Note - Click on photos, then again, for larger image
It looks 'pretty' but as to 'functional', that is a different story. I chose this screw drive style because I liked the 'look' ... kind of retro, industrial age. For stop motion it has a somewhat minimal presence on the table top animation stage, so that the rig would perhaps be easier to digitally erase in post production. My other objective was to construct this with only common hardware parts. NO precision machining. I only used drill press & a power hack saw to cut the metal and lots of hand filing & belt sander. Yes, there are different designs in fabricating screw drive mechanisms such as using aluminum extrusion channels that does not require guiding rods but as I said ... I gravitated to this aesthetic design of ol' school.
I knew, when I almost finished the unit, there were going to be some issues. I made the wrong choice of using only ONE guide rod ... this unfortunately allows some 'slop' in the movement. Usually there are two guiding rods, with the screw drive in the Middle. I thought I could get away with only one guiding slide rod which also would reduce the weight. Also, I used Home Depot cold roll steel rods which are not precision sized, which was a another contributor to the wobbly movement issue.
The weakest component is the Middle Block for the X axis horizontal movement. When the X movement reaches its maximum linear extension, there is more leverage and instability on the ends and the entire 'arm' rests on the narrow center block. These blocks are the important component and I need to redesign with a 'wider' center block and most importantly, use double guide rods made of machinist grade precision sized steel rods.
Even though the design has a somewhat 'spindly look', the angle iron base supported the unit, where it was surprisingly in perfect balance and it did not tip over. Of course, for stop motion use, you would mount the base to some barbell weights or a big clamping vise.
Above was a quick test. I set-up a mirror to the side so I can see the wobble. The X horizontal axis movement was poor & shaky, however the Y vertical axis movement was reasonably 'steady'.
____________________________






.jpg)
No comments:
Post a Comment
Select 'Anonymous' or ''Name' ... you do NOT need to enter a URL website. Just your name, alias name, or nickname is OKAY