Blade direction, how was it designed?

[brooks]

Why is it that portable circular saws cut "up"? I can see the logic of a table saw cutting downward - it helps press the material against the table, which seems like a good idea. So why do portable circular saws cut upward? Do all circular saws cut the same? Do some run "backwards" on the shaft, clockwise?

[Stytooner]

They all cut basically the same way. It is your perspective that is inverted with a circular saw.
The base plate serves the same purpose as a table on a table saw. It provides a surface for the stock to run against. Both cut toward the table or the plate.

[LarryG]

Both cut toward the table or the plate.

And if the motor ran the other way, you'd have to turn the blade over so the leading edges of the teeth will be facing the right way. Otherwise, it wouldn't cut -- although the backsides of the teeth might beat the workpiece into submission .

If you held your CS backwards and pulled it toward you as you made a cut (NOTE: I am NOT suggesting anyone try this!) it would be essentially the same situation as a saw on which the motor turned the other way. IOW, nothing would be changed, except probably the operator's safety (i.e., safety would be diminished).

[mschrank]

And if the motor ran the other way, you'd have to turn the blade over so the leading edges of the teeth will be facing the right way.

And if you did what Larry describes, it seems you'd have a hard time controlling the saw. It would basically become a 12-15 amp motor with a spiked wheel pulling away from you.

Same basic principle applies to routers...which is why feed direction is so important.

[crokett]

Same basic principle applies to routers...which is why feed direction is so important.

Yup. I got a good education on climb cutting after I sent a piece of wood flying across the shop with my router some years ago.

[brooks]

The base plate serves the same purpose as a table on a table saw. It provides a surface for the stock to run against. Both cut toward the table or the plate.

Now I get it. This put the right picture in my mind. The saw's plate is acting as the table and the blade runs in the direction which presses the material against the table.