Yesterday's Tractor Co.
Shop Now View Cart
   Allis Chalmers Case Farmall IH Ford 9N,2N,8N Ford
   Ferguson John Deere Massey Ferguson Minn. Moline Oliver
 FAQFAQ   SearchSearch   MemberlistMemberlist   UsergroupsUsergroups   Traditional YT Forum ViewClassic View   RegisterRegister 
 ProfileProfile    Log inLog in 

fine vs course thread bolts

Goto page 1, 2  Next

 
Post new topic    
View previous topic :: View next topic  
Author Message
Charlie M
Tractor Expert


Joined: 25 Dec 2007
Posts: 2792


Report to Moderator

PostPosted: Sun Sep 22, 2013 11:48 am    Post subject: fine vs course thread bolts Reply to specific post Reply with quote

Any advantage to a fine thread bolt over a course thread. Fine threads seem to be more difficult to find.
 
Back to top
View user's profile
Dean
Tractor Guru


Joined: 29 Jan 1998
Posts: 17423


Report to Moderator

PostPosted: Sun Sep 22, 2013 11:51 am    Post subject: Re: fine vs course thread bolts Reply to specific post Reply with quote

All else equal, fine threaded fasteners produce more clamping force than course threaded fasteners at the same tightening torque and are less prome to self loosening.

Dean
 
Back to top
View user's profile
DouginIL
Regular


Joined: 01 Sep 2011
Posts: 61


Report to Moderator

PostPosted: Sun Sep 22, 2013 11:52 am    Post subject: Re: fine vs course thread bolts Reply to specific post Reply with quote

Fine threads can be torqued to higher values for a given diameter and grade of bolt.
 
Back to top
View user's profile
dpendzic
Tractor Expert


Joined: 05 Mar 2009
Posts: 2016
Location: long island NY and Hancock Ma

Report to Moderator

PostPosted: Sun Sep 22, 2013 11:52 am    Post subject: Re: fine vs course thread bolts Reply to specific post Reply with quote

that are less likely to work loose---a good lock washer on a course thread helps a lot
 
Back to top
View user's profile
greygoat
Tractor Guru


Joined: 30 Dec 2007
Posts: 3582


Report to Moderator

PostPosted: Sun Sep 22, 2013 12:37 pm    Post subject: Re: fine vs course thread bolts Reply to specific post Reply with quote

I find fine threaded,(SAE) bolts/nuts at Menards,
(China), Home Depot, "Blains Farm-Fleet", and,
of course "Fastenal"
 
Back to top
View user's profile
dpendzic
Tractor Expert


Joined: 05 Mar 2009
Posts: 2016
Location: long island NY and Hancock Ma

Report to Moderator

PostPosted: Sun Sep 22, 2013 1:16 pm    Post subject: Re: fine vs course thread bolts Reply to specific post Reply with quote

actually the limiting factor is the yield strength of the bolt. If you need more torque to produce the the same clamping force desired then a fine thread would not be as efficient as a course thread
 
Back to top
View user's profile
60 acre hillside
Long Time User


Joined: 27 May 2010
Posts: 1350


Report to Moderator

PostPosted: Sun Sep 22, 2013 1:47 pm    Post subject: Re: fine vs course thread bolts Reply to specific post Reply with quote

Henry Ford loved them. I have found that proper choice of fasteners are usually used in the right places. I could never understand why Ford used fine thread on plow bolts.
 
Back to top
View user's profile
Brian G. NY
Tractor Expert


Joined: 13 Mar 2001
Posts: 2156


Report to Moderator

PostPosted: Sun Sep 22, 2013 1:52 pm    Post subject: Re: fine vs course thread bolts Reply to specific post Reply with quote

You gotta run that by me once more dependzic!
I'm no engineer, but I think what Dean says sounds reasonable.
After all, walking up a less steep ramp gets you there the same as a steeper ramp but it's just a little easier walkin'.
 
Back to top
View user's profile
MarkB_MI
Tractor Guru


Joined: 29 Aug 2004
Posts: 11274


Report to Moderator

PostPosted: Sun Sep 22, 2013 1:52 pm    Post subject: Re: fine vs course thread bolts Reply to specific post Reply with quote

For a given grade, a fine thread bolt has higher tensile strength than a coarse thread bolt. That's because the threads on a fine thread bold aren't as deep, leaving more of the bolt diameter.

Check out the table at the site below. A grade 5 1/2-13 bolt as a tensile strength of 17,000 lbs. For a grade 5 1/2-20 bolt, it's 19,200. That's why for applications requiring high tensile strength like head and main bearing bolts, fine thread fasteners are used almost exclusively.
Fastener tensile strength

 
Back to top
View user's profile
36 Coupe
Tractor Guru


Joined: 12 Mar 2010
Posts: 6861


Report to Moderator

PostPosted: Sun Sep 22, 2013 2:00 pm    Post subject: Re: fine vs course thread bolts Reply to specific post Reply with quote

COARSE.Course is a golf course.Threads weaken a bolt.
 
Back to top
View user's profile
Dean
Tractor Guru


Joined: 29 Jan 1998
Posts: 17423


Report to Moderator

PostPosted: Sun Sep 22, 2013 2:11 pm    Post subject: Re: fine vs course thread bolts Reply to specific post Reply with quote

Bingo.

Fine thread fasteners have less thread engagement. This is the reason that fine thread fasteners are not recommended for use in materials such as cast iron, aluminum, etc.

Dean
 
Back to top
View user's profile
55deere70
Regular


Joined: 24 Sep 2012
Posts: 480
Location: central Mass

Report to Moderator

PostPosted: Sun Sep 22, 2013 2:39 pm    Post subject: Re: fine vs course thread bolts Reply to specific post Reply with quote

That's why for applications requiring high tensile strength like head and main bearing bolts, fine thread fasteners are used almost exclusively.

Really? Most head bolts and main bearing bolts I've seen are coarse thread. I don't think fine thread would last long in cast iron or aluminum.
 
Back to top
View user's profile
dpendzic
Tractor Expert


Joined: 05 Mar 2009
Posts: 2016
Location: long island NY and Hancock Ma

Report to Moderator

PostPosted: Sun Sep 22, 2013 3:24 pm    Post subject: Re: fine vs course thread bolts Reply to specific post Reply with quote

what i am trying to say is that fine thread has more threads per inch so the friction working against the torque applied is greater. However the strength of the bolt is determined by the yield strength of the steel--not the tensile strength--the limiting area is not the root diameter of the threads but a greater value A- sub t--determined by tests--and of course fine threads have a greater area than course threads so the ultimate allowed clamping force will be greater-but a slightly more torque will be required to obtain that.--In real life situations it is probably insignificant unless you have a required clamping force required. In all of NY state bridge design connection requirements it is standard to use course thread A325 7/8 diameter bolts tensioned to a load of 30000 lbs.-
The torque wrenches are calibrated each day with a load cell---sometimes load indicating flat washers are used---lock washers are never used.
 
Back to top
View user's profile
Charlie M
Tractor Expert


Joined: 25 Dec 2007
Posts: 2792


Report to Moderator

PostPosted: Sun Sep 22, 2013 3:26 pm    Post subject: Re: fine vs course thread bolts Reply to specific post Reply with quote

I have to plead insanity on this one.
 
Back to top
View user's profile
Bob
Tractor Guru


Joined: 03 Jan 1998
Posts: 50875


Report to Moderator

PostPosted: Sun Sep 22, 2013 3:57 pm    Post subject: Re: fine vs course thread bolts Reply to specific post Reply with quote

As an example, Cummins V8-470 and V-8 504 engines have fine- thread head bolts going into cast iron. Probably some pretty good stuff, maybe high nickel content???

Been so long since I worked on a 855 or other big Cummins I don"t remember if those bolts are course or fine.
 
Back to top
View user's profile
Display posts from previous:   
Post new topic    Yesterday's Tractors Forum Index -> Tool Talk All times are GMT - 8 Hours
Goto page 1, 2  Next
Page 1 of 2

 
Jump to:  

TRACTOR PARTS TRACTOR MANUALS
Fast Shipping!  Most of our stocked parts ship within 24 hours (M-Th). Expedited shipping available, just call! Most prices for parts and manuals are below our competitors. Compare our super low shipping rates! We have the parts you need to repair your tractor. We are a company you can trust and have generous return policies. Shop Online Today or call our friendly sales staff toll free (800) 853-2651. [ About Us ]

YT Home  |  Forums

Modern View Forum powered by phpBB © 2001, 2005 phpBB Group

All Rights Reserved. Reproduction of any part of this website, including design and content, without written permission is strictly prohibited. Trade Marks and Trade Names contained and used in this Website are those of others, and are used in this Website in a descriptive sense to refer to the products of others. Use of this Web site constitutes acceptance of our User Agreement and Privacy Policy

TRADEMARK DISCLAIMER: Tradenames and Trademarks referred to within Yesterday's Tractor Co. products and within the Yesterday's Tractor Co. websites are the property of their respective trademark holders. None of these trademark holders are affiliated with Yesterday's Tractor Co., our products, or our website nor are we sponsored by them. John Deere and its logos are the registered trademarks of the John Deere Corporation. Agco, Agco Allis, White, Massey Ferguson and their logos are the registered trademarks of AGCO Corporation. Case, Case-IH, Farmall, International Harvester, New Holland and their logos are registered trademarks of CNH Global N.V.

Yesterday's Tractors - Antique Tractor Headquarters