decided to take the human powered bike out and test the stopping power and handlebar position. On the first stoppie I noticed the front suspension was a little stiff. So I did it again, harder. I burst into laughter as I watched the water squirt out of the forks. These suckers are cheap elastomer forks and should have no liquid of any sort inside of them. I kept repeating: stoppie; laugh; stoppie; laugh; until the water was mostly gone.

Alas, much like my bike, I too have seen better days.

A couple of hours later and my thoracic spine was killing me, the skin on both arms was hypersensitive, the area under both pec minors hurt, and my right pinky had a dull ache. Still hurts today and I’ll need to take it easy the rest of the week while everything settles back down.

I had briefly forgotten about my thoracic outlet syndrome as it doesn’t bother me too much anymore. Unless I tease the dragon, then I’m reminded of it.

I went through a brief moment of worrying that I won’t even be able to ride the bike after I build it.

Nonsense I say! If this one hurts me, out comes the TIG welder and I’ll fab me one that works.


Since I’m doing all the design on this bike, the number of choices is a little overwhelming. To clarify things, I decided to set the mission I’m trying to accomplish. This is a big thing in the private pilot world because everyone wants the big fast plane, but realistically you are better off choosing your mission and buying a plane to fit it.

My primary goal with the bike is to get to and from work. While I can take a bus, the 28 local is routed through downtown and past the stadiums. This means if there is an event at the stadium, or just regular friday traffic, I can spend over an hour waiting for 3 busses to come at once. I hate at-grade public transport. I grew up outside of Boston (Newton) riding the T which is mostly separate from traffic and it set my standard for efficiency. San Francisco was similar, but Seattle really is the pits.

My work commute isn’t very far: just about 3 miles. It’s all downhill in the morning, and has about 1 mile of uphill on the way home. There is a stoplight at 8th and 65th which is on a 6% grade.

  • about 10 miles with some hills on a single charge with no pedaling (gives me errands in ballard)
  • max speed at 20 mph
  • Need enough power for the stop light on the 6% grade
  • Also have a stop on a 4% grade at NW Leary and 8th.
One key thing here is my decision to follow the law about max speed. Lots of ebike people want FAST. I’ve ridden motorcycles on and off since I was 16 (that’s 21 years if you are counting) and I fucking love them. But with increasing speed comes increasing kinetic energy (increases at the square of the speed, so a change from 20mph to 30mph increases your energy, which means more injuries and a need for better protective gear. I don’t really want to break out the Roadcrafter and motorcycle helmet for my bicycle ride to work. I’ll go buy a motorcycle if I want that.
Math geeks need apply:
The kinetic energy stored in my body at 20mph is 3200 joules. 
At 30mph it becomes 7200 joules. 
Therefore the speed increase of 10mph adds 4000 joules of stored energy into me that needs to get dissappated if I smack into something, or turned into heat by my brakes so I can stop.
By limiting my top speed I gain the following:
  • smaller brakes
  • smaller safety gear (with a similar margin of safety)
  • better handling (the steering geometry of my comfort bike is not designed for 30mph)
  • cheaper powertrain

Electric Assisted Bike Legality in WA

While I’m writing about the legal stuff first, that’s actually the last thing I did.

An Electric Assisted Bicycle must:

  • have working pedals
  • motor of 1000 Watts or less
  • 20 MPH or less
  • Can go anywhere a bicycle can go except the sidewalk. No riding on the sidewalk.
  • Just follow bicycle laws regarding helmets and such
  • Bike paths (like the Burke Gilman) are OK.

The next class of vehicle up is a moped:

  • 30 MPH or less
  • 2HP or less (just shy of 1500W)
  • can’t go on the Burke Gilman or other certain rights of way
  • needs registration
  • needs mirrors on left and right
  • must wear motorcycle helmet and eye protection
  • no mandatory insurance
  • don’t need pedals anymore (law changed in 2009)
  • Must follow some archaic 1969 DOT document

As you can see, being a moped (especially creating a home built moped like me) is a much bigger pain in the ass.

For now I’ll start with the Electric Assisted Bicycle and then if I’m dissatisfied with performance I’ll upgrade components and jump through hoops.



“Electric-assisted bicycle” means a bicycle with two or three wheels, a saddle, fully operative pedals for human propulsion, and an electric motor. The electric-assisted bicycle’s electric motor must have a power output of no more than one thousand watts, be incapable of propelling the device at a speed of more than twenty miles per hour on level ground, and be incapable of further increasing the speed of the device when human power alone is used to propel the device beyond twenty miles per hour.
[1997 c 328 § 1.]

Screw you CFS and FAI, I’m building an electric bike!

Two things conspired in 2010 to finally push me off my bicycle for good.

1) My right hip continues to slide downhill. While I had surgery on it back in 2006, it wasn’t enough and the hip is having arthritis again. Bicycling makes it sore, pop funny, and occasionally stabby.
2) Having my heart rate hit 110 or above for more than 5 minutes kicks in my chronic fatigue syndrome and I feel like crap an hour later for 3-24 hours depending on how long my heart rate is elevated. More here if you are interested: http://www.cfids.org/cfidslink/2007/030704.asp.

But I love two wheeled vehicles. I can’t remember when I rode my first bicycle, but I remember my first moped ride very clearly. It was David (blank)’s moped and it looked a little like this:

I was 14 (legal age was 16) and heck it was a lot of fun. I had taken an interest in small engine repair when I was 12 or so and hated shoveling. We had an old snowblower that my father hadn’t fixed because he would send me out to shovel. I learned to like earplugs, small engine repair, and running a snowblower far more fun than shoveling. My history coaxing life into small motors was traded for being able to frequently borrow the moped. Another friend also bought one so I often had access to one during high school.

But mopeds sort of suck. They are really heavy so most of the power is spent moving the frame around. Not to mention the Moped Hunch (TM). I’m 6’4″ and mopeds aren’t really customizable.

Ow. Look at that posture!


I have a bicycle I can no longer ride, the desire for another ridiculous project since my lathe now works again, and we just finished a release at work so I have a little free time to mess with.

Time to take this beauty and make it pedal itself.

Lathe finished

I finally finished the lathe conversion. It ended up being a lot more work than I expected as I ran into problems in pretty much every area.

The lathe is a 1995 era Jet 9×20 lathe. It originally had an incredibly heavy 3/4 HP single phase motor.

– The motor was not a drop in replacement. I had to move the motor mount over about 3/4″. I had to chop off a chunk from the quick change gearbox mounting plate because the motor hit it. I also had to buy a new longer belt. Phew. In this case a Frame 56 motor was NOT a drop in replacement for the motor that it came with.

– Building the pendant and wiring up the enclosure for the VFD took a fair amount of time. Probably 8-10 hours if you add in all the trips to Stoneway Hardware.

– A single set screw is not enough. I had to put in two at 90 degrees to stop the motor pulley from loosening.

– The motor is only good up to 70Hz, so my dream of running with never changing belts isn’t true. I instead just use 3 ranges: 50-600 RPM, 80-1000 RPM, and 150 – 2000 RPM. Since I’m using the vector VFD the motor runs pretty well at the lower limits. It’s also oversized at 1HP so it can absorb the heat.

Overall, I’m thrilled with the performance. I was able to finish a project that had been tripping the clutch. But had I known it was going to take 20-30 hours, I would have put it off for a while.

Note the new holes to move the studs leftwards. If you look closely, you can also see where I hacked at the plate on the right side.

Closeup of Pendant showing custom calibration on speed knob.

Pendant mounted via velcro for easy movement.

Back shot showing overall layout of enclosure and wiring. The thing on bottom right is a 15A fused switch.

two shots of the portal so I can see any fault codes, etc.

This is a 1HP motor from Suplus Center. It is only balanced to 1800RPM :(.