sharpening

[treequip]

Cracking of the hard coating isn’t much of an issue, most saws get sharpened (at least a tickle) several times a day and in arb it’s often more likely that any sharpening is needed because the saw hit a foreign body.

 

Precision grinding of machine tool cutters is usually done with the benefit of a coolant, most positively drown the cutter in coolant, chainsaw grinders don’t boast such refinement, some of the cheaper ones barely boast a decent fit and finish.

 

I can’t say I have noticed chainsaw files differ significantly from any of the many standard bench files I have come across.

[skyhuck]

 

I can’t say I have noticed chainsaw files differ significantly from any of the many standard bench files I have come across.

 

They are extremely brittle and can be snapped with ease.

[tommer9]

near factory sharp finish.

 

I ALWAYS sharpen a new chain straight from the box.....I wouldnt WANT a 'factory sharp' finish as its not sharp enough....

 

I have never met a professional cutter who thinks grinding is quicker or even better.

 

Quite.

 

Well that bit about hardening is somewhat testicular, over heating a cutter will harden the steel and since it is harder it probably won’t blunt as quickly but sharpening it with a file will be near impossible.

 

If you heat steel and quench it, it goes from soft to hard, if you heat hard steel and let it cool slowly it goes soft, try heating a spring and quenching it - it will probably shatter if you compress it!

 

The terms to read up on are hardening and annealing!

 

I have just spent ages on a 26" full chisel that someone had run on a badly worn bar - all the cutter tips were buggered - had to take about 1.5mm off each cutter - it took a while on a grinder and think I would have still been sharpening if I had been using a file.

 

Not saying it can't be done but not a 5 minute job - not by me anyway - how badly damaged is "badly damaged"? Mine was a real mess!

 

I put a new chain on a 390xp running a 28" bar 2 weeks ago, full chisel, and hit an iron bar, making the chain look like a ripping chain...About 15 minutes, ON SITE was all it took to get it flying again.

 

They are extremely brittle and can be snapped with ease.

 

Indeed.

[spudulike]

Prehaps we should start a new post on how to sharpen chains for people that don't know, I buy in and refurb saws, I have seen many faults in peoples sharpening - lack of understanding what a raker actually does is a common one, I have seen them not filed at all which means the chain cutters have the top surfaces polished off.

 

I have seen then filed too much giving a very snatchy chain cutting action.

 

Sharpening the cutters at to acute angle is another - 30 degrees is about right for majority use but many less experienced users find it difficult to file the cutter tip and end up over filing the end of the chisel.

 

Loosing the hook of the cutter is another fault that I have seen - using a bar with too much roll overwearing full chisel cutter tips is another.

 

My grinding experience partially comes from working with hard and soft press tools in 60 ton presses and watching the tool makers regrind them - no coolant needed but the grinding was done on a moving bed and stationary wheel - the coolant was used on the lathes and mills in use at the time.

 

Experience has taught me how to keep the grinding heat down and have a novel way on dressing my grinding disks - my first picture on my earlier post was about the worst I have seen - the chain is in a poor but salveagable state.