Re: Crazy Ideas Vol 1 - cheap bellows

--- In CAD_CAM_EDM_DRO@yahoogroups.com, Stephan Kotzé <stephank@c...>
wrote:

> I need an idea for cheap bellows to protect the linear guides and

leadscrews

> Hi Stephan. When I was a kid my dad made some bellows for an

enlarger, that that he made out of window roller-blind material. I
just tried with a piece of paper to make a 'u' shaped bellow to cover
a slideway and it works a treat.

Think about what a bellows looks like as it changes direction from
through a right angle: what is a peak on one run is a valley as it
goes off at 90 degrees. If you've got a picture of (or better still
an actual) old camera it will help to visualise.

Begin by folding a piece of paper backwards and forwards across its
width into a zigzag say 3/4 inch pitch, half a dozen times is all you
need to get the idea and it need not be exact for the demo.

Then about an inch from one end re-fold the peak into a valley and
the next valley int a peak. the paper will naturally tuyrn a
rightangle when you start pushing the folds ogether. Creases will
form at 45 degrees as you smooth it into its collapsed form.

Once you see how it folds together you can start to lay it out
exactly with pencil lines to show where the corner will be and the
peaks and troughs.

I suspect it might be easier to build the bellows one row at a time
once you get the hang of it

I know the roller blind material works, and I've seen a simple single
plane bellows made from varnished cardboard (though I doubt cardboard
would take the refolding necessary for a 3-d bellows) so there are
other materials you can use, strengthening with varnish seems like
the right thing to do also.

Bellows made like this can be very precise, my dads were a complete
tube, about 1/4 inch pitch, that tapered over the length of the
bellows to match a the lens carrier(~2" square) on one end and the
opening in the light box at the other ~4" square and light-tight.

If this is not enough to get you going maybe a book on origami would
have something. Hope this is not too OT Bill but everyone has to
protect their stuff and it may be of value to more than just Stephan -
jv