We used to get Ramin wood handles but they are no longer available due to enviromental concerns. We have also used Tauari (SP?) wood. Straightness is a huge issue. We take the 10' lengths and treat them with a linseed oil based solution ,rivet on brass couplers and bell ends. These are then sold to the seismic drilling industry for loading holes. We are looking for supplies of the above mentioned woods or a comparable product. I don't know if Bamboo is available in this length?