Crossbow Project

Now this project has only been going about 45 years, so it's still in the early stages.
I'm hoping to build a crossbow that is NFAS compliant so I can have a go at field shooting with it, dunno if I'll use it more than a few times, but I've always fancied a decent accurate crossbow.
Over the years the plan has evolved in keeping with my improved workshop, skills and the improvements in crossbow design.
I'm going to be making a laminated prod, bamboo backed with maybe a heat treated Yew belly. I've been experimenting with the amount of Reflex/Deflex, but like most things with bows there is a huge amount of compromise.
Adding lots of reflex gives good early draw weight and adding some deflex gives a good force draw curve the problem is that you get the early poundage at the expense of available draw length and which is the big draw back (chuckle) of crossbows.

To do some experimentation I got some medium tensile aluminium sheet off E-Bay and sawed out a pyramid profile prod with tiny horn nocks. I then did force draw curves with various degrees or deflex and reflex bent in. Being only a medium strength Ali' I couldn't draw it too far without it taking set, but it's probably roughly equivalent to wooden/laminate bow. I used a slightly scaled down bow for reasons of cost (750mm ~ 29.5") where the real bow (excuse if I mix the terms bow and prod) will probably be about 31-32".
The graph shows a straight prod vs heavily deflexed/reflexed. You can see I've drawn the straight one an extra 3" before the set kicked in ( I should really have repeated the test, but it gives you the idea). I'll probably end up with a bow somewhere between the two.


Modern crossbows (decent ones) tend to have individual limbs and are centre shot, rather than having the bow mounted below the track and set at an angle or the bow having it's tips kicked upwards, this removes the friction of the string along the top of the track (or stock or whatever you want to call it). The bow mounting will be one of the challenges, but a bit of thick plate steel and some welding should do the job, I'm not going to be trying to cast Aluminium... (well not just yet!)
The other big challenge is the trigger mechanism/safety catch. I've made 'em before but not with a safety catch, there are some good videos on Youtube, and I've basically copied this one so it won't be my own design, just my implementation of it. I've made a mock up in plywood initially so I can see it's eminently doable.

Meanwhile the Yew Primitive is waiting to be signed and waxed having had the last few tool marks taken out and some more coats of Danish Oil.

Yew Primitive Finished

I took it out yesterday and shot over 50 arrows through it, checking the brace height as the string settled in. It was chucking 'em about 170-180 yards with my regular arrows. I'd shot 5 arrows through it the previous evening (see pic) and filed the grip a tad to improve comport and alignment. I'd given it a first wipe of Danish oil too, that shows up any tool marks.
I had been a tad anxious as I'd had a couple of blow ups recently, but I soon felt confident with the bow. I was wondering if I'd still need to take a little off the draw weight, but I put it up on the tiller this morning and it was spot on 45# at 28".
(Pic shows it taken to just over 28" to prove some safety factor). So it's good to finish off the fiddling and fetting round the nocks and arrow pass to get them clean and true.

I've spent most of the morning tweaking the nocks and sanding the bow ready for final coats of Danish Oil, I was hoping to get some pics of it finished, but it will take a day or so to get several coats on. I'll buff up the nocks and get a couple of pics just to whet your appetite.

Yew Primitive Getting Close

It's pulling back to about 24" now from a higher brace (still not quite full brace), Both limbs are bending nicely, I've been bringing the right limb round a bit more and the left one now needs easing off a tad to match, that will pretty much get it to full draw along with some narrowing of tips and cleaning up the tool marks. I may get it into a shootable state for a try out on Sunday.

I walked up to the town past the woods and noticed they cleared the edge of the woods where it borders the brook, they taken down a Maple and tidied some Hazel too, the leaves were still on the Maple so it couldn't have been down long so I went back and salvaged a couple of bits. They'd made a right pigs ear of cutting it and the best bit was rather split. Still there could be some bows there. Worst case it can be thrown away later.

Emily the cat is doing well, she has her collar off all day now which is great for her mood... those collars are horrid as the interfere with whiskers and ears which stops 'em running about in a normal manner. We are keeping her on a lead in the garden for a little longer, but I'm letting her wander a bit or sit in the cool of the flowerbed without hovering over her.

Arrow Plate & Feature Knot

I've got the arrow plate done on the warbow, clean simple large and unobtrusive, just the job.
I've shaped the grip a little of the primitive to help me see how far towards the grip I can get the limbs moving that area is commonly called the fade, where limb fades into grip. It's easy to have the grip and fade far too long which wastes working limb length and gives shorter more highly stressed limbs.
The bow was positioned in the stave to put 2 big knots at the grip, one will at the arrow pass and the other smaller becomes a feature knot on the other side. I could have rasped it away and lost it, but I think it will be V attractive on the finished bow, so much so that I could n't resist sanding it and giving it a wipe of Danish Oil. I've got the bow at a low brace but haven't tried it on the tiller today as I've been cleaning up the back, grip and knots, I imagine it's about 45# at 20" by now.
Taking Emily cat to the vet tomorrow, hopefully she'll be allowed out on her own... fingers crossed for her, as she's yearning to run off and roam a bit without a harness (or a collar which is even worse!)

Back to the Primitive

We are still a bit wrapped up keeping an eye on the cat, which today also included pulling her out of the pond! She'd tried to leap it whilst on her lead... whoops.
Anyhow I've managed to get some time working on the primitive and cleaned up the back and filled some knots on the belly, there are a couple of cavities on the back which I've left as filling on the back doesn't really add any strength in tension and they look cool unfilled (they'll get wax in 'em).
The tiller is reasonably even (right limb stiff in out half) but it's coming back enough to brace it now.
My mate JT collected the repaired Warbow and left one that I'd made him a while back which could do with an arrow plate as it's got rather scuffed by the arrows (One guy who makes superb arrows insists they won't rasp away the Yew, but I think it's his arrows that are being used!). The picture doesn't lie.

Update:- The primitive is now at a low brace (about 3") and pulling 18" with the outer limbs moving more now

Warbow Repair Before and After

The title say it all! The right limb still looks a tad stiff, but it can always have some more done once its been shot a bit. Overall the tiller is much better and the weight is up a whisker from when I started as 100# @ 28" equates roughly to about 107# @30" and it's now actually pulling about 115# @30" so I'll call it quits for now, can always take an inch off each end at some later date.

The lower image (after retiller) looks smoother and less stressed despite being drawn an extra 2" !

The picture with two identical circles superimposed on it shows the right limb isn't bending on such tight a curve as the left and there is still a bit off a stiff grip. Much better than before though :-)
Note:- The bow looks almost like a laminate in the middle pic (especially on the left limb), it's where I have rasped the belly and the fresh wood is paler, once it's had a wipe of Danish oil it will be darker, a bit of time will then take it back to the same colour as the rest.
Some vid here:- https://www.youtube.com/watch?v=sGJSuL-r7-s

Warbow Repair Update

The multiple patch looks really good and has stiffened that area. Putting it on the tiller and the other limb looked very whip tillered so I didn't draw it too far.
I strapped the upper limb straight and gave it a good heat treating which has taken out a little set and stiffened it.
Pulling it to about 100# shows it is much improved but the tiller needs some work. I've drawn a circle which fits the upper limb and then a similar one for the lower, you can see they are not centred at the grip. The lower (left) limb still shows as weak mid limb, or rather the whole centre section of the bow is stiff. Over all the upper (right) limb is too stiff.

I will re tiller it and if it has lost too much weight I'll take an inch or so off each tip.
Meanwhile I've been picking away at the knots on the Yew primitive and filling them, also working down the sapwood on the back.


Bottom pic shows the multiple patch approach with 2 deep ones and then a long one over the top.

Emily cat is still not allowed out on her own as she's got a urinary tract infection :-(  .Shes on antibiotics and will have to have a check up next week, happy enough in herself tho' but pining to get out on her own.

Repair Progress and the Primitive

The repair has been unstrapped from the straight plank and cleaned up, I'll give it another 24 hours before flexing it but you can see it's straightened out some of the set. the finished patch feels thicker and the dip in that limb isn't evident. The two part approach with the 2 little patches under the long one looks sound from an engineering and aesthetic perspective. We won't know how it really looks until it is on the tiller. If the fix has restored that lower limb I will evaluate the upper and see if that needs some work.
Pic below shows the first two small patches rasped down ready for the long patch over the top of them.

I've worked down the primitive stave and got it on the tiller for my first look. It's obviously way too stiff still, but the limbs look nice and even. The bit of work I've done taking twist and deflex out has worked out too and it is looking promising.

We are taking Emily cat to the vet tomorrow morning and hopefully she'll be allowed out on her own which will give me more time working on the bows. We've been letting her out on a harness and only putting her collar on at night.

A Warbow Repair

I went out roving with mate JT on Sunday and he warmed up to shooting the 150# Yew Warbow I made for him a while back.
https://www.youtube.com/watch?v=5mNWg68Eg1E
 As he was warming up he showed me one of his other bows (not made by me) which had two nasty pinches/chrysals running from pin knots on the lower limb. He asked if I could repair it and I said I'd give it a try but no guarantees. He then strung it and took a shot, the tiller looked awful, and as he drew up again I called out "Don't shoot it!"
In the full length pic of the bow the area with the pinches is in the far limb wher the bow rests on the bench support (by the mug).
Now this isn't a criticism of the bowyer (Poletti) as all warbows are highly stressed and I've had to patch mine. It's also very easy to see with hindsight why a bow has chrysalled or pinched. However if these things are spotted a bow can often be repaired or re-tillered to great effect. Faults that are visible after a year or so would not have been evident to the bowyer when it was first made.
Conversely I don't think all the bows I see are properly tillered, but I try to withold my criticism unless I'm asked.
It will be an interesting repair that I'll tackle slightly differently to my usual method.
The pinches are relatively deep and go right across the bow any patch would be deep and not very flexible, thus it would be hard to get it to fit perfectly. I will do two individual small deep circular section patches to fill the pinches, these will then be taken down a little and a continuous long patch added to strengthen the weak area in the bow. rather than just patch it in it's current state.
 I've taken the risk of gently pulling it back straight and applying a little heat, so hopeful some of the set will disappear. Note:- I've rasped out shallow scoops between the two big ones to relieve some of the stress as it is pulled straight.
I put it on the tiller before I started and pulled it to about 28" (nearly 100#) so you could see the "Before" shot... hopefully there will eventually be an "After" shot too. Hopefully from the pic you'll see why I called out "don't shoot it!" Looking at the tiller, I can't help wondering if there is a similar weak area in the other limb... hmmm, what do you think dear readers?
It may require a little re-tillering when finished.
Why was there a weak area in the first place? It's that dilemma of leaving extra wood round knots and features, you can easily create a weak point between... you are damned if you do and damned if you don't.
I have a slight advantage over commercial bowyers that I can keep an eye on the warbows I make as they stay close to home. I can see what they are like 2 years down the line.

Meanwhile I made contact with the guy for whom I was making a Yew primitive that exploded last year, he still wants one, so the one I'm working on at the moment is ear marked for him... once I've got this repair out of the way.

Odds n Ends

Taken some thickness off the Yew primitive limbs and taken some twist out each limb with the hot air gun. Dry heat seems to leave the correction/bend/whatever set in much more solid with less bounce back than steam. I used to favour steam, but am now favouring dry heat (with some sunflower oil) more now.
I made up 5 gallons of "Hoppy Copper Bitter" yesterday, which will provide some Summer beer.
Emily cat is doing well after her op', but driving us bonkers wanting to go out.
My daughter popped round with a bottle of Vin Blanc from Binky her White Van (see what she did there?) as a thank you for helping her do the wheel bearings. He's in fine fettle now and much quieter.

I'm slightly in trepidation of posting pics of the Yew Primitive seeing as how I jumped the gun on the last bow and the damn thing exploded. I was V disappointed as I was hoping it would become a bit of a masterpiece, but pride comes before a fall. Onwards and upwards.
Meanwhile I bought some high tensile Aluminium sheet to do some tests on crossbow limb configurations as I'd like to try and make a wood/bamboo crossbow that is competitive, can't say I'd likely shoot it much, but I do have a soft spot for crossbows having made a fair few in my youth.
I think they are greatly maligned and are no more inherently "dangerous" than compounds with release aids. (Just my opinion especially having heard "Oooh that went off when I wasn't expecting it" from a compound archer).
IMO there are silly rules (NFAS) like you aren't allowed to cock the bow until you are on the peg, this wastes time... it should be that you must not cock the bow until you are on the peg or next to shoot, BUT you must not load the bolt until you are on the peg.
Also Aluminium bows are not allowed... I've never had a breakage of an Aluminium bow, and they could easily specify that it must be bound with 3 layers of insulation tape/cloth tape or similar (to prevent a broken limb causing injury. they don't seem worried about longbows exploding!
I think our sport is remarkably safe and unfortunately a few idiots (I daresay they aren't members of an archery organisation) cause headlines for the wrong reasons.
maybe some pics tomorrow...

Back to it

I've started roughing out a pair of sister staves (two halves of the same log). It's a joy to work with Yew especially with a freshly sharpened draw knife, it cuts like cheddar cheese!
We've been a bit distracted with taking Emily cat to the vet to have her tail docked, (it had no feeling or movement) she goes a bit hyperactive after anaesthetic but has calmed down now. She has to stay in for about 10 days and wear a collar, that's driving her crazy, but we take the collar off so she can eat and wash herself . We have to keep a very close watch in case she tries to bite or lick the wound, fortunately she's leaving it alone, but can have a good wash. Her shaved bum and stubby tail aren't things of great beauty, once the fur has grown back she'll let me post a pic of her sporting her bob tail.

The pictures show some of the issues with cutting a log.
It had one big branch coming out the side, so I sawed the log through that branch so it will be on the side of each half and almost disappear in the finished bows. The pic on the right shows how the knot will end up at the arrow pass as an interesting feature.
The down side of that is that the staves have a sideways curve, and laying out a straight line is a bit of a compromise. The pic on the right shows how I've tried to get another smaller knot positioned so it will be mid limb.
When people ask how long does it take to make a bow it's easy to forget how long one spends just deciding where to saw through a log to get two halves.

The other common question is how long does a bow last?
Well, Paul Bailey one of the best field archers in the country shoots a Yew Primitive that I made for him so I asked him roughly how many arrows he shoots in a week. he said on a 40 target course, including practice it's probably about 80 shots, or 100 if he goes to his club woods.
That totals 180-200 a week in total with practice. Call it 10,000 over a 50 week year. The bow is still shooting as good as new with no string follow after 3 years.
So 30.000 shots and still good, mind being a primitive (wide flat limbs) it is maybe a lower stress design than say a longbow. It's also being cherished and used by a top archer so it's behaving itself! ;-)

Some You Win...

The good news is we got the Suzuki van wheel bearing done and he's running much smoother...
The bad news is the Laburnum character bow exploded in my hand as I was flexing it.
Ironically it didn't break at any of the big character knots. It broke mid limb on the upper, which probably was taking extra strain due to being effectively shorter because of the huge knot at the base of the limb. The actual break was near a tiny knot, the wood looked rather dry and the break didn't propagate along the limb hardly at all.
It's a real shame as I had high hopes that it was going to be a bit of a masterpiece, but that's simply what happens when you try to push things to the extreme and that's why character bows are so prized.
I'd cleaned up the top end too, opened up the manky holes and buffed it u[p on the buffing wheel. It was beginning to look good.
hey ho, I'll pick up something else when I feel like it... maybe something simple this time!

Nothing to do with Bows! Well just a little bit...

Blimey I'm knackered!
Spent yesterday helping my daughter work on Binky the Suzuki Carry van,  (Binky is an honorary bowyer as he has carried Yew logs).
She'd asked the garage to change the rear wheel bearings but they didn't want to, spouting some waffle about it being the diff'. I suspect they just didn't fancy uncovering other work which would lead to a bill higher than the "value" of the vehicle.
Anyhow, we set to and got it stripped down, the job actually went pretty smoothly except for a couple of predictable pitfalls, like brake pipes that won't come off and have to be cut.
Many many years ago I'd made a half shaft puller (aka slide hammer) but had since thrown it on the grounds that I wasn't likely to have rear wheel drive cars with half shafts! ... Bugger... decided it was quicker to make one than hire one, problem was finding a weight, but the penny dropped in the end and I found something.
We had to grind off the old bearings and spacer, you'll see from the pic we certainly found the source of the loud rumbling noise! I was surprised it was the drivers side one that was worse, I expected it to be the kerb side one which get more bumps from potholes, man hole covers etc.
We haven't got round to drifting on the new ones yet. I made a couple of calls to Mick the Blacksmith for moral support and he might have some suitable tube for a drift, if necessary, or I may just use the old spacer and a block of Oak... always good to have a back up position.
Having a break from it today as Nic' is busy, but I'll tidy the garage and search for tube/Oak.
We recovered with an Indian Takeaway and I was off to bed V early totally done in!
Last shot shows imaginative use of latex gloves.
Update:- Saturday, done a bit on the bow, it's starting to look pretty, 45# @20" with a nice even tiller. I think I've probably got that knot area just moving a hint now, so I won't do much more there, I think I can just feel it slightly moving in my hand, but hard to be sure. The rest of both limbs is now working. Not sure if I'm working on the van or the bow tomorrow.

Laburnum Character Bow Flexing

I've done some heat bending with the hot air gun and a lot G lamps, bricks tied with string, rubber strapping and some sunflower oil ! The shape is a bit better now with some of the twist taken out and a bit of reflex in the outer of each limb. Overall I like the tips to pretty much stay in line with the grip, trying for too much reflex on a character bow would be looking for trouble. I've taken some video of the first flexing. Predictably the limb with the big knot has been left stiff, since then I've eased it off to get the limbs moving more together and got it at a low brace.
Video here:- https://youtu.be/9naBko3YwEE

You can see in the latest pic (lower) it is more even but the right needs to flex more inner/mid limb. Not sure if I'll ever get any movement near the knot or grip. the outers are uncoiling a bit, so it's coming along.

I couldn't resist cleaning out the big knot to get an idea of how it will look when (and if!) the bow is finished.

Laburnum

I cut this Laburnum back in 2011 when it had died in our garden, it was split yielding two halves, one deflex with a big knot and hole and the other better half with reflex.
I've followed by usual practice of using the bad stave first and this is certainly challenging. It could be argued that the biggest tests for a bowyer are the character bow and the flight bow, this will certainly be a test.
I have used Laburnum before in my primitive crossbow. It's a lot harder than Yew and has rather an Osage feel to it with a big difference between the rings of early and late wood in terms of hardness. It's not so bad to work now I've sharpened my tools!
The two halves had been standing in the corner of the garage staring at me accusingly for the last 5 years and I'd looked at 'em and chalked out potential bow layouts.
Anyhow I was at a loose end so I roughed 'em down a bit on the bandsaw, and then roughed the deflexed one down a bit more.

I s'pose I should have a target weight so I'll say 40-45 at 28".
There are weird little oval pin knots in the wood and at one end they are sort of going through to the back. The stave is only about 62" long which is probably ok, but the end with the weirdness may be the end which was near the ground and had some rot. Worst case I can splice on a clean bit for the tip.
It's starting to flex when I lean on it so the next step is to get it up on the tiller.
You'll see I've been working outside while the sun is out, lovely smell of Lilac every time I walk in or out :-)