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Forgive the quickie sketches here, but what do you call devices like these ?
I thought maybe someone would recognize these (from some outside-audio zone) and chime in ....In my Dual-In-A-Thousand-Pieces project, I'm looking for something like these kinds of things to :
a) adjust belt tension by moving motor in small repeatable increments
b) raise / lower arm platform, also in small, smooth amounts
c) set overhang for arm board, as aboveWe're talking something fairly small in both cases, but beefy, though, and totally non-slip (or maybe lockable ?) and preferably made of sturdy corrosion-resitant metal (like aluminum, brass, or some combination).....
The motor one would only need about an inch of travel, while the VTA and Overhang ones would want something more in the neighborhood of maybe 2 inches....
I keep running into brain-blocks about how to concoct this kind of widget, and I know they exist in some other field. Any ideas ?
( Even "what to call them" would help at this point ... )
J.D.
Follow Ups:
These are used for the positioning of optical components.Newport has a good selection.
http://www.newport.com
Melles Griot also offer a range, and thier webpage lists prices.
http://www.mellesgriot.com/
Best regards,
BK
Yeah, BK, this 'positioning' gear looks pretty close to the kind of thing I'm after. But I think it's mostly to a spec and precision that puts it beyond the pricerange of my project.....What I'm really looking for, I guess, is the Scratch & Ding Translation Stage Outlet Warehouse where everything must go ... for five bucks a toss....
A translation stage is basically a linear bearing with an adjustment screw (and sometimes a lock down mechanism). You might be better off looking for a cheap source of linear bearings and doing the rest yourself.Since you don't need the very smooth movement of a continuous ball type linear bearing a dry bearing (polymer surface) may be enough. These can be reasonably cheap - I bought a couple of 80mm x 200mm Drylin Ns for $100, paying full price from the Australian distributor. You have to be able to better that in the US.
Mark Kelly
Pretty close, like dead on. I'll look into all this and post an update...
Nice sketch, Jim. I've seen similar widgets in several different applications. Could be a press. Could be a positioner. Depends, so I'm not sure this would be offered as a standard jig/fixture. You might name it by the task you wish it to accomplish. Call it the patented "JD adjuster".It wouldn't be too hard to diy one of these given:
the appropriate bar stock, like maybe a thick grade LE Phenolic
a drill press
a saw
drills, a tap and a reamer
decent sanding block with an assortment of abrassive papers.
Buy the necessary fasteners and dowell pins from McMaster-Carr.
Doesn't take a machine shop given a little bit of ingenuity.
Thanks, Steve, that's probably what it will come to once I've scoured the surplus sources I know about and well, naturally, bought up a bunch of non-applicable widgets for other projects.....Wonder if that kind of aeronautics or military surplus shows up on Ebay or craigs ?
If I could score a reasonably nice VTA one from an outside source, I might just take a stab at fabricating the other two, less-precision-required widgets...
That's my specialty, afterall -- less precision.
... back in the lab, back in grad school days.Not that I can find a photo of them at the moment :-(
.
... I looked at all the big lab distributors and they had no photos (and it was getting to be bedtime). Thanks!Dunno if that's what the original poster was getting at, but that's what his drawings made me think of. Is this, like, a Freudian thing?
.
nt
From your sketch, it appears to be something that could be easily machined for you, or even diy'ed by someone with a few tools. What you are showing is basically a vise assembly. A cap screw through two pieces of metal, with the hole through the plate large enough for the screw to slide through at the "head" [bottom] piece, and the top piece either threaded for the screw or a nut welded to the plate for the screw to pass through. The two round shafts are there to stabilize the whole thing. A 'lock' for the screw could be a spring over the cap screw. With this, you can 'clamp', 'pull', or push' as long as you secure one end of the device.Your drawings are actually pretty good, but they would be more helpful if you showed exactly what you want to do with them. Perhaps you can conceptualize that and take it to a machine shop, or post back here.
I realize you are looking for something off the shelf, but this looks so simple you could probably have it made to your exact specs for little or no more than buying something that will be half assed.
Hi,Thanks for your thoughts... and yeah, you're right, a machine shop could bang some out in no time. I could even probably do some mock-useful ones myself, but....
Theres always that 'knowing' it has worked, in numerous applications, and will work in future--- that you don't get with a new fabrication. (And if I'm the fabricator, you don't even know it will work in the first place.. )
I guess my dream-answer-post here would be something like.....
We've had a crateful of those in the back of our shop since the sixties, they're made of Swedish Surgical stainless steel and have teflon glide bushings and metric verniers... six sizes, five bucks a crack. Want some ?
I'm keeping my fingers crossed for that post to show up. Then I'll be getting to work on the Lakers Season Tickets.
Don't forget to spend a lot of time thinking and looking for the necessary servos, motors, controllers etc. that you will need to make it all adjustable from the comfort of your Barc-a-lounger:}
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