More on Sawing/Roughing Out

"Explain more" Was ticked on the last post...

I'll expand a bit about sawing out a log, it requires more care and thought than is obvious. At it's simplest you can just lie something straight along the log, mark with chalk either side and saw it (or run a straight string line and work from that). I have a length of very light weight steel U section the sort of thing that is used by builders putting up partitions or stud walls, its 1.5" wide and I found it in a skip. (see pic). Using it for a first rough out allows plenty of width. If you lay out that first cut out carefully you can remove some knots or place them in the centre of the stave.
The pic top left shows how I laid out the stave over to one edge to remove as much of the big black knot as possible. The pic below it shows the two sides opened out like a book and you'll see there is still a waggle of grain showing but the manky part of the knot is no longer in the stave.
There are still more things to consider as it's easy to mark a straight line on a curved surface and end up with a curve. I was lucky with these staves as they were pretty flat and straight, but with a log that is deflexed, reflexed or has a sideways bend it's easy to mess up when you run it through the bandsaw.
Putting it through the bandsaw is tricky too, I have a roller support behind the saw to support the end of the stave which helps. If it can be run through in a clean straight line with no twist (even if it's just on one of the first cuts) that provides a nice flat surface to rest on the saw table for subsequent cuts. (and for ease of marking out later). It's easy to rotate the stave slightly as it goes through, I try to hold it and guide it as one would a snooker cue using a clean straight action, I try to avoid too much re-positioning of my hands.

 Note, these first cuts are all straight and parallel, (so it resembles a length of 2x2) just to remove the excess wood and and allow me to see what's there before marking out the actual bow, it also allows some margin of error for the wood to move as its internal stresses get released. This is the state that most people will recognise as a stave, not being aware of the work that's already gone into getting it to this stage.

This is fine for a straight stave that can can be roughed out straight and Yew which is tolerant of some grain run out...
On a character stave or a less forgiving wood the cutting is very much by feel and eye. A process of successive approximation and being sympathetic to the grain flow of the wood. E.G See pic on the right. two wonky staves from the same batch of timber, these will need some careful reducing and some steam bending to get decent staves.

Having cut the two sides, it's much easier to handle it and lay out a line for the thickness of the bow. The quality and thickness of the sapwood is now more visible and some thickness allowance can be made for reducing the sapwood if necessary. At this stave I still tend to mark it out parallel. This may seem odd, but allows for error and also means any off-cuts are more likely to be usable. Sometimes cutting some of the final taper can be handy to give two tapered off-cuts which may work as billets. It's all a matter of studying the wood and maximising what you can get out of it sensibly without jeopardising the main stave... always best to have one good stave than two useless ones!
The next step will be to remove the bark and some sapwood where it's been gnarled up with a chainsaw and general rough handling. The wood may get another month or so to season and settle, I think it's a mistake to rush at it as wood may keep moving... some say it needs a year per inch of thickness, so bearing in mind there was a lot more thickness there before it was reduced a bit more time won't do any harm.
Oh bugger!
Just shaken myself up... I was up on the step ladder putting the staves back on the top shelf when the damn thing splayed open and I crashed to the ground. I'm ok, but grazed my elbow, knees, bruised my thigh and my arse/lower back is sore. Took me a while to get up off the floor.. expect I'll be stiff as a board tomorrow. At least nothings broken and I didn't hit my head.
The step ladder is an A shape, but the horizontal brace can be detached to allow it to fold up/extend. Normally that brace stays in place even when the ladder is folded and stored... it must have popped off, and I hadn't checked it... I normally do. By sod's law the rubber feet that I had replaced a few years back have worn through leaving bare steel which skidded on the concrete floor.
Every man is his own safety officer...

Next job, refurbish the step ladder or buy a new one. Mind I can't find one that has quite the same handy configuration.