Congrats on your new mandau Detlef!
The fundamental style of the carvings is reminiscent of those of the Kayans/Kenyah of East Kalimantan, although the execution in this piece is rougher and somewhat more primitive than that of older 19th cent. pieces: It carries the main jaws on the trunk of the hilt, as well as the Makara-like dragon motive with the up-curling nose at the end of the branch of the hilt (Griff-ast to follow the terminology of Hein). On the other hand it is also lacking several other usually motives found on old mandaus of this region, which as far as I know is typical for later 20th cent. pieces. IMO, i agree that this was probably made for work use within the society. Judging from these pictures only and the patina, wear, etc. my guess would be mid 20th cent, but I guess an earlier collection date is also possible if it was acquired early after being made and since stored under very preserving condtitions.
The cap at the end of the hilt is usually made from
damar, but here looks to have been carved from something harder - horn perhaps?
I really like the blade profile and the tip in particular - wonderfully stabby. The seemingly bone-reinforced scabbard throat as well as the two colored rattan binds,
katong evok are cool features as well!
Enjoy it in good health!
All the best, - Thor