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#21
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Machinist in the house?
Nifty trick, thanks for the tip ;-) ;-) That makes sense. I am afraid I will be doing some more projects this summer, so this might be one of them. I have a large surplus shutter and a set of P6 extension tubes that might be modified for an interchangeable mount ;-) speaking of circular images, I have to wonder how wide some of the simpler lenses (17mm disposable optic on a 35mm film camera) are with acceptable on film performance? Again, this project could be a good test bed for such tests too ;-) I suspect a number of full frame fisheyes (kiev?) would do surprisingly well on 6x6cm square for a circular fisheye effect, perhaps the older sigma 12mm fisheye I have would also be possible? The trick here would be a mounting for a camera back mated to a shutter and lens mount. Or perhaps a neutral density filter and use of dropping dark slide as a shutter? Or my modified Harris shutter (mf/tricolor.html) in which the gravity dropped slit shutter gives various speeds depending on the length of the opening cut in the dropping paper slit? ;-) Lots cheaper than a big leaf shutter and less machining too ;-) grins bobm -- ************************************************** ********************* * Robert Monaghan POB 752182 Southern Methodist Univ. Dallas Tx 75275 * ********************Standard Disclaimers Apply************************* |
#22
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Machinist in the house?
"jjs" wrote in message
... In article , "Sherman" wrote: "jjs" wrote in message ... FWIW, check out these folks: http://www.emachineshop.com Very cool business. They have made things for me that I've designed using their software. But in that case we were talking about dozens of copies of each item, not two of each. John, Thanks for that link! I've been looking for an effective way to prototype something I've been working on and it looks like this company may well be exactly what I need. Very cool. The entrepeneur is a very good programmer and machinist. The software is updated regularly and gets better every couple of weeks. If I may suggest that you put together a quick version of a part and run it through to the pricing stage. When you see the cost of one part (say, $120), then check the cost of 20 parts. Chances are good the total for the 20 parts is as little as $150. That's CNC. I love it when the software interrupts and says things like "If you reduce the number of splines, you will save money" or "you have two different sized holes. Make them the same and you will save money" or "You have exceeded the recommended span for this material. Try..." This stuff is very cool! I've been working in TurboCad for this project but I like this software better, easier to use, plus as you said it has "suggestions" from time to time. When I get the base part into this software I'll do as you suggest and price singly and in a small volume run. Thanks again, Sherman http://www.dunnamphoto.com |
#23
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Machinist in the house?
There are so many types of nylon that one of the glass stabilized ones or
delrin should suffice. Remember, whatever the camera is subjected to, the FILM has to survive as well and film emulsion is by far the most fragile material I can think of in this chain of materials... "PSsquare" wrote in message ... "George" wrote in message ... Delrin or nylon...you can buy sheets from MSC-Direct.com George, Since the original post asked for a material that is more stable than cherry, I wonder about the high thermal expansion of Delrin and nylon. No questions that you suggstions are close to wood in machinability. They are also several times higher in expansion than most wood and metal, and some plastics (nylon for sure) absorb a lot of moisture. The requirements were pretty loosely stated for sure. Any thoughts? PSsquare |
#24
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Machinist in the house?
Maple is NOT very dimensionally stable...if you don't believe me, you are
hereby invited to come see the &#!@ maple floors in my house and how they shrink and expand with the seasons (and they are over a heated basement AND I even added a whole house humidifier to try to stabilize these things). "David J. Littleboy" wrote in message ... "jjs" wrote: The requirements a to be stronger than cherrywood, as easy to cut as wood (even if it's harder to cut than cherry). It must be able to stand up to direct sunlight in hot weather without weakening (or weaping) and also stand up to temperatures of -20F with no greater possiblity of snapping than cherry. Dimensional changes due to moisture - well, no worse than cherry. Weight is not an issue. Maple. David J. Littleboy Tokyo, Japan |
#25
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Machinist in the house?
"George" wrote in message ... Maple is NOT very dimensionally stable...if you don't believe me, you are hereby invited to come see the &#!@ maple floors in my house and how they shrink and expand with the seasons (and they are over a heated basement AND I even added a whole house humidifier to try to stabilize these things). It's a lot better than spruce, which is why it's the material of choice for structural components of violins and guitars and the like. David J. Littleboy Tokyo, Japan |
#26
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Machinist in the house?
"PSsquare" wrote in message ... George, Since the original post asked for a material that is more stable than cherry, I wonder about the high thermal expansion of Delrin and nylon. No questions that you suggstions are close to wood in machinability. They are also several times higher in expansion than most wood and metal, and some plastics (nylon for sure) absorb a lot of moisture. The requirements were pretty loosely stated for sure. Any thoughts? PSsquare PSsquare, I am not aware of any polymer absorbing any appreciable amount of moisture, especially not more than wood (though some, like Corian, will absorb enough to stain on the surface). But, the OP can allay any fears in that I believe MSC-direct lists the engineering properties of most of the materials they sell (if they don't, it isn't hard to find them). Also, to put my answer into proper perspective for the OP, I am an amateur machinist and an amateur woodworker. By profession, I am an electrical engineer which means that in my distant past I've had materials courses but it really hasn't come up for professional use much (though I did use Delrin in a test application that involved heat and it performed well). George |
#27
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Machinist in the house?
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#28
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Machinist in the house?
In article , "David J. Littleboy"
wrote: "George" wrote in message ... Maple is NOT very dimensionally stable...if you don't believe me, you are hereby invited to come see the &#!@ maple floors in my house and how they shrink and expand with the seasons (and they are over a heated basement AND I even added a whole house humidifier to try to stabilize these things). It's a lot better than spruce, which is why it's the material of choice for structural components of violins and guitars and the like. Surprise for you, David. Spruce (a rather broad category) can be a good violin wood. It all depends upon how it was aged. Ever heard of the bonanza better than a gold mine we have in the Mississippi river? Wood, including spruce, that has been underwater for fifty to 100 years. Violin makers are crying for the stuff. |
#29
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Machinist in the house?
In article , Charles
wrote: You might post this in the rec.woodworking group. they know a lot about wood. I haven't played with cherry, so I can't comment on how different woods would compare. I use cherry all the time, and I like it but this is a prototype of something that will finally be made in a stainless steel. Wood is not strong enough for the design I am trying to show. The thing collapses. I'm about to cave in and change the whole thing. I should have married a rich machinist. :0 |
#30
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Machinist in the house?
"jjs" wrote in message ... In article , "David J. Littleboy" wrote: "George" wrote in message ... Maple is NOT very dimensionally stable...if you don't believe me, you are hereby invited to come see the &#!@ maple floors in my house and how they shrink and expand with the seasons (and they are over a heated basement AND I even added a whole house humidifier to try to stabilize these things). It's a lot better than spruce, which is why it's the material of choice for structural components of violins and guitars and the like. Surprise for you, No surprise at all: I grew up in a violing repair shop. (Really) There's a Dutch violin made in 1795 sitting right here, although it's the Gibson L5 that gets played nowadays. David. Spruce (a rather broad category) can be a good violin wood. It's used for the acoustically active members of both violins and guitars. Note that I said _structural_ components for maple. It's the spruce soundboards on violins, violas, and especially cellos that get trashed by New England central heating, repair bills on which put me through college. It all depends upon how it was aged. Ever heard of the bonanza better than a gold mine we have in the Mississippi river? Wood, including spruce, that has been underwater for fifty to 100 years. Violin makers are crying for the stuff. Yes. Apparently some percentage of logs sink, so rivers which had extensive logging in their environs tend to have underwater wood of interest especially to furniture makers. David J. Littleboy Tokyo, Japan |
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