What & how to use them

[DellParticipant @dell]

I think these are for measuring a taper but not sure , has anyone got any ideas as to what they are and how to use them.

Dell

[peak4Participant @peak4]

Is this patent of any assistance?

Bill

[Pete RimmerParticipant @peterimmer30576]

I suspect you are right though it would be easier to tell if they were rotated so we could read the engraving. What does the paperwork in the lid say?

 

[DellParticipant @dell]

Thanks peak4 that is somewhat helpful.

the two extra pictures are largest & smallest slid out showing the tapered shafts.

Pete the paperwork in the lid is just protecting paper but I have taken a couple of other pictures and they are calibrated in inch.

[Robert Atkinson 2Participant @robertatkinson2]

Look more like small hole gauges than taper. Taper measurement requies two points of measurement. Also units are an angle, percentage or diffence per unit distance e.g 0.002″ per inch.

Do the markings on the scale correspond to the diameter of the pin?

[Robert Atkinson 2Participant @robertatkinson2]

Error post

 

[Roderick JenkinsParticipant @roderickjenkins93242]

Hi Dell,

They look like bore gauges to me as well.  Direct reading ones like this can be can be difficult to read if a countersink is involved:

This type, which looks like yours, is remote reading – the spring loaded taper pin is fired into the hole and the diameter is read off from the indicator at the top of the instrument:

I don’t actually recall ever having the need to use of any of them.

Rod

 

 

 

[DellParticipant @dell]

This is the description from the link that Bill posted, but it’s quite heavy reading.

Rod these are not spring loaded.

https://worldwide.espacenet.com/patent/search/family/010331052/publication/GB763416A?q=pn%3DGB763416A

[Robert Atkinson 2Participant @robertatkinson2]

The patent confirms they are small hole gauges. Typical patent language.

You slide the taper out, insert it fully in the hole to be measured then slide the body down until it contacts the surface and read the hole diameter off the scale.

[peak4Participant @peak4]

As far as I can see, it’s essentially a more accurate/higher resolution version of one of these.
Poke the tapered rod into a hole, and read off the diameter, or check for ovality etc.
Resolution is likely to a thou or so from what I make of the patent; Fig.3 shows a modified from of the tool to allow for recesses in the surface

Bill

edit; typing at the same time as Robert by the looks of it

[Paul LousickParticipant @paullousick59116]

The engraving on the side says “DIA .001 INCH”.

Direct reading bore gauge ?

[DellParticipant @dell]

Well they are no good for measuring the taper of a blind hole because I tried to measure the female taper of a Pultra P type tailstock, I could measure the depth of the hole but that’s all .

Dell

[CirclipParticipant @circlip]

NOT for measuring tapers. Used these years ago for checking hole DIAMETERS in PCBs after piercing.

Regards  Ian.

[Michael GilliganParticipant @michaelgilligan61133]

Ian is correct, of course

… thereby demonstrating that a hole is two-dimensional, not three

MichaelG.

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