Loose Tenon Mortiser jig

Loose Tenon Mortiser

This is a simple loose tenon mortiser jig for a handheld Makita type of trim router with a diameter of 65mm. It is inspired by the Festool Domino and a number of more or less cheap ripoffs I’ve found on cheap chinese sites and also some DIY youtube clips. 

SAFETY FIRST!!!

First thing’s first: this is not a toy!!! This jig is intended as a router tool operated by individuals knowledgeable of woodworking and router operation, especially on how to mortise using a hand held router. If you don’t know how to safely operate a handheld trim router you should not build this jig or use it. This jig will expose a possibly lethal high speed router mortising bit to the operator. I will take no responsibility for any injury or accident caused by improper or noobish handling of this potentially very dangerous tool.

BOM

8 x LM8U 8 mm Linear Motion Bearings

2 x 8mm aluminium rod, length 130mm

2 x 8mm aluminium rod, length 146mm

8 x M4 8mm Insex bolts

1 x M4 12mm Insex bolt 

2 x M4 20mm Hex bolt

1 x Short spring

11 x M4 heat inserts

Printing

All parts except the upper and lower collar are printed in PLA 0.2, infill 55%, 6 walls for maximum strength. I printed the collars with (white) ABS for thermal resistance.

Parts

1 x Collar Lower

1 x Collar Upper

1 x Frame

1 x Gantry Back

1 x Gantry Front

1 x Guide

1 x Handle

2 x M4Knob

4 x Plugg

n x Spacer

Assembly

1. Mount the heat inserts (pic 4, 5, 11, 13, 21)
2. Press fit four (4) linear motion bearings into the lower collar (pic 6, 7)
3. Attach the spring to the lower collar (pic 8)
4. Press fit four (4) linear motion bearings into front and back gantry (pic 9, 10)
5. Cut the aluminium rod into two 130 mm and two 146 mm long linear rails (pic 12)
6. Insert the 130mm long rails into the back gantry (pic 13)
7. Insert the gantry into the lower collar (pic 14)
8. Insert one of the 146mm rods through one of the front axis mounting holes on the frame, approx 10 mm deep, then insert the rod through the front gantry and finally press it through the opposite mounting hole. Secure the rod in both ends with plugs (press fit or glue them into place) (pic 15, 16, 17)
9. Insert the lower collar and back gantry rods into the front gantry. Also attach the spring to the back gantry (pic 18)
10. Insert one of the 146mm rods into the back gantry and plug it. Now is time to press the rods so the whole assembly aligns with the back resting points. After that you should try to break in all the rails/guides so they all move smoothly forth/back and left/right (pic 19)
11. Mount the handle to the guide plate using a M4 insex bolt and some glue (pic 20, 21, 22, 23)
12. Mount the router using six (6) M4 insex bolts. Make sure the collar is flush with the front of the router spindle (pic 19, 24)
13. Adjust the router plunge depth and width using spacers. You can scale these to any preferred width in your slicing software. I used spacers of 5mm (pic 1 and 24) width to create the mortise in pic 28 which is 30mm wide and 30mm deep. Print the spacers and click them on to the rods (left/right and in front of the router gantry). 
    
    IMPORTANT!!!! You need at least one 8mm spacer to prevent the router collet from plunging into the front frame, click it into place between the lower collar and  the front gantry.
     
14. Print two M4Knobs and use them to attach the guide to the frame using two M4 Hex bolts (20mm) (pic 2)

Future work

After using the jig for a project it is clear that somekind of dust collection is needed.