| Author | Message | ||
     Ferrisbuellersdayoff |
front motor mount vibrated one bolt out of the head and sheared the other off, gonna replace them, but my tap and die set is 300 miles away, anyone know what size and thread they are? in a small town with no stealership, gonna be doing some hardware store parking lot heart surgery in the AM. | ||
| Ducbsa |
For an '07, it is PN AA0712.02CZB 7/16-14 x 1.5" lg socket head Probably want Gr 5 or 8, but you knew that. | ||
| Cataract2 |
He will want Grade 8 for those bolts. Don't skimp. | ||
| Nobuell |
I do not believe there is a Grade 5 or 8 as it relates to inch series american, Alloy Steel Hex Socket Cap Screws. They should be made to conform with ASTM A-574 and should have 180 ksi minimum tensile and should be heat treated to 39-45 Rockwell C hardness. There are no multiple grades that I am aware of. They should not be listed with any grade other than ASTM A-574. Metric sizes are available in class 8.8, 10.9 and 12.9 however. | ||
| Terrys1980 |
There are different grades in american sizes. On the head of the bolt a grade 5 will have 3 markings or lines, a grade 8 will have 6. Grade 8 bolts will have a golden color. (Message edited by terrys1980 on July 17, 2010) | ||
| Eldredma |
Grades 5 and 8 are non-engineering speak for the specs you referenced NoBuell... there was a time when ASTM didn't exist. They are still differentiated by the markings as Terrys said; however, they aren't necessarily only gold anymore. At a hardware they will still be labeled "Grade 5" or "Grade 8"... have you ever seen anything at Lowe's that says "conforms to ASTM" anything? | ||
| Nobuell |
I actually did not want to be smart about it. I was just saying that there is no such thing as a grade 5 or 8 american threaded hex socket cap screw. I know the head markings are on a hex head cap screws but there are no markings on a hex socket cap screw. I just did not want him looking for a grade reference or mark that does not exist. ASTM has existed for over 100 years and has had fastener standards since the 60s. | ||
| Terrys1980 |
We are all confused. All socket cap screws follow ASTM and are grade 8 or better, as long as its not stainless. Hex head bolts follow SAE. | ||
| Gunut75 |
Terry is right. Stainless fasteners are softer than the black steel ones. | ||
| Nobuell |
It is not that clear. There are many standards out there for bolts: ANSI, ASTM, SAE, ASME and IFI to name a few. There are many over lapping areas of standards. SAE bolts will typically have the lined grade markings were none is grade 1, 3 lines are grade 5 and 6 lines are grade 8. Many ASTM hex head bolts have the standard number stamped, i.e. A-325. ASME fasteners will have a standard number stamped such as B7 or B16. A good rule of thumb would be to consider a hex bolt with no head markings to be Grade 1 or approximately 60 ksi tensile strength versus a Grade 8 at approximately 150 ksi yield. It can be very confusing if the bolt standard is not known when buying from a hardware store. However, all socket cap screws made of alloy steel meet the requirements of ASTM A-574. The standard does reference stainless steel and does not specify different mechanical requirements so they should be the same strength wise. So, socket cap screws from a hardware store should meet the ASTM requirements. Unless they are Chinese counterfeits that are starting to show up. But that is another story altogether. | ||
| Nobuell |
A clarification on the stainless socket cap screws. A stainless socket cap screw that conforms to ASTM will have the same mechanicals as the alloy steel version. The stainless for an ASTM screw will be a heat treatable high grade such as a 17-4 PH. Most hardware store stainless steel fasteners will be an 18-8 grade (300 series) and will be about the same as a grade 1 carbon steel bolt depending on the amount of work hardening and normalization. |
