Monday 13 January 2014

Trimming Staves

I was hoping to put some temporary nocks on the Derbyshire Yew but the garage was full of the Yew which I was given the other day.
I sorted it out, and painted the ends of the decent bits, I've probably kept more than is sensible, it's a triumph of optimism over realism, but it can always be thrown or turned in firewood later. There's a bow or two in there, so it's worth the effort.
(You can see it in the background of the lower pic... not much heartwood there, and rather small diameter)

The problem is I have no more room to store it. A reorganisation of staves was called for.
The stuff that was cut last June is stored as half logs, with the corners trimmed off these it has generated an empty shelf for the new wood. From the pic , you can see how I've sawn along the heart sap boundary. Holding the timber flat side up as it goes through the bandsaw allows me to see where I'm cutting, unfortunately having the curved surface on the table allows the log to vibrate, rock, rotate and snag unless it is held very firmly. I actually reach round behind the bade with my left hand and support the log as it goes through I brace my hand firmy againstthe back edge of the table making it into a sort of flexible moveable guide. My right hand feed in the log, but never gets close to the blade (The front edge of the table is close enough!). I use a coarse blade with alternate set teeth when ripping down timber, this helps to stop snagging, as does putting a small wedge in the cut a good way from the blade to hold it open. The tension in the wood can close up the cut and grip the bade, so a little wooden wedge is V handy.

The above practice will doubtless have some people throwing their hands up in horror as being unsafe.
It requires a good deal of care especially when nearing the end of a log. To minimise the danger, I'll generally stop halfway and then saw from the other end. Knowing how to deal with a jam or snag is also key, slight movement of the wood will often free it, or I simply hit the stop button and then free it.
One must not wrench on the log or try to pull it back as there is a chance of pulling blade from it's guides with potentially very nasty results if the blade snaps. Please don't consider the way I work as a recommendation, every man is his own safety officer! I'm simply saying what I do... it's not necessarily best practice or even good practice! It's about the only way of seeing where you are cutting tho' . Out of interest, I have made up various guides for curved timber but they don't really help unless you have perfectly cylindrical logs... it's a bit of a catch 22. Once the timber has been run through it has flatter faces for the next cut, but early on it's rather tricky. A helper can be very useful on long stuff, but they do need to know what they are doing.
If anyone has a design for a good jig for this sort of work (or a link to it) I'd be interested to see it.

The June Yew is pretty marginal too, maybe a couple of full length staves, which are rather wobbly, but a good few billets. There are a couple of odd bits which were screaming 'make me into a crossbow prod' as they were short, fairly wide with a nice curve to give up swept tips.
It's hard work running it all through the bandsaw (I still haven't finished) but some of the off cut sapwood (seen on the floor) may come in handy. I have this idea for maybe cutting it into thin strips and laminating together as a bow backing or making a laminated Yew bow. Dunno if I'll get round to it, getting it all nice and even thickness and then gluing would be tricky. It could give a very good back for bow.
A bit more work and I'll get the garage back to a usable state.

8 comments:

  1. Nice to see someone actually DESCRIBING how they bandsaw a stave - would love to see a video of it (moving pictures and 1000 words and all that)

    What sort of size do you aim for when cutting a "log" to rough stave size? (Inches please - I don't
    speak French :-p)

    I realize it's all going to depend on various factors but as my English yew that I acquired about a year ago has dried out enough for me to reduce it to a more workable size now and as it will be my first attempt at an ELB, I need all the info/help I can get, lol

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  2. Hi, there's some roughing out dimensions elsewhere on the blog (the search works pretty well).
    It depends if I'm after a heavy or lighter bow, and how problematic the stave is, but for a lighter bow from a good clean stave I go 30mm (1 3/16") square at the centre running parallel for about 8" either side of centre than tapering to 20 mm (just over 3/4" at the tips.
    I rough out square and then the belly will need some reducing. All this assumes the back (sapwood) is about the right thickness to start with or has been reduced to about the right thickness (3/16 - 1/4"). When in doubt leave it bigger, it's only practice and confidence that lets you cut a bit finer. Always good to leave extra width at the tips as longbows can try to bend sideways or twist on you... you narrow the ends once it's 80% finished.
    For warbows about 1 1/2 - 1 5/8" square in the middle, running parallel for about 8 -10 "either side of centre then tapering to about 7/8" at the tips.
    This is just roughing out, working from a stave isn't like working a laminate which can be cut to much closer to finished dimensions. With a log, you don't know what's lurking in the middle so it's better to reduce it by degrees, it gives you some wriggle room on knots and problem areas.

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  3. In reality, what I've described in the previous comment is the next stage after the trimming shown in the post.
    The first trimming is just to save space on the shelves and to help the seasoning. I like to work it down by degrees. the last bow I've done (Nov 2015) was supposedly seasoned for 3 years... but it was left in the round (e.g. a log) It simply wasn't properly seasoned and it still felt wet at one end and it warped and moved like a damn snake.
    So to summarise:- Start seasoning as half logs (or if it's a stick chop off the bad side) after 9 months reduce it as shown in this post. After another 2 or 3 months rough it down as described in the previous comment, then start the real tillering.

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  4. Thanks Del :-) I did actually search for bandsaw and discovered this post from it...the problem is knowing WHAT I need to search for to get roughing our dimensions, lol.

    I split the logs into quarters and sealed the ends with PVA last October and they've been sat on a shelf near the roof of my garage ever since - hence I have some ruddy great quadrants of wood I need to make more manageable.

    Now I have a better idea of sizes although I'll have to reduce the sapwood on the one I've debarked as there's way too much. Guess I need to try and rope in a mate to help hold 'em steady while I take the pointy edge (the bit towards the middle) off to give me a flat surface to start from...or do you do that with a drawknife?

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  5. Roughing out dimensions works quite well ;)
    http://bowyersdiary.blogspot.co.uk/search?q=roughing+out+dimensions

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    Replies
    1. So it does!! Lol. MY problem was, I couldn't think of that phrase. I tried rough stave size but no joy however I'd previously seen the post about "bandsaw wrestling" you did and figured it would be an appropriate place to ask :-D

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  6. Oh, yeah, draw knife or axe will quickly take off the pointy edge (I certainly recognise that term) and the other corners. bandsaw is always easier once you have one relatively flat face to work from.

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  7. Noted, time to give mine a sharpen then, thanks :-D

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