Tuesday, 16 May 2017

Tracksaw setting gauge

For all you users of tracksaws (Festool, Bosch, Makita etc) here is a design of a measuring gauge to make setting cuts far easier.

The one problem with cutting sheetgoods using a tracksaw is measuring. You create a good edge from stock by cutting about 1/8" off. Then using a tape measure and a pencil make a couple of pencil marks relative to this edge.
Then you set the tracksaw track onto the pencil marks and suddenly you can't see them. You move the track a little to expose the pencil line. Go to the other end and find that pencil line is 1/8" away from the rubber splinter guard. You move it back to the line, goto the other end and find you have obscured the pencil again.

This scenario does happen and sometimes you end up with a board cut that is slightly out of parallel and oversize because you covered the pencil line. There must be an easier way of setting this.
The good news is there is.

Steve Maskery of Workshop Essentials designed a simple setting gauge with integral rule that compensates for the track width and results in parallel, accurate width, repeatable cuts every time.
I take no credit for designing this but set about making one.
(Steve also says this has probably been done many times before in the dim and distant past but he was the first person to show it being created on video.)

Here is my Sketchup version of Steve's original design
Tracksaw Gauge Head


First of all I found a length of hardwood on my shelves around 1.2m (48") long. I milled this square to about 20mm (approx 3/4"). It is not essential that this is dead straight over its length and a slight about of bow is acceptable. If you can make it straight and it maintains then all the better.
Cut both ends square.
Relieve the arris on each side of the stock to remove any sharp edges and splinters.

Head fabrication

Next the head was made from a length of walnut cut to 20 x 30 x 90 mm (3/4" x 1-1/4" x 3-1/2").
I cut 2 blocks 20 x 30 x 35mm long (3/4" x 1-1/4" x 1-3/8") from walnut. Into one of these I drilled and tapped a hole for M6 (1/4" threads can be used in US). I also counterbored one end 12mm diameter x 10mm deep (1/2" x 3/8").

The walnut blocks were then glued on with a 20mm division to form a U section. I used the actual hardwood bar to space the blocks. There can be a slight amount of clearance here of about 10 thousands to allow the bar to slide easily back and forth. I further dowelled these blocks into place.

Graticule plate

Next an acrylic graticule was made from some 6mm (1/4") perspex or plexiglass I had in stock. It measures 30 x 90 x 6mm (1-1/4" x 3-1/2" x 1/4" thick) I scratched a line on the backside and highlighted it with a Sharpy to make it standout. Then I drilled 4 small holes, 1 in each corner, and countersunk them on the opposite face to the scratched line.

Then using small countersunk screws the transparent graticule plate was attached, line side down, across the blocks. All corners were then chamfered on my disc sander. I decided to radius 2 corners as a visual reminder as to which way around the reference face goes.


Use a finger screw or machine bolt if you don't have one and insert it into the threaded hole. I found a plastic rod of suitable diameter and cut it to 8mm (5/16") long. This is the pressure washer to prevent marring the stock in use.

Then insert the stock and set it to a random length.

The final part is calibrating the gauge. At this stage there is no scale on the gauge.

Take a random sheet from your racks and set it flat on your cutting bench. Cut one edge with your tracksaw to establish a straight edge. Then move the track over to the other edge of the board. Take your gauge and set the head to register on the straight edge, extend the stock until it touches the back edge of the track and lock the head in position.
Move the gauge to the other end of the track and ensure the track also is located correctly. 

Move the gauge back to the original location to ensure it hasn't moved.
 If you have track clamps lock them into place. The rubber strips on the underside of the track hold it into place 99% of the time but there is the odd time where you can knock it yourself.

Then make the cut with your tracksaw. Note that you have NOT measured anything whatsoever yet.

Remove the track saw and track.
Next using your most accurate steel rule take a measurement of the width of the board you have just cut. Make a note of this.

Applying the measuring tape.

You can buy self adhesive metal measuring tape that is intended just for this purpose. I bought one which came on a roll starting at 0mm and ending at 1000mm (0-39" approx). The ends of the tape have a large un-etched section intended for trimming to any size you wish. I bought one that works from right to left. You can also buy them that start from left and increase as you get to the right as shown below.

The tape is thin enough to slide underneath the graticule plate and between the face of the stock. Slide it into place and set it so the measurement you took is under the scratch line. Then using a few strips of blue tape temporarily stick the tape into place so it can't move. Remove the head.

Next cut the tape with tin shears to be shy of the end face. Now remove a small portion of the backing release paper and start sticking the tape down to the stock. Pull out the backing paper at 90 degrees to the tape whilst smoothing the tape as you go along. When you reach the first bit of blue tape remove it before carrying on. Do this until the entire tape is stuck down.

Using the tin shears again cut off the end that it surplus.

You will then have a gauge that starts at 127mm (5") or whatever the width of your track is.

Gauge head with measuring tape applied

My completed full length gauge

Reassemble the head into place and make a test cut this time setting the gauge to a determined length.

Measure the resultant board width and you will find it is spot on. If it isn't you can slot the holes in the graticule plate and move the scratch line slightly.


You can put a brass threaded bush in the hole if you like but I haven't found it necessary

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