Question regarding "standard" bolt shoulder lenghts

[ctmtwilliams]

Is there standardized formula or rule of thumb, for determining shoulder(shank)length versus total length, of a grade 8 hex head bolt? I am looking for a chart or a rule of thumb that shows the how long of a bolt is required
to get specific shoulder length. For instance. How long of a 5/8" bolt would I need to have 3 3/4" shoulder?

Thanks in advance.

 

[desertfox]

Hi ctmtwilliams

have a look at this link:-

http://www.steammechanic.net/newMPS_MSD/msd/MDS_Series_N%B02_Screw_bolts_and_nuts_1910.pdf

desertfox

 

[dvd]

minimum thread length = (2 X diameter)+1/4"
maximum thread length is longer

If you want a specific length of unthreaded shoulder then you may need to buy a shoulder bolt.

In your example above: minimum thread length = 2x5/8 + 1/4" = 1 1/2" so you would need a 5 1/4" long bolt, except they don't come in that length.

 

[flash3780]

For inch fasteners less than 6 inches:
Min thread length = 2*D + .250"
For inch fasteners greater than 6 inches:
Min thread length = 2*D + .500"

Shank length = Total Length - Thread Length

Ref: Shigley, Mechanical Engineering Design (2001)

You may also want to look into Bickford's book for more details about bolts and bolted joints.

 

[ctmtwilliams]

Thanks for the input. In my particular application I am dealing with shouldered bolts that we cut some of the threaded length off. We may use a 5/8 bolt that needs 5" of shoulder, but we only need "?" of thread. Since they don't make a 5/8 bolt with 5" of shoulder that has only "?" of thread, I use a standard full length bolt, and cut the un-needed threads off. Is there a way / formula to calculate the total bolt length given the shoulder length (not thread length)?

 

[dvd]

It's time to get to the library or use your books if you can't get the answer from the information above. Good luck!