Wedge Stabilizer Design
by Ed Stewart <stargazer skymtn.com>
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I put my Meade 7" Maksutov on a wedge and experienced the instability that
has long been a problem with fork mounts in the equatorial position. A member of the Meade Advanced Products Users Group (MAPUG),
Doc G., has determined by using scientific testing methods that the source of most instability lies in the RA bearings.
And there is little that can be done about it short of redesigning
the entire mounting. My work-around solution is to provide additional
support to the overhang of the wedge from the tripod head. This changes
the frequency of oscillations and dampens them in about half the normal
time. My solution is a very simple to make system comprised of:
- A wooden clamp that attaches to the tripod leg directly under the wedge's overhang.
- A thick metal strap that runs along the bottom edge of the wedge to provide pressure points for:
- Two 0.5" X 18" all-thread rods that go from the wooden clamp to the
ends of the metal strap.
The result is not only physical support of the weight of the overhanging
wedge, but triangular stiffening in two dimensions. The effect is a magnitude
increase in stability. I can now focus at 150x where before the shaking
was so bad it was impossible to interact with the focusing movements.
Painted black, and with black tubing over the threaded rods and with the
silvery bolts, the system is "Meade'ish" enough to look factory
original. Note: depending on the orientation of your wedge on the tripod
head, you may have to have a clamp on two legs with only one rod going
to each.
See this at: Chris
Vedeler's Page.
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Drawings:

End View

Clamp Top View

Side View
I believe the design drawings speak for themselves as to construction
details except for the ball joints, which are simply shallow depressions
drilled into the wood clamp's top surface with a .5" drill bit (about
up to the edge of its flutes), and then rounded ends of the rods sit in
the depressions--it's very effective since the Baltic Birch plywood I
used is so hard. Other wood will probably be OK too just make sure the
grain runs at a right angle to the tripod leg. Takes about 2 hours or
so to build.
A further thought has occurred to me to use wingnuts instead of the bolts
on the top end of the all-thread so a wrench wouldn't be needed to adjust
the tension.
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