Rulers – my pet peeve

[Peter G. ShawParticipant @peterg-shaw75338]

Neil,

 

A long time ago I discovered that some of the rule(r)s I own did not agree. Furthermore, I also discovered discrepancies between the various micrometers, manual verniers and electronic verniers. Eventually I bought the three smallest metric Mitutoyo micrometer standards and started comparing both for identical readings and for tolerances. Generally, where possible I estimated to tenths – not possible on digital stuff, but can be done on the manual micrometers, both metric and imperial.

 

I then borrowed an imperial micrometer from an ex-toolroom toolmaker friend as it had the tenths vernier scale. Much to my surprise, I found that my estimated readings compared very favourably with the actual tenths micrometer and on mentioning this to my friend found that he was not at all surprised. He said that the human brain and eye was very capable of doing this.

 

For myself, I would have expected 1/4, 1/2 & 3/4 of a division to be reasonably easy to do, and somewhere I picked up the idea that the graduations are usually approximately equal to 1/10, so probably 1/10 and 9/10 should be ok, but this then leaves 2, 3, 4, 6, 7 & 8 tenths as probably being the most error prone.

 

Regards,

 

Peter G. Shaw

 

PS For what it’s worth, I ended up with a metric micrometer reading 0.005mm high at 25mm, a slide vernier caliper with a resolution of 0.05mm appearing to be exact,  a Draper dial caliper with a resolution of 0.02mm reading consistently high (and since given to my grandson), a Rolson digital caliper which appears to be reading up to 0.02-0.03mm low (within spec), and a Workzone digital caliper from Aldi which reads anything up to 0.11mm high and isn’t even consistant.

 

Since then I have bought a Starrett 25-50mm micrometer and a Starrett 150mm dial caliper with a resolution of 0.01mm. Both of these seem to be accurate. Hence I now use the 0.05mm slide vernier as first choice with the micrometers and the Starrett dial caliper second choice and the Rolson digital third choice.

 

Anybody want a Workzone digital caliper? Going cheap for postage!

[Speedy Builder5Participant @speedybuilder5]

Hi John,  I have a Rabone Chesterman  300mm rule CF 49  to Bs 4372 square ended satin finished stainless steel.  -easy read for pensioners.

 

One face is in mm,  the other in 1/2 mm graduations.  The top reads right to left (albeit upside down) ,  the bottom left to right.  It has square ends -and its all mine !

[Speedy Builder5Participant @speedybuilder5]

John,  quick,  check out E-bay  Item number: 350414102041

 

Rabone CF 49 is up for sale – its the satin one with a hole in it.

 

Good luck

[John Stevenson 1Participant @johnstevenson1]

Robert,

Sorry not following you?

That one is marked in 1/2mm which is what I want to get away from.

What I want and have now found and ordered from Germany are rules with full mm divisions on all sides.

 

I’ll post some pics when they arrive in the new years, nobody will be shipping until Tuesday anyway

 

John S.

[Gordon WParticipant @gordonw]

When I was an apprentice (what dread words) we were given 6″ rules. Then taken to the holy place (tool room). Rules set in a square on surface table ,and with a tool room height gauge set to standard increments ,ie. 1″, 1 1/2″ etc. the rules were scribed. This showed the true division mark, after that we were expected to measure to 15 thou. with them.

[Sub MandrelParticipant @submandrel]

I’m going to do an experiment – I have a 1″ standard and I’ll take photos of each of my calipers and micrometers on it. You’ll have to trust me to zero them properly!

 

Neil

 

P.S. My workzone caliper is the one I use most as the chunky body fits the hand and it seems at least as relaible as the others!

 

P.P.S. Any dirt at all on the ‘scale’ is the enemy of accuracy and consistency with digital calipers.

[Nicholas FarrParticipant @nicholasfarr14254]

Hi Neil, I hope you are going to maintain them all at their specified accuracy temperatures during your experiment..

 

I was checking a couple of 2″-3″ mics last night and just handling the 2″ and 3″ standards made a difference of 0.0005″. I had to get them all up to my handling temp before I got consistant readings.

 

Regards Nick.

Edited By Nicholas Farr on 07/01/2011 20:08:22

[Peter G. ShawParticipant @peterg-shaw75338]

When I was checking my devices, I brought them into the house overnight before checking, thus ensuring that they were all at the same temperature, 20°C or as near as the storage heaters could get it.

 

In respect of the micrometers and the standards, they were all held by the plastic insulating pads: my understanding is that these, especially on the standards, are designed to minimize heat transmission from the hands. The calipers are rather more awkward since they are mainly all metal. One way is to hold them as much as possible in say a portable vice fitted with plastic jaws. Provided the vice has also been left overnight in the same room, it should then be at the same temperature as the caliper under test and the standards.

 

Regards,

 

Peter G. Shaw

[Nicholas FarrParticipant @nicholasfarr14254]

Hi Peter, I think your ideas are very valid. My standards don’t have any plastic insulating pads. I was also thinking that it would be easyer if they were gentle nipped in a vice, as trying to hold the mic and the standard and working the mic’s barrel all at the same time was rather akward to say the least. I’ve got an ali vice which will clamp onto a table top, somwhere which was a freebie with a cheapo workmate type thingy, I’ll have to see if I can find it.

 

Regards Nick.

Edited By Nicholas Farr on 07/01/2011 21:27:48

[Dave Jones 1Participant @davejones1]

Being from a slightly younger generation, I had the luxury of missing out of capital punishment in school! on the downside this means it was not explained to me why you cant call it a ruler.  So why is this?

 

This also means I have had to teach myself how to work in imperial instead of metric, but that is a whole other can of worms!

 

Dave

[TerrydParticipant @terryd72465]

Hi Dave,

 

I am from an older generation but I don’t know of any reason why you can’t call it a ruler, but there are reasons why you can

 

Quote:

 

“ruler [ˈruːlə]

n

1. (Government, Politics & Diplomacy) a person who rules or commands

2. (Engineering / Tools) Also called rule a strip of wood, metal, or other material, having straight edges graduated usually in millimetres or inches, used for measuring and drawing straight lines

 

Collins English Dictionary – Complete and Unabridged © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003“

 

end quote.

 

 

That’s good enough for me,

 

Regards

 

Terry.

 

[John Stevenson 1Participant @johnstevenson1]

Well they arrived from Germany via DHL on Thursday,

Just as it says on the box, 13mm wide, very flexible and just right for the top pocket.

 

Bought two 100mm long ones, two 150mm long, two 200mm long and one 150mm one that reads right to left so should be set now for a while, one set into the shop and one set as spare in the office.

 

[Edit] one 150mm and one 200mm has already gone into the shop.

 

John S.

Edited By John Stevenson on 08/01/2011 12:00:45

[blowlampParticipant @blowlamp]

Posted by Dave Jones 1 on 08/01/2011 11:36:49:

…I had the luxury of missing out of capital punishment in school! …

 

Dave

 

 

 

 

Good job you did, or we wouldn’t have the pleasure of your company

 

 

Martin.

[DustyParticipant @dusty]

Hi guys

     Remember that when using standards to set measuring equipment that whatever you are setting is only accurate at the size of your standard, you are relying on the inherent accuracy of the tool thereafter. If you have the use of a set of slip gauges then you can check across the range of the tool you are trying to set. If you then find you have an error then I would suggest that you balance the error over the range of the tool.

i.e. set it so that it is accurate at the midway point.

[NJHParticipant @njh]

Hey John

Like the look of those – maybe I will order a couple.

 

As far as the top pocket goes though take care that you don’t stick the 200mm version up your nose!! (Insert smiley here – but of course I don’t do those)

 

Regards

 

Norman

[TerrydParticipant @terryd72465]

Hi Chris Stevens,

 

I also have a metre stick!

 

Best regards,

 

Terry

[Dinosaur EngineerParticipant @dinosaurengineer]

Has anyone noticed that it’s much easier to read a rule measurement if the division engraved lines are no more than 2 as long as the division interval ?

I’ve always found the 1/100th inch division lines too long and it makes it difficult to read but when division lines are are much shorter it’s much easier to read .

[chris stephensParticipant @chrisstephens63393]

Hi Guys,

I know the politically correct nutters think you can use the language anyway you like, but I am not one of them.

In my Shorter Oxford English  Dictionary, you know the 1500 plus page version, the correct term is a “RULER”. it even gives an example where it says under the word “RULE” 1, “to mark (paper, etc.) with parallel straight lines drawn with a ruler or by machine 1440. 2, To form or mark out (a line) with or as with a ruler 1599. Indicating that “rule” is a verb (to rule), not a noun.

Rule can be used for Ruler but if OED uses the extra “R” in its examples that is good enough for me and should be good enough for you lot too.

You chaps will have to forgive me being a pedant on this but it took me years to learn to speak English, which is my second language,  my native tongue is Gibberish!

chriStephens 

[The Merry MillerParticipant @themerrymiller]

Here’s another viewpoint on the issue.

 

1. A rule is used for measuring.

 

2. A ruler is used for ruling (drawing)  lines.

 

As derived from the Oxford Dictionary.

[John Stevenson 1Participant @johnstevenson1]

Whatever, these stainless steel sticks have mm graduation on both edges and irrespective of what they are called allow one to measure parts in millimetres.

 

That will do for me.

Edited By John Stevenson on 08/01/2011 20:46:14

[NJHParticipant @njh]

Chris   I know you are going to quote the O.E.D as the definitive source however Chambers ( a neat and handy volume) gives rule as : a straight – edged strip used as a guide in drawing straight lines or as a measuring rod, or a means of mechanical calculation……….(etc etc )

Further it shows ruler    as a strip or roller for ruling lines

So, as I can’t afford the O.E.D. nor yet have space for it in the library, I will rest content in my chambers, druling  over the pics some of you guys post, confident that I know just what to pick up when I next want to take a measurement.

 

 Norman

[John OlsenParticipant @johnolsen79199]

People tend to quote dictionaries as if they are some sort of authority of correct usage. Actualy in English there is no authority for correct usage, and the dictionaries only reflect past usage. The way it works is that the dictionary compilers collect examples from published works of spelling and usage, and as time goes on update the dictionaries to reflect the way words are actually being used. There is no such thing as a legally defined correct English spelling, and even if there were there is no way to enforce it on reprobates such as the Americans, the Canadians, the Indians, the Singaporese, the Australians, and other nations who use English, or something resembling it, often in their own unique ways.

 

This is quite different to the way it works in say French, where the French Academy can lay down the law as to what is and isn’t correct French.

 

The process as described for English does have one weakness, in that the dictionary compilers tend to be literary types. This tends to mean that usages and spellings that appear in literary works are far more likely to be reflected in the dictionary than technical terms. When they do appear, technical terms are far more likely to be dealt with poorly, and for the classic example, refer to the definitions of terms related to sailing ships in Doctor Johnsons first Engilsh dictionary.

 

From a writers point of view, what we have to ask ourselves is ” will the reader understand what I mean if  I use this particular word, spelt in this particular way”. The dictionary can provide a good guide as to what the reader is likely to understand, and is what they will get for guidance if they don’t understand and decide to look it up. So it is useful, but not the final word, especially in technical matters, where words are only likely to appear in the dictionary long after the technology is obsolete.

On a more on topic line, somebody above was commenting about rules/rulers with half divisions at one end being hard to read. I took a look at what a local supplier has the other day. Facom make a ruler/rule that does not have the half mm divisions at the start end, they are full millimeters on both edges all the way along. The one I saw was 300 mm long, with millimeters on both edges. Square at the zero end, longer at the other end with a hole to hang it up by. Most of the items in stock did have the half mm divisions, but they do make at least one model that does not. So you may be able to find something like that. 

regards

John

[Ian S CParticipant @iansc]

If you look at words such as ‘anneal’ in the Concise Oxford dictionary you may be a bit confused.  Ian S C

[michael mParticipant @michaelm]

Many years ago I bought a 6″ steel rule (M&W) which I’ve always used in a rule holder on a small surface plate for setting the pointer of a scribing block.I didn’t have an engineering background and was advised to do this by a proper engineer who also suggested that the rule should not be kept in the overall pocket and not used for general workshop use.

The rule has now disappeared. A couple of weeks ago I had a big cleaning up session and remember removing the rule from the holder, cleaning it with a paper towel and lightly spraying with WD40, it being a carbon steel rule. Exhaustive and repeated searches have failed to find it and I suspect it may have been inadvertently binned along with the soiled cleaning materials.

Can anyone help me to source a replacement? Sounds easy but the problem is that modern quality ones have very light photo engraved graduations, some seem almost printed on. In fact I read in another forum of the risk of rubbing off the graduation marks from a Rabone Chesterman rule.

The beauty of deep engraving is that one can feel the scriber point click into the graduation, a great help, as the years go by, with diminishing visual acuity. Curiously, a lot of the cheap rules available do have decently engraved depth but accuracy is usually an issue. They tend to be sheared rather than ground and the first division is invariably too small. I’ve seen some real shockers at model engineering exhibitions. (Surprise).

I’ve tried searching on the internet to no avail, so can anyone help please?

Thanks

Michael

 

 

[NJHParticipant @njh]

Hi Michael

 

I have sent you a message. ( Look in ” My Messages” in “My Account” at the top left of the home page )

 

Regards

 

Norman

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