Retipping Sawmill Blades
An operator can do it in a pinch, but it's really a job for a specialist. August 31, 2005
Question
I need a fixture that will hold the carbide tip in place so I can braze it on. I have all the equipment except a fixture. I plan to re-tip my circular sawmill blades. Any ideas where I can find a good used one?
Forum Responses
(Sawing and Drying Forum)
It's a lot more complicated than just sweating a new tip on. The proper way to do it is to solder on an oversize carbide, then grind it down to the correct size with the correct angles. You can get your tips pre-profiled but I haven't figured out how to get them in the exact position. I'm a long way from the nearest saw doctor, so I was forced into doing it myself. If you're near someone qualified, that's the way to go.
There are a couple of different types of fixtures and tables available. They range from a lazy Susan type table to fixtures that allow you to adjust angles and clearances. The more advanced ones allow you to take a pre-ground tip, one that is already ground to precise tolerances, and braze it to the blade with even side clearance. I don't know where there are any used ones, but look for the word Accuground (as in Pacific Hoe's fixture) or "adjustable laying block" if you plan on using pre-ground tips.
From the original questioner:
I think I will stay away from the re-tipping fixture. I checked the run out of two blades and there is .016" run out on one and .020" run out in the other. I think a sawblade doctor could put them right on the money by grinding the tips after installed. I also feel there would be less vibration if the blade and tips are held to a closer tolerance. Does anyone know what steps a good saw doctor does to make a finished blade?
They would check the plate for flatness and tension with a straight edge and adjust it with either a stretcher roller, hammer and straight edge, or both. Then if the blade needed to be retipped, they would tip with a regular (unground) tip, then side grind, face and top grind so the clearances would be even. The smaller shops without grinding equipment use the pre-ground tips and a fixture so they don't have to side grind the tips - they face grind only.
