Friday, 14 February 2020

QR50 - Fork Sliders

I've mentioned the condition of the fork legs in previous posts. The stanchions and sliders are completely ruined by water ingress, the shrouds and bump stops are missing and the springs have mostly rusted to dust. Due to the cost and scarce availability of new legs, I decided to make some new ones on the lathe. this probably won't save much money, but it will add to my skills and will be fun - and I can adapt them if I want to.

The old parts were good enough to give me some idea of the measurements I would need, and the wheel spindle mounts were sound. I cut them off for re-use, and to enable me to get the forks apart to look at spring and bush dimensions.

Buying new springs was easy through eBay, but they came from a coil and didn't have closed ends. With a fine blow torch, it's quite easy to direct the flame to precisely enough to be able to manoeuvre the last coil without affecting the temper of the rest of the spring:

So, onto the slider and I start by fitting the bottom I cut off into the four jaw chuck. I turn off the remains of the old slider and form a 2 mm x 2 mm shoulder for the new tube

The new tube is welded in place with the TIG welder set at at 60 A, with a 2 mm electrode and a #4 shroud:

With the two sliders welded up, we can see that the tubes are parallel and the spindle is perpendicular:

This goes back in the lathe supported by the fixed steady. I've trued it up using the DTI and can now start to face off the end ready for boring.

Each slider is faced to length, bored to create a step for the top bush to sit on and then using a specially ground tool we make a square groove for a circlip to retain the top bush:

You can see the step and the circlip here:

Two identical sliders, finished - almost. One needs the brake plate stop welding in place and then we are ready for paint.

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