2009/6/12 Douglas Pollard <dougp...@verizon.net>: > The Germans have have a set of metric standards the English have > ISO standards and the Spanish have still another.
I _think_ that DIN (German) BS( British) JIS (Japanes) and the rest have all converged on ISO (Inrternational) but I might be wrong. > Imperial bolts are designed to break before the threads pull out > of the parent metal. The best thread pitch is picked for the bolt > diameter to achive this partially by having a smaller or larger root > diameter. Ah, but you eschewed the One True Thread angle (Whitworth 55 degrees), rounding up to 60 degrees, which has a fractionally less optimum ratio of self-locking to tension. The least useful standard I have come across is UNF, which seems designed to seize irretrievably at the first hint of corrosion. In contrast I have dismantled bits of old commercial vehicles left in fields for 70 years where the hexes on the (Whitworth) nuts were half their original size, and they just unscrewed like normal (once we found a random socket that nearly fitted) This might be a good time to point you at my "Thread identification table" which lists all the threads from all the standards I could find at the time in the same table, in size order. In retrospect I omitted the metric sizes below 3mm, and similarly many of the smaller American sizes. http://www.bodgesoc.org/thread_dia_pitch.html (You can click the headers to link to lists sorted differently) -- atp ------------------------------------------------------------------------------ Crystal Reports - New Free Runtime and 30 Day Trial Check out the new simplified licensing option that enables unlimited royalty-free distribution of the report engine for externally facing server and web deployment. http://p.sf.net/sfu/businessobjects _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
