Hello,
First be sure the problem is due to dullness. It may be that the blades have become too loose (clearance between them) or are not stroking enough to actually cut (broken or worn drive mechanism.
Please be advised a lot of these are simply not meant to last or be serviced. Yes there is such a thing as throw away equipment ment to be sold cheap and forgotten about. Generally, if the blades are rivetted, the system is meant to be completely replaced, not serviced. If the blades have gib bolts holding the blade assembly together, it means it is adjustable and it is possible to disassemble and sharpen or service.
You can sharpen both kinds, if you have at least a dremel type stone rotary sharpener and a lot of time, or if you have nothing to do for the rest of your life, you can try to hand file.
It is not adviseable, for safety reasons to try to cut on the side of a wheel, though this is the quickest way.
Sharpening consists of removing material, maintaining the cutting angle/relief on the cutting faces of each tooth, (without burning the steel which softens it if it becomes hot enough to turn straw color or darker), both front and rear. If the machine has cut into fence or guy wire, it may need a blade replacement. The next part of the sharpening is the reassembly and resetting. This is about as important as the sharpening. The blades must move reasonably freely, but with no flex or excess clearance between them. They should be oiled frequently.
Hope this helps.
Walt Galer
WE Sharpen It.com
walt and eileen galer, July 2005
