Flex mounts - solid base fixing?

[m0f]

The rail system isn't ideal for many cases. Perhaps for mounting dichroics but what about building diode modules, etc. A one size fits all approach won't work for everything. The purpose for the adjustable mount is so once the mirrors is glued, one can still adjust it, so glue certainly is necessary for affixing ones optic. Again if all optics were the same size, then it would be possible to design mounts to fit the optics, but so many different shapes and sizes are in use.

On a side note, has anyone worked with the cheapo goldenstar flex mounts ? At $5 they're hard to pass up on, but have always been to skeptical to use in builds. Anyone have anything good or bad to say about their stability ? How close to a regular flex mod ?

[norty303]

I've never encountered them, but i did sell a GS projector to a client who had trouble realigning them. They're due to be sending the projector to me for a service and align some time, so I'll get to see just how awkward or otherwise they might be.
Winni sent me a half decent pic a while back, and on the back of that decided on some of Robs instead.

[buffo]

epoxy of most sorts has a habit of not keying properly and cracking off.

Have you tried JB-weld? I swear by that stuff. With a little roughening of the surfaces, it should lock it down really well.

Cyano perhaps?

NOOOOOO! Don't ever use any type of cyanoacrylate glue (commonly known as super glue, or "Krazy Glue") in your projector! It will out-gas over time and coat your optics, giving them a frosted look that will dramatically reduce their efficiency. Very bad! It can also get into the bearings on your scanners, causing "crunchy bearing syndrome", where the rotor shaft will tend to stick at certain points, screwing up the displayed image.

Bottom line: Never use any sort of super glue in a laser projector. 2-part epoxy is the preferred adhesive.

(And yes, I realize that you know the common names for cyanoacrylate glue; that info was for anyone else reading this.)

Adam

[planters]

OK,
I would recommend what I do on all of my custom mounts. If you turn the flex-mount over and look at the base you will see a small step machined in the base to allow the small amount of bending for the up/down flex adjustment. The other part of the base with slot in it needs to have a depression milled (you can even file this metal away-this does not require precision) so that the only part of this surface that contacts the main base plate is a small amount on either side of where the screw will be. You can do this longitudinally (parallel with the slot) or laterally; both work very well. You will see this material has been removed from the base of my mounts in many of my videos.

Andy...argh.

[buffo]

Eric;

Is this to increase the force per unit area (and thus the net clamping pressure) on the foot?

Adam

[norty303]

I guess it just decreases the surface area the force is being applied to, increasing the pressure density, akin to increasing the energy density of a laser beam. Ultimately, it gives a bit more 'bite'. Shame I don't own a mill...

Not sure who makes Robs mounts. Could be Briggs, I might suggest the idea of a channel in the bottom.

[planters]

That helps, but the overwhelming reason is that the points of contact with the base plate are as far from each other as possible and this increases the torque (by increasing the moment arm) required to rotate the part. Imagine if the flex mount had a very slightly convex base surface ( in real life, nothing is perfectly flat) centered around where the screw is positioned. No matter how hard you screwed it down it would rotate. Try pressing down on a ball bearing and rotating it then try pressing down equally hard on a tube with the same OD as the ball's diameter. This then becomes obvious.

You do not need to mill this because the only surface that matters is the part you do not mess with. I could modify a flex mount in 30 seconds with a hand file.

[norty303]

I could modify a flex mount in 30 seconds with a hand file.

Yes, after I typed my post my brain had a chance to digest the issues properly and I realised a round/half round file across the base would do the trick just nicely.