Automatic Brazing

Automatic machinery isn’t

Overheating embrittles steel

Saw blade ripped shoulders

I have just spent a couple of hours helping a gentleman in Canadawith a saw failure problem.   This is a sawmill and the shoulders are ripping off the saws.

They are using a Kaehny automatic razor with an automatic annealer.    These are good machines and they work well.

The problem that comes in is the meaning of the term automatic. They may run automatically but they still need some maintenance.

Over the years I have seen three problems with these machines.

The lens or cover over the heat sensor becomes clouded over due to the flux fumes. As it gets cloudy it lets less light through so the sensor reads lower. This means that the saw steel gets overheated and thus becomes brittle.

There is an induction coil and the induction coil is supposed to put the heat into the carbide saw tip. Often this coil will be moved or changed so that the bottom lines up with the saw tip that the top lines up with the saw plate. This can put too much heat into the saw plate. A simple solution to this is to spread the top part of the coil out so it is further away from the plate. It is generally pretty easy to gently bend the top of that coil out. If you bend it so that the top of the coil is about three times as far from the saw plate as it used to be then you have cut the amount of heat going into the plate 1/9 th.

The third problem I have seen is that the automatic annealor is set to restore the steel to the proper temper but it depends on the steel having been heated to the proper temperature during brazing or welding.  If the steel is overheated during brazing or welding then the dealer will still run the same cycle it always has. Because of steel is overheated the standard annealing cycle will anneal enough and the saw steel will still be brittle.

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