Thread Pull Out

8 comments

Rate

Adam Mercer Participant Join Date: Apr 2014 Posts: 1	Thread Pull Out 04/16/2014 3:59 PM
	Trying to determine what the pullout force difference would be on a 1"-8 machine I-bolt that is engaged into P20 steel at two different depths. 1" and 1 1/2".
	Register to Reply
	User-tagged by 1 user

Interested in this topic? By joining CR4 you can "subscribe" to
this discussion and receive notification when new comments are added.

Check out these comments that don't yet have enough votes to be "official" good answers and, if you agree with them, vote them!

lyn Guru Join Date: Oct 2008 Posts: 42355 Good Answers: 1693	#1 Re: Thread pull out 04/16/2014 4:23 PM
	Pullout force difference in pounds, or %. How do you know the bolt won't fail? Are you lifting injection molds? I don't suppose 1 1/2 time the force for the deeper hole will work for you? Also be nice to know if you're lifting 1 ton or 5. Pull angle is straight? What thread class? What have you done, so far? I'm not sure it matters after you go beyond three full threads. The bolt is likely to fail anyway. Details are always nice.
	Register to Reply

WJMFIRE Guru Join Date: Apr 2009 Location: USA, Florida Posts: 1595 Good Answers: 125	#2 Re: Thread Pull Out 04/16/2014 6:05 PM
	Pull out forces are determined by bolt manufacturers by testing. They will then chart the results and have a testing laboratory (like UL) verify them. They normally will not discuss the material embedded into. They only list the tension and shear forces for their bolts. These forces are determined by bolt diameter and length, and assume full embed. __________________ An obstacle is something you see when you take your eyes off the goal.
	Register to Reply

Anonymous Hero Guru Join Date: May 2006 Location: The 'Space Coast', USA Posts: 11119 Good Answers: 918	#4 In reply to #2 Re: Thread Pull Out 04/16/2014 6:18 PM
	Yes, and the standard length of engagement is at least the thread diameter, so 1" is a good number.
	Register to Reply

Anonymous Hero Guru Join Date: May 2006 Location: The 'Space Coast', USA Posts: 11119 Good Answers: 918	#3 Re: Thread Pull Out 04/16/2014 6:11 PM
	As Lyn said you need to know the grade of the bolt, class of thread, and the reciprocal material type that it is threaded into. What you are looking for is the Proof Load of the fastener. This site will give you some ideas. The depth of thread is not going to make much of a difference at those depths. However, you can calculate it yourself with This Online Calculator
	Register to Reply Score 1 for Good Answer

PWSlack Guru Join Date: Jan 2007 Location: In the bothy, 7 chains down the line from Dodman's Lane level crossing, in the nation formerly known as Great Britain. Kettle's on. Posts: 32175 Good Answers: 839	#5 Re: Thread Pull Out 04/17/2014 7:37 AM
	Well, that would vary depending on whether the steel were virgin new material or some old rusty rubbish that has been immersed in seawater for 50 years. The only way to know for certain is to carry out a test under controlled conditions, if necessary to failure. __________________ "Did you get my e-mail?" - "The biggest problem in communication is the illusion that it has taken place" - George Bernard Shaw, 1856
	Register to Reply

Codemaster Guru Join Date: Jul 2005 Location: Stoke-on-Trent, UK Posts: 4496 Good Answers: 137	#6 Re: Thread Pull Out 04/17/2014 3:38 PM
	I suppose the 8 is 8 threads per inch? What is an I-bolt, same as an eye-bolt? I don't know the properties of P20 steel, but if it's reasonably good stuff my guess would be that in both cases the bolt would break before pullout. But it would take a helluva force! __________________ Give masochists a fair crack of the whip
	Register to Reply

Tornado Guru Join Date: May 2009 Location: Richland, WA, USA Posts: 21017 Good Answers: 795	#7 Re: Thread Pull Out 04/17/2014 4:31 PM
	Are any off-angle forces involved? __________________ In vino veritas; in cervisia carmen; in aqua E. coli.
	Register to Reply

TerraMan Power-User Join Date: Nov 2011 Posts: 473 Good Answers: 13	#8 Re: Thread Pull Out 04/19/2014 8:26 PM
	I believe the short answer is no difference since the eye bolt will break before the threads let go in the P20. Yeild of P20 is about 120ksi. Don't know of any standard eye bolts with that type of strength.
	Register to Reply

Check out these comments that don't yet have enough votes to be "official" good answers and, if you agree with them, vote them!

Copy to Clipboard

	Got Something to Say?
	Ask a Question Start a Discussion

	Aerospace
	BioMech & BioMed
	Chemical & Material Science
	Civil Engineering
	Communications & Electronics
	Education and Engineering Careers
	Electrical Engineering
	General Discussion
	Instrumentation
	Manufacturing
	Mechanical Engineering
	New Technologies & Research
	Software & Programming
	Sustainable Engineering
	Transportation

	Site Directories
	Forum Directory Blog Directory User Group Directory RSS Feeds CR4 Rules of Conduct CR4 FAQ Site Glossary Who's Online (75 right now) Show Members