Optics and Mounts for Holography

This is the standard optic mounting system my whole bench is designed around. The base is a magnetic base that a machinist would use. You have two choices when you purchase them, the cheap ones have 8mm x 1.25 threads and are about $15, the more expensive ones are $30 and have a 1/4" x 20 TPI thread. If you buy the more expensive ones you can buy pre threaded rods for cheap from Thorlabs. If you buy the cheap ones you have to make your own posts. I decided to make my own 1/2" drill rod posts. I got the bases from Reid Tool and the drill rod from MSC.

The cross clamp is made from 3/4" square aluminum bar. The mirror mount is a piece of aluminum angle and the mirror is held on with silicone adhesive. . I cut and drilled the 1/2" cross post. I try to tap one end 1/4" 20 TPI and the other #8 24 TPI but I have many with one hole. If you make your own mounts make double what you think you are going to need. It is amazing how many mounts you need when you have a good setup and you need to add an interferometer or something. I would make at least 20 to start.

The circular mounts I made are from plumbing pipe. I took some 1/2", 3/4" and 1" pipe and cut it into 1/4" wide rings. Using a template I laid out the four holes and drilled and tapped the three adjuster screw holes and drilled the mounting hole. I use them to mount diodes, lenses, laser pointers and anything round.

It is very important to grind the faces of the screws because the thread forming process leaves a bur that will chip glass. If one was really ambitious you could use small leather pads on the adjusters. I made 8 of each size in 4 hours for less than $15.

 

This is just a standard mount with a 1/4 x 20 threaded hole and a sliding mount from Edmund. The variable beam splitter is from Edmund as well. The back side has a piece of 1/4" float glass glued on with Norlan adhesive from Thorlabs. This is VERY important. It allows you to card off the stray beam. (Note the step to allow the linear mount to clamp.) I did not realize the subtle ways the stray beam can destroy your careful work. Thank you, Jonathan Head for catching it for me.

 

This collminating mirror was removed from a Coulter 10.1" Dobsonian telescope. There was a small circle in the center for allignment I had to remove with acetone. The mount is made from 1 1/4" plumbing pipe. I thought it would be very hard to get it to sit stable on four legs but it worked the first try.

 

The wooden mount for the mirror is part of the telescope. The mirror is glued to spacers that are glued to the fiberboard. The top shows a pipe hanging bracket that is screwed on with machine screws into threaded inserts.

 

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Copyright 2002 Colin Kaminski