Building bike wheels with DIY tools
Recently I needed to rebuild a rear bike wheel. It's an old Mavic XC717 rim on a new-old-stock Shimano XT hub. All I had was a spoke key but it seemed overkill to buy tools just for one job.
Here are the results of my DIY approach. This is the third wheel I've built, but it's the first dished wheel.
The spoke lacing doesn't need any special tools (an electric screwdriver is handy though). Then you have the problem of dishing. To build a dishing tool I carefully measured the rim width (at it's widest) and subtracted half that from 67.5mm (half the usual 135mm dropout with). Then I cut two hardwood pegs of this length and screwed them at opposite ends of a long (straight!) piece. Finally I drilled a hole with the same diameter as the hub axle in the middle of the wood. I clamped it on the wheel using a QR skewer, tightened the spokes to approximately the right tension (by feel) and then switched to the other side. Then repeated several times. Hopefully the picture below is easier to understand!
Getting decent dishing turned out to be easier than expected. Next I got the spokes approximately the same tension (just by feel). Then I did a basic truing, with the wheel in the bike frame. At this point it seemed prudent to check that all the spokes were approximately the same tension. I built a simple tool from old Meccano. The goal is to get discriminatory power, i.e. check whether a given spoke is tighter or looser than a reference spoke, rather than say "this spoke is X kgf". It took several tries to get right and I experimented with different lever lengths, elastic bands and springs lying around the shed. Here is an early version with elastic bands. I later switched to a stronger spring and added reinforcements to the main arms to cope with higher tensions.
Soon I was happy that the spoke tensions were close to the reference wheel (On-One XC). Next came the task of ensuring the wheel was circular and true. I used the frame with a coloured pencil held in place with an elastic band to help (this can be finely adjusted and marks the wheel at bad spots). I continued checking the spokes had consistent tension throughout. It required a lot of patience but was worth the effort.
The resulting wheel rides well and has not needed re-truing yet. I will check the spoke tensions and truing after a few more rides in any case, however.