Hitachi C10RJ Insert

Disclaimer: No guarantees on whether this fits your particular saw, but it fits mine “good enough”.

Since my print bed is not big enough to print a full insert in one piece, this is broken up into two halves with some joiner pieces. I've tried to locate the joiner pieces in areas that won't get chewed into so as to keep structural stability.

Print Settings

Here are my print settings. YMMV

• PLA
• 0.2mm layer height
• 3 perimeters (more torsional stability)
• 6+ bottom layers (aka more top-surface thickness)
• 25% infill, cubic or grid (need a good amount of internal structure, since we're cutting into it)
• organic supports, 40% overhang threshold (for the pin latches)

Instructions

You also need CA glue and a poking device (flathead screwdriver).

1. Print all the pieces.
2. Test fit the front half and back half; if you need to do some cleanup/sanding, do so now.
3. CA glue the front half and back half together.
4. Add CA glue in the slots, and press the insert pieces into their respective slots. Use your poking device to make sure the inserts are fully inserted.
5. Lay (top surface facing down) on a flat surface with some heavy weights until the glue cures, trying to make sure the top surface is nice-and-flat.

If your top surface is still not flat, tape a sheet of sandpaper to a flat surface, and sand it out!

Table Saw Instructions

I doubt these instructions are the proper way to do this, but… it's what I did.

1. Remove or lower the riving blade completely.
2. Loosely place the insert into the slot, making sure the back of the insert is fully engaged. The front of the insert will not fit because it touches the saw blade.
3. Use something to clamp the back of the insert so it doesn't move (push block, 2x4, clamps…). Turn on the saw and slowly raise the blade just enough to cut through the top of the insert. Turn off the saw.
4. Now that the insert can fully rest into the slot, cut the full height of the blade. (If you did not remove the riving blade, then you won't be able to raise the saw blade fully.)
5. Flip the insert over lengthwise, making sure the slot lines up with the saw blade. It won't fully fit into the recess, since the insert isn't symmetrical.
6. Repeat all the cutting steps. There now should be enough room for the riving blade.
7. Take a knife/chisel and clean up the slot. Clean up any PLA slag inside the table saw.

YMMV. This felt very sketchy and unsafe.

History?

• Revision 2 (2023-11-03) – initial release.
• Revision 2 (2023-12-25) – added full piece (for those with large bed printers)

Future idea/todo list:

• variant with a 1/8" kerf + riving blade already pre-measured in the STL
• adjust around where the blade will cut through to be thinner to reduce effort
• test with a dado stack; verify structural stability and tolerances
  • 2023-12-10: cutting through with dado stack takes a little bit more effort; make sure to cut riving slot first (since it still gets in the way) or fully remove it  
• test 45 degree bevel; verify fit, structural stability and tolerances