Last week I took a run up to Ottawa to discuss the possibly of working on a few small components of a new exhibit being created for the museum of Natural History. It was a fascinating glimpse into a very creative endeavour. I now need to assess whether my contribution can bring value to their project and what I can deliver in the required delivery timeline. It's a fascinated opportunity!
Here's the fix for the oops in the last blog. I notched and extended the follower. On final assembly I will discover whether there is enough weight to rotate the eye attached to the follower back into place. If not I can and a little more "lumber" on the top of the roller at the end the follower, and possibly add interior metal weights. We will see.
It seems to me lately that the spatial recognition neutrons in my brain have taken a vacation. I have missed numerous interferences that I usually notice when working up the CAD layout of the mechanism. This follower shown below is a classic. The follower in the foreground is the one that will swivel one of the eyes in the head. You can see that it doesn't not even sit down on the cam but is hung up on a pedestal in the right foreground. The same follower for the other eye a little further back in photo does not have this problem as the spacing allowed the similar pedestal on the other side to be placed further out.
The obvious fix is to cut enough of the counterweight off until the follower can sit on the lowest point on the cam. This may result in removing too much weight to allow the eye to be pivoted back into position by gravity. The first revision would be to extend the follower are far as possible to the right to replace the weight lost by cutting. At first glance the follower will remain fairly thin over the pedestal to work, so one of two other things may also be required. One is to shave the top of the pedestal, or add hidden metal weights in the extended follower, or both!
As much as thing mechanism seems large I have already had to redesign several pedestals, cams and shafts to fit things in, and yet I still find surprises like these. That is why a temporary assembly on a complex piece is always a good move. Now to throw out a few bits and make some new ones!
The Bipolar Brain has a strange combination of motive parts. the mechanism that opens the head is large since it requires a long travel length and lifts a relatively heavy weight compared to the other active components. So the mechanism ends up with a lot of smaller gears mounted higher up on tall pedestals.
I have mounted everything on a temporary base for fitting things since it is also fairly tight. For this I use latex glue, the same kind used for gluing noses and stuff to actors faces. The pieces can be pulled off later and the glue easily peeled off to do the permanent mounting. Anyway here is how things look without cams and followers in place.
A calming moment. A few hours cutting gears in the shop for the Bipolar Brain! Put some tunes on, relax, but stay focused!
We were at the OWCA carving competition and show called "Magic in Wood". We had a fairly meagre display this year only taking pieces that had not been shown there before with the exception of one piece that was there 4 years ago. One recent piece went directly to a client and was not available for the show. Good to see a lot of old friends again.
Next Sunday we are off to the the Hamilton Wood Show at the Ancaster Fair Grounds where Conquergood Creative will be giving a "Making Automata" presentation at 1:15 pm. Hope to see some of you there! I will also be at the OWCA display in the carving area for a bit before and after the seminar.
Automata is a creative blend of my life interests , engineering, art and woodworking.