Is there some reason for the hardness variation in chain cutters and gauges?

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ham

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It doesn't seem to matter the brand or size... sharpening a chain and it seems like there is a pretty big variation of how hard the cutters and depth gauges are. Some insanely hard, brand new file skates across it. Others seemingly super soft. Even the stihl chains have noticeable variation. This must be intentional. The hardening process is very precise. Is it to allow some stretch to the chain, to have some links softer? Some other reason?
 
Grinding (as in sending out) or perhaps striking something is what I attribute file damaging hard to. Just a bit of grinding gets to fileable tooth. It is rare and one tooth only, recently enough to remember.

The depth gauge is the front of the cutter. Sometimes they seem a bit hard for raker files. Maybe due to punching the parts out. I have a square file, somewhat coarser that usually works better.
 
I’m pretty experienced at filing metals and have noticed this on brand new chains as well as ones down to the wear mark. Stihl, Oregon, carton and across different gauge chains. I don’t think it’s an oil thing. Seems like if it had to do with the way they were punched or ground it would vary as the chain is worn and the slight surface hardening is filed away. What’s odd is all chains have the same 1 in 10 or so random cutters or depth gauges that are super hard. Who knows maybe they harden them in a pile, ones at the top of the pile get more heat. Ones in the middle of the pile are soft.
 
Been wondering about this question for years. Been using Woodland Pro chains from Bailey's and my chains never see a grinder, so it's a factory issue before I ever touch file to chain. Curious thing.
 
I’ve only noticed this on cheaper chains. Stihl are all hard but workable, then Carlton is pretty hard too, then Oregon much softer but uniform.

Trilink is good for having a few nearly un-fileable teeth in every loop.
 
I’ve only noticed this on cheaper chains. Stihl are all hard but workable, then Carlton is pretty hard too, then Oregon much softer but uniform.

Trilink is good for having a few nearly un-fileable teeth in every loop.
What prompted this was that I recently had to sharpen three brand new stihl loops. Yellow .325, yellow 3/8lp, green PMM .043. All three had the super noticeable 2-3 links that were file skate across hard. It isn’t as noticeable as Oregon but there’s definitely a difference. If anyone has the mohs hardness test kit I would be super curious what they find next time they sharpen a chain
 
Post covid QC issues maybe?

Maybe, but I've definitely noticed this pre-covid even with Stihl chains. I almost only run stihl chains and buy them new
 
It doesn't seem to matter the brand or size... sharpening a chain and it seems like there is a pretty big variation of how hard the cutters and depth gauges are. Some insanely hard, brand new file skates across it. Others seemingly super soft. Even the stihl chains have noticeable variation. This must be intentional. The hardening process is very precise. Is it to allow some stretch to the chain, to have some links softer? Some other reason?
I also found the depth gauges were miles out, both low and high on new stihl chain. Disappointing seeing the cost of a loop...
 
Sometimes we inflict our own pain by overheating the chain & then spraying it cool with WD40 or a water sprayer, because GBar is too hot to touch.
No wonder we can't get the file to make the right noise, while hand filing. ❓
 
I was sharpening a few chains this week (40 or 50 altogether) and found one in particular, Stihl manufactured, that the depth gauges were inconsistently hard. It seems to be a very surface effect, once I got the fist swipe with the file the rest of the way was fairly normal. I have seen this a number of times; in my experience anyway is always seems to be limited to the surface and once you make a swipe of two with the file the rest is pretty normal. I always attributed this to some work hardening or case hardening effect from working the chain or getting it hot then quenching it either in the air, the snow, of the nice damp soil behind the log.

Mark
 

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