Experimental bow: Irish oak pyramid bow

[FilipT]

Totally bored while waiting for my saplings/staves to be dry enough for building bows. I got a lot of plain sawn boards at home, of Irish oak (Quercus petraea).
This is very common type of board in my country, one of the main sources for furniture timber. Hard, heavy wood, with really nice smell when working with it.
Board had complete crown and bark, basically making it just well shaped wide stave, instead of just "board" made from middle of trunk.
So I didn't had to do any ring chasing, nor selecting suitable grain. I just debarked and as it was straight in grain draw basic profile of a pyramid bow.

I roughed it out, it is 70" nock to nock, with limbs 2,36" wide (60 mm) tapering to about 0,5" wide tips (12 mm). Handle, with fades is 8" long. I left enough thickness so I can easily tiller without worrying it will come "light" at the end.
Goal is to have anywhere from 50 to 60# at 28".

This bow is supposed to be purely for fun and experiment, as I don't have any information about using mentioned wood as a bow wood. Does anyone have any experience with it?

Interesting thing is that my first bow was longbow made from quarter sawn Irish oak board. It eventually broke, but only after hundreds of arrows and attempt to shorten it and re-tiller it. Also I had violated some knot on back.
That told me that this wood is at least worthy enough to try to build a bow.

Tomorrow I will have to just do minor corrections in thickness (even some bumps). I will put pictures and go for few days away on little vacation.
After I come back I will start tillering and post more pictures here.

[Knotty]

Never even heard of that wood, new one to my book!
Looking forward to the pics!

[FilipT]

That is one of the most common European native trees. Other is Quercus robur, or English oak. Eng. oak favors flat terrain, swamps, near water in generally. Irish oak favors hills, that why its really hard and dense wood.
My draw knife actually dulled itself while working on it these few days.

http://treesplanet.blogspot.hr/2014/04/quercus-petraea-sessile-oak-durmast-oak.html#.V6kD8hKBolQ

[Frodolf]

Irish oak doesn't grow where I live, but I've tried making a couple of bows from English oak (Quercus Robur) which, from what I've been able to gather online, is very similar in properties to Irish, used interchangeably. The heartwood of English oak seems to be very strong and elastic in tension, in my experience. Probably a great candidate for a sinew or bamboo backing. The sapwood seems to be week in tension in comparison. One self bow I made, with sapwood in the back and heartwood in the belly, broke in a spectacular fashion. Air humidity was up, so if anything the wood was a bit wetter than I would have wanted, and still it took almost no set whatsoever and the break was a textbook tension failure with no signs of compression damage anywhere. Another bow I made (lower weight) stayed in one piece with the help of a rawhide backing.

Again, I haven't tried Irish oak but assuming it's identical in properties to English, I'd say this. The bow you describe is a big one. It's at least 1 cm wider and about 8 cm longer than my go-to dimensions for elm for a bow of similar design, weight and draw. With a flat enough back, it should stay in one piece just fine with some careful tillering. It's a pretty dense wood so take care to keep those tips as light as possible for a smooth cast. With a rawhide backing, you'd probably be able to shorten the bow a 2-4" without any risk of breaking it, and I think you'd get a more smooth-shooting bow.

But then again, It is a different species so all this is basically guesswork...

[FilipT]

This plain sawn board was probably from at least three feet diameter trunk, so this bow is completely in sapwood. Only part that has heartwood is the top of handle (looking from belly side).
When looking, there is no clear distinction from heartwood and sapwood, just some thin line, slightly darker in color.

As with white woods there is no need for ring chasing, we will see what will happen. I don't plan to put rawhide (can't get, no experience), this will be just a self bow.

[FilipT]

Here are pictures of the possible bow. Note the weird dip in the back of limb. I had to follow grain around it and I think I did good choice. Not sure though, will it last and what is that thing, a weird type of knot?

Bow has 0,8" of deflex and weighs 707 grams.

Did some calculations using Mass Calculator. By typing in length of 70", deflex, draw length of 28" and draw weight of 60#, I got 650 grams.
That means I have 57 grams excess and I am sure some of it will come off during cutting in nocks, but most of it while being tillered.
By typing 50# instead of 60# I got 593 grams, here is excess 114 grams.

I think its better to have excess of mass (actually 57 and 114 grams is not a lot in wood) then be too light and fail to produce desired draw weight. I want around 60# and that will be primary goal.

Basic profile


One limb, belly side


Other limb, belly side, note the bumb needed for "knot"


Same limb, back side, "knot" in first plan


Handle and fades, belly side


Handle and fades, back side

[Urufu_Shinjiro]

That seems to be a very pretty wood, I bet it finishes up real nice, I look forward to seeing it.

[Frodolf]

Looks good to me. It sure looks a lot like the english oak around here. I like the mass calculations, sounds good. I would have guessed that your bow would come out at around 150 grams over mass principle calculations. Maybe the sapwood is lighter in density than the average wood density? That could explain it. Either way, looks great! Go for it!

[loon]

Looks very nice, looking forward to seeing the tillering

[FilipT]

I forgot to say few things.
First is that I am slightly worried about bluish discoloration near the tips that was there when I debarked the wood. It doesn't seem like rot, as when I inspected that area and put sharp object against it, it didn't go in, like it would in rotten area. It is as hard as other wood in bow.

Second is that I don't really get the difference from English oak. They are basically same in consistency, color and hardness, both highly sought timber for furniture, both relatively cheap, but English oak is just little more sought for timber, more like a first choice, with Irish coming immediately behind.

Third is that I really like the smell of wood while working on it, it has such a nice aroma. Also its pleasure to work with. Even though its hard and dulls sandpaper and tools, tools just chip off pieces of wood, even if you go against the grain. I really like that, opposite to dogwood and hazel, which are little softer but in my opinion you must be more careful working with it.

Tomorrow in high noon, bus takes me to the adriatic sea, so you will all wait a couple of days for tillering, while I am sipping wine on nice beaches.

[Jjpso]

I am new to bow building, but shouldnt the fades extend to the widest part of the bow? They seem to end before...

[FilipT]

They are but you cannot see that because of the angle I took photos

[Knotty]

Looking nice so far! Keep it up.

[FilipT]

I am home from vacation and I started today with tillering. While being on vacation, Cupid shot my heart through with broadhead and my bowyer skills are a bit slow at the moment. But I am doing as good as I can!

Do you think it is ready for full brace height?

[FilipT]

FAIL!

Bow broke after I braced it. Before I braced it, I established good bend in both limbs, watching carefully for the slight hinge on the right limb. I removed bit of wood around the hinge and that made better situation.

Encouraged by this, I put on the stringer and braced it. Immediately I heard slight cracking and I knew bow is dead. I put it on the ground and watched it for 4 seconds after which outer third of the right limb exploded.

Before it broke though, I noticed that it has really good full brace profile so I am a bit perplexed why it broke. It didn't break on the hinge but lower.
Weird...