A huge dial indicator. Why?

[luke8888]

Some time ago I found this nice German made 1micron resolution +-100 microns scale NOS vintage dial indicator on a local ad site. I bought it after seeing a blurry photo without any obvious indication of its size expecting a normal indicator. Imagine my surprise when it arrived and it turned out its face is approximately 5in in diameter and the mounting stem is about an inch thick.

I'm pretty happy with it, but I've always wondered why? Why make a huge/expensive version of a dial indicator that requires a special rare stand when there are plenty of smaller ones just as precise and with larger ranges? It is far too nice to be a "production line QA device" made big solely for the purpose of better visibility.

I happen to have a very precise microkator stand (with a 3 point mount table, mirror lapped flat, flexure adjustment down to fractions of a micron) and a microkator that uses the same thick stem. Both are old Soviet made so I assumed this mounting system to be some old Soviet standard. This indicator fits the stand so I took few pictures on the stand. Perhaps it is a German standard soviets copied?

Also wearing the table on such a precise stand by using it with a micron resolution indicator seems a waste. I might 3d print a cover for the table.

The knurled cap in the middle screws off and there are a series of holes there that fit a kind of key attached that sets two red arms. I have no idea what the knurled thing on lower right does. One would expect it to be a face rotation lock, but no. The face doesn't rotate. It appears to be an access port of some sort held on by a tiny screw with a bit of white paint on it. Perhaps calibration adjustment?




The clip visible next to the (changeable) tip is there to raise the indicator to a predetermined position to aid in swapping parts to be measured.

As far as I can tell the tip is normal hardened steel. No carbide nor sapphire, like on microkators.

I also have a box and the paperwork that came with it. I can post photos if there is interest.

I'm mostly interested in finding out where these were used originally. Why were they made?

 

[guythatbrews]

The reason for the big dial may be as simple as having enough room to easily see +- 100um without having to resort to a revolution counter. Maybe the dial lower quandrant isn't used because it is harder to read. Makes a little sense if this was used all day by some poor person in a factory. A smaller dial, more fatigue.

I like it. Looks like a nice piece

 

[Bakafish]

I have one of those, re-badged as a Mitutoyo. The dial on the side actually is a zero adjuster, but it uses a rubber wheel which has either dried up or fallen off on yours. The red arms are adjustable by removing the center cap, they are just go/no-go markers. The size is because these were used on both big machines and inspection stations and the large dials make them easier to read in both cases, the inside is mostly empty, they could have made it a lot smaller if they wanted to. They were made in East Germany IIRC from the 50's to the 70's and exported pretty widely. I'll find the name of the OEM ( Feinmess Suhl GmbH ), but request you make a zip file or pdf of the paperwork you have so I can put it with mine.

 

[luke8888]

I have one of those, re-badged as a Mitutoyo. The dial on the side actually is a zero adjuster, but it uses a rubber wheel which has either dried up or fallen off on yours. The red arms are adjustable by removing the center cap, they are just go/no-go markers. The size is because these were used on both big machines and inspection stations and the large dials make them easier to read in both cases, the inside is mostly empty, they could have made it a lot smaller if they wanted to. They were made in East Germany IIRC from the 50's to the 70's and exported pretty widely. I'll find the name of the OEM ( Feinmess Suhl GmbH ), but request you make a zip file or pdf of the paperwork you have so I can put it with mine.

Wow, it is the same one, just branded Mitutoyo. Very interesting.

I thought there was a booklet with it, but I confused it with another item. So sadly "the paperwork" is just a warranty note in pdf attached :-(





I'm also attaching few pictures of the box.

 

[Bakafish]

No worries. At least you have a wonderful stand for yours. I 3D printed a bracket so it can mount to an old Nishimura Jig squareness comparator stand, it's not functional, just for looks. I love the clean German design.

 

[ballen]

I have a handful of old KS (Feinmess Suhl GmbH) measuring instruments including some 1 micron resolution passameters and 1 micron resolution inside bore gauges. The quality is outstanding. I have taken several of them apart over the years because they were sticky. Removing the varnish inside (oxidized oil) and relubrication fixed them. IMO they are in the same class as Compac, Tesa, Mitutoyo and similar. The people who made them were aiming for "as good as we can make it" rather than for a price point.

 

[sfriedberg]

Dial indicators with 3" dials (for easy reading) are still a thing. For a 5" dial, I tend to think of odd scenarios: Paranoid supervisor wants to look over the shoulder of the QC guy without standing right there. Front of classrom for group instruction. Or, maybe just for really easy reading.

 

[Luke.kerbey]

Metrology tools are also but not as commonly known as

“Distance amplifying equipment”

Having a larger dial increases the distance the needle tip moves in relation to the stylus displacement compared to a smaller dial. Therefore increasing the overall resolution.

Increasing the actual accuracy on the other hand, that’s another discussion.

 

[Bakafish]

If you take the virtual tour in the Mitutoyo museum I linked to, the sharp eyed amongst you can see these mounted on actual machines and understand why being this size was helpful in the days before consolidated digital displays. The virtual tour is really well done I think, worth the time.

 

[luke8888]

If you take the virtual tour in the Mitutoyo museum I linked to, the sharp eyed amongst you can see these mounted on actual machines and understand why being this size was helpful in the days before consolidated digital displays. The virtual tour is really well done I think, worth the time.

I did :-)
Thank you for linking to it. I think you're correct they were made like that for ease of visibility of the entire scale and to see both at the same time (no need to lean over one etc).

I found this one for example :