Good Day, Bad Day

I got going on the Elder bow and made some good progress, videoing it as it progressed until ...
Well watch this:-
https://youtu.be/UlRuJkeD_5U

I decide to extract maximum fun from the broken bow by doing a destruction test on the other limb!
https://youtu.be/ua0Iwe-AP2U

Shooting the Crossbow at 3Ds

I had a great Saturday morning over at Cloth of Gold (COG) with Mick the Blacksmith and Brian.
It's the first time I've shot a crossbow at 3D targets and I hadn't done much sighting in. The previous day I'd finished making some final modifications to the prod mount, adding an extra mounting screw (I'd planned on adding this once everything else had been finalised). I tried a quick couple of shots in the garage which were a couple of inches high at 10 yards, but I left it at that for fear of messing up what was reasonably good.

At COG it was just me and Mick when we started out, the first shot being a small crocodile at about 10 yards and I put 2 bolts over the top, after that I was hitting most targets with a little vertical error but very little horizontal error. It soon became apparent that either my distance judgement, or my previous calibration was a bit out at longer ranges.
After a few shots I let Mick try it at about 30 yards. I shot first to check the sight was about right, he put his shot about an inch from mine and closer to the inner kill. I was pleased with that as it shows the crossbow is pretty solid and consistent. Mick actually made a fine shot with his bow too, so I took a pic. (top left)
It was just after this target that Brian caught up and joined us.

 Basically out to about 30 yards, my sight marks and estimation were reasonable and I could hardly miss as long as I set the sights slightly short, it almost seemed too easy! Beyond that was trickier and on the longer shots I tended to shoot over, if I put one over, a slight adjustment would put the second on target.

We shot 18 targets going round once shooting from both A and B sets of pegs, this allowed us to get our shooting done in time for a ham sandwich, bowl of chips and a pint at the pub.

Unbeknown to me Brian took some pics of me cocking the bow and shooting which he sent to me, thanks Brian :-)

I'll probably leave the crossbow for now although there is plenty I could do to fine tune the performance, mostly by improving the sighting and actually making some bolts that are visible! The bolts are cheap ones with anodised aluminium shafts which are a pinkish red colour, now you'd think they'd show up, but I have a slight red/green deficiency (like many men) and in a dark woodland they don't show up in flight. White or yellow bolts would be much better, this mainly matters if you miss with the first shot as you'll know if you've missed high or low. On one long shot I simply never saw the bolts despite having both eyes open. As it happens they were all high, but I couldn't tell.
Update:- I reviewed the sight marks (on the Monday) on my adjustable scope mount by clamping it in a workmate with the scope lined up at a distant reference point. As I adjusted the mount I could see the crosshairs didn't move until I got beyond the 20 yard mark due to slop/backlash in the mechanism. Up to about 40 yards the graticule in the scope was enough to adjust for the elevation. So a fixed mount would probably be more reliable sighed up at say 30 yards, the graticule would then be used for range compensation. Sometimes simple is best!
I probably won't shoot the crossbow at an open shoot but it was fun to have a go at 3Ds shooting with friends. There are a couple of reasons why I won't shoot it much, but it's mostly that I feel it doesn't have the same intimate connection with the archer that a self wood bow has and that it would be easy to get lured into chasing perfect scores. I feel it becomes more of a distance estimation test and about scoring tactics rather than pure fun.
I tend to shun competition as it's easy to spoil the enjoyment.
Indeed on Facebook there was recently someone who said that the thought taking kneeling shots with a crossbow was cheating, despite the NFAS rules specifically saying using any part of your body for support was ok.
They said, if you take the rules literally then it's within the rules! I did ask what other way you could take the rules? The irony is that the person involved actually used a strap ,which IS arguably against the rules! (Which I quote below)
"The archer must not use a rest of any description which provides an additional point of support for the bow whilst shooting. This does not include the archers own body".
That little incident nicely sums up why I don't shoot competitively.

Anyhow, why did I make it? For the fun of the engineering challenge, to improve my skills and understanding, so I could see what it was like to shoot, so I could compare the performance against my usual bow, and so that I'd have an appreciation of shooting a higher velocity bow.

For now I'm working on the Elder stave with the Willow levers, but I reserve the right to tinker with the crossbow if I get the urge!

Quick Arrow Puller and a Goody Bag

The bolts from the crossbow are damn near impossible to pull out of my target if they hit an area that hasn't been shot up a bit.
So I sketched a quick dirty arrow puller, and made a try out from scraps I had lying around.
It basically worked first time but needed a bit of fiddling to get the lever lengths right.
The important bit is the rubber lined groove to grip the bolt without damaging it.

I had a look for pics on the interweb to see if there were any good designs out there, some were over complex and others had more than one part (you can guarantee to lose one bit). I went for the generic basic design, but kept it simple by having a single sloppy joint where the arms meet rather than a fancy hinge with 2 degrees of movement.
It needs some movement to allow the device to be fitted round the bolt/arrow shaft.

Hopefully the pics, show how it works. The important thing is to pull for a short stroke and then re-position the clamp down the shaft, as one very long pull could bend or damage the shaft (you can make up your own jokes there! ).

Post just  arrived with some goodies from my Brother, some slitting saws which will go on my mill, and a couple of locks from old shotguns for me to study.

Sighting In Some More

I took the crossbow over to Now Strike Archery fairly early and had the ground all to myself in glorious sunshine
It's impressively fast and flat out to 30 yards with only slight elevation needed on my scope mount.
As the range increases the downward component of velocity increased as the arrow accelerates downwards due to gravity, making the trajectory more curved and the bolts were briefly visible in flight. The changes to the scope mount were much less than with the Boo/Yew prods, so much so that I got it sighted out to 60 yards.
I didn't spend too much time trying for tight groups, I was just trying to get the elevation about right for each 10 yard increment, shooting about 6 bolts at each range.
What surprised and confused me was that when I sat on the rear sill of the car (with the hatchback open) and leaned against the rear pillar to get a solid shooting position I always shot high!??
I actually put two shots over the boss when trying to shoot like that, but I found them both.
Discussing this with my brother later in the day, it turns out that this is a recognised effect with spring type air rifles which have a similar slow action with a moving mass (apparently they are bad at shaking up scopes too). Trying to hold too solid increases the effect of the recoil (and possibly the reaction to a fairly heavy trigger pressure), whereas holding more lightly allows the bow (or rifle) to find it's own balance/stability due to its inertia. (dunno if that makes sense)
When I stood and shot in a more relaxed manner without gripping the crossbow so hard, I shot much better.
With all the shots the horizontal dispersal was minimal, it was only the vertical variation that gave any trouble.

All in all a good session, the only minor problem being that I forgot my arrow puller, and it was hell's own job pulling the bolts from the target, so much so that I felt my back complaining, so I quit while I was ahead.

Tomorrow I can review the marks on the wheel of my adjustable scope mount and compare with theoretical figures, making minor adjustments and engraving decent marks onto the wheel.

The only outstanding question was the draw weight.
So, in the afternoon, I got the bow bolted down at floor level and drew it via a long double hook of 6mm steel bar with the spring scale on the end.
Turns out it's 108# which is about what I expected.
I took a quick (rather shaky) video showing the arrangement used for measuring draw weight.
https://youtu.be/1JVTiy5BKXk

Tarting Up and Sighting In

I've had a cold all week, (just about gone now) but manged to do some tarting up of the crossbow prod mount yesterday, adding some nice curves, done on the milling machine as a series of overlapping holes and cleaned up on the belt sander.

I got the tele' sight back on it this afternoon and did some sighting up. First thing I noticed, it was shooting high at 10 yards, being faster than the previous wood/boo prods, and I had to modify the adjustable mount to elevate it a tad.
I got that sorted and was about to quit but I realised I had good opportunity to sight it at 20 yards diagonally across the garden as the missus was out ;-) and the cat was asleep indoors.
I adjusted the sight a bit by guess work and the first bolt was scarily close to the top of the boss, whoop! I set it back a bit and the next shot hit the 2" square of paper I was aiming at, I quit while I was ahead.
My son was around so he had a try out at 10 yards, it was tricky for him to hold, as he has balance problems being in a wheelchair. The feedback I got confirmed that the trigger pull was rather heavy, so that will need some work.

The whole thing is an ongoing project, an maybe I'll start on a decent stock for it some time (I have the wood), as at the moment the comb isn't high enough to be comfortable with the tele' sight and it's ugly!

It feels very smooth to cock, heavy early on, but doesn't seem to get stupidly heavy as you pull back. When shot, it rings a bit and there's some recoil, but I think the string is over twisted, making it a tad springy and the brace height needs finalising. A lower brace gives a longer power stroke but can put extra stress on the limbs. I may even try making string buffers (I'm thinking rubber bungs on ali' pillars).
Anyhow, plenty to tinker with, but trigger pull first, then sight it up at some longer ranges (maybe Sunday) and eventually some field shooting.

Finished Crossbow Prod Mount

The mount is finished and it's holding the prod very securely, there is sheet rubber beneath the limbs and elsewhere too. I've removed the shim of 3 ply from under the stock to get the string sitting just a whisker above the track. (see pic)

I think it looks a tad Brutalist with maybe a hint of Art Deco. I might round some corners and remove some excess metal later to improve the aesthetics.
With the masking tape removed, the limbs look rather handsome with the Maple showing through the clear glass.

I took a quick full draw shot...
I'm not entirely happy with it as it is working hardest mid limb, but the outers are flexing. I could maybe take a few mm off the underside of the last 6", tricky to see with out a decent comparison with the unstrung shape.
The close up of the nock shows the construction. There is a wedge of maple adding thickness to the wooden core, a horn piece is overlaid over the glass backing, this is then recessed slightly and bound with carbon fibre/epoxy to minimise the risk of the string splitting down the nock. These are lessons leaned from earlier prods.

I haven't actually measured the poundage at full draw (it's difficult to set it up for such a measurement) and measuring it won't actually effect the reality! It's relatively comfortable to draw, so my guess is about 100# or a tad over, it certainly seems to have decent speed vs draw weight. (255 fps at last measurement)
I'll have to try it through the chrono' again later, as the improved rigidity may have given it another couple of fps, mind I might not get round to it as I have a cold and may retire to my bed!

Update:- Just tested it 258.5 fps :-)
And here's the unstrung pic for comparison.
I've combined the 2 pics here:-

A Waiting Game

I've done a lot of work on the crossbow prod mounting and it will be much more solid when finished, the limbs won't be able to lift at all at the tips. I've had one more test shot at a fractionally lower brace and it was about 1.5 fps faster which is a refreshing change from the natural material prods which lost speed with each shot.
Once the mounting is finished, I've made a new string and optimised the brace height it should be pretty respectable... I recently saw a 175# crossbow advertised as having 145 fps which makes mine look rather good as it's prob only about 100-120# tops.
I've had to order a variety of screws for the prod mount and while I'm waiting for those, I've taken a little more off the Elder primitive. I've also had a chuck of wood with a nice natural curve which I'll use to make short levers for the Elder drying out on a radiator, still not sure if it's Ash or Willow, but once I start working with it, I'll probably find out!
That's about it really, done some pruning and tidying in the garden and generally been enjoying the fine weather.

Done some more and cut the splice for the levers, here's a pic of one dry assembled.

Successful First Crossbow Shot

I made some new deflex wedges for the crossbow limbs with less deflex, I made a couple of stringer clamps too.
That all took longer than it should as I had one of those days where I couldn't pick anything up without dropping it and I couldn't put anything down without losing it! I wanted to take a tad off one of the wedges using the belt sander. The belt was drifting to on side and wouldn't adjust ??? Then the bracket that mounts the adjusting screw fell in half, damn... I set to and made another.
Finally I tried to sand the wedge but the belt sander wouldn't switch on!... It would run while I held the button, but the relay wouldn't latch on.
I opened it up, cleaned and tightened the connections, then finally it worked... but where had the wedges gone? Arrrrggghhh! I tided the bench, looked everywhere, even emptied the rubbish bin... nope.
There was only one possible place they could be, down the slot in the table of the table saw where the blade comes up (the table saw gets used as a secondary work bench). I shone a torch in there.. yes! I had to lie the table saw on it's side, take the bottom off and clean it out. Having recovered the wedges I stuck some duct tape over the slot in the table saw as I only use it about once every 10 years as I tend to use the bandsaw or my circular saw.
Anyhow, I eventually got the crossbow all back together and glued on the string catchers which I'd salvaged from the previous prod. Ready for testing, once I could brace it, and that took an age, the first stringer string just stretched too much, eventually I used an old crossbow string with the clamps I'd made and got it braced to a decent height and tried a first test shot. It seemed pretty good and didn't shake itself to bits. The string settled down a couple of mm above the track, so the prod mount will need a little adjustment, but that's no problem.
Video here:- https://www.youtube.com/watch?v=XcI_GfUmB1A&t=38s

Next step will be to inspect it all to check it's all secure, then make some improvement to the prod mount and to adjust it a bit.
I've already checked to see if the prod has taken any set, it has, but just 1/2mm over the straight central section of each limb, and I feel that's ok.
I'll shoot it some more and measure the speed through the chrono'.
Update:- I shot it through the chrono' 255fps I'm very pleased.
The limbs are tending to twist upwards slightly as the string line is above centre, the limbs being tapered up from the lower edge. Some tweaking to the prod mount should sort that out.

Prod Tweaking Progress

I got the prod mounted, but it's almost impossible to brace. I got a string on as tight as I could and videoed it to see how it was moving.
It looked a bit stiff at the inner area where the limbs thicken up, but rather than jump in and remove material from the bow I've made up a couple of wooden wedges which fit between the limbs and the mounting, effectively angling them back towards the archer as if deflexed by about an inch and a half. That doesn't seem like much but it allows me to get a taut string onto it at a low brace and it look promising.
It's difficult to quantify the effect, but string movement (draw) on a braced bow, is about 3 times the tip movement, so it's quite significant. Bear in mind a crossbow is high poundage short draw so, say 120# at 12" draw is going to be 10# per inch of draw, so angling the bow back may have taken 45# off the draw weight!
So, it may be that the final arrangement is a smaller wedge.

I spent a deal of time making some stringer brackets, but they tended to slip along the limbs. I'll probably make some more like the ones I made for the 275# steel prod on my repro' medieval light sporting bow which can bee seen in this post unfortunately those clamps are won't quite fit on these limbs.