Dial Gauge Advice

[Cornish JackParticipant @cornishjack]

Mick B1 – quite so. I have two such items – one on a 3MT arbour with an adjustable cross-slide, tailor boxed , by Pratt and Whitney and another on a 2 morse. If I was more competent and did more in the shed, they would probably be used more!

rgds

Bill

[Brian WhelanParticipant @brianwhelan75518]

Wow – can't believe the response. Many many thanks to every-one. Food for thought indeed.

I'll re- read the posts after tea.

ATB

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Howard Lewis on 31/10/2018 17:17:19:

Because of the variations introduced by the angles of the probe end of the finger clock, they are not really suitable for absolute measurement. Mine is used almost exclusively for centering work (OD or ID) in a 4 jaw chuck. Finger clocks (Sometimes referred to as Verdict clocks, after one of their makers) …

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I agree, Howard : They are 'indicators'

That said; it's worth noting that the "pear-shaped" tip, supplied by Verdict, confers much better linearity than the common ball-ended probe.

MichaelG.

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http://mjallen.co.uk/application/files/4614/7686/2624/Styli.pdf

Edited By Michael Gilligan on 31/10/2018 18:11:52

[ZanParticipant @zan]

I use my plunger type once a decade, the lever type almost every machining session it works in both directions and is invaluable on Miller, and lathe in bores and trimming . Do get a micro adjusting stand to go with it. There were some at the Foss as a complete set for about£26.00

[not done it yetParticipant @notdoneityet]

Zan,

Have you already used it this decade?

[Brian WhelanParticipant @brianwhelan75518]

Thanks for all the comments and advice. Didn't realise there would be so many variable opinions on this. I was aware of the dial gauge but posted the question after watching a video on YT where the chap used a finger type gaude nearly all the time. Also I did not realise about the base and stand (I thought they would all be the same).

So in a nutshell – I am extremely grateful for all the input you have provided, (Its a big nutshell).

Many thanks

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Michael Gilligan on 31/10/2018 18:09:04:

… it's worth noting that the "pear-shaped" tip, supplied by Verdict, confers much better linearity than the common ball-ended probe.

.

Just noticed that ega had already mentioned this on page1

[Mick B1Participant @mickb1]

Posted by Brian Whelan on 01/11/2018 08:21:46:

Thanks for all the comments and advice. Didn't realise there would be so many variable opinions on this.

….

Many thanks

Model Engineering itself is an idiosyncratic hobby.

You can expect big differences in the way its hobbyists have learned to resolve the problems they come across.

For example, I use my plunger and finger clocks about equally, but I mount them on a bit of flat bar in the toolpost, or in the lathe or drill chucks.

I only wish I had a magnetic base about once a decade…

[Martin Johnson 1Participant @martinjohnson1]

I only have a plunger type, and I would only buy a quality make. I have been at this game about 50 years now, and 40 years as a chartered engineer.

I have always found the very limited travel of the lever type to be a complete pain – very good for certain types of work as noted above, though.

HOWEVER I have a little pivoting lever attachment I made up years ago that fits around the stem of my plunger type dial gauge, which gives it most of the functionality of the lever type. Except for getting into the really tightest of tight spots. There was a design for such an attachment in the early issues of Model Engineers Workshop – sorry I don't have the reference any more.

Martin

[VicParticipant @vic]

If you decide to get a DTI have a look here.

**LINK**

The Swiss made ones are reckoned to be the best.

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Martin Johnson 1 on 01/11/2018 09:04:31:

… HOWEVER I have a little pivoting lever attachment I made up years ago that fits around the stem of my plunger type dial gauge, which gives it most of the functionality of the lever type. Except for getting into the really tightest of tight spots. There was a design for such an attachment in the early issues of Model Engineers Workshop – sorry I don't have the reference any more.

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MEW issue 1 [Summer 1990], pp14-17

Attachments for Dial Test Indicators : R.J. Loader

MichaelG.

[egaParticipant @ega]

Posted by Michael Gilligan on 01/11/2018 08:49:00:

Posted by Michael Gilligan on 31/10/2018 18:09:04:

… it's worth noting that the "pear-shaped" tip, supplied by Verdict, confers much better linearity than the common ball-ended probe.

.

Just noticed that ega had already mentioned this on page1

I was glad to get confirmation of this point and, having followed up your helpful link, I see that I should have said eliminate rather than mitigate ie Verdict claim accuracy within the angular limit given. Their diagram is rather small and they don't give the underlying maths; I was hoping that some of our more scientific members – you, perhaps – would weigh in with the proof.

Andrew Johnston:

I have just installed a pear-shaped collet tray on the lathe; so far it hasn't gone belly up!

[Michael GilliganParticipant @michaelgilligan61133]

Posted by ega on 01/11/2018 09:38:17:

I was glad to get confirmation of this point and, having followed up your helpful link, I see that I should have said eliminate rather than mitigate ie Verdict claim accuracy within the angular limit given. Their diagram is rather small and they don't give the underlying maths; I was hoping that some of our more scientific members – you, perhaps – would weigh in with the proof.

.

Thankfully, I don't need to clutter the forum with my attempt at a proof

It's very well detailed in Verdict's patent:

https://worldwide.espacenet.com/publicationDetails/originalDocument?CC=US&NR=3161963A&KC=A&FT=D&ND=3&date=19641222&DB=EPODOC&locale=en_EP

MichaelG.

Edited By Michael Gilligan on 01/11/2018 09:55:21

[OldironParticipant @oldiron]

Posted by Mick B1 on 31/10/2018 14:35:03:

True, but Baty at least make, or used to, a bellcrank-type finger-lever that clamps onto the plunger sleeve and allows the gauge to work in that situation. Still a bit of a faff compared to a finger-type gauge, though.

 

I have one dial indicator that is permanently fitted with cranked finger. I find it very useful & easy to read without putting on the optivisor.

I got a box full of these in an auction lot and sold many on Ebay. Still have a few pieces left in that box somewhere I think.

To the original OP, you will not go wrong with both types as they have their own separate uses

regards

Edited By Oldiron on 01/11/2018 10:43:34

[egaParticipant @ega]

Michael Gilligan:

Thank you. The answer seems to be in the last paragraph of the patent (which I assume has now expired).

I suppose another "proof" of a sort would be to compare the readings from the same setup using both spherical and pear-shaped styli.

[Howard LewisParticipant @howardlewis46836]

Lever adaptors to allow a Plunger clock to be used in a bore were made commercially. May still be, if we could find the right place to look.

I have a secondhand John Bull Plunger clock with one of these among its accessories, although very rarely used. The Verdict finger clock is the device normally used, for centering the bore or the OD. once it is reasonably near by eye.

Howard

[OldironParticipant @oldiron]

Posted by Howard Lewis on 01/11/2018 15:14:54:

Lever adaptors to allow a Plunger clock to be used in a bore were made commercially. May still be, if we could find the right place to look.

Howard

Try here:- **LINK** There are probably others available.

regards

[EmgeeParticipant @emgee]

If anyone wants to make their own conversion to use a plunger type clock in a bore there was an article in ME many years ago providing full details. I made mine ages ago to check bores were parallel when bored.
Perhaps someone with a full index could check for the issue number.

Emgee

[Rod AshtonParticipant @rodashton53132]

Ref Oldiron Link, – It is worth noting that the linked site has a dimensioned drawing and 3d CAD files for download.

[EmgeeParticipant @emgee]

Well spotted Rod, I didn't scroll down when I noticed the difference to the attachment I made, that was to enable measurements to be taken in the bore or slot, I will look it up and post a picture.

Emgee

[fishy-steveParticipant @fishy-steve]

How about Harold Halls site?

**LINK**

Steve.

[Author]

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