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Tips and tricks to achieve saw filing success

May 6, 2020  By Josh Penner

Hello fellow filers!

I wanted to touch on an aspect of saw filing that I feel most of us enjoy doing: training new filers in filing techniques. Specifically, teaching someone how to read the tire position, tension and back length of a band saw.

As with many techniques in saw doctoring, there are multiple ways to achieve this and, in my opinion, as long as the end result is a saw that runs straight and true for the duration commonly expected at your mill, then you’re doing alright.

The method that was shown to me, and subsequently what I demonstrate to others, is using the gap of light under my tension gauge (for all you nosy filers, I use a light gap under a 50 tension gauge for Northern B.C. SPF on a six-foot twin and six-foot horizontal. I know there is much more information on this, but we don’t have all day). Then when I “break” the saw, I want to see the front tire one-inch wide and one-inch down from the edge of the gullet. I also target a one-inch back tire, one inch up from the back edge of the saw. If I continue to apply pressure (with one end of the saw lifted, of course), I should easily be able to evenly black out the body of the saw across the width, as if it were “winking” at me.


“But how much pressure?!” is often one of the first questions a trainee asks me. It is hard to mimic exactly how much pressure I’m exerting, especially if you have never done it before. I have found that drawing the tire lines where I see them when I break the saw, then instructing the trainee to adjust their pressure until they see the tires in those spots, is a great way to help get them going.

When measuring the back of a saw with a trainee, I always check the back length myself, and map it out on the saw. Write down the length of the starting point (-five long for argument’s sake), and then continue along the rest of the saw, marking the value when the saw deviates more than say .002 inches from that initial point. Then get your trainee to do it, and they can get a sense of how much (or how little) pressure you are applying to the back gauge when measuring the back of a saw.

You can take it a step further by dividing the saw into sections that are longer or shorter than your target back length, then going over individual sections to determine why they are different than the rest and how you can best rectify the situation.

This helps the benchperson know that the trainee is seeing the same thing when gauging the tension, tires and back. Down the road, a person can adjust or change the technique entirely once they have the approval of their benchperson.

Another thing that was done for me as an up-and-coming filer was asking me to assess the saw – write down on the saw what I saw and where I saw it. Then the benchperson could review my notes and see if I was gauging the condition of the saw correctly or if I was way off in left field. The next step was to get me to add what I would do to fix the defects, and finally to fix those defects on my own before showing it to my instructor. Being able to get feedback at each step before proceeding helped build up my confidence and assured my supervisor that I was progressing accordingly.

As an apprentice, I was hesitant to work on a saw for fear of messing it up. If you rolled a round saw a little too hard or quartered it, it wasn’t seen as too big a deal. A band saw was a little more valuable in terms of the actual cost and how many were available to practice on. I appreciated being able to work on fixable saws – not just impossible wrecks that were beyond salvation.

I know there are many great filers who can fix pretty well anything. You guys are awesome! Pass that training and skill on!

I hope this has not muddied the waters for those of you interested in starting to bench band saws. And remember, there is always more than one way to achieve saw filing success!

The article is part of our 2020 #FileWeek coverage. Read more here.


Josh Penner is a saw filer with Canfor in Chetwynd, B.C.

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