What ist?

I wonder is it a form of reamer to ream out an old bolt that has sheared ?

Do the twists follow through or do they go in opposite directions?

Is it some sort of adapter? If the small end fitted into summat, using the nut in the middle to screw it in to the summat, you'd end up with a bigger, open end - or, in reverse. you'd have a smaller end piece and it would be a reducer.

I know what I mean even if 99.99999999999999% of the rest of the world haven't a clue.

Do the twists follow through or do they go in opposite directions?

Is it some sort of adapter?  If the small end fitted into summat, using the nut in the middle to screw it in to the summat, you'd end up with a bigger, open end - or, in reverse. you'd have a smaller end piece and it would be a reducer.

I know what I mean even if 99.99999999999999% of the rest of the world haven't a clue.

Ir you look down the length from the 'nut' they each twist to the right from either end if that helps?

Sorry veggie, include me in all the nines!

MrB think's its some sort of drive coupling that seized and twisted it.

He says they're twisted because it works at 90 degrees, connected to the bevelled gearbox, or something. Or maybe a spiral bevel gear, he's just said (he's been googling all evening, liking an engineering conundrum).

Likewise PP! Just it bugs the excrement out of me when I can't find anything similar.I understand the principle of a crown wheel, pinion and planet gears but can't figure how this would equate?

Where's Fred Dibner when you need him?

I'm glad someone understands 

And as for Fred Dibner, felling chimneys in the sky!!

He says they're twisted because it works at 90 degrees, connected to the bevelled gearbox, or something. Or maybe a spiral bevel gear, he's just said (he's been googling all evening, liking an engineering conundrum).

Likewise PP! Just it bugs the excrement out of me when I can't find anything similar.I understand the principle of a crown wheel, pinion and planet gears but can't figure how this would equate?

Where's Fred Dibner when you need him?

I'm glad someone understands 

And as for Fred Dibner, felling chimneys in the sky!!

I read Freds lifestory book. He was also an innovative engineer building his own winding gear and pit shaft in his back garden and restoring and running Steam Traction Engines.  One of life's characters!