As a winter project i have slowly been building a 4th Axis. I did seriously think about making a scroll chuck but decided on buying a Sherline 3 jaw for the project. All the other parts (excluding the flex coupling) have been made from stock, some parts CNC'd others made on a lathe or mill.
There is still a lot of work to do but I thought I could post some pictures of the progress so far.

Pretty dogone nifty there Tweakie !
Is there any way to adjust/remove any backlash ?
Again....COOL,
RC

I hope you documented your design for the rest of us ;-)  I think a 4th axis is my next project after my Miser and maybe concurrently with CNCing my watch lathe.

Vince

Hi RC,

This is difficult to describe but as the 4 main parts of the case are not directly fixed to each other (they are keyed vertically) the small end plates can be moved vertically (and shims inserted) to increase the mesh of the gears to eliminate any backlash. The front and back plates are then clamped together by the 4 screws, trapping the end plates in position. The top and base plates trap the shims and make the whole assembly rigid. The stepper position will also be adjustable.

I am certain that initially there will be some degree of wear between the gears as they 'bed-in' so adjustment for backlash is essential.

Tweakie.

Hi Vince,

I took a few photo's during making some of the parts and I will try to document the construction of the project on my website.

Tweakie.

Looks great, I look forward to seeing someone actually use their 4th axis.... 

Dave

Very nice Tweakie.    Looking forward to seeing it in action.

Brett

Hi Vince,

I took a few photo's during making some of the parts and I will try to document the construction of the project on my website.

Tweakie.

What is your website address?

Vince

Vince,
 Click on this little guy.
RC

Thanks Tweakie,  I like you approach to the backlash adjustment.
RC