This very nice Wimshurst machine with 27cm diameter discs was purchased on
ebay. My main purpose in buying it was to modify it for doing
testatika experiments. It's a
shame since it's such a fun Wimshurst machine to play with and is very robustly built.
It worked right out of the box on the first try!
The mug is for size reference.
The crank screws into place. Hopefully it'll be easy to
replace with a motor shaft.
The collector's combs surprised me by how far away they
are from the disc surfaces.
Here you can see one of the neutralizer brushes which
actually does brush against the sectors.
The main reason I picked this Wimhurst machine was because of the
large diameter black disc bosses used for attaching the discs to the shaft. They will
make it easy to replace the disc with other ones due to their size and the fact
that the disc is only screwed on to the boss (i.e. they're not glued.) As a side
note you can see the twisted pulley belt on this side which is what makes this
disc turn the opposite direction of the other disc (the Wright brothers did this
to make their propellers counterrotate.)
The wiring of the Leydon jar electrodes to the terminals
See the following page of a fun experiment using
two sectors of the
Wimshurst machine and a coil wrapped around the pulley as an RF LC
As stated above, my reason for buying this Wimshurst machine was to modify
it for trying to make a testatika so
after trying it for the first time, I then took it apart...
If you make your own disks for this machine, to attach to the bosses/hubs
you'll need to drill three holes as precisely located as possible and
bevel them. If this isn't done perfectly then you'll have some warping
in the disk once it's attached to the boss. To get around this, I found some
replacement screws that didn't require bevelled holes in the disk. Instead,
the heads of the screws lay flat against the disk surface. This makes for
an immediate reduction in any warping. The threads are metric,
size M4. The length that worked well for my disk thickness was 6.
I purchased them in the bins in the hardware section at Home Depot.
The original screws are on the left, the flat headed
screws whose heads lay flat against the disk surface are on the right.
I'll probably replace the hand crank in the future with something else, such
as a motor. I found that the threads that the crank screw into are
metric, size M6. I found the bolt below in the bins in the hardware
section at Home Depot.