router jig makita 640 x 360

How to make a stair stringer router jig

Making your own router stair jig is easy and so there is no reason to purchase commercial tools. In this blog, I will demonstrate how to make and use a simple jig designed by Marcus Kett.

How I built my router jig

router jig cut stringer 640 x 360

When I am commissioned to build a new staircase I first calculate the rise and going as to ascertain the angle. From that, I make my own router jig usually from Formica plywood. My favourite material for making jigs is Formica faced 1/2″ plywood or sometimes MDF. A Stair jig is used in conjunction with a heavy-duty router, I suggest a plunge router of around 2000 watts.  

Materials needed to build ‘Stair Jig’

  • sheet material approximately 18 x 18 x 3/8 inches all for the Europeans 450 x 450 x 15mm or larger
  • 4 strips of hardwood approximately 450x15x10mm
  • 450 x 100x 20 mm wood for fence
  • Wood glue, any will do such as PVA but I prefer to use cascamite.
  • Pins or brands
  • Sanding sealer

Tools required to build a router jig

  • A pencil
  • A rule
  • Framing Square
  • Panel saw or table saw
  • Jigsaw or bandsaw optional
  • A hammer or Brad nailer
  • Clamps

Design checklist for jig

  • What router will you be using
  • Are you going to use a roller guided router bit or a fluted straight router bit and router guide insert?
  • How much clearance do you need for the router guide?
  • I made my jig on the basis of a 45-degree staircase. A 45-degree staircase has an equal rise and going.

My stair jig design uses

  • Makita 1850w router (my recommended Router)
  • Guide insert for the half-inch router bit
  • 1/2″ CMT router cutter
  • Two 2 inch g-clamps

How to make the stair router jig template?

If you are still considering making a stair router guide or jig. I have put together this tutorial and a step by step of me making my jig. I have also made a video which you can see me make my jig. Watch the Video or read on below.

Step by step of marking out the position of the tread on the new jig

  1. Draw line on the bench at 45 degrees from edge
    router jig mark with square 640 x 360
  2. Place plywood Square onto the 45-degree angle
  3. Using your framing Square place the square ninety degrees to the edge of your bench. 
  4. The narrow face of the square where should be facing at 90 degrees and the longer leg of the square should be parallel with the edge of the bench. This represents to rise and the going of each tread. 
  5. Approximately 2 inches 50 mm from the corner of the square to the edge of the plywood approximately. 
  6. Using a pencil draw the right angle on the plywoods. This will represent the top of the tread and the face of the rise.
  7. Because this stair jig is designed for use with wedges the housing for the stair treads and risers need to be tapered. The taper is for the wedge to slide into once the tread and The rise are in position. The wedge will force the tread to the top edge of the housing? This will be a much neater finish what is the traditional way of building a staircase.
  8. The taper of the housing needs to be about 3/8 of an inch or 10 mm for the length of the rise and the length of the going.
    router jig mark with square taper for wedges640 x 360
  9. Mark two lines parallel with the face lines.
  10. Allow for the clearance of the guide insert (for the purpose of this tutorial we will allow 4mm but your router and guide may be different)
  11. For instance, if your tread is 1 inch or 25mm allow 29mm at the front of the tread but at the back, you will need to allow for the taper of the wedge. 
  12. I allow 10mm taper so at the back of the tread I allow 39mm
  13. Repeat this process for the rise but compensate for the thickness of the risers.
  14. My risers are 15mm thick so at the top they are 19mm and the bottom is 29mm.

You should have something that resembles the profile for the stair housing including wedges.

My stair jig upgrade

I line the edge of my jig with hardwood strips for the router guide to slide against. I have found this to be a better solution than just having a raw ply edge. 

How I cut my jig out of the plywood

I have upgraded the way I make my stair router jig. The reason is that I found that using the plywood on its own left a rough finish to my finished housings. 

1. I use my table saw to cut out the jig and finish with the band saw. 

router jig cut with table saw 640 x 360

2, You can use a panel saw if you do not have the machines.

router jig cut with bandsaw 640 x 360

3, I clean up any ragged edges using a chisel and block panel

Assembling the new stair jig

1, Now you have all the components cut to the line you need to assemble the jig ready for glue-up.

router jig guide placed 640 x 360router jig guide placed 640 x 360

2, Add two hardwood strips and trim ends

3, Add two additional strips to the outside edge for reinforcement

4, Apply wood glue to the mating surfaces, I prefer to use Cascamite

router jig guide placed glue up clamps 640 x 360

5, Clamp the assembly together and brad nail the components

6, Leave to set solid

7, Remove all the clamps and sand flush

router jig guide air sand 640 x 360router jig guide air sand 640 x 360router jig guide air sand 640 x 360router jig guide air sand 640 x 360
router jig cut with makita 640 x 360

I hope this tutorial has helped you understand the concept of design and build of a stair router jig. But if you have difficulty in understanding the concept please feel free to send us a message to so we can help.

My conclusion in the practical solution of bnuilding your own stair jig.

I have been using my own basic stair router jigs for years with great success. The cost of commercial stair router jigs is in, my opinion overpriced but if you want to use a commercial unit instead Then I recomùmend these:

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