ed kang
27-May-2001, 16:39
Hi there folks. I'm currently machining what I call a "MiniNar" for my personal use, which is very similar to a Sinar P2/X in terms of the way the movements are put together, but on a smaller scale with 2/3 the movements of the real camera. The material used is 6061-T6 aluminum with 60 degree dovetails cut via m42 tool ing. Simple brass racks and delrin pinion gears are used, 32 pitch. The movement s are "self-arresting" by use of gibs captured by end-screws. The final product will be hard anodized with NITUFF to 0.005" through NiMet Industries in South Be nd.
My question is involving the tilt mechanism on the sinar. I know that Sinar uses what is commonly known as a Goniometer Stage for their tilt mechanism. Machinin g fairly precise linear dovetail slides for me is an "easy" affair - their manuf acture is straightforward. However, I'm really at a loss as to how to manufactur e a Goniometer Stage efficiently.
The method that I'm currently planning to use is bar-stock with screw-mounts dri lled into them. The bar-stock will then be attached to the headstock of a lathe, and some custom made dovetail forming tools will be use to form first the radiu s of curvature of the top edge, then the female dovetails. The same method will then be used to cut the same radius of curvature on the top of the stage with th e corresponding male dovetail cuts.
Has any of you ever made a goniometer stage? Any experienced machinists out ther e? Will my method work? I've worked it through with some other machinists and th ey seem to agree that this is the only way to do it without having strange and d angerous tooling whipping around on a mill. I'm always looking for hints and/or tips.
Also, does anyone know how the drive mechanisms work on a goniometer stage? Is i t done via rack and pinion, or by lead/ball screws?
Also, another alternative for me is to use Delrin Homopolymer to ease in the cre ation of the goniometer stage. It's significantly easier to machine, so I wouldn 't have to make lots of new custom tooling to make my cuts (6061-T6 smears like nobody's business. If anyone has an economical source for 6013 or 7075 barstock, I'd love to hear about it). The questions I have is how well does it respond to wear applications against itself?
-ed
My question is involving the tilt mechanism on the sinar. I know that Sinar uses what is commonly known as a Goniometer Stage for their tilt mechanism. Machinin g fairly precise linear dovetail slides for me is an "easy" affair - their manuf acture is straightforward. However, I'm really at a loss as to how to manufactur e a Goniometer Stage efficiently.
The method that I'm currently planning to use is bar-stock with screw-mounts dri lled into them. The bar-stock will then be attached to the headstock of a lathe, and some custom made dovetail forming tools will be use to form first the radiu s of curvature of the top edge, then the female dovetails. The same method will then be used to cut the same radius of curvature on the top of the stage with th e corresponding male dovetail cuts.
Has any of you ever made a goniometer stage? Any experienced machinists out ther e? Will my method work? I've worked it through with some other machinists and th ey seem to agree that this is the only way to do it without having strange and d angerous tooling whipping around on a mill. I'm always looking for hints and/or tips.
Also, does anyone know how the drive mechanisms work on a goniometer stage? Is i t done via rack and pinion, or by lead/ball screws?
Also, another alternative for me is to use Delrin Homopolymer to ease in the cre ation of the goniometer stage. It's significantly easier to machine, so I wouldn 't have to make lots of new custom tooling to make my cuts (6061-T6 smears like nobody's business. If anyone has an economical source for 6013 or 7075 barstock, I'd love to hear about it). The questions I have is how well does it respond to wear applications against itself?
-ed