How do I use this darn bench micrometer!?

[The Cathedral]

We have a Starrett 673z bench mike (pic below.) Does anyone have a user manual, or any first hand knowledge of how to use it? The Starrett website say's it's useful for comparison readings within .00005", but I can't get it to repeat like that. It's got all kinds of doodads and woozles, but really just seems like an oversize micrometer. I'm sure I'm missing something. Any pointers? I know the knob on the left adjusts the anvil pressure from .5 to 3 lbs, or at least that's what it is suppose to do.

 

[chris m]

Squareness of the part to the gage is immensely important on that type of instrument. We don't have any of the gage you are showing, but we do use the Dorsey J2 Jaw Gage, which is the same basic idea but no micrometer adjustment.

 

Try a couple of things to see if you get better results:

 

1) Make sure the "foot" that the part sits on is in good condition, and parallel to the base of the gage, as best you can tell

2) Mark the "clock" position of the master, or part, you are measuring (we have a laser-marked line on the master which must be in-line with the spindle on the indicator when zeroing the gage) and make sure it is oriented the same way every time

3) I assume that the lever in front is for unloading the spring pressure of the indicator to take parts in and out. If so, "banging" one side or the other of the indicator swing throws off the zero on our gage. We need to VERY gently open the gage (but not enough to bottom the indicator), remove the part, and place the master back in to keep from bottoming the indicator going the other way. If we just let the indicator out to the end of its travel between parts, the zero is off.

 

May not help you, but that is my experience with similar stuff.

 

C

[FROZEN]

We use some thing like that to set bore gauges. They are Sunnen instead of Starrett.

[Matthew Hajicek - Singularity]

That gauge sucks, you don't want it.  Send it to me.

[chris m]

How did you make out?