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OT - Common threads in USA - equiv to M3

I am currently having to convert a metal electronic enclosure ( think of it as a usual 2U rack case with the usual "Pem" fasteners, standoffs etc etc) from a European context to a USA context.

Can people give me a clue as to the most common thread sizes people use in the USA that are equivalent to the Metric M3 range for both self tapping and ordinary threaded machine screws. There are also few self tap screws into plastic as well - I have M3 equiv threads for these - what is the equivalent common USA thread form to use as an equivalent.

I suppose I'm asking - when a service engineer or someone takes off the lid and then loses the screw, as we all do :-) - which one will he pick first from his jam jar of spare nuts& bolts to try out in the hole.?

The product is a usual consumer/semi pro piece of electronic/AV equipement.

Jonathan

Reply to
jjs
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I think 10-32 is the normal screw thread for rack mount.

TOP

Reply to
TOP

Thanks Paul for looking

I have that the EIA standard for 19" racks. Its more the generic sizes that people specifiy for PEM fasteners (pcb standoffs, pem nuts , etc within the cabinets. In general - what is the first thread size US engineers think of using. Over here the first size for this sort of work is M3 ( 3mm OD dia threads) and the corresponding nuts etc, but the M3 size (and M2.5) tends to be at the core of it all.

I'll probably stick to M3 as it is also being shipped world wide as well.

Just wanted to see if anyone had thoughts on the clash of these two systems and how the play out in the global mmarket.

Jonathan

Reply to
jjs

If you are looking for what somebody would buy in the local Radio Shack for electronics work it would be the 10-32, 8-32 and 6-32 series with slotted head. All your crimpers are setup to work with these sizes.

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Reply to
TOP

Thanks Paul - thats the sort of info - what the common man uses and would expect to have to use

I presume as you didn't mention the 4-40 its a bit to small at 2.8mm OD compared to the 6-32 at 3.5mm OD and not the common size used.

Thanks again

Jonathan

Reply to
jjs

Here is a chart that I have found handy as a quick reference between metric and imperial screw sizes. Hopefully others here will find it handy as well.

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Reply to
jlbeen

Nice. In the M3 size range, keep in mind that 5-40 is rather uncommon, but 6-32 and 4-40 are everywhere.

Best regards, Spehro Pefhany

Reply to
Spehro Pefhany

Your chart has an error. #2 = .086 not .096

Reply to
Eddie

Thanks for the heads up. I have updated it with the correct value.

Reply to
jlbeen

Thanks for all your advise - and help

Jonathan

Reply to
jjs

Actually, we use 4-40 quite a bit in electronics. The inserts that are used to put metal threads in plastic parts usually come in one OD and are threaded either in Metric or English. Quite often the M3 part is used for

4-40. The M2 part is usually used for 2-56.

Jerry Steiger Tripod Data Systems "take the garbage out, dear"

Reply to
Jerry Steiger

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