Dial Indicator on Concentricity Gauge

[Filipson]

Hi. My name is Phillip. I’m new to this forum and a novice Reloader. Glad to be here.

I have a concentricity gauge with a Mitutoyo dial indicator just like the one in the picture attached.

The dial indicator in its resting position is at about the -0.0025 position. I was wondering if this is normal, and why the resting position is not zeroed? My thought was it is set at negative so when actuated with slight pressure on a case it will tend to adjust closer to zero. Also I understand it doesn’t really matter as I am looking for variation as the case is turned.

All of that said, I would still appreciate feedback as to whether it is common for a dial indicator to have a resting position slightly negative ... since these indicators are very expensive and would prefer to exchange it if something is not set to spec. Many thanks.

 

[dcali]

Can you not adjust the bezel and line the zero up however you like?

 

[Filipson]

Can you not adjust the bezel and line the zero up however you like?

The instructions do not tell me if and how I can zero the dial indicator. I thought to ask here before doing further research.

 

[chuckshooter]

in general, dial indicators are measuring in reference to a arbitrary starting point. when it is at rest it does not have it's first measurement to compare to. A dial caliber measures 0.0" to 6.0" like a ruler where there starting point is 0.0"
you would zero or spin the dial to zero once the first measurement is acquired

 

[arkcomatt]

Can you not adjust the bezel and line the zero up however you like?

He is correct, you can rotate to any starting position you want.

 

[dcali]

The instructions do not tell me if and how I can zero the dial indicator. I thought to ask here before doing further research.

You just rotate the bezel. The numbers will go with it.

 

[jsn]

Search Youtube with "zeroing a dial indicator" to see some practical applications of dial indicators.

Visual examples can frequently show what instructions can't or lack.

 

[ireload2]

You indicator is normal. I have used dozens of different dial test indicators over the last 50 years and they are all designed to have the needle about 1/8 revolution past zero. I bought my first Brown & Sharpe Best Test in 1968.

The rest position is offset for a reason.
1. You cannot judge contact without some motion or travel of the indicator needle. Without contact you will have some error due to lost motion.
2. That style of indicator is intended to be used with a mount or stand with a fine adjustment feature.
The fine adjustment allows you to contact the work piece and then move the indicator needle to zero. The dial can be turned orient the zero point to any place convenient.

In the linked video you can see the operator zero the indicator using the fine adjustment at about 17 seconds.

 

[Filipson]

You indicator is normal. I have used dozens of different dial test indicators and they are all designed to have the needle about 1/8 revolution off of zero.
The rest position is offset for a reason.
1. You cannot judge contact without some motion or travel of the indicator needle. Without contact you will have error due to lost motion.
2. That style of indicator is intended to be used with a mount or stand with a fine adjustment feature.
The fine adjustment allows you to contact the work piece and then move the indicator needle to zero. The dial can be turned orient the zero point to any place convenient.

In the linked video you can see the operator zero the indicator using the fine adjustment at about 17 seconds.

Thank you. I suspected this was the case. Glad to have the confirmation though. Thanks again for everyone’s comments.

 

[1066]

Also Phillip, I guess you are aware, that the little pointer bit is also able move. They are often quite stiff when new but do move ok.

At 2.30 minutes into this video I explain how the dial and the contact lever are adjusted.

Concentricity Gauge Needed

 

[Intheshop]

Go to Mahr Federal tech articles.They may not have "wrote the book" but dang,they're pretty close.