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Sunday November 21, 2004

A Truly Technoid Gear Shift Knob

Yesterday, I noticed that my right hand hurt when I tried to pick things up. I couldn't remember doing anything to it, so I started having disturbing thoughts about possible "creeping disabilities". I make my living typing and using a mouse, so this is not an inconsequential issue to me.

I mentioned this to Vicki, so today she asked me how my hand was. It seemed better and I said so. Then, a bit later, I was driving our Scion xB and I said "This is what's hurting my hand. The gear shift knob is pressing on the inside of the joint".

We both agreed that this wasn't good. Vicki suggested that we stop by Kragen Auto after breakfast, to see if they had replacement shift knobs or soft covers. We went; we looked. They didn't have much, but we did try a small ball-shaped replacement knob. I liked it; my hand held it differently, so it didn't cause the problem. But Vicki didn't like it, because it didn't fit her hand.

We tried the "Dive Shop" next, looking for a scrap of neoprene wet-suit material - maybe I could make a soft cover... Unfortunately, the shop buys all of their suits from other providers, so thay didn't have any scraps. Then Vicki mentioned that she had a spare ball from a Kensington Turbo Mouse (trackball), sitting in a drawer at home. Hmmmm...

So, we went home and Vicki dug out the trackball. We played with it a bit, confirming that it felt good to both of us. Now, I just needed to mount it on the shift lever...

I made a few measurements, dug out some tools, etc. I thought I was ready to drill the hole (I wasn't), but I couldn't find any taps. In retrospect, I think I don't actually have any. So, I called my friend and neighbor, Rich Pastor. Rich has some tools that I don't have, because he works on car engines, etc.

Not too surprisingly, he had a set of taps and was willing to loan me one. OK; I headed down the hill with assorted pieces and parts. Once I get there, the question became both easier and harder. Easier, because Rich was doing most of the work and knew what he was doing. Harder, because his measurements and concerns complicated the problem.

By his measure, for instance, the shaft wasn't 1/2". Rather, it was 15/64", a size that wasn't included in his set of taps. He also indicated that the local OSH probably wouldn't carry this size and the local tool store wasn't open (on Sunday).

He also speculated that the trackball might be hollow; it seemed to flex a bit when squeezed hard and felt lighter than it really "should". This could seriously complicate the issue of tapping; I might have to fill the innards with epoxy, first!

After some discussion, we tackled the "hollow ball" question by drilling a small hole into the ball. It never "punched through", so we breathed a sigh of relief and went on.

We tried drilling and tapping a piece of plywood, to see how well it worked on the shaft. Felt rather loose, but then, plywood isn't a really machinable material. Also, I expected to have a deeper set of threads than the (rather thin) piece of plywood allowed.

Looking at the tag for the shift knob that Vicki and I had purchased, I saw that it was listed as 1/2". And it had worked. So, we decided to proceed, using some teflon tape to fill in any incidental looseness in the threads.

We drilled the ball about four or five times, working our way up to the desired bit size. This, with Rich's light touch, kept the brittle plastic of the ball from "chipping". It also kept the drill from "grabbing" the ball, melting it, etc. Tedious, but definitely the right approach!

Once the hole was ready, Rich started the tapping process. After he had it well started, I asked for a chance to finish it up. This let me feel like I had actually "done something", although I knew that Rich had done all the real work.

Once the ball was tapped, I went out to the car, wrapped some teflon tape on the shift lever, and - very carefully - screwed on the ball. I was also cautious about how hard I tightened it; the last thing I wanted to do was strip out the threads.

Fortunately, all went well. Vicki and I both like the feel of the ball, the light grey color matches the interior color scheme of the Scion, and it gives us a bit of "techiana" to go along with the "cutesy" cloth lizards that Vicki had already attached to the fuzzy ceiling, using Velro "hook" material.

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A Truly Technoid Gear Shift Knob in Computers , Technology - posted at Sun, 21 Nov, 22:48 Pacific | «e» | TrackBack