Friction Torque direction query

Tyler Hathaway wrote:

The scale, of course, just reads pounds.  It's multiplying by the distance from the center that makes it foot-pounds, inch-pounds, or whatever.

Absolutely! we need a force (kg, newtons, pound) and a datum length (mm, m, inches) to calculate a torque!

Byron, just one word of caution.  The force you are looking for is the one when it is actually sliding...not the break-away at the start of the movement.  Sometimes there is a slight stick at the start and it will drop a bit as it moves.  What we need to measure is the force of the springs against the dogs inside the gearbox.  If there is a very large drop from break-away to sliding it suggests that you may be developing a "pocket" at the ramp to dog position.  Some high time engines develop this and usually these will have complaints of vibration also.  Just my observations on high time gearboxes. 

Cheers

Well, but isn't static friction always greater than kinetic friction?

What would we consider as a "very large drop"?

Read the poundage as you pull through the entire arc. It may start at the very begining a tad higher, but as you pull through the arc it tends to smooth out. This also depends on the person pulling on the gauge not to be jerky. Just a nice even steady pull. It can vary a half pound or so as you pull from not being a steady pull. That said I usually do it 3 times just to make sure my number is good and I take the average. If when you pull through and the number is let's say 16.5 lbs. and it bounces a little up to 17 lbs. as you pull then pick the average of 16.7 or 16.8 lbs. Remember this isn't a critical absolute number. It just has to be within the normal working friction spec range. So if your final number in total inch pounds is off 5 -15 inch lbs it won't be a big deal.

So if you did it once and the result was 480 in/lbs and you did it again and it was 470 in/lbs it won't make any difference. It's just so long as you are within specs.