Wanted to buy: posts for mirror mounts

rzeheb · Post by **rzeheb** » Mon Jan 24, 2011 6:52 pm

Hi All. I need 4 or 5 posts suitable for holding mirror mounts (e.g., MM-1) and the like. Almost any length of post would work though posts in the 2 inch to 5 inch long range would be ideal. I need to upgrade my optical bench a bit. Please let me know if you have anything that you would be willing to part with or if you have any suggestions of were to look. I've been scanning ebay but so far no luck. TIA. Ron

holomaker · Post by **holomaker** » Mon Jan 24, 2011 7:13 pm

generally you see them on Ebay all the time (quite cheap too), and naturlly i dont see any now.

here the next best thing, you will need a drill press, a 1/4-20 tap and a hack saw!

http://cgi.ebay.com/1-2-500-Stainless-S ... 29fd8f0f4c

http://cgi.ebay.com/1-2-Diameter-6061-A ... 2551c7e3d0

rzeheb · Post by **rzeheb** » Mon Jan 24, 2011 7:22 pm

Hi Dave. Yes, plan B was to make my own just as you suggest. Sadly, I have neither a drill press (with vice) nor a die and tap set (though I was thinking of investing in both). So, for the time being I'll hold out in the hopes of finding a few posts ready made that I can buy. However, if it takes very long I'll probably find a way to make my own. I might even have a neighbor or friend who has the necessary tools. Ron.

holomaker · Post by **holomaker** » Mon Jan 24, 2011 8:43 pm

in the past i purchased 12" long posts with 1/4-20 thread on one end, and a 10-32 thread on the other end, i then cut them into two 6" rods...........

Johnfp · Post by **Johnfp** » Tue Jan 25, 2011 7:15 am

gosh, for $10 you can beat these.

http://www.harborfreight.com/multiposit ... -5645.html

Jeffrey Weil · Post by **Jeffrey Weil** » Tue Jan 25, 2011 10:42 am

Hello There,

John is right, those mounts are the best and very cheap. When I was starting out I had a whole silver system based on those. The were great for the price. At one point I must of had over 2 dozen of them.

If you do get them look for the ones with round or triangle knobs. Much higher quality than the ones with flat knobs like in John's link.

Also, some of them come without the fine adjustment on the cross bar. Get some of those too. Having a non-flexable full length arm is the way to go for many optics. Other times the fine adjustment is nice to have. There's a threaded pin that's held in the end with the clamping screw pressure, it pops out when the knob is loose. If you take that out, you can replace it with a 1/4 threaded screw or rod, now it'll take spatial filters and other things. There's also holes that allow you to put 1/8 diameter rods in there too.

See if you can find a small enough bar clamp, the bar has to be 1/4 or less in size. You can grind it down if its too big. Something like this.

http://www.sears.com/shc/s/p_10153_1260 ... ckType=G10

I think the price is wrong. They cost 9 bucks for a 2 pack at Home Depot. Depot links don't work but do a search for this number on their page, 53006

You can cut the length of the bar way down and trim it's diameter a bit if it needs some to get into the hole where the mounts threaded pin goes. Now you have a very nice, cushioned lens mount for just about any non-micro sized lens. It should work for plate beam splitters too. Those bars were not available when I used these mounts. I've not actually used the clamps but they look perfect for the job.

My table is loaded up with Newport and my own machined equipment but I still have a few of these mag mounts too, they are handy. I suggest you get at least a drill press and some other basic tools. If your going to make holograms you really have to make some of your own stuff.

If you want to get serious about holography I suggest you get a little into real machining. I have 2 milling machines,2 lathes, and some other stuff around in my machine shop. Words cannot express how important those tools are to me. If I needed a post, I could go to the lathe, grab a piece of whatever stock I have around and make it the right diameter and thread the holes right in the middle of a holography job, 10 min and it would be on the table. My plate holders are pretty complex but they are milled out of a single solid piece of metal. They would never be as stiff if they were bolted, or glued together. Plus, it would actually take longer and more work to make them that way.

Jeffrey Weil
NorthBeach Holography Inc.

rzeheb · Post by **rzeheb** » Tue Jan 25, 2011 2:53 pm

Hi John and Jeffrey,
Thank you for the heads-up on the mag mounts from harbor freight. I totally agree with your assessments. As it turns out, I have about 6-8 of those and they are the mainstay of my optical bench. It seems you can't have too many! I also have lab clamps that I use in various combinations to attach optical components (e.g., spatial filters) to the magnetic mounts. But, what I really need are just a handful of short (3" or so) drilled and tapped posts so that I can attach my mirror mounts to the end of the post and then I can clamp the whole assembly to the magnetic mount. I suspect that the easiest and most cost-effective approach will be to buy some stock 1/2 inch aluminum rods, cut them to size, and drill and tap one end. It would have been a no-brainer if I had the shop tools at home. This Saturday I'm invited to dinner at the home of friends who are both mechanical engineers (husband and wife). I'm hoping with that background that their basement may be equipped with the tools I will need. If not, then this might just be the push I need to beef up my own capabilities as Jeffrey suggests.

Jeffrey Weil · Post by **Jeffrey Weil** » Tue Jan 25, 2011 4:36 pm

Hello Again,

You don't need the posts at all! Take you mirror mounts and find what screw fits inside them. Get a few of those screws, put them into the mounts and then that screw will fit into either the 1/4 or the 1/8 hole where the threaded pin goes in the mag mount.

O, don't forget a nut to lock the mirror mounts down onto the screw, then put that screw into the mag mount. Easy and very cheap.

Here's some shots.

Notice the pin at the end of the arm. With the big nut.

You can either replace that with a standard screw that fits the thing you want to mount or drill and tap your part to use that pin itself. You'll have to take the big nut off of course.

Here's a few shots showing a wave plate rotator, a mirror mount and the screw thats holding it. There's also a shot showing a 1/4 20 threaded rod inside the mount. That would be for a spatial filter, or an m6 if your metric. The mount will hold just about anything from a number 6 screw to over a 1/4 inch.

Just remember to use a lock nut or you'll have to bottom out the screw in your optic mount or spatial filter to keep it from rotating. That might damage it, just use the lock nut.

That's the pin I'm talking about

Here's a screw to replace the pin that will hold that optic mount. In this case a rotator.

Here's the screw ready to take a mirror mount or a rotator, or anything that uses this screw size