Is it true, that if you use a grinder to sharpen your chain once, it hardens the steel, so you cannot properly sharpen it again with a file.
No.
Every chain you use was ground at the factory. Contrary to popular imagination, STIHL, Oregon, etc., do not employ hundreds of workers to hand file each cutter on the miles of chain they produce every day. These chains all can be filed later.
If you overheat the steel, and let it cool quickly (like it does in air), you
can harden the surface. This usually involves:
- sustained contact with the grinder;
- dull grinding wheels;
- a change in color of the steel (especially blue or black).
If you do this you can usually grind through this layer, and you will once again be able to file the cutter.
I learned of this theory from a video.
You need to watch better videos.
I usually sharpen my chains with a grinder, and if I am in the field, and try to use a file to touch up, the file just glides over the teeth, removing no material.
Learn how to grind better. Use sharp files.
I have ground at home and filed in the field for years. The hardest part is maintaining the same cutter profile between the 2 methods,
- grinding wheels get dull: that means you are rubbing dull abrasives against the steel tooth at several thousand RPM, creating friction and heat. Dressing the wheels frequently exposes fresh, sharp abrasives, which cut the steel and remain cooler. I dress my wheels lightly once per loop of chain.
- cheap wheels (e.g. the ones that come on cheap grinders) are lower quality than better wheels (which cost more). I use the Oregon, Tecomec, Total, or Molemab wheels. Resinoid wheels are also less likely to overheat the cutters.
- tap the cutters lightly, rather than for a sustained period; this is not a chop saw. If you took Morse Code training as a Boy Scout, use all '
dots' and no '
dashes'.
- practice on some scrap chains: intentionally overheat a cutter until it turns blue. Then work backwards to see how to prevent that on the remaining teeth.
Ground teeth can be a crap shoot to file, so the answer is YES grinding can harden chain teeth.
Operative word is '
can'. Does not mean the same as '
will'. '
Crap' is also an operative word when it comes to misinformation about grinders!
Philbert
