3D printed Helical focuser BB - V3

[Chriske]

Hi,

During open door at our local observatory last weekend there was much interest in my set of focusers. Because of its focusing-smoothness my Helical focusers with ball bearings(far left) got lots of attention.


The only drawback is that this focuser requires a aluminium eyepiece-barrel. Not to many people have aluminium tube that size in their workshop, let alone a lathe to handle that size of tubes.
To solve that problem I redesigned this focuser and replaced that alu-barrel and a printed barrel will be used now.

The perimeter of a printed cylinder does not allow very smooth focusing. As a matter if fact it actually does, but not to my standards. Making a focuser it should have a very smooth action just the same as any expensive commercial focuser.
To deal with these tiny irregularities from the barrel's outer perimeter I need to remove  a very small fraction of that perimeter. It's only 'cleaning up' that has to be done, so just a fraction of a millimetre will be removed. Only drawback is : there's  still a lathe involved, there's no way around that.
Second : to prevent deforming of that barrel(in time) I drew the barrel's wall rather thick. 5mm will do the job nicely.
And I also changed the angle of the ball bearings inside the focuser, V1 has a 6° angle. In this new design, V3 I changed to 4°.

[Gasman]

Excellent stuff Chris, what software and printer do you use please? just toying with getting into 3d printing?

Steve

Edited September 12, 2018 by Gasman

[Chriske]

Software : Autodesk Inventor (I do have a license from my last employer)..Lucky me...!

Printer is of own design.
Together with a few friends we've built about 20+ different models over he last 5 years. All these models/drawings were downloaded from the internet. Non of them were 100% to our satisfactory. So in the end I decided to build my own printer. I call it Ulti-Printer.
Busy building a few(5) Ulti-Printers-Mark3 300x300x500 this very moment. A few friends copied it and are very pleased with it.
Mark 2 was provided with fast interchangeable hotends.
Mark 3 I added interchangeable filament, meaning I can easily switch between 1.75mm and 2.85mm filament in a matter of seconds.
 

 

[Gasman]

Nice one, I've been thinking about the Creality Cr-10s which seems to get good reviews but the price varies from £375 up to £600 depending on where you look. Don't know enough about them to start making one although I could be persuaded if the instructions were clear enough (ie ok for thickos).

Cheers

Steve

[Chriske]

If you still go to school(and of course you do...) you can download a Autodesk Inventor version for free. You have to give a name of a school and your done.
Best 3D design software ever(together with SolidWorks).

[Cycliste737]

Hey, I know this post is a bit old but wanted to see if you would provide source files for the Helical BB design. I make my own telescopes and am a 3D printing enthusiast, would love to try my hand at sizing the helical design to 1-1/4" eyepieces in Fusion 360. If you don't want to post publicly just send them in a private message, not looking to steal the design just use for my own purposes.

Thanks much,

~Nick