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Does anyone know why a 10mm metric bolt/nut sometimes has a 17mm head and more and more often these days (it seems) has a 16mm head. 12mm fastners are the same (use to always be 19mm but 18mm seems to be gaining popularity, I've also come across a few 11mm heads on 6mm bolts (generally 10mm).
Any thoughts?
Dan
Yeah Buy a Shifter! ;)
Mwahahaha... :D
The price we paid for going metric. To the best of my knowledge all Aussi bolt manufaturers still make Whitworth threads. Metric stuff is imported and it depends on the country of origin as to the standard they follow. Reflected in the price, Whit still cheaper!
Glenn
My guess would be that those bolts come from countries that buy redundant/outdated tooling. The bolt heads are still done in presses that are actually for imperial bolts. The thread is cut on metric machines. Quite often if you measure the unthreaded part of the bolt you will find that it is not metric but actually closer to a imperial equivalent. A 11 mm spanner usually fits a 1/4" bolt head and a 10 mm spanner fits a 6 mm bolt head.........mix the two and you get a 6 mm bolt thread with a 11 mm head. Same apply to the nuts that they supply.
Could that be called.........cutting corners and making a buck no matter what?
Thats my guess for what its worth
Most bolts/nuts in Oz are now made in SE Asia. Even Ajax outsource most these days from there (or so I heard).