bipe2,
I've made a couple of sets for 1/4 scale models, and they work very well. Here's now I make them:
I make the inner tube from 1/4" stainless tube. The lower end is drilled for a 4-40 bolt, and the upper end has a 1/4" long sleeve silver soldered onto it, made from the next two sizes of brass tube, with a small brass sheet cap to cover the end.
The outer tube is made from brass tube that is three sizes bigger than the 1/4" inner tube, so that the sleeved end of the lower tube will fit inside it. Solder a 3/8" long sleeve into the lower end of the outer tube using the next two sizes down. This forms a shoulder on the inside of the tube, so that when the inner tube is slid into the outer tube and brought to full extension, the two shoulders meet, and stop the inner tube from falling out.
To complete the upper end of the outer tube, solder a 3/8" long brass tube doubler onto the outside of the tube.
Then I make the removable top fitting from a piece of 1/4" dia mild steel rod. It's about 3/4" long with a mounting hole drilled through it for a 4-40 bolt at the top end, and a 3/8" long sleeve sleeve soldered onto the lower end, from two sizes of brass tube. This fitting will now slip fit into the top end of the outer tube, and can be drilled through for a 4-40 retainer bolt.
Now, you can go to the hardware store and find the biggest dia spring that will fit inside the outer tube. You will have to experiment with spring lengths to get the correct amount of pre-load. Load the spring, and bolt the top fitting into place. Bolt to the landing gear fittings on the model with 4-40 bolts.
If you go to my gallery and look at the Monosport, you can see these struts in use.
I hope this description is sufficient...Good Luck!
Cheers, Nigel
