Thursday, 23 January 2014

The planet gets a wedgie

I have been otherwise engaged these past few weeks. All will be disclosed in the fullness of time I imagine. What this means is that I haven't actually had much good quality shed time lately. I have managed to make the locking bits for the gear side con rod however. These are the tight fitting wedge and the bearing locking dog.

The wedge was roughly milled using the same techniques as the sun gear wedge. The planet gear wedge is slightly longer though and I had to machine it eccentrically to get the width I needed from the scrap of bar stock I used.

Mill out the D shaped profile.

And then mill the 4 degree angle to the wedge. Very careful measurements were taken to ensure the wedge didn't get too skinny and pull too far up the ramp. I don't yet have a machine to mill metal back on again.

Milling the ramp.

Then the wedge can be cleaned up and marked and cut to the correct length.

Finally do a trial fit. Lovely.

Next machine the screw to pull the wedge up the ramp and lock the con road to the planet gear.

Cut the 1BA thread.

Machine a slight dome to the cap with my ball turning attachment. The screw is held in an arbor.

Then using a slitting saw, cut the two slots to tighten the screw up.

The screw tightens up without bottoming out the wedge, which is nice.

Next cut a little scrap of plate to width for the bearing locking dog. Mark the teeth on it...

... and file them to fit.

Last thing is to drill and countersink to accept the 4BA screw.

Now that this part is all together, it's quite fun to spin it around. Has anybody else studied double pendulums at some point? The motion is very reminiscent of them. Of course in use, the bottom pivot will be constrained to be the midpoint of the lever and won't spin around like this, but it's fun anyway.

Hours of amusement.

Hopefully I'll be able to start on the pivots next week.

You may have noticed that many of the fasteners on this bike use proprietry tools to tighten them up, there are lots of slots and holes etc. I've made a rough series of tools as I go along but at some point I'm going to have to make some decent tools to prevent damage to the slots. I have a cunning plan for this, more later.

In other news the long summer school holidays are drawing to an end. I like the school holidays because the traffic is so much lighter for my ride to work. In less than two weeks we'll be back to the usual mayhem. My lovely wife is running out of activities for the kids to do and they seem ready to go back to school. I had promised my son that we'd make a trebuchet over the holidays but I suspect it will have to wait. I also want to make a vortex cannon but that's going to really annoy the neighbours. I think I'll do it.


  1. That is a work of art Bob - nice one!

    1. Thanks Bob, I should have more free time as of next week. Things should start progressing again.

  2. Like a robot exercising! (that video clip)