I concur with Craig Smith's advice in MMD 16.12.16 regarding the repair
of "overhauled" screw threads in wood.  I too have used cyanoacrylate
(CA) glues to reinforce the remaining threads in the wood.  CAs come in
several consistencies, and I find the "gel" type easier to handle and
a little more predictable that the runnier types.

Along with the usual precautions to take when handling these glues,
I typically place the tip of the bottle over the hole and give it a
healthy squeeze.  The resulting pressure helps force the glue into the
recesses and fibers of the wood, and the gel formula helps insure you
don't get an uncontrolled spray onto surfaces (including your skin)
where you don't want it.

This, of course, results in a "puddle" of the glue filling the cavity,
so after about 30 seconds, I follow up with a jab of a wooden toothpick
to help "form" the hole to receive the screw.  Let this "cure" for
_much_ longer than you think might be necessary, perhaps several hours.

CA glues develop their best bonds in the absence of air, so in this
"open air" environment it will take longer to firm up.  You absolutely
do not want to reinsert the screw is there is _any_ uncured adhesive
still in the hole, for reasons I should not have to explain.  The type
of wood, hard or soft, will also have a bearing on not only how many
insertion cycles can occur before having an overhauling problem, but
how long the cure time for the CA will be.

This technique works best for wood screw sizes up to about #8 or #10.
For larger repairs, such as the huge wood screws frequently used to
attach pedal lyres and cheek blocks, I opt for threaded inserts.  These
are hollow metal cylinders with wood thread geometry on the outside and
tapped machine thread geometry in the bore.  Once installed, these can
provide much greater assembly/disassembly cycling.  See

https://www.midwestsupplies.com/brass-dual-threaded-insert-for-wooden-tap-handles 

One caution is that the size of the pilot hole for these is _critical_
and may be different for different woods.  If you have a choice, use
inserts made of steel rather than brass, as the screw driver bearing
surfaces on the brass inserts have marginal strength and can easily
break off if the pilot hole is undersized, therefore requiring higher
insertion torque.

I install these once to the desired depth (usually flush), _then_
I back them out, coat the threads with CA and reinsert them.  In this
case, you don't want them to come back out when you remove the machine
screw, which can happen if the pilot hole is oversize or there is a
burr on either the screw or the insert.  While there are inserts of the
size (#4?) that would work for the Steger pneumatics, their use there
would be overkill, expensive and extremely time consuming to install.

I would add that Luke Myers should avoid making any changes in the size
of the rectangular holes at the hinge-end of the pneumatics.  This is
the hole through which the pneumatic "breathes" to return to it's open
position, and should be roughly the same surface area size as the
effective transfer surface area of the valve poppet.  This area can be
calculated by multiplying the circumference of the internal "atmosphere"
hole against which the poppet seats by the poppet travel distance ("gap").

The original designers probably got it right.  Reducing the rectangular
hole size by any appreciable degree risks causing the pneumatic to become
sluggish on reopening,.  If there is leakage there when the pneumatic
is powered, that is likely a problem of the poppet not seating
correctly, not the size of the hole.

John Grant