3A style topstage

Starting to think about the other parts of the steadicam, working on a 3A style top stage, here’s what I have so far.  I worked off some photos I found online, so the dimensions are a total guess.  I found a rack and pinion gearset on mcmaster carr, the rest should be pretty straighforward.  Going to glue the rack in the top plate, and add some screws to add friction to the sliding parts, as well as some hard stops to make sure the camera doesn’t fall off.

Changes changes

Did some thinking, and I’ve made several changes to the cam/ride mechanism which should help with the issues I’ve been having.

1) made the bottom of the lift assembly thicker so it will have less chance to twist on it’s bearings.  I may at some point change this further to grip the post tighter- right now it’s just a set screw, but it might need to be a clamp instead.

2) the ride mechanism gets new larger bearings and shafts- going from 1/4″ to 3/8″ should help with the twisting.  

3) I moved the lift adjust screw to the side so the pivot for the ride mech. can be closer to the post, meaning a shorter moment on the twisting action

4) see #2- did the same thing on the bone side of the ride mechanism.

5) changed the cam, now it’s a single piece with a 3/8″ post sticking out.  

 

Hopefully these changes will help.

Design + Development = wow, I respect engineers even more now.

I added a second cam and connecting rod to my arm yesterday.  It definitely solved the twisting problem.  In the long run, I’d rather just have a single cam, because adding the mechanism to adjust the offset from the cam will be twice as difficult with 2 cams.  For now, twin cams, fixed connecting rod length.

The most obvious problem right now is that as the cam switches from pushing UPwards on the connecting rod, to pushing DOWNwards on the connecting rod, the whole assembly clicks and jumps a bit.  

I’m also getting way too much friction in all the little rods and bearing surfaces, part from the design, and part from my lack of holding tight tolerances in the machining process.  This friction is so great that the arm is sluggish, and I doubt would do much stabilizing in use.

 

 

Prototypes are frustrating

I finally completed a prototype of my Steadicam G-series style arm.  Yippie!  

The bad news is that there are some pretty severe design flaws in my plans.  Not sure how the G-series arms cope with this issue- that the cam at the top is pushing only on one side of the top of the spring attachment mechanism… makes the whole thing torqued sideways, as you can see in the top view.  Going to try to add a matching cam and rod to the other side to compensate.  I’m starting to see how things get over-engineered.

 

Shock mount for boom pole

Shock Mount adaptor

So I finally made the first usefull thing with my new machining skills and tools.  My good friend Aaron sent me a boom pole that he got free for some reason, and finally got around to making an adjustable adaptor to mount my DIY shock-mount on the pole.  The shock mount is 4″ ABS pipe, cut off in the middle, and some elastic shock cord from an old pair of pants.  

The top of the boom pole has a 5/8″ threaded rod poking out of it, so I machined up some 1/2″ aluminum, added a thingy to adjust the angle of the shock mount, and voilla!  I actually made something usefull!  Probably not going to get it anodized, since it’s not exactly fine craftsmanship.  It works though.