In this book, page 50 starts with the newhouse traps. Has anyone noticed any discrepancies in jaw sizes listed? Also, it lists the 4.5 as a 8" jawspread but i always thought it was 8.75"?
Kinda new to this, thanks.

Not familiar with that book but here's a pic of 4 1/2 jaws with the tape measure. (Easy to picture with the springs removed). I suppose the measurement depends on inside or outside jaw spread.

I just measured the jaw spread on my Newhouse traps for the first time. They are all OC traps measured at the base of the trap when not set. Here is what I got.
#0 - 3"
#1 - 3.5"
#1.5- 4.25"
#2 - 4.25"
#2.5 -4.875" also #21.5
#3 - 5.125"
#4 - 6" also #14,#44,#48
#3.5- 6.5" also #31.5
#114- 6.5"
#4.5- 8"
#50 -9" also #150
#5 - 11" also #15
#6 - 14.5" I measured a 41AX because I don't own a NH #6

Pat tc,
That is the way I would measure. And the Newhouse #6 is 15.5".

Glad to here that, Snakecollector. No way I'm going to set all those traps to measure them on the other axis. My 41AX is also 15.5, I just typo'd it. Here are some more Newhouse fun facts about the springs.
I measured the springs from the end of the eye to the bend. End to end. Here is what I have measured.
#0 4"
#1 5"
#1.5 5.75" also #2
#3 6.75"
#4 7.25" also #2.5, #21.5, #3.5, #31.5, #14, #44, #48
#114 9" also #4.5
#50 10.5" also #150
#5 13" also #15
#6 ??"
This is only what I have on my own traps, I could be off a little on the exact measurements.

Pat tc,

#6 Newhouse, machine springs are 16.5". Of course trip hammered springs on slick pans and Community traps will very in length, mine are 17.5" to 18.75".

This is some good info! Thanks

I have a #4 user with a (dont shoot me) PIT pan on it that i use for beaver.

Interesting opinions on measuring jaws spreads. As a trapper I always measured to the business parts of the jaws with the trap set. But I can see for the collector the measurement along the base would be easier and the trap needn't be set.
Makes me wonder now how the manufacturers come up with their measurements....

When trying to determine the jaw spread of a trap, I would think that the correct measurement would be the largest, inside measurement obtained when measuring in-between the jaws, with the trap in the set position. That measurement can be obtained without having to set the trap. JMO