ID on Hilger and Watts level?

[J Tiers]

Picked up, for a very small amount of money, a Hilger and Watts "stride level" which appears to be in perfect condition.

The only model number for these I can find on the web is "TB.40", but there is no such model number on the level I have. There is a series number, and "O17S", which comes up empty.

Unit looks just like a TB.40, but.....

The only spec I can find, for the TB.40, is 0.0012" per 10 feet sensitivity, although this one seems not to be that crazy sensitive. Maybe the spec is given in a slightly different way.... as in the least error that is made visible.

There is only one hash mark, you match the ends of the bubble in a mirror arrangement similar to using a navigation sextant.




P.S. the sale was packed full of goodies.... Moore Special Tool end measuring rods, tons of indicators and other measuring stuff, gage blocks, 30" Cadillac gage, 2 lathes and a BP clone, pantograph engraver, etc. The deceased owner had been 60+ years in the trade, both employed and on his own.

[John Garner]

J Tiers --

The Brunson Instrument Company in Kansas City makes an "American cousin" of your level as their Model 187-S, and they make a pdf copy of the manual for downloading (no charge). http://www.brunson.us/p/ListManuals.asp

Brunson's longstanding claim is that a tilt of 1 arcsecond -- 0.001 inch at 17 feet -- away from the null position, where the ends of the bubble visible in the coincidence viewer are correctly aligned, produces a visible offset between the bubble ends. That supports your theory that the H-W sensitivity citation is not based on the more-usual "bubble displacement through one vial-graduation interval".

John

[J Tiers]

Thanks

That one is pretty similar in principle, but all the adjustments are done differently, of course. Luckily the units are fairly self-explanatory.

Same idea, minimum visible difference of bubble position, yes. With one mark, and a differential viewer, it can hardly be any other way.

I expect that this one is a 2 arc second unit, like TB.40, despite the lack of ID on it.

[jep24601]

Nice find!

[J Tiers]

Nice find!

it was at the St Charles sale last weekend.... the one that had "Enco mill" in the advert. The one that I almost didn't go to because the ad was so non-descriptive.

it was just sitting on the shelf, waiting for me to find. Just like the box of 30 Criterion and Bokum boring bars of various sizes.

ENTIRE garage and basement were stuffed to the gills with machines, tooling, more machines, more tooling, drawers and drawers of stuff, racks of stock, more tooling, more stock, more tooling, ......... measuring tools here and there and everywhere.

There were drawers the family didn't get into until the sale, because there were machines in front of them.

Fear not, they will have to have another sale.

BTW, the "Enco mill", which I assumed might be a mill-drill, was a 2 meter tall Bridgeport clone.

[Asquith]

Hilger & Watts were taken over by Taylor Hobson many years ago, and it may be worth asking them for information:-

http://www.taylor-hobson.com/