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*************************

"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

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

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

"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

"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

On Sat, 14 Feb 2004 09:34:48 -0600, (jjs)
wrote:


This is not quite OT. From the Repair Filter thread it is clear that many
of you have machine-shop experience. I have made a prototype camera using
wood (cherry) and would like to make the next protoype in a material that
is more stable, stronger and can be cut and shaped using woodworking
tools. If you can nudge me in the right direction, offline if it is
appropriate, I would be quite greatful.


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.

Some of the posters were talking about using fiberglass. I would
suggest trying a penetrating epoxy, such as the west Systems Epoxy. I
have used it on some projects and been satisfied with the results.


--

- Charles
-
-does not play well with others

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.

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

"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