What’s this for…no.9?

[beeza650Participant @beeza650]

Is this some sort of freebie or another apprenticeship part. Given the J.H.GRANT ERITH engraving I’m guessing the later.

This isn’t really a what’s it for post but I was on a roll. Thought it might be interesting though

[Roderick JenkinsParticipant @roderickjenkins93242]

Its a lever test indicator.  Each division is 1 thou. Cheap and cheerful device for setting up material to run true.

Rod

[Nigel Graham 2Participant @nigelgraham2]

It is indeed a lever test-indicator and commercially made, not an apprenticeship exercise.

Mine too, is stamped The Unique; also, on the opposite side, Pat. No. 23947.1.

The additional stamping on yours was probably an owner’s name, perhaps a company rather than individual.

Whether they were ever given as “freebies”, I have no idea. More likely they were issued to turners in jobbing-workshops.

……..

A digression…

My evidently not-unique ‘Unique’ lives in a little tin, just the right shape and size for it.

The tin is itself a museum-piece. It once held tobacco or (as it so small) even snuff.

The underside is heavily stamped DUTY FREE HM SHIPS ONLY. Was my little lever-indicator once used in the “tiffy’s” workshop below-decks? It is not “crow’s-foot” stamped.

The lid is printed with the Royal Coat of Arms and the legend By Appointment Tobacconists To H.M. The King.

Which king? George VI, perhaps? His reign ended in 1952 when he succumbed, aged only 56, to lung-cancer.

[Nicholas FarrParticipant @nicholasfarr14254]

Hi beeza650, just as Rod has said. These were a commercially made produce back in the 50’s, and my father had two of them, but I only have one, the other one was lost many years ago.

Regards Nick.

[SillyOldDufferModerator @sillyoldduffer]

Having identified it, next question is, “do I need one?”

Maybe, probably not.

These days we’re spoilt rotten because Dial Test Indicators are affordable. A century of improved manufacturing technique has progressively reduced the cost of making them, unless you want the very best.  DTI’s were horribly expensive when this device was invented because they contain precision gears;  a good one would have a jewelled movement and other refinements.   More like a Rolex than an egg-timer!  Expensive and delicate, to so not ideal in a jobbing workshop.

The purpose is to centre work in a chuck or faceplate.  Victorian turners often did this with a piece of chalk held at a fixed distance from the rotating job, which marked the off-centre high side.  Never tried it!  I think practice required, and not particularly accurate.    When better was needed, a lever was mounted in the tool-post, with the short end resting on the job.  When an off-centre job rotates, the lever wags, and the turner tweaks the work-holding to eliminate it.   More accurate than chalk, but takes time plus skill and judgement.

The UNIQUE device is faster and easier to use than chalk or lever because the needle measures how far off centre the job is.   The turner can halve the error, which is semi-skilled and quick.    The problem is accuracy; the device is good enough for ordinary work like reducing a rod to size, but less suitable when set-up accuracy is critical, as when an existing part is skimmed, and the new surface must be concentric with existing surfaces.

Now that DTI’s are affordable, most of us own one, and use them to centre work rather than the alternatives.   Even a cheap DTI is more accurate than a UNIQUE indicator.   Three-jaw chucks centre round work automatically, so perhaps the most common need is centring in a 4-jaw chuck.  These are extremely versatile, but work has to be centred in them manually.   With care and a DTI, 4-jaw chucks can be centred more accurately than a 3-jaw,  which is often useful.   Ditto faceplates, but I’ve only needed to use mine twice in 10 years.

If Beeza’s collection includes a working DTI and stand, his UNIQUE becomes a bygone curio.   But useful as a standby, or it might save buying a DTI and stand if they’re not used much.   That depends on what the lathe is used for:  many turners do everything they need with a 3-jaw chuck, and don’t need a dial or UNIQUE at all.   I guess 80% of my jobs are held in a 3-jaw or collet, and my DTI only comes out when the job calls for a 4-jaw.   Those who have the knack of centring 4-jaws quickly, or have to turn odd shaped jobs, often use nothing else – as I said 4-jaw chucks are versatile!

Another comment: with older tools it can be difficult to tell the difference between apprentice pieces, DIY, and manufactured.  In this example the give-away is the UNIQUE stamped brand-name and other markings.  Otherwise the device itself is crudely made down to a price.  That doesn’t matter, there’s no need for it to be well-finished and it’s robust.  Functional, not pretty.  Could be home-made if need be, probably cheaper to buy one.

Beeza’s collection is a rich mixture of manufactured tools, home-made, and dismantled parts.  My workshop  is similar – whoever inherits it will be puzzled!

Dave

 

 

[Michael GilliganParticipant @michaelgilligan61133]

Please forgive the digression … but Sunday morning is a good time for exploration of rabbit-holes: here’s a Starrett patent for something broadly similar, but more sophisticated

https://worldwide.espacenet.com/patent/search?q=pn%3DUS1953028A

MichaelG.

[Nicholas FarrParticipant @nicholasfarr14254]

Hi, I compared the Unique one I have against a Mercer dial indicator once, and was surprised who accurate it is, and they are small enough to get into fairly restricted places.

Regards Nick.

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