Thread (as in bolts etc) query

Message

MartDude · #1 Post by **MartDude** » Fri Feb 04, 2011 7:29 pm

How close, or otherwise, is 3/8" Whitworth to 3/8" UNC?

Need to make some joining bits for modding some shelving I've just bought.

Willopotomas · #2 Post by **Willopotomas** » Fri Feb 04, 2011 7:44 pm

Hmm.. Good one. Both 16tpi.. The angle of the thread is different though.. Whitworh is 55deg, UNC is 60deg. Also the pitch may be different.. Whitworth threads are quite a fine pitch (depth of the thread). Will locate me zeus book if no one else can help.

MartDude · #3 Post by **MartDude** » Fri Feb 04, 2011 7:54 pm

I think you've answered my question, Will. The bolt supplied, which goes in to a threaded insert, looks to have a deeper thread than the 3/8 Whit. bolt I offered it up to, although the thread spacing (that the right terminology?) is the same. So, UNC?

Willopotomas · #4 Post by **Willopotomas** » Fri Feb 04, 2011 8:10 pm

Every chance it's UNC then..

Out of curiosity.. What's it for? Most modern units are metric threads.. 3/8" is roughly 9.5mm, so it could be M10, which is also a 60deg angle. Not sure on TPI though.. Not worked out the same ye see.. Being metric n' all..

MartDude · #5 Post by **MartDude** » Sat Feb 05, 2011 8:52 am

Each shelving units consist of 4 chromed tubes, ca. 30 mm dia. These are linked by the shelves themselves, with a clever & discreet sliding/clamping arrangement at each corner, through which the tubes pass. Each unit is ca. 870 mm. high. I want to stack one on top of the other. The easiest way to secure the two together seems to be to invert the bottom unit (the shelves & clamps will work either way up), & utilise the threaded inserts, provided in each tube to receive the threaded adjustable feet. I'm planning on threadlocking, or soldering, a ca. 75 mm. length of threaded rod into the one, & screwing the other tube on to that. Should be strong enough - there'll be no lateral stress on them, the load will be vertical.

The thread is definitely not M10. The units are made in China, so perhaps they're made to suit the US market - imperial sizes are still widely used there.

The purpose of the units is to achieve and sustain marital harmony - Gill has been expressing a distinct lack of empathy with, and sympathy for, my need to keep helmets on the dressing table, boots under it, and gloves, biking underwear etc. wherever I can find a corner. I've promised I'll rationalise the bike kit storage, if she'll do the same for the NATO strategic stockpile of old coffee and jam jars cluttering up the kitchen. I'm keeping my part of the bargain - but no movement of the jam jars as yet; a surreptitious tactical stock reduction programme may have to be implemented.

Willopotomas · #6 Post by **Willopotomas** » Sat Feb 05, 2011 9:44 am

Mart.. I feel your pain mate..

Can't see the Yanks using Whitworth, so UNC it is..

MartDude · #7 Post by **MartDude** » Sat Feb 05, 2011 10:01 am

Cheers, Will.

MartDude · #8 Post by **MartDude** » Sun Feb 06, 2011 10:24 pm

Got some 3/8 UNC rod and it fits. Job's a good 'un.

Willopotomas · #9 Post by **Willopotomas** » Sun Feb 06, 2011 10:31 pm

Happy days