Jump to content
  • Join the online East Midlands astronomy club today!

    With active forums, two dark sites and a knowledgeable membership, East Midlands Stargazers has something for everyone.

Dob friction control


Tweedledee

Recommended Posts

My 14" dob has a big lazy susan bearing which has allowed a very free azimuth movement, so that a nudge with the eye at the eyepiece could too easily lose the target.

 

Graham has made me a superb adjustable friction mechanism utilising one of the original PTFE pads. The bracket will bolt to the underside of the ground board so the pad can be screwed up against the rotating base board. The mechanism is designed so that the PTFE pad has no lateral play (Backlash) and cannot rotate. Hopefully this will be an advantageous mod...

 

20180525_090058-1200x1600.jpg?raw=1

Drag files here to attach, or choose files... 
Max total size 0.5MB

 

20180525_090119-1600x1200.jpg?raw=1

 

20180525_090426-1600x1200.jpg?raw=1

 

 

  • Like 3
Link to comment
Share on other sites

51 minutes ago, Ron Clarke said:

Looks a good idea, how you going to fit it?

 

Ron

Ron, this is my original sketch showing how it bolts to a corner of the triangular ground board. Graham did some nice modifications to make it more stable and prevent any unwanted movement of the PTFE pad...

20180513_193656s.jpg?raw=1

Edited by Tweedledee
Link to comment
Share on other sites

It's a nice, simple mechanism that should allow me to dial in a little extra friction as required. 

Link to comment
Share on other sites

Did a bit of messing about with the dob today and thoroughly enjoyed it. ?

 

Got the friction control fitted and it is just the job. Had to do a bit of soldering on my mirror fan cables.

 

20180601_111050s.jpg?raw=1

 

20180601_123501i.jpg?raw=1

Drag files here to attach, or choose files... 
Max total size 0.5MB

 

20180601_130435s.jpg?raw=1

 

20180601_163223s.jpg?raw=1

 

  • Like 4
Link to comment
Share on other sites

Simple ideas are normally the best Pete. Well executed job. I love just tinkering, makes the day really enjoyable.

Link to comment
Share on other sites

Love the thrust bearings on the levellers, (Just the one! ?)  that's a nice touch!

Link to comment
Share on other sites

28 minutes ago, BAZ said:

Love the thrust bearings on the levellers, (Just the one! ?)  that's a nice touch!

Cheers Mick and Martyn. 

 

There's another smaller thrust bearing hidden inside - it's a proper job Martyn! ?

 

It just let's you adjust the leveller super slick and precisely so nothing else rotates or scrapes. 

Link to comment
Share on other sites

You just cannot beat a bit of tinkering.

Love the photo of the rear end.

Not a lot of room left with all those fans.

Are the three circular bits counter balance weights ???

Link to comment
Share on other sites

30 minutes ago, Graham said:

You just cannot beat a bit of tinkering.

Love the photo of the rear end.

Not a lot of room left with all those fans.

Are the three circular bits counter balance weights ???

Cheers Graham, very pleased with the friction control you made. It's like a single pot disc brake. ??

 

The circular bits are counter balance weights. Both the original ones and some extra ones I had machined and powder coated. Just in case I ever get any heavier than average eyepieces to balance. ?

Edited by Tweedledee
Link to comment
Share on other sites

A nice little mod there. 

 

Never bothered with lazy Susan mods personally, as you've pointed out im not sure benefits significantly outweigh the downsides.

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.