View Single Post
  #37   Report Post  
Posted to rec.woodworking
BoyntonStu BoyntonStu is offline
external usenet poster
 
Posts: 103
Default A walk-along circular saw plywood ripper.

On Apr 15, 6:59 pm, "Greg O" wrote:
"Greg Neill" wrote in message

m..."BoyntonStu" wrote in message





On Apr 15, 9:04 am, "Mike Marlow" wrote:
"BoyntonStu" wrote in message


...


Imagine a short handled wheelbarrow,


Compared to a longer one, less torque at the wheel applied by the
operator.


Imagine a long flimsy handle on that wheelbarrow. One single long
flimsy handle...


--


-Mike-


Why imagine long and flimsy?


A 4 foot 2x4 is not long or flimsy.


Imagine 2 crowbars: one 4" long, the other 4 feet long.


Which one applies the most torque?


The hold-down torque is applied about the handle fulcrum point located
at the rear of the saw plate.


No, the torque is applied at your wrist. You rotate your
wrist to rotate the 2x4, supplying the downward force on the
saw which is at the end of the 2x4.

Look at it the other way around. If, for whatever reason,
the saw wants to jump up, it has the mechanical advantage
due to the length of the 2x4 to twist your wrist about
its pivot point at the end of your arm.

Have a friend come over. Take a 6" long stick in your hand and have your
buddy try lever it back and forth in your hand. Now take a 4 foot long
stick, hold the end of it, and your buddy on the other end, and have him
lever it back and forth, then get back with us on which one takes less
effort for you buddy! (in this example your buddy equals the saw!)
Greg


The stick in my hand is the saw in the slot.

You have it backwards.

Consider a shovel with a short handle to dig a hole? No way.

YOU use the long handle to increase YOUR torque on the shovel head.

In a like manner you use a long handle to keep the saw in the groove.