- Take lots of small taps to avoid overheating the cutters.
- Dress the wheel frequently to expose fresh abrasive.
- Practice on some scrap chain first.
Definitely agree with the last two, unsure about the first one.
Have chewed the fat over with a few guys about this many times
The theory is that on a chain the steel behind the hard chrome coating on a sharp cutter does virtually no cutting.
The majority of the cutting is done by the hard chrome plate covering the cutter edges which is not affected by grinder heating and this also stays very hard even under red heat, a bit like like HSS
IN practice filing does not sharpen anything, all it does is remove enough supporting steel under the Cr to generate a new hard chrome edge.
When a saw goes blunt this means the chrome edges have started to peel off further exposing the raw cutter steel underneath, which rapidly rounds over and makes increasing amounts of what is called cutter edge "glint" , and of course much powder.
Efficient sharpening effectively removes just enough steel to remove the "cutter glint".
To maintain a "glint-less" cutter top and side plate requires frequent touch ups.
Below shows an extreme example - it's a cutter from one of my full comp cross cutting chains after cutting a couple of hardwood slabs.
The what looks to be two top plate cutting angles is because this chain is mid conversion from 25º to 10º .
The lower part of the cutter edge with almost no glint has been filed several times at about 10º and the top part is the original angle that has been left at 25º
Over successive sharpening the 10º segment gets longer while the 25º segment decreases in size until it disappears.
The 25º segment has severe "glint" because the chrome plate has been peeled right back exposing the cutter steel underneath.
The 10º segment has about the glint I expect after a cut or two in hardwoods I mill.
BTW This also suggests that converting a cross cutting chain in this way is not as efficient as converting it by degrees, ie 25 then 20 then 15 etc so that there is always no glint right across the cutter edge.
Talk about nerdy chain stuff eh! I better stop here.
My mate who always uses a sharpener argues that overheating a cutter enables the Cr plating to peel off easier. Because I rarely use a sharpener I have not be able to assess his argument.