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Thread: Rob's Homebrew - Magmounts the next generation

  1. #1
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    Default Rob's Homebrew - Magmounts the next generation

    Hi All
    As you have seen in my post about the work on my RGB projector I have taken my magnetic adjustable mounts to the next level. They were initially discussed here
    http://www.photonlexicon.com/forums/...ead.php?t=2529

    Now I have had the opportunity to see what can be done with them and to see how they can be improved I have made a few mods to them to come up with the design you can see in the images below.

    The main two areas that is improved with these mounts have been aired before but I have developed the ideas a little more therse are the incorporation of magnets sunk into the uprights to allow a much closer fit of the fixed and adjustable section, and the use of ball bearings not only at the pivot point as previosly used but now also on the ends of the adjustment screws. In the original design I drilled a slight recess in the green PCB material used for the moveable section and used a bench grinder to put a slight point on the ends of the screws. This was OK but as I couldnt grind them perfectly and consistently - the points were invariably off centre - they tended to shift the movable section around as you turned the screw. This put a jump into the adjustment which was not good. I then reverted back to plain screws but they had a tendancy to try to thread themselves into the the recess in the PCB material.

    I decided I need a bearing for precision so the ball bearing came in. I thought at first of glueing them to the end of the screws and then putting a brass insert into the movable section to provide a seat. Then I thought why not fix the ball bearing to the moveable section and put the recess in the screw. As Stevo-o pointed out in the post about the projector you can see the recess in the end of the screws on the pics. I didnt however get the recess central in the screws which caused me to go back to the jump in the adjustment. So I went back to plain screws which work just fine.

    The only downside with these screws is that they are 0.5mm pitch thread which though works does not give the fine adjustment I would prefer. I will get some slightly bigger finer threaded screws at some point but until I have a tap that matches they will stay as they are. I could make the screws but my lathe wont do threads as fine as I need and I'm not well practiced in cutting threads yet so off the shelf they come!

    The other main difference between these and previous models is the fact that I have now made the fixed section as tall as the moveable part. This has allowed me to put the adusting screws further appart which makes for finer adjustment and the whole thing looks better and more substantial.
    You may also note that there are less magnets in fact now only 3 per mount. A pair at the bottom near to the pivot - this is the most important position, and one on the moveable section behind the ball bearing for the top adjustment. This provides just enough pull to keep the screw and the ball bearing snug as you adjust.

    The 2 identical mounts I used for the dichros in my projector were made together and in the pix you can see threaded holes one each at the top and bottom. This is where the 2 fixed sections were screwed together while machining and drilling to ensure they were clones.

    The optics I use are Edmund 12.5mm dichros so I bored 16mm holes through the fixed section then milled a 45 degree lead in and out to give the maximum area for the beam to pass.

    Just to prove how unsophistcated these are, the upright fixed sections are cut and milled from new Ally but the base is a piece I liberated from an old electrical distribution consumer unit I binned last year. I got some nice brass and copper parts from it too .

    Finally I wanna just say that I make these parts rather than buy them for one reason only - no its not cos I'm a cheapskate, though this may be true - its because I love the satisfaction of making these parts. To me its just as satisfying as seeing the end results - some people I know hate the building phase but I love it. The bulk of my projector is my own work - hell if I could build the lasers I would. Actually I do have a DPSS project on the go but more of that another time.

    The pics below speak for themselves in the main but are as follows :-
    first image - front and rear views of the complete mounts minus the optics.
    second image - this shows the mating faces with one of the pivot magnets and the ball bearings.
    Third image - just a close up of the 'inside' of the upright.
    Forth image - installed adjusted and in action. Yes the top screw of the left hand mount is behind the other mount - hence the nut on the screw so I could turn it - though tonight I have just made a little brass lever to go on it so its even easier to adjust now.

    Hope you like 'em and hope I havent waffled on too much - If I have and you have drifted off - WAKE UP ! (I bet I know someone who has a smiley for this )

    Rob
    Attached Thumbnails Attached Thumbnails magmount1.jpg  

    magmount2.jpg  

    magmount3.jpg  

    magmount4.jpg  

    If you need to ask the question 'whats so good about a laser' - you won't understand the answer.
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  2. #2
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    Nice work Rob!!
    Gotta love building your own stuff!
    I built my optic mounts too, and enjoyed the building process immensely also, (although mine arent quite as sophisticated.)
    Great ingenuity- maybe a patent is in order

  3. #3
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    Steve
    I remeber seeing yours when you posted. It does not matter how god or bad they look or how sophisticated of not they are. If they do the job and you made them yourself then that is worth everything. Its the sense of acheivement that I love looking at the gorgeous multicoloured beams and thinking thats my work thats done that. Priceless.
    Keep at it and keep looking out as I have im my head the plans for the ultimate in my magmounts. One will be built this week and you will all see it on here first.
    As for the patent - this has been suggested though Im not certain its an original idea I guess its worth looking into. Will keep y'all posted on this.

    Rob

    P.S. Steve - I dont pretend to know what went on and frankly I dont care but Im glad you are stickin around - the place would not be the same without you.
    If you need to ask the question 'whats so good about a laser' - you won't understand the answer.
    -----------------------------------------------------------------------------------------------
    Laserists do it by the nanometre.

    Stanwax Laser is a Corporate Member of Ilda

    Stanwax Laser main distributor of First Contact in UK - like us on Facebook http://www.facebook.com/FirstContactPolymerCleaner
    www.photoniccleaning.co.uk

  4. #4
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    magmounts
    NICE NAME!!!

    I dont pretend to know what went on
    Sorry I caused quite a stir. Frankly I didnt know that many people would have read that post. I tried to retract it quickly but I guess it was too late. I temporarily lost my mind (to the best of my recollection)..
    Pleading temporary insanity.. and posting while drinking..
    Oh well.. life goes on..

  5. #5
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    Cool

    Hey Rob... I'm trying to understand the magnets; I see that there's one in the mount itself that pulls on the magnet mounted in the bottom of the removable piece, but what does the magnet on the top corner of the removable piece pull on? The adjustment screw? I can't see any other ferrous material for it to be attracted to...

    Adam

  6. #6
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    Quote Originally Posted by Buffo View Post
    Hey Rob... I'm trying to understand the magnets; I see that there's one in the mount itself that pulls on the magnet mounted in the bottom of the removable piece, but what does the magnet on the top corner of the removable piece pull on? The adjustment screw? I can't see any other ferrous material for it to be attracted to...

    Adam
    The one near the pivot is the important one and I have experimented with just this one alone. However this does not provide enough pull for the top screw - it probably doent help that its much further away from the pivot than the lower screw - so to provide the small pull needed to keep it in check the single magnet at the top is located directly behind the ball bearing making this appear magnetic which in turn attracts the steel screw keeping them together.
    Voila!
    Rob
    Last edited by stanwax; 08-28-2007 at 00:35.
    If you need to ask the question 'whats so good about a laser' - you won't understand the answer.
    -----------------------------------------------------------------------------------------------
    Laserists do it by the nanometre.

    Stanwax Laser is a Corporate Member of Ilda

    Stanwax Laser main distributor of First Contact in UK - like us on Facebook http://www.facebook.com/FirstContactPolymerCleaner
    www.photoniccleaning.co.uk

  7. #7
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    Are you using neodymium or samarium magnets or regular alnico or ceramic?

  8. #8
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    Quote Originally Posted by steve-o View Post
    Are you using neodymium or samarium magnets or regular alnico or ceramic?
    Speak english man!

    I'm not sure I think they are neodymium - they come from the focussing part of CD/DVD drives so hopefully thet will tell you. Alls I know is they are plentiful, cheap (dead drives), and do the job mag(netically)nificently.

    Rob
    If you need to ask the question 'whats so good about a laser' - you won't understand the answer.
    -----------------------------------------------------------------------------------------------
    Laserists do it by the nanometre.

    Stanwax Laser is a Corporate Member of Ilda

    Stanwax Laser main distributor of First Contact in UK - like us on Facebook http://www.facebook.com/FirstContactPolymerCleaner
    www.photoniccleaning.co.uk

  9. #9
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    do the job mag(netically)nificently
    HA-ROFL!!!
    Yes I believe they use the NIB rare-earth (very strong) magnets in those.
    That's good.

  10. #10
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    Default

    rob, how much for one. i need something small the hold that mirror you sent me with the cube?

    cheers
    Eat Sleep Lase Repeat


    Aluminium Optic Mounts

    http://www.laser-man.co.uk/opticmounts/

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