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jallml · ‎11-22-2018

Can't figure out what this is for. It seems custom made. the entire piece is non magnetic except for the big chrome permanent magnet inside. I think it is a neodymium magnet. I think it is an adjusting gauge for compasses but have no idea how it is used. any help is appreciated

ohnojoey · ‎11-22-2018

It's a dial indicator. I don't know how it is used in relation to that box. Is there a movable plunger under the dial in the box, maybe touching a movable bar or plate?

Federal Dial Indicator
https://www.ebay.com/itm/253957382343

https://www.ebay.com/sch/i.html?_from=R40&_trksid=p2047675.m570.l1313.TR5.TRC1.A0.H1.TRS0&_nkw=Feder...

Concepts of Alignment: Dial Indicator Basics
https://www.youtube.com/watch?v=r8VXU-lZnXQ

jallml · ‎11-23-2018

Thanks for the info. I just can't see how the magnet comes into play and what it is used for.

lacemaker3 · ‎11-23-2018

I agree, this is a dial indicator.

I think probably used as a probe indicator.

https://en.wikipedia.org/wiki/Indicator_(distance_amplifying_instrument)#Probe_indicator

I can't tell from the photos what details are shown in each of the views, so I can't get an idea of how the device works. But, I think the whole device would be called a check gauge. They are used to check the dimensions of a part as manufactured, to make sure that it meets the dimensions that were specified on the drawing. The magnet is probably intended to hold a part in place while it is being measured. Other parts of the device would be intended to make sure the part is placed and oriented correctly while being measured.

Check gauges are usually one-off items. They are designed and built specifically to check critical dimensions on parts.

ohnojoey · ‎11-23-2018

@jallml wrote:
Thanks for the info. I just can't see how the magnet comes into play and what it is used for.

I also thought the magnet was maybe to hold the box to a metal object but it looks like the magnet "floats" and the bar that the magnet is attached to pivots up or down according to the strength of the magnetic pull from whatever is beneath the magnet. The stronger the magnetic pull, the more the bar compresses the spring which in turn adjusts the tension on the probe from the dial indicator.

Would that make sense as a adjusting gauge for compasses? Or something else?

jallml · ‎11-23-2018

the magnet is split and runs from front to back. the split in the magnet will create 2 seperate fields.the plate with the hole is on the bottom so it must be placed on top of something for it to get a reading on the gauge. Any idea of value?