Hello folks,

I'm looking for a book that has specific content.

Back in my trade school days (about 1988), I read a library book that had the following description inside one of the chapters.

Picture a T-Handle for a lathe, the handle is perpendicular to the chuck square drive shaft. Both the handle and shaft are of same material. At what ratio of the diameters are they of equal strength?

IIRC, the answer given was the handle at 40% of the larger shaft.

It's quite possible that you are looking for information from "Machinery's Handbook".

Excellent suggestion, but IIRC, it was some sort of book specifically on Mechanical Design. It had a lot of practical examples like the one mentioned.

I could be wrong on my memory, it might have been a shear pin and shaft of same material.

Sounds a lot like a design example from Beer and Johnston's "Mechanics of Materials" which was a staple in many Strengths of Material classes at the time. There were other similar books and a number since then.

I did a quick glance in B&J's version and couldn't find the example noted, but it's entirely possible I missed it. In addition, I'm not sure if the book would have been used in a trade school instead of an engineering classroom. That said, I still consult it occasionally in my engineering work today.

quote:

Originally posted by StarTraveler:

I did a quick glance in B&J's version and couldn't find the example noted, but it's entirely possible I missed it. In addition, I'm not sure if the book would have been used in a trade school instead of an engineering classroom. That said, I still consult it occasionally in my engineering work today.

Thanks for looking and the suggestion of a similar book. Gives me something to into.

My school had a Stress analysis machine. They had us make samples to test on it. Also had us do a simple Strength of Materials class.

The two mechanical design textbooks that almost every mechanical engineer has copies of are “Shigley’s Mechanical Engineering Design” and “Marks’ Standard Handbook for Mechanical Engineers.”

My copies are in storage so I can’t check for that specific example, but they’re full of stuff like that.

Not sure this is what you are looking for, but it is a good reference for this kind of thing. - Mechanisms and Mechanical Devices Sourcebook by Sclater and Chironis.

Next option - try typing the problem you described, as accurately as possible, directly into a search engine (yahoo - whatever) Sometimes this will bring up the original source. I used to do it with college term papers (I was the professor). I could type a few sentences and the original source would show up, showing me what the student had copied and tried to pass off as their own work. Jeez they thought we were stupid….

My guess on your handle problem would have been the handle needed to be 50% of the shank diameter.

I tried various terms in a search engine. The only thing that was close was a scientific research paper published about 2005.


I went my local library and found a book that hasn't been checked out since 1941 stamped on the card in the inside cover pocket. This library went digital with check outs about 1995. So it wasn't out during those 54 years!


****Correction: "Great Feats Of Modern Engineering" was the book that has not been out in a while. Picked it up as it looks interesting.****


"Simplified Problems in Strength of Materials and Structure Design".
That's a long title! I will look over that one for a bit to see if it may help.

This message has been edited. Last edited by: TRIO,

quote:

Originally posted by maladat:
“Marks’ Standard Handbook for Mechanical Engineers.”

My copies are in storage so I can’t check for that specific example, but they’re full of stuff like that.

I've seen that title before, but didn't think to look there. Thanks for the great suggestions.

StarTraveler, I sent you an email.

Trio, interesting question. Response inbound.

As a Mechanical Engineer I feel obligated to point out that the shaft diameter for the Lathe Chuck in question is not given. I'll also point out that the recess for the square drive handle is obviously the weakest visible point of the shaft. As a result the remaining material has to be used in this comparison and the stress riser created at the transition must also be factored in.

I believe the OP question as a restated textbook question is intended to ask the student to recall the equations for bending and torsional stress, and compare the two. Most often these can be detailed with parameters such as little d and big D, and careful setup of the system of equations.

If the handle were to fail in bending, and the main shaft in torsion, the basic equations can be applied.

The student must recall the typical ratio of the torsional vs the bending stress limits also.

StarTraveler, I sent you a results email.

This place is great. You post an off the wall question and someone with knowlege is willing to discuss it. Thanks for those who responded to this post.

A special "Thank you!" goes to startraveler as we discussed further that led to a successful conclusion to a test I was doing.