I realized after cutting the frame blanks that I forgot to modify the templates to account for a change in how I am attaching the rear swingarm+uprights. Originally I was going to have straight wooden beams acting as the swingarm but, as ever, when mocking it up in cardboard the spread at the rear was huge to account for it going from 2.5" to 4" (at the axle) in just 6" of length. These were to be clamped onto the frame using bolts. I changed the design to make curved swingarm sides that are glued (and pinned) to the frame at an oversized mounting point.
When I cut the frame I forgot to add this oversized section, I had already transfered the template to the wood and with one thing or another made the "first cut" after coming back to it days after making changes to the design! I was about to make another but decided to try and retrofit some disks onto it. If it doesn't work I can always cut my losses and do it again.
So I cut out enough disks to pad the mounting point to the required 2.5" and glued them onto the frame with a 6mm threaded bar through the whole lot with nuts+washers at the ends. It looks like it will be more than strong enough which is good. Once the swingarms are done I will drill the 6mm hole and clamp them to the frame with the bar+nuts before shaping it. Once shaped I will be glueing it all up, clamping it on the rod and hiding the nuts (somehow).
So, onto the curved swingarm... As previously mentioned bending the 4mm ply I have is a bit sketchy, it is prone to cracking with fairly minimal bending so I steamed it first. Works well enough. I made a jig out of some wood, made sure everything was square and glued+clamped.
In these pics you can see some leftover circles I used on the frame. I will put pics of that up when I remember...
Out of the jig the arms retained the curves with no perceptable springback which was good.
Next up I will be shaping these blanks and making the uprights that will serve as the twin shock setup the TZ750 FlatTracker used.
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