Wednesday, 28 September 2016

Reworked Laminate and a Warbow Stave

I've got the nocks finished on the laminate and narrowed the outer limbs a good deal. It's tillered to 32", but I've just taken it to 30" to have a look at the tiller, it looks fine and is pulling a bit over 75#, I'll make a new string, apply some finish (slightly tricky as I don't know what the original finish is) and it's done.

Meanwhile I've made a start on the other Pacific Yew Warbow stave, there were some tricky knots to fill on belly and a big undulation near one tip. I was worried that, in trying to rough it out to avoid the knots I'd left it too narrow at the tips and also take too muck off the belly. Would it ever make the target weight of 115# ?
Only one way to see, glue on some temporary nock overlays and pull it to 115#.
Whew... it looks like I have plenty of wood still! Obviously the tiller is awful, the left limb is flexing and the right is only flexing in the area I was worried about near the end, but it's not too weak.

Monday, 26 September 2016

Bit of Work on a Laminate Bow

A guy from the club came over with some bows, one needed the nocks replaced and a little off the length. One nock had split and a hasty repair done which wasn't satisfactory.
It's a nice fast bow used for clout, Bamboo back Ipe? core and an Osage belly, it has taken a little set mostly mid and inner limbs. I could see the outer limbs could be tapered into the nock more and the nocks could be much smaller.
It's slightly unusual insofar as the arrow pass is at the geometric centre.
Anyhow, I jumped in quick and got the top nock done just to see what the wood combination was like to
work... short answer, all the woods are rather hard. The bamboo is rather flat so to help it blend into the round nock I glued on a tiny sliver of yew. I also rasped a good bit off the width and rounded the corners of the bamboo down, right back as afar as the first node, which was also reduced a tad (they can actually be taken completely flat, but I never go that far myself).
I remembered to take a "before" picture". Oddly the limb tip almost looks fatter now because the nock is so much slimmer!

Sunday, 25 September 2016

150# Warbow Completed

It's finished now and up to full brace which seems to have made no difference to anything. The right limb seems to be bending just a hint more and can be seen to be bent more at brace, e.g. distance from string to mid limb is greater on the upper limb than the lower, that's fine because the lower limb has a hint of reflex and conventionally that distance should be a little more to allow for the asymmetry of drawing the bow (commonly called positive tiller).
I'll post a video of the bow later and add a link to it (don't expect to see me drawing it, I can only draw it about 20" !
Mean while here are the pics.
The bottom nock could do with more polishing where I'd adjusted it a bit to get the string sitting better. You may notice the serving on the string is opening up due to the huge tension on a warbow string, this can have a little extra serving whipped on later if necessary when the string and bow have settled.
 One pic shows a dip in the back of the lower limb, you'll notice, I've let the belly swell just a hint to compensate. The view of the waggly tip shows the other side of the limb to the braced pic and you can see how the two sides of the same tip differ, it was quite a challenge. I'm not saying I've dealt with it perfectly, but I do see bows where areas like this are left carrying ridiculous amounts of extra wood, creating a series of stiff areas where there are "problems" IMO, this just creates a series of weak points between those areas where the bow will probably fail. Similarly you will see bows where the back undulates nicely, yet the belly follows a straight line! Belly and back should follow in sympathy, tapering towards the running the limb twixt finger and thumb will locate any thick spots.

You'll also see some islands of growth rings at the grip showing the slight swelling there.
Can you ever be 100% happy with the tiller of a bow? I'd say probably no, you need that obsessive eye for detail, but also enough pragmatism to know when to quit. Above all resist improving it to the point of ruining it!
There's an expression in the electronics industry MBR (Mended Beyond Repair)

Someone has ticked explain more, so I've done a sketch showing how I thin undulations/ knots etc should be dealt with. Knots aren't too much of a problem except where they come through the back, in which case a little extra width will give more sapwood to maintain the strength of the back. They are only a problem on the belly if any loose crumbly material isn't picked out and filled.
The dotted line is how think the belly should be shaped, a little extra material can be left if it is felt necessary but still somewhere between the solid and dotted lines.
All just my opinion of course.
Video here:-

Friday, 23 September 2016

150# Warbow Virtually Finished

Its got its string now, it's had a few scrapes off the right limb since this picture, but it's been scraped, sanded and had a quick wipe of Danish Oil just to show off the nice character near the upper limb tip.

Thursday, 22 September 2016

150# Warbow Nearly Done

I've got the horn nocks on, but not polished and the tips narrowed. The bow is now back to 30" at 150#, by the time I've been over it with the scraper and sanded it down it should be back to 32".
Someone asked for pictures of the horn nock before shaping. This is the bottom one which is rather a large chunk of horn, as the tip of the horn has been sawn off and used for the top nock.
Note, in the top pic, there is a bit of the Elm temporary nock showing still. Gluing an extra bit on the tip can be a good way of adjusting the tip angle or alignment which will end up being reinforced and concealed by the horn nock. The top nock is much darker than the lower despite being from the same horn.

I'm taking a hint off the upper limb as I'm tidying it up, rounding the corners/edges and scraping quite hard as it's still a tad stiff.

The undulation at the tip of the upper limb is looking really characterful, I'll get a pic of it tomorrow when the nock is polished up..

Wednesday, 21 September 2016

150# Warbow Back to 28"

Here's the video:-
This is a still grabbed from the video.
To get it back the last 4" won't take much, bear in mind the tips of a bow only comd back about 1/3 as far as the string! So the tips are only going to come back just over another inch, which doesn't give me much room for tiller improvement.
I think the right limb is a tad stiff, (try holding a CD up to the pic and you'll see what I mean) but just cleaning it up, rounding the edges, scraping out the tool marks and narrowing the tips will bring it back a bit. I s'pose it's not at full brace height so that will bring the tips back a bit more too.
I've already glued on the top nock, but haven't shaped it. Hopefully I'll have it pretty much done tommorrow, but then there is the finishing, nock shaping etc. I may add an horn arrow plate as war arrows with binding on the fletchings can rip into the side of a bow eventually.

Tuesday, 20 September 2016

Low Brace 150# Warbow

I've teased it back to 150# on a low brace, I need to get the outers moving, but she's looking promising.
One problem is the sapwood is much thicker on the lower limb so I'm having to reduce that over the last 10" of the limb, that's involved sawing off the temporary nock, reducing the sapwood and re-gluing the temporary nock.
Here's the video:-

I've now put a coarse belt onto my belt sander and run the sides of the bow on it to true 'em up and loose a hint of width, I'm aiming to make this bow relatively narrow especially at the tips. I want this to be fast as well as brute poundage.
It's back on the tiller and is now back to 26" at 150#, just out of interest that interpolates to about 184# at 32" ... that should be enough for JT ;-)