Depth Gauge Gauge

Anatomy of a chainsaw chain:

Here is a picture of one cutting tooth.  The depth gauge controls how much the cutting edge of the tooth will take off.  The bigger the difference in height between the top of the depth gauge and the top of the cutting tooth will result in a bigger chip.

But, if that gap is too big, the chainsaw motor will bog down.  If the gap is too small, you're not cutting as well as you could be.  I have researched and found this gap should be about 0.025 to 0.030 for hard woods.  If you're cutting softer woods, you can increase that gap up to 0.035 to 0.045, but that sounds like an awful lot to me.

Somehow, I needed to figure out a way to check the height of that depth gauge in relation to the top of the cutting tooth.  I could just hold up a straight edge between a couple of cutting teeth, and see where the chain saw depth gauge is, but how do I quantify that?

Lo and behold, I thought up of a little device and fab'd it up - the Depth Gauge Gauge.

To use this crazy thing, I place it flat against the side of the 

chainsaw bar, and then push it down on top of the cutting teeth.  

It straddles 2 cutting teeth to create a flat plane.

My dial indicator is on the chain saw depth gauge.

Then read the gauge.  In this picture, I previously set zero to 0.030 below the plane of the cutting edge teeth, thus the gauge is showing 0.026  (that is 0.004 shy of 0.030).

My shopping list was:
1.  A "plunger style" dial indicator - $3.99 off of Ebay.
2.  A nice chunk of walnut - free from a friend.
3.  A chunk of stainless steel - (a re-purposed 3/4" bolt)
4.  Small screws - $0.49 at the hardware store.

The dial indicator was a steal.  Just because it's old and ugly doesn't mean it won't work.  It works just fine.  Total travel distance is 0.100.  The face shows 0 to 0.020 and then back to 0 for a total of 0.040 per one revolution.

The face of the gauge can be rotated to set zero at any plane.  I made the gauge to provide a 0.050 stroke max - I don't foresee any depth gauge on my chainsaw being more than that height.

By making all the chain saw depth gauges to the same height, the chainsaw should run much smoother and shouldn't chatter in the log.  After making this measuring device, I measured every tooth on the saw - all 39 of them.  Depth gauge tooth ranged from 0.018 to 0.029.  And now after a little filing, all 39 of the the depth gauge teeth range from 0.028 to 0.030.  Smooth as silk.