Last updated: 31 March 2004

ETX Hex Key Sizes

Subject: Hex Key Wrench
Date: 3/28/04, 18:47
A suggestion to Yagi and others who have problems finding the right hex
wrench: buy a big set of them sized from tiny (0.05 inch) to large (3/8
inch). I bought two sets over the years, each with 25 wrenches. Some in
inches, others metric. They are not that expensive and I use them for
other projects as well. I put a dab of yellow paint on those I use on
Meade products. 

Good luck, George Dreitlein
And this:
From: John Hall (
For what it's worth, I found a hex key that is a good fit for the
setscrews on the focus knob and RA lever on my ETX-90, and measured it
with a vernier caliper. It appears to be metric, 1.25 mm.


Subject: Hex Key Sizes
Date: 3/30/04, 07:21
From: Don Sutherland (
Billy was wondering about the hex key size for the azimuth locking lever
on the ETX 125. I have a 105 and the set screw in the lock lever takes a
0.050" hex key, as does the focus knob.

The key supplied by Meade has a ball end on the long arm of the key, to
make it easier to engage the set screw in the locking level, however,
the ball end is a bit of a loose fit and slips. On my hex key, the ball
end is 0.048" instead of 0.050", so maybe Meade received a batch of hex
keys with undersized ball ends.

The short arm of the hex key engages the set screw solidly, but is
difficult to use because the long arm hits the telescope tube. The long
arm can be shortened to clear the telescope tube or a good quality
0.050" ball end wrench can be purchased.

All of the other hex head screws on my ETX 105 use inch standard hex
keys, 1/16", 5/64" and 7/64". The same sizes are likely used on the 125.

The 0.050" hex key is not the smallest made; 0.035" and 0.028" sizes are
also available. Be warned that there are metric keys which are nearly
the same size as these small sizes, 1.3 mm = 0.0512", 0.9 mm = 0.0354"
and 0.7 mm = 0.0276".
I hope this is helpful.
Don Sutherland

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