Corbin's Treehouse - Corbin Dunn, Santa Cruz, CA
Plug Bug

LED Cyr Wheel on Stage

Some pictures of my work with Velocity Circus at an event for UCSF



Photos by Hiromi Yoshida, Courtesy of Gregangelo & Velocity Arts & Entertainment

Photography: LED Cyr Wheel v2 Self Portraits

Self Portraits, Corbin Dunn, LED Cyr Wheel v2, September 11, 2014. Canon 5d, a timer of 10 exposures manually set for a specific aperture and shutter speed.






Pattern Test


Single Pattern Test


Final drive ratio in an electric conversion car

So, I’m getting a new transmission for my VW bug (number 3), and probably buying it from What drive ratio should I get? They can do a few different options.

My bug is/was currently running the stock stuff for a 69 bug:

Screen Shot 2014-09-04 at 6.10.30 PM.png

I have 165R15 coker tires, and the diameter was calculated via: &

The ratios I got from the VW manual, and the screen shot is from my Numbers spreadsheet (email me and I’ll send it to you).

Here are my current speeds for a given RPM and a given gear. Max motor RPM is around 5000 (maybe 5500, but that is pushing it), so I have to shift before then. I don’t use first; it is pointless (I have enough torque to not need it), too jerky, and would have to quickly shift.

Screen Shot 2014-09-04 at 6.12.07 PM.png

I always start in 2nd, shift into 3rd at about 40mph, and 4th at 65mph; this keeps me under the 5,000 RPM limit. I have a top speed of a bit under 100mph, based on the RPM.

So, the diff ratio is 4.375 (also called 4.38); also known as the “ring and pinion” gear ratio. What if I get a freeway flyer 3.88 ring and pinion? Dropping that into my spread sheet gives

Screen Shot 2014-09-04 at 6.19.11 PM.png

So, if I did this, I would: start in 2nd, shift to 3rd at about 45 mph, and shift into 4th at about 75 mph. I rarely go 75 mph; the car starts to shake a bit at high speeds, and it just isn’t designed to do that. The lower ratio would probably make the car less torquey, so I’ll stick with the standard ratio.

Electric VW: Transmission Killer

In my last post on the bug, I had mentioned that I replaced my brushes, hoping it would fix some noise I was getting in the transmission/motor area. It didn’t help, and I then replaced two CV joints, as one was worn pretty bad. That also didn’t help.

So, I bit the bullet and removed the transmission/motor. This isn’t fun; I have to remove some of my cells in the rear seat area as they cover the hatch that lets me undo the transmission from the shifter. It isn’t too bad; I simply undo the red hold down strap, disconnect the BMS and cell wires, and then pull out the center set of cells.


The hardest part about getting the rest of the stuff out is to remember how to do it. I had made a motor mount thing that I used to slip under the motor and get it out, but I forgot that it doesn’t work anymore (for some reason), and I simply use a piece of plywood under a jack to lower the motor/tranny combo. I have to first remove the “ears” on the transmission to get it to do this; it is a pain. Once I remembered all the tricks, it slid right out (this took a while).


Now, here’s what failed. The bearing that holds this shaft in place is blown (not the throw out bearing, but the bearing on the case itself):


The shaft wiggles like mad, and the bearing has clear damage that I can see, and it is obviously leaking when it shouldn’t leak from there.

So, time for a new one. Last tranny was from Bugformance in San Jose, CA. I’m going to try this place next: which means waiting a few weeks…

Kitty Cabinet: Finished

I finally finished my Kitty Cabinet. I had to wait for some more Water Based Poly finish to come; I had accidentally ordered “gloss” when I really wanted “satin”, so it had to be put on hold until I got back from a vacation in Italy.


I use water based finishes from Target Coatings.


It looks rough in the picture, but it turned out quite nice. I put one coat of a shellac amber sealer on, followed by 4 coats of satin poly (water based).

Without the doors:





Kitty entrance:


Photography: Rome Street

Rome Street


Camogli, Italy. August 2014. HDR from 5 exposures. Canon 5D Mark III, 24-70mm lens. No tripod; supported by a plant for a bit.

Photography: Camolgi, Italy



Camogli, Italy. August 2014. HDR from 5 exposures. Canon 5D Mark III, 24-70mm lens

Electric VW Bug: Brushes replaced

The rear end of my car has been making quite a bit of noise lately. It seems to only happen when I apply power, and I wasn’t too sure of what it was. If I put the car in neutral or pushed in the clutch it would also go away, so it seemed to be related to the motor. I was guessing it was the brushes; on the two brushes per section, one seemed worn about 1/8″ to 1/4″ more than the other. The brush springs aren’t worn out, but I figured they might need replacing:


So, I got some of the newer better brushes (with 4 wires in the top) from .


It shows how much wear has happened, assuming the original brushes started out this size. I put them in and ran the motor on a 12v battery for a while (not too long before it was dead…I’d charge it a bit and run it again). I then did some slow driving for about 80 miles…still lots of noise. So, it wasn’t the brushes, but the new ones should work better.

Brush change electric mileage: 37,550.

So, I did some searching on bugs, and it seems to be the CV joints (Constant Velocity joints) on the old VW bugs. I pulled the CV Joint dust cover off, and a ton of oil poured out! I wasn’t expecting this; they are supposed to be filled with grease, so now my ground has a big oil stain on it. It turns out the cap on the transmission popped out, and allowed transmission gear oil to seep into the CV Joint. This low viscosity oil is not good for the CV joint, and it caused it to wear away. I see visible grooves in the joint from the bearings, and lots of bits of metal. So, I got new ones from Bugformance in San Jose. I’m going to just replace the ones next to the transmission. HI bought the good german ones (more expensive).

Unfortunately..even after changing out two CV joints, it still is making quite a bit of noise. It is either the motor or transmission; I’m going to just drive it…

Kitty Cabinet: Finishing

one coat of Target Coatings shellac (amber), lightly sanded and then one coat of their water based Polyurethene (9000). Time to order more….




Kitty Cabinet

I’m building a little cabinet to hold the kitty litter box, and some accessories. On top I plan to put the cat’s food and water bowls, to keep them out of reach of bad doggies.

Screen Shot 2014-07-19 at 2.06.44 PM.png

Download the sketch up file – Cat Box and Food area.skp

I have a bunch of old redwood from my water tank. I have been drying it out for years, and I just haven’t had the right project for it. Redwood is really soft, and this stuff is partially rotten, so I’m not sure how well it will work out. Here’s how it started out:


Jointing, and then planing to 3/4″ gives me:


I call it “spalted redwood”, and it is quite beautiful, but really fragile.

Several pieces biscuit jointed together:


Face frame setup sample fitting:


I need to buy smaller biscuits and a smaller blade for my Porter Cable plate joiner. The 0 size are too big; I need FF, which requires a special blade:




(c) 2008-2012 Corbin Dunn

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