What is this Starrett Gage for?

TGTool · Mar 18, 2014

Someone I know asked me about this gage, which someone gave him, but he doesn't know what it's designed for. My first thought was a cylinder gage, but on second look I'm not so sure.

The indicator is a tenths reading head with .025" travel. The head also has two spring loaded buttons adjacent to the plunger. In the right end of the case is a foot which has the rim on the bottom relieved to leave three feet and the rods fit into the foot and the top of the gage head. Since the rods are in roughly half inch increments it can't be general purpose since there's not enough travel. In addition, the two spring buttons are flat faced, not rounded so it wouldn't adjust to a bore. Jig borer setup and rods maybe?

aerodark · Mar 18, 2014

Sure looks like some kind of bore gage.

bjorn toulouse · Mar 18, 2014

Is there a Starrett number on the indicator case or on the wood box?

Rex

rivett608 · Mar 19, 2014

Kind of looks like a modern version of their old strain gauge.......

jkruger · Mar 19, 2014

Bore gage set? Are you sure one end of the stems is not radiused?

TGTool · Mar 19, 2014

Can't be a bore gauge. First clue is that the spring loaded feet on either side of the indicator plunger are flat, in line, and protrude past the plunger end. So the gauge has to be pressed down to register and won't accommodate a curve. Second possible clue. A rod in the opposite end also isn't radiused, and if the foot component is added you've got a wide flat surface opposite the plunger.

I didn't see a Starrett number but I should look more carefully when I'm back by there. In fact, I'm not sure I remember a Starrett name on the box so it might be a third party product using a Starrett gauge.

TGTool · Mar 19, 2014

rivett608 said:
Kind of looks like a modern version of their old strain gauge.......

Hmm. The spring pads might be calibrated springs such that compressing to a gauge zero equates to a certain force? That might be possible. The tenths indicator doesn't mean tenths, just that over a short distance spring compression force changes a lot. I'll consider that.

manualmachinist · Mar 19, 2014

I’m thinking a gauge to check parallel of two surfaces. Maybe even made for a machine tool builder.

WizardOfBoz · Mar 19, 2014

No idea, but I'm thinking the grooves on the rods, at different distances, are a clue. Any idea of what they are there for?

allloutmx · Mar 19, 2014

Lets get a pic of the back of that gage please.

Three pads on that base makes me think that its trying to sit flat on something which would be relevant in checking height/depth.

Another guy here was thinking it was to measure travel on the old manual masheens

Chris Lesiak · Mar 19, 2014

bosleyjr said:
No idea, but I'm thinking the grooves on the rods, at different distances, are a clue. Any idea of what they are there for?

I suspect those are joints where shorter rods have been screwed together.

dgfoster · Mar 19, 2014

bosleyjr said:
No idea, but I'm thinking the grooves on the rods, at different distances, are a clue. Any idea of what they are there for?

Is that misprint saying the rods differ in length by .500 and not .050? I would have thought the grooves were a simple code for x, x+.050, x+.100, x+.150, x+.200 The spring loaded plungers could push a gage block onto a given surface further increasing the measuring range of the device. Must measure two parallel flat surfaces and most likely horizontal planes--like the distance "between the floor and the ceiling." The round three-footed pad goes on the "floor."

Denis

Marty Feldman · Mar 19, 2014

All speculations will change to a definite identity when you find the Starrett item number.

Krutch · Mar 19, 2014

Starrett tools have an ID # on them somewhere. Find it and contact Starrett for tool use.
Could it be a depth gage?

Nmbmxer · Mar 19, 2014

Do the rods fit into the back? It looks like it could be a squareness checker, the indicator could mount in 1/2" increments above base and the spring pads could square the indicator to the surface being checked in reference to the round base.

Red James · Mar 19, 2014

I don't think that is a Starrett gage, just a Starrett indicator. What does this look like when you assemble it? Pic?

TGTool · Mar 19, 2014

Well, I ran out today and looked a little more without getting a lot more illumination.

The box is clearly printed Starrett on the top but no other markings on sides or bottom.

The back (or sides) of the device doesn't have any number either but here's what the back looks like. Spring loaded pads on either side of the plunger are flat and protrude past the plunger so have to be compressed a ways before the indicator registers.

This is what the foot looks like on the underside for whatever that means. At the least it's intended to register on the face of something.

Some people asked about grooves in the rods. It's actually different length rods stacked in the case. I pulled a couple to look at the ends and that's interesting too. They're not ground or lapped. Flat ends with some showing vestiges of turning marks so there's no precision to them, just spacers somehow.

I don't know anything about the force gauge referenced in an earlier post but the high precision indicator coupled with the low precision rods suggests measuring something other than actual length. It's possible too that since it seems to be assuredly a Starrett product but doesn't carry a number, it might have been specially produce for some mfg but was never a catalog product.

manualmachinist · Mar 19, 2014

TGTool said:
Starrett product but doesn't carry a number, it might have been specially produce for some mfg but was never a catalog product.

I'm with you on this. I still think it was to check how parallel two surfaces were to each other. Could have been built for a machine builder. The fact that the rods are not ground or lapped makes me think it was only a reference and not intended to measure an actual dimension.
I hope you are able to find out what it is, I'm curious.

Modelman · Mar 19, 2014

I may be way off base here, but is this a setup for a positive displacement indicator on a machine table, similar to what jig bores used before the days of DRO's? It seems the indicator could be held in a stationary fixture by the spring plunger pads, while the rods went through a hole to a target mounted to the table; the rods being added of subtracted for distances greater than the indicator travel.

Dennis

Jared · Mar 19, 2014

Dang i was hoping the mystery had been solved by now.

Hoping someone pops in and can answer this for sure.

What is this Starrett Gage for?

Titanium

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