45 degree mitre shooting board

June 8, 2026.  I replaced v2 and 105 files with files labeled v3.  The difference is that I added a strong chamfer to the leading lip or front edge.  The problem with the earlier files was that the user had to carefully avoid contacting the lip with their little finger so as to avoid injury.  So the chamfer adds even more pinky clearance.  Many thanks to Traumahead for making me aware of the hazard.

This shooting board guides a Veritas low-angle jack plane in making accurate, 45 degree mitres at the ends of workpieces.  (Other planes can be used as explained in the last paragraph.)  The jig is composed of a core, which holds the workpiece, and one or two wings to guide the plane's travel.  It accepts boards as wide as 4 inches or 100 mm.  Its ideal use is in cleaning up mitres that have been cut on a table saw, but it seems to work as well in converting a square end into a 45 degree mitre from scratch.

The core holds and aligns the workpiece.  As seen in the photos my own shooting board uses a wing before and after the core.  I think only one wing before the core might be sufficient.  Once the core is screwed into a ¾ inch or 19mm board, the wing can be pushed against it and aligned with a cleat pushed down into their plane tracks.  Screw positions can then be marked or ideally dimpled.  The cleat should have its pushed-down faces properly square to each other.  Mounting holes are suited to Number 8 round head wood screws, 1-¼ inch (32 mm) long.  Robertson, naturally.

I used PLA and 20% infill.  I printed the core with “support everywhere” for a clean bridge at the top.  Wings print without support.  Note that in the photo of my print, the infill is visible at the front edge of the jig.  That's because the original design had too high a front edge so I sawed it off because I wanted to keep my little finger.  The files uploaded here are corrected with a low front edge, but I was too cheap to reprint a proper version for myself.  On a Prusa mk4 the wings took a little over four hours, 39 m, and 115 g of filament each whereas the core took six and a quarter hours, 56 m and 167 g of filament.

While this remains untested, I heard in Episode 94 of the podcast "3D Printing Today" that linear infill patterns (like grid or rectilinear) tug more strongly on walls than do other patterns of fill.  It's possible that linear fill may cause differences between the core and wings leading to alignment troubles.  So maybe it's best to use a fill pattern that avoids long straight lines.

I included the OpenSCAD source code so that if you know your way around OpenSCAD, you can modify the mitre angles.  You may want to change the 45 to 45.1 or 45.2 or thereabouts so that the external edges close tightly.  Or you may want to change the mitre angles to support five- or six-sided, etc., cases.  I suppose you can change the board widths too, to accept more than the 4-inch (100 mm) maximum width.  Enjoy!

The OpenSCAD source may be modified to accommodate planes other than the Veritas Low-Angle Jack.  Substituting the plane's body width and the iron width is all that is needed to print the shooting board for a different plane.