my first starrett

[kd0afk]

I just bought what appears to be an 81-136. It has a huge post on the back. I took the back off because it's sluggish and the thing is emaculate. I will go over the pinions with alcohol to see if that works but does anyone have one of these? It also has a removable cap on the top covering the top of the shaft. Is there supposed to be a spring in there?

 

[chipenter]

No springs outside the body on those , there is what looks like a clock spring attached to a pin on the rack , after cleaning oil with the lightest machine oil one drop is to much , use a needle and wipe it on the side of the bottle before rubbing the oil on , it goes a long way .

 

[GWRdriver]

The alcohol could free it up but it could also leave the mechanism dry. I think I would take it to a jeweler and have him dunk it in his hydrosonic cleaning tank and then put watch oil on the pivots.

 

[kd0afk]

The local jewelers was already on my list today. I also bought an x825a but it hasn't come yet. It looks like a meat thermometer, I guess that would be called a back plunger type. Can't wait to see how well it works.

 

[TroyO]

That cap may (??) be a kind of air dampener... I have one with a similar cap and it acts to smooth out the dial a bit.

 

[kd0afk]

So i took it to the jeweler to have it cleaned. He said he couldn't do it because it would require him to dissasemble it. So he put a drop of oil on the shaft and sent me on my way.
He was on the other side of the counter but I swear to god i felt him pat me on the head as I left.
I HATE SMALL TOWNS.

 

[Swifty]

The cap comes off to allow the fitting of a lift lever.

Paul.

 

[old-and-broken]

If you've disassembled it, you may have lost your 'preload' on the spring.

The dial pointer will jump around and not always return to the same point and may seem bouncy.

The solution is to rotate the dial hand 1 or 1.5 turns before the rack is engaged with the face plate. The spring tension keeps the rack and gear engaged with a small counter force and the dial will seem rock steady with no bounce.

This is the proper way to set (most)Dial Indicators that have a pancake type spring driving the dial.

To much tension, or not enough in any of the internal springs will affect overall linearity of the indicators, but this fault, while not accepted by calibration standards would not prevent using the indicator for transfer or centering jobs with proper accuracy.

 

[kd0afk]

Haven't taken it apart, only took the back off.

 

[GWRdriver]

kd et al,
The purpose of the cap is to cover the hole to keep the dirt out.

The Hole (ie, the boss and the mechanism inside) on the other hand is there for two reasons. The first is to provide a protected slideway to allow the indicator shaft to have straight-through support, two bearing points, to eliminate shaft deflection which would affect the mechanism and thus the reading. The second, on some models, is to provide an attachment point for a lifting lever which is used to raise the stylus and bring it to rest gently. Some DTIs also have accessory styluses (styli?) which attached at this point so that a deep internal or poorly accessible reading can be taken at 90° to the DTI axis.