Diagnosing tooth shape

[STOVE]

I was looking over a chain last night and I noticed some of my teeth have a bulge in the leading edge. See the sketch below. I will also take photos of the chain.

What causes this in a sharpening stroke? Trying to understand what I am doing to lose the straightness of the tooth edge

 

[SawAddictedFarmer]

I was looking over a chain last night and I noticed some of my teeth have a bulge in the leading edge. See the sketch below. I will also take photos of the chain.

What causes this in a sharpening stroke? Trying to understand what I am doing to lose the straightness of the tooth edgeView attachment 481740

Assuming your using a file that's just from not keeping it at the same angle every stroke.

 

[Woodtroll]

Or it could be that you're rotating your body during the file stroke, instead of pushing straight through with just your arms. Sometimes it's tough to isolate the arm motion to just a push that is both straight (on a 30-degree or whatever angle you choose) and also flat relative to the top flat plane of the tooth. If you have a shop vise that helps a lot, especially if you can get in a position to rest your upper body against the vise or bench to keep it in a consistent position, and pull each tooth into the same position on the bar before you start filing.

I think a filing guide helps establish a straight motion, as you can easily tell visually when your file angle starts to get off. I like this one because it's simple and a clear visual reference yet it doesn't require any clamping of the file or extra hardware, but I'm sure there are others:

Amazon.com: Tecomec New! Magnetic File Angle Plate 25° & 30° for Chainsaw Sharpening USE : Patio, Lawn & Garden

Amazon.com: Tecomec New! Magnetic File Angle Plate 25° & 30° for Chainsaw Sharpening USE : Patio, Lawn & Garden

www.amazon.com

 

[Wilhelm]

You are not pushing Your file in a straight stroke.

I really like the Archer FastFiler roller guides, they also help keep near identical cutter length featuring side and depth rollers.

Con is You are comited to the guides angle, unless You make custom side rollers.
I did the latter.

 

[Seachaser]

There’s several YouTubers that explain what happens. They even do it and then how to straighten the edge back out.

 

[Lawless]

Could also be dipping and raising the file handle in the stroke, which is harder to watch for than top plate angle.

 

[Stihl036]

It's a saw chain, not a fiddle!

 

[STOVE]

It's a saw chain, not a fiddle!

A great picture you painted

 

[STOVE]

I appreciate all the responses, I will be going some more filing shortly. I am also wondering if the handle shape promotes a certain stroke.

 

[Philbert]

One of the reasons I strongly recommend holding the bar / chain securely in a vise of some kind, and using both hands to guide the file.

Think of a pool cue: once you decide on the angle you want it to travel, you don’t want it to change part way through the stroke.

Philbert

 

[MtnHaul]

One of the reasons I strongly recommend holding the bar / chain securely in a vise of some kind, and using both hands to guide the file.

Think of a pool cue: once you decide on the angle you want it to travel, you don’t want it to change part way through the stroke.

Philbert

I agree that using both hands really helps to guide the file while the bar is held in a vise. I do have to watch that I don't end up pulling the file instead of pushing it since pulling seems to make the file turn into the tooth at the end of the stroke, at least with my skill level and technique.