Sunday, August 26, 2012

Mary the Mannequin Part 3

I'm kicking myself because I don't have many pictures of the construction of the head for the mannequin. It all started with a couple of chunks of four by twelve doug fir header lumber. By sheer luck alone I managed to glue them with the grain in the better of two orientations. Blind luck is truly 50/50. I only mention it because I'm mad at myself for not thinking about it when I was putting it together. When I glued up the two pieces I wanted to avoid any metal in the head because of the severe sculpting we had planned. I used wood biscuits and Titebond wood glue to connect the head halves together.

Have you ever seen the guys that carve wood sculptures with a chainsaw? There is a guy in Berkeley near Urban Ore and McBeath hardwood that does that kind of sculpting work but I never get to see him working. All I know is his friendly guard dog that is there over the weekends. I always slip him a biscuit through the fence if I happen to go by there. So I have always wanted to try one of those chainsaw blades that fit in a small grinder. This seemed like the perfect job for one of these blades.
Most of the shaping and carving on the mannequin was done with flap sanding discs and the chainsaw meat shredder disc. This is truly a material removal tool. I am reminded of some scene in the Soprano's or the movie Fargo whenever I use the thing.
It behaves itself surprisingly well for such an aggressive tool. Its sold by King Arthur tools and available online from Amazon or several other resellers. Be sure to check out the videos they have on their site to get an idea what these things can do. I found it really controllable partly because it runs so smoothly. You would think that something like this would be hard to balance at 15,000 rpm. I guess not.

So what happens when a machinist type does an art collaboration project? We I'll tell you,
 They use all the tools at their disposal that's what happens. Here I'm marking the feet for the toe articulation. I wanted the cut to be in the same place on both feet and perpendicular to the long axis of the foot. This was just the easiest way to mark them quickly. I need to fabricate a pencil holder that fits all my different height gages but I guess that will be another article.
This picture shows how I worked out where I wanted the pivot point for the toe section. I traced an elevation view of the foot and cut the template were we decided to make the pivot. The problem was the optimal place to put the actual pivot dowel. Its hard to see but there is a push pin simulating the pivot on the paper pattern.

In the shop you are always thinking about not running any body parts into your machinery. This project was a little creepy in that I had to bandsaw all kinds of anatomy during the building of the mannequin. The feeling was especially strong when I had to saw the toes off the foot. It kind of goes against everything you have been taught and learned the hard way about keeping body parts clear of machinery.
I managed to get past this queasiness and make the required surgical cuts. We had to add some material to form the hinge for the toes. Its just thin Baltic Birch plywood glued into the body of the foot and sanded to match the foot profile. The pivot is quarter inch diameter hardwood dowel.
I always say two heads are better than one. The head was the most difficult parts of the mannequin. It had to be proportioned correctly and have the right kind of neutral humanoid look without getting into fine detail like noses and ears. I did the initial scary roughing work with the chainsaw blade. The forensic evidence is on the floor in the background. My wife did the final serious artsy detail work. I got to a point with the chainsaw blade where I didn't want to go any further for fear of bozoing the head and having to glue up another one. Nothing like the threat of more work to make you be careful.
Ever feel like your head is in a vise? Well this is what it looks like. Here I'm getting ready to drill the hole for what is probably like cervical vertebra C1. This got one of the ball joints and clamp plates like the shoulders, ankles and wrists.
She's really starting to come to life here. Its weird when you are moving all the joints around and it just looks like an inanimate object and then suddenly it drops into a very scary human like pose. I'm sure this thing will scare the crap out of us for years to come. Incidentally the one tanning salon arm is a test for a staining color we will use for the whole thing at some point. 
The hands were the next tricky spot. We bought some hickory at the hardwood lumber yard to make the hands after testing the soft Douglas Fir out. For anything with small detail this is the only way to go. It cuts like soft aluminum and holds detail in small cross sections. In this shot the palm blanks are roughed sawed out like a couple of mittens. We decided that the fingers would need to move also so I figured out a way to do that and attach them to the palms.
The pivots are made from brass wood screws that I soldered some copper discs to. A single slit with the bandsaw forms the slot the copper disc slips into. The pivot for the finger is a shorter brass wood screw counterbored into the finger. This mannequin has some pretty burly man hands.
Here I'm trying to explain to the patient just how the legbone is connected to the hip bone. Now everybody that comes over gets their picture taken with Mary and put up on a bulletin board in the shop. We call it paying the toll when we have guests. So make sure you take a shower and comb your hair and wear a nice shirt if you come over.

Hope you liked this series. We had some serious fun making Mary the Mannequin. The shop is coated in fine dust but it was worth it. We are thinking metal for the next one.

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