bolts

[ubhat]

how to identify whether a bolt is metric or british or unified series by just looking at it?

[Bridger]

look at it right next to a thread pitch guage....

[Juergen Hannappel]

Take some metric, british and unified bolts, mark them, practise until you can. If in doubt, measure.

[bw]

Better quality bolts have head markings.

[Edwin Pawlowski]

If you join the Handyman Club Of America, you can get a gauge that has different holes to check sizes. You can order a nifty jacket also.

[john]

very easy(usually), metric bolts have DIN number on bolt head ie 8.0,

8.8, 10.0 and so on. this number signifies hardness and the hardness increases with the number. unified (which I call SAE, Murican, and the way things ought to be in this world!) are graded with hash marks and are called grade 4,5,6,8 with 8 being very hard. no mark means soft or junk or from the farm store (no offense, I like farm stores!)

aircraft (AN) are (almost) always a fine thread and the diameters are respectful of the Murican, SAE convention but (almost) always have an "X" on top and are superior in tenstile strength.

metric bolt pitch is signified in threads per mm. 1.00, 1.25, 1.50 threads/mm

remember, when it comes to fasteners the term "always" is never used

john

[Phisherman]

Well yes and no. You need a set of (English and metric) thread gauges which will tell you (by looking carefully) the English or metric size. Without the gauges, you could count the threads against a ruler with both English and metric divisions.

[Philski]

ROFLMAO!

Philski

[Silvan]

I saw someone wearing one of those the other day. Had to hide my mouth behind my hand so he didn't see me chuckling at him.

[Edwin Pawlowski]

Talk about timing. I said this in jest and guess what arrived in the mail yesterday? They sure make it hard to say no when they offer such nice gifts, indluding address labels with the Handyman logo. Maybe if I sign up, I can be a tool tester and get a free X-5 Unisaw.