what is proper bolt nomenclature,

I have a bolts I want to purchase more off.

Went to HomeDepot and sized the bolt in their display and it fit the M8 - 1 hole.
What does that mean?

The threads are 15mm in length and the head is 5mm in width for a total length of 20mm.

I assume my bolt is a 8 - 1 - 15 is that correct.

It is also a Torx head, are they described similarly as other bolts?

Scott

"M8" refers to thread pitch.

I'm not to keen on metric fastoners - But I do beleive that "8-1" means 8 thread per 1mm.



Torx (with IS trademarked) is just the form of head on it. More commonly you'll see SHCS (socket head cap screw) FHCS (flat head cap screw) Carrage bolts, and Button head's. I recommend looking up "Industerial Fastoners" (with the correct spelling, of coarse) in your local yellow pages. The guy behind the counter will more than happy to assist you in finding the proper bolt, and depending on quanity, he might just give you it, and it's not even worth his time to ring up (their around $.08/ea.)

__________________
-1983 VW Rabbit LS Diesel (5speed, VNT/Giles build)

I do not know what the #1, is but metric bolts are identified as follows:

8mm (major diameter of threaded area, not head size or root of thread), 1.0 (thread pitch, crest to crest in mm) You will find thread pitchs of .5 (very fine), .75 (fine), 1.0 (average), 1.5 (medium), 1.75 (coarse).

American standards are identified by TPI (threads per inch), ie 5/16-18 (5/16 diameter X 18 threads per inch.

If in doubt do a google search on metric hardware.

Michael

EDIT:
Length does not include the head thickness, the only exception is with flathead hardware, flatheads are measured by total length.

Ninety300E is correct. Also to be considered is material(alloy), grade(strength) and finish(plating). Metric nomenclature usually starts with "M" such as M8-1 x 15 Socket Cap etc. The book I have here (from Tacoma Screw Products) shows standard M8 to be pitch 1.25 and M6 to be 1.0. However that doesn't mean you don't have a M8-1. A pitch of 1mm = 25.4 TPI and 1.25mm = 20.3 TPI so you can measure how many threads in an inch and figure out the pitch. And the diameter is pretty easy to measure.

Mike

__________________
1998 C230 330,000 miles (currently dead of second failed EIS, yours will fail too, turning you into the dealer's personal human cash machine)
1988 F150 144,000 miles (leaks all the colors of the rainbow)
Previous stars: 1981 Brava 210,000 miles, 1978 128 150,000 miles, 1977 B200 Van 175,000 miles, 1972 Vega (great, if rusty, car), 1972 Celica, 1986.5 Supra

Every know and then I like to just thank everyone for ALL the incredible answers to all my questions - lots of time I get private answers where I cannot write back and thank that individual.


I used a gauge at Home Depot to get the 8 - 1 size and after using the techniques here on this forum it may well be a 8 - 1.25 pitch.

I wanted to duplicate the Torx style head but at this time I just want an allen head due to the bolt location. On Monday I'll go to some supply hoses and see what I can find.


Stay cool and safe!


Scott
1998 C230 86K - best car I could imagine owning.

Ethan, check out www.mcmaster.com for your hardware needs as well as to gain all info needed on bolt grades, sizes etc.

Do not attempt to "change" metric to inch........metric is a superior method of measurement.

Michael