Dial Gauge Advice

[Brian WhelanParticipant @brianwhelan75518]

Hello. Have recently bought a Drummond roundbed and I am enjoying wittling on the lathe. I am an absolute novice by the way. I was a wood machinist for a lot of years, now semi retired.

However, back to my question – I am looking at dial gauges and have seen two different types. One is conventional where the end has a telescopic needle and the other is where the needle is on a pivot. I realise having both would be preferable but am favouring the latter at the moment.

Any comments would be appreciated.

I am sure everyone knows – buying tools and parts can run away with your wallet, so want to keep spending down.

Many thanks

[Brian WhelanParticipant @brianwhelan75518]

[HopperParticipant @hopper]

The former, with the telescopic plunger, is more the "base model" and can be more versatile,as well as more sturdy.

The pivoted lever type, aka dial test indicator or finger indicator, is nice to have, but can not measure (ok, indicate) over as great a range as the first type.

Either one will probably do you ok for what you need. If I had to have just one, I would choose the first type largely because it is more sturdy. I'm sure there is a myriad of opinions on that, though!

[SillyOldDufferModerator @sillyoldduffer]

When you try and take a measurement getting the instrument into position can be awkward. The lever and pointer types complement each other.

On my lathe the telescopic type gets used most by far because it, and its magnetic stand, suit the layout of the machine better. On my milling machine, again because of positioning issues, the lever type gets much more use than the telescopic one.

I'm self-taught and may be doing it wrong!

I'm afraid keeping the spending down is a forlorn hope. Sooner or later you'll want both…

Dave

[EmgeeParticipant @emgee]

Hi Brian

One advantage of the lever type indicator is it can also be used in a bore or groove to aid set-up.

Usually though the range of movement is much less than other types, a case of horses for courses.

Emgee

[Anonymous]

They're different animals, with different uses.

The dials with a telescopic needle are dial gauges. They usually have a significant travel, 12mm or more. They are used to measure parts or travels. They can be used in a stand on a surface plate as a comparator or on a machine tool carriage to measure distance. The latter was common prior to the introduction of DROs.

The dials with a pivoted needle are dial test indicators (DTI). They are used to set parts or fixtures true. While they are marked with dimensions they actual dimension changes with the position of the pivot. So they are not used for absolute measurement but to indicate relative movement.

I've got several examples of both, but use the DTIs orders of magnitude more frequently that the dial gauges. Two common uses for the DTI are setting work running true in the 4-jaw chuck and setting the machine vice jaws parallel to the table on the milling machine. My DTI lives in the workshop on a magnetic base ready for use, by contrast the dial gauges are in the tool store, aka the dining room.

If you're only going to buy one, get a DTI. And buy a quality one; there's nothing worse than a sticky needle on a DTI.

Andrew

[Nick HulmeParticipant @nickhulme30114]

Dial Guage gives you measurements over it's full travel travel, Dial Test Indicator gives clear indication of small deflections but if you use it for larger deflections the angle of the arm changes with deflection, apply geometry here to work out the errors as deflection increases.

[mechman48Participant @mechman48]

Hi Brian

It depends on the application you want to use it for; as you state that you're a novice I would stick with the conventional dial gauge to start with, these are normally calibrated to read to thousands – .001" or .05mm in metric which is fine to check runout, set up in a 4 jaw chuck or on vee blocks. The pivoted needle type are generally calibrated to tenths of a thou' or .00254mm but unless you're working to this tolerance then the lever type can be added later. For general use & accuracy the hobbyist will not go wrong with the conventional dial gauge.
Other posters will also offer their opinions no doubt.

George.

[egaParticipant @ega]

I think Verdict claimed that their pear-shaped probe mitigated the error.

I agree that the DTI is more likely to be useful to the ME.

[Russell EberhardtParticipant @russelleberhardt48058]

I picked up a DTI at an autojumble many years ago. Swiss made it has 0.0001" resolution and a turns counter to give it a decent range. I can't understand why the vast majority of DTIs on sale now don't have this turns counter facility.

Russell

[Anonymous]

Posted by ega on 31/10/2018 10:48:10:

I think Verdict claimed that their pear-shaped probe mitigated the error.

I have enough things going pear-shaped in the workshop as it is without deliberately introducing more pear shapes.

Andrew

[Clive Brown 1Participant @clivebrown1]

In common with many, I have both types, acquired over the years. I use my Verdicts very frequently. Can't remember when I last used one of my plunger types.

Edited By Clive Brown 1 on 31/10/2018 11:09:15

[Roger HartParticipant @rogerhart88496]

I agree that the DTI is a good first choice. I got a 0.001 inch one at a boot sale many years ago and it is the most useful I have. It is robust, useful travel and not too nit-picky. For most jobs this is the one.

I have a couple of much better DTIs and a finger type gauge, but they are a d%^n nuisance to use with the needle going round several times until you have got the work nearly central. In this case posh is not necessarily better unless you want real accuracy and that is whole ball of wax on its own.

[Anonymous]

My go to DTI is a Mitutoyo where each division is nominally 0.01mm. Indicating on machined surfaces when setting up in the 4-jaw chuck, or on the machine vice jaws, I expect to get better than one division. It doesn't take long, and if you're going to do something you might as well do it right.

Andrew

[Tony Pratt 1Participant @tonypratt1]

Same as Andrew, my best DTI is a Mitutoyo 0.01mm per division, if you go to .005mm per division it's of no real advantage & a real pain.

Can't remember the last time I used a plunger clock, either Toolmaking or ME hobby use.

Tony

[Ian S CParticipant @iansc]

We used a finger type gauge on overhauled propellers, I think it was +- .125" x .001", they are quite delicate, one of the gauges we had , had a broken spindle on one of the pinions, caused by excessive movement of the finger, it's around here somewhere I think.

The surface table was by Starret, and was ex RNZAF.

Ian S C

[not done it yetParticipant @notdoneityet]

I would make a guess, and say that many of those who use the pivot type, almost universally, already use digital read outs with their mills.

I have one dial indicator that only discriminates to 0.01” per division – better for woodworking than metal. Most dial calipers likely only indicate to that resolution.

The plunger type are perfectly OK for the vast majority of lathe work.

[Mick B1Participant @mickb1]

Posted by Emgee on 31/10/2018 10:23:53:

Hi Brian

One advantage of the lever type indicator is it can also be used in a bore or groove to aid set-up.

Usually though the range of movement is much less than other types, a case of horses for courses.

Emgee

+1 for this.

I don't think the dichotomy of plunger-type being a Dial Gauge and finger-type being a DTI is definitive. Both names have been applicable to either all the time I've been in engineering.

Finger-type can reach and give readings in places the plunger-type can't, unless it's fitted with extra accessories. The finger will usually operate over a wide range of angles, accessed by overriding click-stops defined by a spring detent, but it's nearly always fiddly to set, while the plunger-type is usually more straightforward where it can be used.

I've got both. My plunger was given me 30 years ago by the Chief Inspector of the firm that made it, and it operates exceptionally smoothly even now, but my finger-type was a recovered scrapper due to the direction-shift lever being broken; fixed with a bit of paper-clip.

Edited By Mick B1 on 31/10/2018 14:05:57

[Tony Pratt 1Participant @tonypratt1]

DTI [dial test indicator] can obviously apply to both plunger & lever type. Ref to 'not done it yet' having ' one dial indicator that only discriminates to 0.01” per division', I must confess I've never seen one & can't think of a use for it in machining metal to any degree of precision.

Tony

[Anonymous]

Posted by not done it yet on 31/10/2018 13:21:51:

I would make a guess, and say that many of those who use the pivot type, almost universally, already use digital read outs with their mills.

Yes and no; I mostly use the pivot type and I do have a DRO on the mill, albeit only one of my three mills. I'm not sure what conclusion you can draw from that?

It's somewhat difficult to use the plunger type when indicating on the inside of a hole.

Andrew

[Mick B1Participant @mickb1]

Posted by Andrew Johnston on 31/10/2018 14:18:24:

Posted by not done it yet on 31/10/2018 13:21:51:

I would make a guess, and say that many of those who use the pivot type, almost universally, already use digital read outs with their mills.

Yes and no; I mostly use the pivot type and I do have a DRO on the mill, albeit only one of my three mills. I'm not sure what conclusion you can draw from that?

It's somewhat difficult to use the plunger type when indicating on the inside of a hole.

Andrew

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.M. OUTAHEREParticipant @i-m-outahere]

To answer the OP question in short buy a plunger type first , don’t buy an expensive unit until you have some experience using them as they are easily damaged . I for the most part use cheap Chinese made units for the most part unless the part i’m makining calls for high precision then i dig out the compac .

You can use a plunger type indicator on the lathe to indicate a bore or hole using a dead centre but thats another story and starrett also do a clamp on unit to allow a plunger type gauge to indicate a bore .

Now lets throw the cat amongst the pigeons ! Let’s talk magnetic indicator stands as you will also need one of these and they range from high quality units that are a pleasure to use down to damned awful . Skimping here will just cause you headaches and there is no use having a quality indicator on a crap indicator stand , Eclipse , starrett , mitutoyo are all good as is noga – especially if you want one of those stands that has one locking knob to lock the arm ( I’m not a fan of them personally and prefer the one that a youtuber called stefan gotteswinter made for himself ) . If you buy anything mitutoyo make sure you buy from a certified distributor as there are clones of most of the mitutoyo stuff .

[David George 1Participant @davidgeorge1]

Hi Brian, Welcome to the forum. I have a few dial indicators around as a friend who has retired from engineering has passed his tools to me and if you like I could pass one on to you. just send me a message using the message tab at the bottom of this post to send me an address, and I will post it to you or collect if you are not to far away.

David

[not done it yetParticipant @notdoneityet]

Posted by Andrew Johnston on 31/10/2018 14:18:24:

Posted by not done it yet on 31/10/2018 13:21:51:

I would make a guess, and say that many of those who use the pivot type, almost universally, already use digital read outs with their mills.

Yes and no; I mostly use the pivot type and I do have a DRO on the mill, albeit only one of my three mills. I'm not sure what conclusion you can draw from that?

It's somewhat difficult to use the plunger type when indicating on the inside of a hole.

Andrew

Andrew,

I would be extreeemly careful about drawing a conclusion from a population of one! Can’t even be able to take an average, let alone sort out the probability of a spurious result.

Tony,

The 0.01” indicator came out of the local CFE. Possibly used, many moons ago, for the very basic starters, until they mastered the art of getting within a tenth – of an inch! I’ve never used it, but I daresay it might come to the surface somewhen. Likely very abuse resistant, too, as it would turn the hand/needle so much more slowly when ‘tested out’ by some of the students before they were ‘tamed’ – or told that engineering was not for them.

[Howard LewisParticipant @howardlewis46836]

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) are usually made with fine graduations, 0.0005", but have travel limited to about 0.030" for imperial ones. If you can get work running true to within 0.0005", it is not far out.

A Plunger Clock will have a much longer travel, and being linear, can be used for measurement, rather than just comparison. Being larger, (Having dial diameters of 38, 50mm, or even larger, they can be less easy to read if working very close to, and fouling, the chuck jaws). Obviously, can be used to check / measure the depth of steps or slots, or offset movements, on the milling machine.

For accuracy of measuremet, the plunger needs to be perpendicular to the work surface, in both planes.

Either type can be mounted on a Magnetic Base, a Scribing Block (surface gauge), a holder on a Height Gauge, or in a Toolpost.

Ideally, to cover all eventualities, both have their uses in a workshop.

As already said, "Horses for Courses"

Howard

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