Transmission Bolt Measurement Please

[JJ 911SC]

Related to this oversize hole; Another M12 Transmission Mount Hole Screw Up

What is the overall lenght of this bolt? Pelican Parts - Product Information: 930-375-317-01-M100

By scaling it about 68mm, which match what I have (64mm without the point) but once you put the Lock-washer (7), concave Washer (6) and tread it through the mount (5) there is only 12mm of tread sticking out which seem short mind you there is not that much weight at that end.

Thanks

JJ

[kerthunk]

Overall length is 68mm. About 12mm of threads stick out from the top of the mount. This is with the mount on the bench, so there is no compression of the mount happening.

[JJ 911SC]

Originally Posted by kerthunk

Overall length is 68mm. About 12mm of threads stick out from the top of the mount. This is with the mount on the bench, so there is no compression of the mount happening.

John

Thanks. Its exactly what I got but I find it "strange" that a 12M bolt only goes 12mm in.

On my mount there is no compression possible as there is a steel bushing in the center that is about 2mm above the rubber on both side.

[Jim2]

JJ, I don't know how to describe this in a technical fashion, but once the thread engagement length equals the bolt diameter, the thread engagement strength equals the bolt strength. So 12mm bolt and 12mm of thread engagement sounds correct.

[proffighter]

Originally Posted by Jim2

JJ, I don't know how to describe this in a technical fashion, but once the thread engagement length equals the bolt diameter, the thread engagement strength equals the bolt strength. So 12mm bolt and 12mm of thread engagement sounds correct.

I've learned max is reached at 1.5 times diameter for regular threads... But here it's a fine thread, so it seems to be fine and I don't think the M12 here is forced to the limit

[JJ 911SC]

Thanks guy

Working daily with 1st Level fastener (for submarine) as per Roland mentioned 1.5 is the norm but the with there is not much weight involve here.

Finally found it from: http://www.roymech.co.uk/Useful_Tables/Screws/Thread_Calcs.html

The following rules of thumb are suggested for arriving at reasonable lengths of thread for steel screws used with screwed holes in weaker materials.

For steel a length of thread engagement of at least 1 x Nominal dia's of the thread
For Cast Iron or brass or bronze the thread engagement should be at least 1,5 x Nominal dia's of the thread
For Aluminium , zinc or plastices the thread engagement should be at least 2 x Nominal dia's of the thread