A submachine-hammer looks pretty much like a regular hammer, save for the Parkerized or nitrided finish and the perforated shroud around the head; it even acts like a regular manual hammer. But...

Pulling back the cocking handle, located on top of the head, chambers the first round and turns it into a semi-automatic power-hammer, each 'shot' set off by the shock of hitting a nail on the head.

Unfold the trigger hanging off the head, change your grip appropriately, and it becomes a small semi- or even fully automatic pile-driver.

Innardsly, it's pretty much a simple submachine gun - recoil operated, triggered from the open breech - with an hammer head screwed into place instead of a barrel, fed by full-load blanks residing in the handle. The heavy (depleted uranium core) breechblock acts as the sledge in a double-strike hammer <link> fashion.

et cetera : stripper clip loading, magazine cutoff for manual operation, set screws for powder strength and breakpoint, various safeties.
-- FlyingToaster, Oct 02 2015

Adding a bit of oomph to Double_20strike_20hammer
[FlyingToaster, Oct 02 2015]

St.Darwin's Day celebrations. https://www.youtube...osive+sledge+hammer
early proof of concept. [FlyingToaster, Oct 02 2015, last modified Oct 03 2015]

[+]

Want.

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-- 8th of 7, Oct 02 2015


What [8th] said, except that I have only one bun to give.
-- Voice, Oct 02 2015


Excellent. An alternative use for bullets - but will this not detract from the current population control program?
-- MaxwellBuchanan, Oct 02 2015


Oh, not much worry of that: see second link.
-- FlyingToaster, Oct 02 2015


Could you get away from the depleted uranium breechblock, gas control by having the explosion vent like a rocket? Casing removal from the breech would still be needed. With the swing of a hammer, there is usually not much is behind the hammer head's arc. Power control could be done with a changeable blast cone shape. Builders working in semi light would be visually pleasing.

Idea reminds me of a hammer tacker.
-- wjt, Oct 02 2015


Ah, not mentioned in the post are the venting ports from the back of the chamber, leading back and to the sides: there would be some fireworks.

The blast can't be straight back though. While in normal mode the handle is gripped near the bottom with one hand, it can also be used, semi or full-automatically, in "piledriver mode", one hand just under the head, finger on the trigger, the other pushing the hammer head down onto the nail.

Making the core of the sledge very heavy (and the rest of the head relatively light to compensate) stems directly from the open breech design, which is less fiddly and has better cooling than closed breech. In the context of a machine hammer it's also safer, and more ergonomic (the hammer won't bounce around as much).

Given that, it's better to have a light hammer give the breaking(unlatching) tap and have the heavy sledge augmenting the power pulse, rather than the other way'round.
-- FlyingToaster, Oct 03 2015


Cool, seen from straight afar . I'm happy.
-- wjt, Oct 03 2015


Yes, me too. What 8th said. Cool, very cool.
-- blissmiss, Oct 03 2015


The hammer is vented, but I didn't include it in the post 'cuz then there'd need to be a section entitled "So You Didn't Read the Owner's Manual and Now You're On Fire".

If you mean open vs closed breech (Sten vs Uzi) actions, then it's a matter of user ergonomics: 'closed' transfers all the breechblock's bucking momentum to the operator all at once whereas 'open' splits it up, making the hammer easier to manage in semi-auto mode.

If you mean heavy vs light breechblock(sledge), that could be a personal preference but bear in mind that a light sledge means that if you don't break the nail's stiction during the manual part of the blow then you're wasting most of the energy you put into it.
-- FlyingToaster, Oct 03 2015


Is there a flamethrower version? Something gas-powered could work just as well while also shooting flames everywhere.
-- sninctown, Oct 03 2015


Want. Bun.
-- whatrock, Sep 20 2016


Just make sure you've hit the nail on the head.

Although, the sten hammer might be used, cleverly, to make a nice scaly pattern in a piece of timber.
-- wjt, Sep 21 2016


+ Criminally inventive!
-- xandram, Nov 16 2021


I thought the guiding principle behind the design of the original sten was that it could be manufactured entirely out of standard plumbing spares. I wonder whether that would still be true of this variant.
-- pertinax, Nov 16 2021



random, halfbakery