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Sep 13, 2017

Socket spanners for small hex nuts


After years of messing about with makeshift methods of tightening small nut sizes, the increasing complexity of my models, declining digit dexterity and the need to do multiple fit and disassembly pointed to a need for hex sockets from 3mm to 10BA bolt sizes.

Not finding them available on the net required them to be made. Being blessed with years of collected bits that will 'come in useful ', the answer lay in the accumulated Allen keys that seem to have bred over time and the shanks of damaged pin and other punches.


After annealing the punch, the pointy end is turned or ground square to the shank with a size just larger than the hex head in question . The punch is then drilled with a hole diameter equal to the distance across the flats of the hex nut.

Selecting an Allen key with the closest size to the nut in question (slightly smaller is better than too big) the end of the key is roughly ground to provide a lead into the hole.

Heating the end of the punch to cherry red the key can be started into the hole and hammered in. With subsequent cycles, usually two or three, the hex hole is formed deep enough to just allow the nut or bolt head to sit flush. A bit of wiggling when the punch is at red heat will allow a smaller key to make a larger hole.

Naturally these sockets may be made from silver steel stock. Each socket has its size stamped at the blunt end and the working end hardened and tempered.


The sizes shown in the picture are sizes from 3mm to small head 8BA,

my 10BA has gone walkabout hence the bait box now holds the sockets.

The process takes less time to complete than to write about.

New Posts
  • Noisy Andrew
    Jun 17, 2018

    I came home form Hairy Forebears (Hare & Forbes, our local machinery shop) with 250kg of semi precision metal. I imagine the thing and I may have a initial problems communicating as it speaks Mandarin with a Deutsche accent. But it seems happy to be sitting in my workshop (aka glorified garage) for the moment. I'l post a pic and thoughts about it when I have it assembled and on a bench. This household blames you for the sudden need to create swarf. ~ smiles ~ Actually the need is not all that sudden. You've just poked me along. so forum members, I'f you've just bought a machine? Why not use this thread to post a pic of your new setup (with initial costs to get going etc), as a guide to folk who may want to get grease under their fingers
  • lonniekoehn
    Jun 7, 2018

    I am having a devil of a time trying to find anything ba or me here in the states. Im fairly new to the world of model engineering so I’m still figuring out where to source all the fiddly bits that are required. I’m currently machining out a stuart double 10. Is anyone aware of any dealers here in the states I can find “ba“ bolts and nuts and “me“ fittings? As of now it appears as though I will be ordering everything from across the pond and paying out of the nose for shipping. Any advise you experienced gentlemen and ladies can send my way will be greatly appreciated.
  • charliepipes
    Jun 17, 2018

    In Keith's video ASSEMBLING A HIGH QUALITY MODEL STEAM PLANT - PART #16 he discusses a set of BA wrenches that are available from Blackgates. Living in the U.S.A. I have acquired a number of English Steam Projects. To date I have not found an American supplier that could help me with the BA stuff. So I ordered the ones in the video. I was contacted by Jacquie from Blackgates the next day and thru the wonder of the internet they should be here this week. Total cost in the USA with shipping was $14.00.