RatRig V-Core 4.0 XY Spacer for Toro Ti Tube

Note: You will also need to download this sizing guide.

Design Intent

• On the bottom face of the tube, the metal-to-metal clamping stack in the stock design  is maintained without adding a layer of printed part in between the nut and the bolt head.
   
• The tolerances on the titanium tube are quite large: +/- 0.3mm. Designing to accommodate the largest in-tolerance dimension (20.3mm) would leave a 0.6mm gap for the smallest in-tolerance dimension (19.7mm). So this mod is offered in multiple size combinations (in 0.1mm steps), and a sizing guide is provided to help select the best fit for your particular tube.

Printing

Follow the RatRig printing guidelines here. This is a precision part. Print it on a well-calibrated machine with a suitable profile. Adjust for material shrinkage in your slicer - the parts are not pre-scaled.

Print the sizing guide first. The centre hole in the guide is 20.0mm. Each raised dot indicates 0.1mm above 20.0mm (so 3 raised dots is 20.3mm). Each recessed dot indicates 0.1mm below 20.0mm (so 3 recessed dots is 19.7mm).

For each end of your tube, find the width by inserting the end of the tube in the sizing guide, trying the holes in turn. You're looking for a snug but not forced fit. Repeat for the height. Then select the appropriate width and height combination for each end of the tube. See Optional Variants below for details of STL filenames.

Your tube should be a good fit in one of the middle 7 holes (zero, 1, 2 or 3 dots). If the best fit is in one of the 4-dot holes, your tube may be out of spec, or you may have an issue with material shrinkage or shrinkage correction. If your tube is good (between 19.7mm and 20.3mm) then it's most likely a shrinkage or shrinkage correction issue which you should fix as it may cause fitting issues with the other parts of the x-axis.

To fit, insert the stock t-nuts into the channels in the xy_spacer part. Note that they are inserted “backwards” on purpose to suit the design.

Then insert the tube and assemble as per the RatRig build instructions. Avoid tipping the part over during assembly as the t-nuts could slip out.

NB: “width” means the dimension of the tube in the y-axis (front/back) as installed, “height” means the dimension of the tube in the z-axis (up/down) as installed.

Optional Variants

The standard designs have filenames like:

vc4_xy_spacer_v2_for_ToroTiTube_19.6w_19.6h_by_tg73_r1.stl

The optional variants add some extra letters after ToroTiTube, for example:

vc4_xy_spacer_v2_for_ToroTiTube_ep_19.6w_19.6h_by_tg73_r1.stl
                               ^^^^                          

Extra Length Variant

STLs with _xl_ ("extra length") in the name have the surface indicated above moved down by 0.5mm (in print orientation as shown). This helps to accommodate tubes which are too long for the available width between the y carriages when assembled. A couple of users have requested this, but typically it is not required.

Easy Print Variant

STLs with _ep_ ("easy print") in the name have the corners indicated above squared off. It can be difficult to print the rounded corners in the original RatRig model. Several users requested this variant to make it easier to print.

STLs with _ep_xl_ in the name have both extra length and easy print features.

Updates

Adapted to suit the Toro3D Titanium Tube, a replacement for the stock 2020 aluminium extrusion x-axis beam which is about 30% lighter and seeks to eliminate temperature-dependent x-axis bowing due to the differing expansion rates of the steel linear rail and the stock aluminium beam.