My astronomy project:
Repair and adjusting focus friction

Content:

Repair the friction coupling:

1. Introduction focuser
2. Disassembling the focuser
3. The friction parts
4. Assembling focuser together
5. Implement of high friction surface
6. Spring compensation load
7. To be continued

Look at these projects too:

1. Repair and adjusting focus friction
2. 3D CAD design of a 3" Rack and Pinion focuser
3. 3D CAD design of a 3" Push Pull focuser
4. Focus and camera rotator

Note:
I take no responsibility or liability for what are written here, you use the information on your own risk!

1: Introduction focuser

It's very common focuser today have a friction coupling, that's fine and give very smooth focusing compare to a rack and pinion focuser. But problems can arise if you have heavy load on the focuser, a camera or similar. I have problem with that, when telescope is pointing upwards the friction coupling slips and can't move the camera. I have adjusted the force that regulate the friction and got it a little bit better. Sometimes when the telescope get wet because of moister the problem get worse, the water act as a lubrication between the friction surfaces.

Now I decided to take the focuser apart and see if there is something wrong or something that I can rebuild and make it better. My focuser is a 3" dual speed mounted on a TS130 APO refractor, this is a special option, normally there is a 2.5" focuser on this telescope.

Here are some information about focusers:

• https://en.wikipedia.org/ wiki/ Crayford focuser Crayford focuser, Wiki
• https://en.wikipedia.org/ wiki/ Dual speed focuser Dual speed focuser, Wiki

I have built a compact motor focuser to my telescope. It's not so easy to see that there is a focuser down there.

As usual I will spend another day working with my telescope, luckily me I feel to some degree it's fun.