Barrel threading, how to do it?

[DM80]

I've done quite a few it's easy when you know how 😂

Dave.

[DCL_dave]

I've done quite a few it's easy when you know how 😂

Dave.

Hi ya,

That's the thing...it's the learning curve and the inevitable cock-ups in between that can frustrate, isn't it?...I'm guessing most engineering folk will have scratched their heads on their first few attempts at single point screwcutting?

I am not an engineer...The equipment I use is ancient - how many proper engineering folk have used a 100 year old treadle lathe?...not many I'll wager)...still happy to have a crack though, even if it usually means whittling a barrel down shorter and shorter and shorter...

[MartynB]

still happy to have a crack though, even if it usually means whittling a barrel down shorter and shorter and shorter...

At least you're honest

[DCL_dave]

At least you're honest

To thine own self be true...

On a side note, in the first response to this thread, Rich quite rightly mentions that if a big enough lathe is used then the breech block can just be fed inside the bore straight through the headstock. Whilst this is true, I guess it is worth mentioning that, to carry a HW breech block for instance, you would need a bore of at least 48mm through the headstock and it would still need to be held tightly in a custom made bush of some type to support the barrel along its length...my old Herbert lathe has a bore of 42mm, so that sucks!

[RobF]

Couldn’t you just use a lathe with a short headstock so you only have the barrel in it and the block is free?

Is that bore radius or diameter Dave, how big is the block?

[DCL_dave]

Couldn’t you just use a lathe with a short headstock so you only have the barrel in it and the block is free?

Is that bore radius or diameter Dave, how big is the block?

Hi Rob,


Yes I guess you could use a lathe with a very short headstock (know you of such a beast?) ...but you would still need to support the unequal mass of a HW breechblock that would be sticking out the back of the headstock (I think this is what a lathe spider would be used for?) otherwise, as it is spinning, the centrifugal force would try to throw the breechblock out/away from the centreline of the lathe spindle with disastrous results.


A HW80 breechblock is roughly 35mm x 18mm in cross sectional area, with an approximate bias of 24mm towards the bottom edge of the block (the bit that houses the barrel plunger and the cocking link) so to keep the barrel turning true to the centre of rotation along it's entire length, you would need a lathe with a spindle bore diameter of at least 48mm to accommodate the breechblock inside the lathe spindle.


I hope that doesn't sound too much like gobbledygook?...but I suspect it does...

[RobF]

Hi Rob,


Yes I guess you could use a lathe with a very short headstock (know you of such a beast?) ...but you would still need to support the unequal mass of a HW breechblock that would be sticking out the back of the headstock (I think this is what a lathe spider would be used for?) otherwise, as it is spinning, the centrifugal force would try to throw the breechblock out/away from the centreline of the lathe spindle with disastrous results.


A HW80 breechblock is roughly 35mm x 18mm in cross sectional area, with an approximate bias of 24mm towards the bottom edge of the block (the bit that houses the barrel plunger and the cocking link) so to keep the barrel turning true to the centre of rotation along it's entire length, you would need a lathe with a spindle bore diameter of at least 48mm to accommodate the breechblock inside the lathe spindle.


I hope that doesn't sound too much like gobbledygook?...but I suspect it does...

No that all makes sense. I just saw some short headstock lathes on a gun smithing page on Facebook so wondered.