Zhumell Mod: Tension Springs

The Zhumell Dobsonian line of telescopes uses a spring system to add tension to the altitude bearings. The springs pull down on a bolt that holds the telescope firmly in its cradle. The more tension on these springs, the more "stiction" the altitude movement has. This can help if you have a heavy eyepiece or Barlow. Heavy springs, however, can be difficult to attach in the field. One could use lighter springs, but then you would lose tension.

A good compromise is to use a short spring that is just as stiff as the stock springs, and use a clip to attach the springs. This mod can be done using parts from your local hardware store and the setup I came up with for my 10" Zhumell cost me less than $10 at Lowe's. Lemme tell you, it makes a world of a difference when assembling the telescope!

This is what you'll need:

• 1" welded ring (Quantity: 2) -- $0.47 each at Lowe's
  
• 3-13/32" brass double-ended bolt snap (Quantity: 2) -- $1.67 each at Lowe's
  
• 5/8" x 2-1/2" x 0.072" extension spring (Quantity: 1 bag) -- $3.47 at Lowe's
  

Once you have the pieces, this is how to put it together:

1. First, remove the stock springs and the posts which they attach to.
   
   
2. Put the welded ring on the top post. Put the ring on, then the spacer. It will not fit over the knob. This is an intentional safety feature, so your springs cannot fly off and whack your expensive 2" eyepiece in the eyepiece rack.
   
   
3. Next, put the spring onto the bottom post. The spring will not fit over the washer, you'll have to put the washer on, then the spring, then the spacer. Again, just a safety feature. You shouldn't need to remove the spring or the welded ring ever again. Then clip the double-ended bolt snap to the spring.
   
   
4. Reinstall the posts onto the telescope. Once the posts are back on the telescope, simply grab the double-ended snap, and hook it onto the welded ring like this:
   
   

Now you can easily hook up your tension springs, while only sacrificing a tiny amount of tension. I find that with my 32mm "hand grenade" eyepiece, I still have no problems needing more tension. It seems to be just like stock for me. But now you won't have to worry about flying springs and pinched palms!

This should also work on any telescope that uses a spring based tension system. I believe Orion uses a similar system. If the telescope is any other than a Zhumell 10" Dobsonian, you may need to experiment with different spring sizes.

Disclaimer: I cannot take any responsibility for any damages, to you or to your property, occuring before, during, or after performing this telescope mod or resulting from any advice taken from this website. Do so at your own risk.

Clear skies!