wizer":2bzr1lum said:
Maybe I am missing how they work. But if the digital gauge is not measuring the actual wood, then how can you rely on it being absolutely accurate?
I guess it depends on your fussiness or tolerances.
I have the JPT-260 BTW
No need to make a fuss about the accuracy of the digital gauge, it is no more or less accurate than the original dial system, the only reason for installing it is to avoid the need to bend over to overcome parallax.
The accuracy of either system depends on the accuracy of:
:the rise and fall leadscrew
arallelism of the blades in the block
:Block to bed parallelism
All this gauge does is measure turns of the handle. One turn of the handle represents 4mm of bed rise, and as long as you measure on the rise to avoid backlash issues, it is repeatable to sub thou accuracy. It is measuring the position of the table. So once you have set it for a given knife setting (which is easy to do), you get repeatability within the tolerance of knife wear. The difference between a blunt set of knives and a sharp set is much less than a thou or two, so achieving consistency to within less than 0.1mm is easy.
So as I stated above, you can easily thickness to 0.05mm accuracy.
Tom, where do you think there is inaccuracy in the method? After all, measuring the position of the tool / workpiece is the method that all lathes, milling machines, shapers etc. have used for years to yield accurate results.
I final thickness all my stock to 0.1mm over final dimension, then finish off with three or four sets of shavings with a hand plane.