Boiled linseed oil used to be, well, boiled, but these days it just has chemical driers added to get it to harden within a reasonable time scale. If you use raw linseed oil, you'll be waiting for it to harden 'til doomsday. Alternatives might be a danish oil type, with a varnish oil mix, that'll give a shinier finish, faster. The old rule of thumb for oil finishes is once a day for a week, once a week for a month, once a month for a year, and once a year for the rest of its (or your) life. For a working tool handle, some oil when it starts to feel like it needs it is probably the best guide.