Looking for a gas strut for my Sieg X3. From my surfing, I believe
that I have the 2:1 gear on the Z axis (crank it a few times and you'd
agree).

8mm shaft, 18mm dia cylinder, 250mm stroke, 564mm extended length.

http://uk.rs-online.com/web/search/searchBrowseAction.html?method=searchProducts&sear chTerm=686991&x=20&y=13
RS Stock No. 686-991
Manufacturer Camloc by Arvin Meritor
Manufacturers Part No. SWY8060600058

Where can I get a compatible unit in the US?



Gas Spring (replacement). The standard gas spring fitted to the Z-axis
to support the weight of the head stock is non adjustable and does
actually over compensate for the weight. The actual weight of the head
stock is about 30Kgm. The compliance of the correct gas spring should be
just enough to support the weight. I replaced mine with an adjustable
one. These are widely available. RS-Components supply suitable springs
(stock number 686991), unfortunately only in packs of 2 units. I got
mine from RS, fortunately I was able to pass the extra one on to a
friend. For a supplier contact the manufacturer Arvin Motion Control
Tel. 0116 274 3600.