Link Pin pinch bolts

[rrcade]

Anyone know who carries the M10x1.4x45mm Pinch bolts? Also what hardness should they be? I hear they should but hardened which to me means 10.9 minimum but the old ones say 8G on them which I hear is equivalent to US grade 5 bolt, so what should they be?

[Piledriver]

Fastenal.

If they don't have it, they can get it.

[Dale M.]

SAE Grade 5, 120,000 psi.
Metric 8.8, 120,000 psi.

If you want more robust...

SAE Grade 8, 160,000 psi.
Metric 10.9, 151,000 psi.

Should bolt not be listed as M10x45x1.4 ( diameter, length, thread pitch) ... Also not sure if 1.4 mm is valid thread pitch, most are either .75 or 1.0 or 1.25 fine thread or 1.50 mm course thread pitch in that diameter range...

http://www.engineeringtoolbox.com/metri ... d_777.html

Metric bolts are everywhere...

Dale

[Piledriver]

They are probably fine pitch 1.0mm.
(choices are 1.0, 1.25 or 1.5mm)

Pick a random 8mm bolt out of your bolt pile (1.25mm is German std) , if they are finer thread than that they are 1.0.

[rrcade]

That was a typo, they ARE 1.5

[rrcade]

O.K., lets assume I live in the USA...because I do. If I want to replace my chewed up pinch bolts should I be looking for 8.8 or 10.9 hardness? Not being a bolt Expert I wonder are the harder bolts also more brittle? I would prefer to replace my old ones with the correct new ones not someones best "guess"

[Ol'fogasaurus]

I did a search on "pinch bolts" as they were not something we used. One thing of some importance that I did find out that they do weaken up over time as they are "readjusted" which I could call cycles which most bolts do do. If you can identify the strength of the fastener I would stay with it as there is probably a reason for the engineer specifying the strength maybe because of properties of (one or more of the) component parts.

Brittleness is not a component of grade changes but of other things. Failure of a fastener at a certain point is something in a special design feature and brittleness is probably not the right word for it. And yes, there are explosive bolts and require specialists (licenced?) to work with them.

The statement that an 8.8 (metric) and an grade 5 (SAE) were the same sounds about right; it is the equivalent grade SS bolts that are slightly less than the Grade 5s.

Slightly off topic is that some bolts are measured by stretch not torque and (this is something new to me) some bolts are measured by diameter; e.g., thinning due to stretch.

Fasteners are fun to look into and when I could do it I was into the design book as much as I could be.

Lee

[PhillipM]

O.K., lets assume I live in the USA...because I do. If I want to replace my chewed up pinch bolts should I be looking for 8.8 or 10.9 hardness? Not being a bolt Expert I wonder are the harder bolts also more brittle? I would prefer to replace my old ones with the correct new ones not someones best "guess"

10.9 are fine in terms of 'brittleness' - so are 12.9s, so long as they're not in a corrosive environment (they can suffer from stress corrosion cracking under certain conditions - that's why 10.9's are more common for wheel studs, etc)

[Ol'fogasaurus]

I think the term "brittleness" is being confused with "yield strength". As part of the heat treating process there usually, usually after the main heat treat there are/can be several other heat treats one of which is to take brittleness out of the fastener. If you do a search on "dot edu" and my name as the origionator I posted some urls to videos on makeing stuff and the forming of bolts is in there.

Yield strength is one on the reasons there are charts showing torque limitations of the different bolts that are tightened. The other options are measuring the length change or diameter of the bolt.

Lee