Origin of the Tombak?

[KuKulzA28]

I think lembing and tombaks are both spears, but different types.. I think that lembing tend to have a central ridge and be thinner (better for stabs) and tombaks tend to be broader. I am under the impression that these are spear-heads... which can be mounted as daggers or on spear-shafts...

I hope I'm helpful, but I eagerly await the responses of the experts...