Double-ended edge finders

[ruralearl]

Hello, Thank you rklop & shred, learned something, never heard except the marv fingernail maneuver. Regards, Earl

 

[Bolster]

...approach one side of the shaft at a Z height such that the middle of the edgefinder cone touches the shaft surface. This will be at something like 30 degrees north latitude on the shaft, so to speak. When the cone "kicks" off to the side, zero the Z axis and whichever other axis is perpendicular to the shaft axis. Get clear of the shaft, move to the other side, get back to Z=0, then re-approach the shaft from the opposite direction. Note the reading on the other axis when the cone kicks. The center of the shaft will be exactly half the reading on this axis...

This is assuming DRO, correct? I assume that a humble manual user such as myself must factor in backlash...?

 

[mklotz]

I just mike the diameter of the shaft, touch off with the edgefinder, and then move (in the same direction) half the diameter plus half the edgefinder cylinder diameter. The cone isn't used and backlash isn't a concern.

 

[Bolster]

OK. That would be using a standard edgefinder at the 3 o clock position on the cylinder I assume. Should work well for smaller cylinders where you can get an edgefinder into the 3 oclock position.

 

[mklotz]

OK. That would be using a standard edgefinder at the 3 o clock position on the cylinder I assume. Should work well for smaller cylinders where you can get an edgefinder into the 3 oclock position.

The "other kind" of double-ended edge finder has the standard 0.2" diameter probe on one end and a 0.5" diameter probe on the other end. Since the body is 0.5" diameter, one can't get the 0.2" end to touch a large diameter workpiece but the 0.5" probe works just fine. Visualize it and you'll see what I mean.

 

[Allthumbz]

One thing that I find annoying is getting the edgefinder back together when the spring pops off. Someone tolf me to use thread to guide the spring through the center, but thread isn't strong enough. Anyone have any other tips?

Thanks,


Nelson
Hobby-Machinist.com