Focusers

[Chriske]

Busy making a list of all different focusers we all know and use.
Purpose is to make 1 of each type to compare them in action side by side.
All these focusers will be printed and(if possible) a dual speed knob will be installed.
In all of them(again if possible or needed) ball bearings will be added.
And all of them will be used with 2" eyepieces.

I already made and tested, and even in use : 

1- Crayford
2- Collapsible(Clement focuser)
3- Helical

To do :

Reversed Crayford

Any other focuser type worth trying...?

[billdan]

A 3D printed rack and pinion focuser would be challenging, unless it was a hybrid using a brass rack and a brass pinion.

 

[Chriske]

Forget that 'old' rack and pinion focuser...
It would be a challenge indeed to replace these metal parts.

[Gina]

You could probably so it with Nylon 12.  Anyway, there are many modern scopes with R&P focusers.  No slip with a heavy camera and EFW on.

[Chriske]

18 hours ago, Chriske said:

Forget that 'old' rack and pinion focuser...

That should have been 'forgot' instead of 'forget', sorry about that.
I surely give it a try.
Nylon would not be my first choice, but maybe I try that. If I'm not mistaken a friend of mine has a reel of nylon filament.

[Chriske]

Meanwhile I've been thinking and came up with something completely different.
As many scopes are used with parfocal eyepieces, there's no need for long travel.
Keeping that in mind I think of a small and low profile focuser.
I'll make a drawing first....

[Chriske]

1 hour ago, Gina said:

You could probably so it with Nylon 12.  Anyway, there are many modern scopes with R&P focusers.  No slip with a heavy camera and EFW on.

No slip has nothing to do whether it's a R&P or other focuser imo.
Most important issue is what kind of friction system is involved to prevent that slipping.
The only focuser that can handle heavy equipment is the collapsible focuser (Clement focuser).

[Gina]

Yes a Clement focuser looks good.

[Chriske]

Printed me a collapsible focuser(Clement) a while ago, works fine.
The only disadvantage is it's size. You can't call it slim-line, can you...

[Horwig]

38 minutes ago, Chriske said:

Printed me a collapsible focuser(Clement) a while ago, works fine.
The only disadvantage is it's size. You can't call it slim-line, can you...

I second that comment on the Clement, but for a DIY build it's quite straight forwards, if very fiddly.

Huw