Micrometer - what's this second adjustment hole?

[Andrew Vanis]

Micrometer - what's this second adjustment hole?

.... And how does one use it?

Searched online without success. Tried things like "micrometer ratchet adjustment hole"

 

[KnurledNut]

Thats the locking nut for the thimble. The thimble is held in position by a tapered seat, clamped by this nut that is integrated into the ratchet stop.
To adjust, the spindle is held in a vise, nut is loosened, thimble is pulled to separate the taper, repositioned, nut is tightened. Fine tuning of adjustment is done with the other pin hole in the sleeve.

 

[Andrew Vanis]

Thats the locking nut for the thimble. The thimble is held in position by a tapered seat, clamped by this nut that is integrated into the ratchet stop.
To adjust, the spindle is held in a vise, nut is loosened, thimble is pulled to separate the taper, repositioned, nut is tightened. Fine tuning of adjustment is done with the other pin hole in the sleeve.

Thanks for reply...

Why reposition the thimble?

and what should one know about the screw at the end of the ratchet?

here are the parts you cited for reference

 

[KnurledNut]

Thanks for reply...

Why reposition the thimble?

and what should one know about the screw at the end of the ratchet?

The thimble can slip on the taper if forced and thus needs repositioned. Like when your co-worker uses your mic as a C-clamp.

The screw on the end of the ratchet stop is what holds the ratchet assembly/knob together.

 

[Andrew Vanis]

The thimble can slip on the taper if forced and thus needs repositioned. Like when your co-worker uses your mic as a C-clamp.

ahh. thanks.

So this guy didn't need to mill his thimble to see more of the 0 line and could have just adjusted the spindle/thimble relationship? (at 3:03 discussed and then 10:54 onto the lathe)

 

[Andrew Vanis]

The thimble can slip on the taper if forced and thus needs repositioned. Like when your co-worker uses your mic as a C-clamp.

ahh. thanks.

So this guy didn't need to mill his thimble to see more of the 0 line and could have just adjusted the spindle/thimble relationship? (at 3:03 discussed and then 10:54 onto the lathe)

....
I think I'm wrong and the guy in the vid is looking to adjust the sleeve/thimble relationship and that takes physical modification because there isn't an adjustment for that.

Maybe the spindle/thimble relationship adjustment would allow the user to move the 0 line on the thimble to be at zero elsewhere axially? ...like in plane with the frame, for example? ....or on the "other side" of the micrometer for left-handed users?

 

[The Cobbler]

So this guy didn't need to mill his thimble to see more of the 0 line and could have just adjusted the spindle/thimble relationship?

no, because that would throw off the calibration of the micrometer .