Machinery's Handbook Errors?

[BigTank]

Has anyone ever definitively uncovered errors, either technical or typographical, in the honored Machinery's Handbook?

I believe my printing of the 26th edition has errors of both types in the beam stresses and deflections equations. Algebra led me to believe that these errors existed, and a review of previous editions carried by others around the office seemed to confirm what the algebra suggested (barring those editions aren't the ones in error, but the engineering mechanics and algebra suggest the newest edition is the one in error).

I searched the wonder that is the internet to find a whole lot of nothing. I emailed Industrial Press to pose the question in more detail as their website doesn't seem to offer the visitor any information regarding these types of errors. I have a feeling that effort might have been in vain.

So...has anyone else experienced this suspicion and a subsequent confirmation of it with this particular reference?

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[drawoh]

BigTank,

My old 21st edtition came with an erratum.

Which equations are wrong?

JHG

 

[zekeman]

" Algebra led me to believe that these errors existed, and a review of previous editions carried by others around the office seemed to confirm what the algebra suggested (barring those editions aren't the ones in error, but the engineering mechanics and algebra suggest the newest edition is the one in error).'

What algebra?
The equations must be unique.
Why don't you post the beam stress equations that you think are in error and get confirmation from this forum. Or, google for the proper equation to confirm your suspicions.

 

[dinjin]

It might be interesting to find out where the latest edition was proof read. There will be errors in almost every publication.

 

[mrainey]

This fellow claims to have found some.

http://www.boltplanet.com/Un/errata.htm

Software For Metalworking

http://closetolerancesoftware.com

 

[BigTank]

22 Mar 10 20:09
" Algebra led me to believe that these errors existed, and a review of previous editions carried by others around the office seemed to confirm what the algebra suggested (barring those editions aren't the ones in error, but the engineering mechanics and algebra suggest the newest edition is the one in error).'What algebra?The equations must be unique.Why don't you post the beam stress equations that you think are in error and get confirmation from this forum. Or, google for the proper equation to confirm your suspicions.

The beam case is Case 24: continuous beam with two unequal spans, unequal loads at any point of each

The factor in error is the factor 'm'. My 26th edition has l1 in the denominator of the second term under W2a2b2. The 23rd edition has l2. In addition, the 'I' that is in the numerator of the first multiplier seems that it should be a '1', as it is in the 18th edition. My reason for thinking is should be a '1' is the fact that the equation for this 'm' can be derived from the 3 moment equation for a statically indeterminant situation. (I used the equation for this from Rourke's, and manipulated it to be nearly the same as 'm'. I could get it to be the equation for 'm' as I think it should be, but I just don't care to finish the algebra.) Also, one of the maximum stresses will be at the intermediate column, the equation for which is m/Z. The units do not work if 'I' is in the equation for 'm' as it is shown.

This beam equation appears to be fairly specific. A google search didn't yield this particular case. It doesn't appear in the AISC Manual of Steel Construction or, either. Rourke's treats the beam equations differently, and this case would need to be derived from their equations.

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[BigTank]

Sorry about that butched bbs code...

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[hydtools]

What you are saying is that the subscipts for the denominator are in error. My 20th edition shows the subscipts to be consistant,i.e. l1 under the first term and l2 under the second term inside the parentheses.
Also, my edition does show the number '1' and not the letter 'I' in the first term numerator.
Looks like your have found errors.
Is not 'm' the bending moment and not just a factor?

Ted

 

[IRstuff]

This is what the 27th edition looks like, assuming I got the right page:

TTFN

FAQ731-376

 

[Canadieng]

I believe the mystery of the 'I' & '1' is just a typeset issue throughout the entire affected editions.

Compare the 'I' (acutally it is a '1') in the first numerator in case 24 to the title "Case 1" in, well, case one. They are the same typeset. Then look at the 'I' in the deflections, it is italicized.

I am specifically looking at the 25th edition right now. And you can turn to any number of pages to see this typeset 'I' is actually a one. In fact, look at any page number with a one. It looks like a capital 'eye'.

 

[BigTank]

Yes, hydtools, 'm' is the bending moment present at the location of reaction 'R' (the middle support).

IRstuff, it appears as if the 27th edition has been corrected.

Funny, though, that I found the 18th edition to be correct, the 23rd to have the correct denominators, but the 'I' instead of the '1', and the 26th edition to have both factors wrong.

It looks like someone made a typo somewhere between the 20th and 23rd editions with the 'I' v. '1', and somewhere between the 20th and 26th editions with the denominators.

A little scary that these mistakes are noted somewhere very accessible...

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[BigTank]

Canadieng: In my 26th edition that is not the case. The 'I' I mention in case 24 that is incorrect is definitely a capital 'eye', and the '1' in "Case 1" is definitely a one as are the page numbers throughout the book...however, as you point out, the 'I' in case 24 is not italicized as it is when used for the moment of inertia.

In addition, a few of the reactions shown in other cases are 'cut off'...that is they did not print entirely and therefore must be derived or found from another reference. There isn't enough there to tell what they should be.

An additional detail: my book is the large print version.

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[BigTank]

Correction: a little scary that these mistakes AREN'T noted somewhere explicitely accessible.

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[Canadieng]

hmmmmmm.... those editors, typesetters, proofreaders, finishers, .. really made a mess through the years.

 

[KENAT]

There was a post a while back where someone said machinery's had basically been banned at their employer due to errors in it or something. Maybe you can find it, I can't recall the details.

Posting guidelines faq731-376

http://eng-tips.com/market.cfm?

(probably not aimed specifically at you)
What is Engineering anyway: faq1088-1484​

 

[BigTank]

MAN! Now I'm finding sign errors after deriving the moment equation using Roarke's....

The reactions found using MH didn't balance with the loads...the beam would've been floating up into space! Faster for larger beams!

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[BigTank]

After deriving the moment equation from Roarke's, and manipulating that found in AISC, I've come to the conclusion that the 27th edition is very close to correct, but Machinery's Handbook apears to have done something different from the norm with their sign conventions.

From now on, I will just use Roarke's and not try the short-cuts.

Now I can see why MH would be banned.

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Fitter, happier, more productive

 

[kurcules]

I found an error, or at least very misleading situation, while analyzing semi-elliptic springs for a steam locomotive rebuild. In Machinery's 15'th edition (1956) page 486, where the equations are listed, the suggested modulus is 25,400 ksi. But the shortcut tables for evaluating the equation don't match what you get via the equation: I did a little curve fit and found they used 32,800 ksi for the tables. I looked in books.google.com and found the error going all the way back to 1915: the error (if it is that) lasted 50 years!