Those coupling-sleeves again...

[Crispianus]

The photo scale of 1/3 and the "sleeve" measurements of 3.2cm do not coincide, being around 50% larger when compared with the large spearhead socket width of 3.6cm which is also at 1/3 scale, in other words the sleeve photo should be reduced by 1/3.
Its clear that the length measurement is wrong and should be no more then @11cm.

The "Sleeve" is made from a piece of iron plate that has been formed into a tube, rather like the grip (Högonas sword) I previously mentioned from an earlier era, except that the join appears to be open, not brazed (or welded) shut, although this may have been destroyed during cremation.

Andronicos actually gives the length of the supposed coupler at 0.17m or 17cm = 6.7". Again, I cannot for the life of me see that as a coupling device.

The size is given as 17cm length x 2.8-3.2cm width,  17 cm is clearly an error, the problem is that this seems to have been accepted by every author since including its identification as a coupling sleeve, for which there is no real evidence.

Heres a sketch, the first sleeve is 17x3.2cm as per measurements from "Sarissa" Andronicus, the second is 11x3.2cm based on the photo of the same article and the photo of the cast copy with ruler posted by Giannis K. Hoplite, which one most looks like the original in proportions:

   

The earlier Högonäs sword Grip of Tubular iron which is somewhat similar:

   

Noted for its early use of brazing the joint on the grip which was made from an iron plate as well.
Source: "Notes on Prehistoric and Early Iron in the Old World" By H.H.Coghlan.(Pitt Rivers Museum) 2nd edition 1977.
Originally from: "Metallteknik under Förhistorisk Tid", A.E.Oldenburg 1942-3