Parametric xTool RA2 Rotary Chuck and Backstop Fence

Motivation

The xTool RA2 rotary is a great accessory, but it can be challenging to square the workpiece up to the RA2 rotation axis.

Solution

Design and print a fence to achieve the following objectives:

- Allow workpiece to be held square to the RA2 rotation axis while tightening the chuck jaws

- Fully parametric providing customization of all dimensions (e.g. diameter, thickness, etc.)

- Ruler indices to take accurate diameter measurements even after the workpiece is mounted to the chuck

- (Optional) Spacer to allow the fence to sit completely flush to the underside of mounted jaws without unnecessarily printing the entire fence at the full thickness.

- With the default settings, you will lose ~3 mm of available minimum diameter since the slides will not be able to fully close

- The fence works fine without this spacer if you press the workpiece evenly against the fence while tightening the chuck

Customization

The Fusion file is included. In the process of designing this and my Custom Chuck Jaws , I also reverse engineered the chuck mechanism. That design is included in the Fusion files along with the bundled Chuck Jaw and screw assemblies (.f3z).

You can customize the parameters ( DESIGN | SOLID | MODIFY | Change Parameters ) to suit your workpiece and needs. The most common parameters you should need are Favorited. The non-favorited parameters should work as well but may require more tinkering to repair broken downstream features. Here are a few notes to clarify some of the favorited parameters:

I prototyped a honeycomb structure to save filament but found that made the fence too flexible (at least at 2 mm thickness). That component is suppressed but I left it available for further modifications.

I designed and prototyped on a Prusa MK4.

Let me know ( Messenger | Printables.com ) if you have any questions.

Printing

See the attached .3mf for my settings. I recommend printing with 100% perimeters.

(New in v1.1!) Lasering

I was asked if it was possible to make the backstop fence using a laser. It seems only fitting, so I added projected sketches to the Fusion file that should allow for export even after customization by right clicking on the respective sketches and selecting ‘Save as DXF’. The geometry in these sketches is optimized for laser processes and you can find them using the LaserProcessSketches selection set. I've included those five .dxf's for the default 100 mm target diameter - four for the backstop fence and one for the optional spacer. Since I have not personally cut these files and your laser kerf may vary, please pay attention to these notes:

- There is only 6 mm (~15/64") from the face of the rotary chuck body and the front surface of the jaw slides. If the thickness of your material (or combined thickness if using the spacer) exceeds 6 mm, you will have problems getting your jaws to slide smoothly over the backstop fence and mate properly to the jaw slide.

- For the backstop fence cut sketch, I used Fusion to create three offsets for each of two paths at 0.1 mm steps so that you can ungroup and delete a total of six paths leaving only the two paths which should provide the most accurate cut based on the half kerf of your laser. Keep in mind the direction of the waste side of the cut - the inner geometry that will key around the jaw slides is offset inward while the outer circle is offset outward.

- For any sketch with geometry that does not allow for it to be concentric when aligning to centers, I added a large circle that should be deleted after alignment but before processing. This should make sense in XCS but let me know if you have questions.

I welcome feedback so that I can make any necessary adjustments to the Fusion and .dxf files.

Installation

The default tolerance is 0.2 mm. For me, this was exactly right, but does require a little flexing of the fence to install it.

Shameless Plug

If this model helped you solve a problem, save some time, or in any way made your life a little easier then please consider clicking the Like button and posting your Makes! If it fell short after clicking on the title of the model, please let me know ( Messenger | Printables.com ). Either way, Thank you!

Related

Complete exhaust configuration

Adapters - Convert machine exhausts to ducting diameter and/or MagDuct

- xTool P2 Exhaust Duct Adapter (configured as 4 in)

- MagDuct xTool F2 Ultra UV Slip Adapter

- MagDuct CORE One Exhaust Adapter and Gasket

Ducting

- AC Infinity 4" ducting

- AC Infinity 6" ducting

- xTool pipe (included w/ xTool IF2 2.0 and xTool F2 Ultra UV)

- xTool 72.5 mm ducting (included w/ xTool P2)

Couplers - Convert flexible ducting or pipe/rigid ducting to MagDuct