How to correctly read a .0005 res test dial indicator?

[ome]

How to correctly use a .0005 res test dial indicator?

Trying to bring buck adjust tru to .0005 , Hi reveryone,
could anyone tell me what is the value of each line on the dial face of a B & S test dial indicator 599-7031-3 with a measuring range of .030" and 0-15-0 marking on dial face 1.5" dial face
I am showing on the dial when i turn the chuck with a test bar of 12-13 lines away from zero
on a .001 res test indicator it showed 1 thousandth off zero

also need to know absolute most rigid way of putting in lathe tool holder?

thanks for all your help
jon

 

[Bill Gruby]

I believe you have mastered this one already.

"Billy G"

 

[dbird]

Re: How to correctly use a .0005 res test dial indicator?

could anyone tell me what is the value of each line on the dial face of a B & S test dial indicator 599-7031-3 with a measuring range of .030" and 0-15-0 marking on dial face 1.5" dial face
I am showing on the dial when i turn the chuck with a test bar of 12-13 lines away from zero
on a .001 res test indicator it showed 1 thousandth off zero
jon

I recently went through something like this with my DTI (reads 0-4-0). To me, a neophyte at this, the answer was only obvious after I figured it out. The way the DTI is designed to be used is to first place it in contact with the work, then set the zero at that point. At that point, the zero is the reference point. The DTI can potentially read either way from there. When the pointer swings CW, the displacement is positive toward the plane of the dial, when the pointer swings CCW the displacement is away from the plane of the dial. Easiest way to get a direct feeling for this is to just push the probe both ways and see which way the pointer swings.

What you have to watch out for in setting the zero reference is that you may run out of the range of the DTI. It is not always obvious when the probe is not in contact with the work or whether the probe is maxed out at the end of its range. For measuring runout in a lathe, I just adjust so that I get a total swing of the pointer that is well within the range of the indicator. You have to watch the indicator during setup to see where the needle swings from and to in order to get into the measurement range of the DTI. For traming or similar it can get complicated and very confusing.

From what you describe, your DTI is reading 12-13 mills away from a zero reference point that has not been set. In this case what it is telling you is that the total runout is .001 mill (.013-.012=.001).

Hope this helps.

Dave