How To Make A Stair Tread Gauge

When stair treads sandwich between vertical surfaces such as walls, stringers or skirting, the dimensions and angles depend on the squareness and orientation of the opposing surfaces. The sides of a staircase are rarely parallel, meaning you must carefully gauge distances and angles to determine the desired dimensions of a tread. Building custom stair tread gauges or jigs requires only standard power tools, inexpensive hardware and scrap wood. The jig functions as an adjustable measuring device that creates a full-size template for each tread.

1st Method

DIY Stair Tread Gauge

So how does it work? Basically, it’s a couple of triangles attached to a center piece. The triangles are movable. They can go in and out and they can angle. You simply place the tool in place, loosen the wing nuts, slide it out and make it touch the outward edges of your stair well, and lock down the nuts. Once you do that you carefully remove the tool and place it on one of your treads and trace your lines where you need to cut.


Here I am using the tool to measure for a stair tread. Just loosen the wing nuts and slide the triangles out until they flush with the wall. Then tighten down the wing nuts and remove the tool.

How to make your own stair tread gauge

First, you’ll need to assemble/create a few parts:

Here are the parts:

  1. 2 wing nuts, 4 washers, and 2 bolts.
  2. 2 triangle shapes. I made mine from scrap wood. The side of the triangle that faces the wall is the same depth as the stair tread.
  3. 1 center section. Length will vary depending on the width of your stairwell. To figure out how long it should be, place your two triangles on the step at the stair edges. Measure the approximate length from the center of one triangle to the other and cut your board to this length.
  4. 2 spacer pieces that will go under the triangle to keep the bolt up off of the tread. This makes it easier to trace the line. The spacers should be about the same length as the widest side of the triangles. They need to be thick enough to keep the bolt off the stair.


Here’s how to assemble it:

1. Use a drill or jigsaw to wallow out a hole in each triangle. I made my hole about an inch long. This will allow the triangles to pivot and move in and out. It doesn’t need to be a big hole because there won’t be that much difference in tread lengths. (There was only about a 1/4 inch difference in our stairs.)


This is an important part. You can see how the hole where the bolt runs through is wallowed out. This allows for the movement and adjustment of the triangle piece.

2. Lay everything out on your stairs (center piece and two triangles) and dry-fit your tool. Use a pencil to make a mark through your hold (in step 1) that you’ll use to know where to drill your holes in the center piece. (See parts photo above.) Drill those holes.

3. Attach the triangles to the center piece, using a bolt, two washers (one on each side of the triangle), and a wing nut. The wing nut needs to go on the top so you can easily tighten and loosen it while you’re using the tool.

4. Nail the spacers to the ends of the triangles.


Here’s another important detail. I found that I needed to put a spacer under the edges of the triangle pieced so that the bottom of the bolt didn’t touch when I was measuring and drawing my lines on the treads. This raised the center part of the tool up enough to keep it flat.

As I said above, you simply place the tool on the tread, loosen the wing nuts, slide the triangles out and fit the ends snugly against the sides of the stairwell, and then tighten the wingnuts down.

Then, you put the gauge on your tread, and mark your cut lines.


I cut all my treads with a compound miter saw. The advantage of this saw is that it allows you to make angle cuts easily if the walls aren’t exactly straight. These saws can be expensive, but Harbor Freight has one for less than 200 bucks. It’s been a good buy so far. I’ve used it quite a bit and like the way it works.

You can read the entire article from This (sorta) Old Life here. Thank you Rita and Cane.






The Step Doctor

The Step Doctor

$19.99 - Stairtek at Home Depot

$19.99 – Stairtek at Home Depot


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