Takao,
I think now is the time when you decide just how much your comitted to knifemaking . The reason I say this is because you will be hard pressed to get the same results by hand that you can get with a good variable speed belt sander. The beauty of a good belt sander is the ability to make almost anything your mind can immagine,rather than limiting yourself. Belt sanders like Bader, BurrKing , Dozier, Wilton, Hardcore,are all excellent the key is to make sure when you buy one to get a VARIABLE speed machine .This allows you to0 work at your own speed.It allowes you to blend ,contour,shape Hard to soft surfaces together without burning your knife handle or blade .It also allows you to utilize finer grits without the potential of burning your knife .
Another thing that is a huge plus to owning a good quality belt sander is the attachments you can get to convert your belt sander from a flat grinder to a hollow grinder, you can purchase a small wheel attachment that would shape and blend those finger grooves in minutes. The combinations are limitless and will improve your abilities as soon as it arrives .
Once you get one ,you must get to know your machine you will need to know everything about it,it should become an extention of your mind. Sounds like B-S I know but it's a Zen experience.In time you and your machine will become one and thats when you will create things that just kinda happend,things you didn't even know you could build . Hope this Informes as well inspires, now go out and build a great knife.
Aloha!!! Ken Onion