Bolt Specs....?

[tdfsu9]

I have a drawing with a bolt description:

2x4 LG S.F. Tap Bolt - 8thd

Can anyone give me a heads-up as to what these terms mean?

Thanks a bunch.

 

[mog69]

Assuming all other dimensions on the drawing are in imperial units, I would normally interpret it as a notation for 2" diameter thread, 4" long ("LG"), 8 tpi (threads per inch ["thd"])which would probably be defined by the Unified Constant Pitch Series.
However the term "S.F.Tap Bolt" appears to be an abreviation of Self tapping bolt, and I haven't come across a self tapper this big before !

 

[unclesyd]

In the trade "Tap Bolt" normally referees to a bolt threaded all the way to the head.

I asked around and no one picked up on the "S.F." part, still asking.

 

[tdfsu9]

Thanks guys.

"thd" is the same as "tpi" (threads per inch)? I would never have guessed that.

 

[unclesyd]

That's is just another part of the vernacular around the fastener supply houses. I have very seldom heard the term threads per inch used, it is always "give me 20 2"x12" 8 thread, 7 thread, or what ever.

Another quirk is the length callout on fasteners, especially studs. If nothing is said the length will be end to end which takes a little usable thread off due to the chamfer. More and more people were calling out 1st to 1st , the first good thread. Now that material cost has gone through the roof the callouts are back end to end.

 

[tdfsu9]

Any recommendations on where to purchase bolts of this size?

Thanks again.

 

[diamondjim]

Try this:

http://www.thomasnet.com/products/bolts-large-diameter-6611008-1.html

 

[unclesyd]

You might contact MIke Jones at:

http://www.ameribolt.com