latest build in progress

First topic message reminder :

I'm pretty pleased with the design and build quality generally, but there's a few kinks I need to iron out before I call this one done.

 The prod is from Slobows, the "SB BB": 3.5" brace height and 11" powerstroke, rated at 165 pounds. It's over 31 inches wide spanned, compared to less than 28 for the more typical steel prod from Alchem or Slobows, so it seems a bit of a monster compared to my previous builds.

 The main wood is Cherry, with accent pieces of Laurel. I really was focused on trying to keep a good balance and not go completely front heavy as is common with steel prods, hence the thick and meaty looking shoulder stock and cord binding. I planned from the start to use a red dot sight, though I have a rear iron sight that mounts to the same rail at the same height as a backup, I just need to come up with a front sight that will work with it. 

 Black Delrin roller nut, and the trigger mech is the same two-piece action I came up with when I rebuilt my first crossbow recently. It's a long pull, but very smooth and easy.
Didn't get a picture of this trigger mech, but here is a shot of the one it's a copy of:




 I'm pretty stuck on brass bolt tracks by now, but a new feature for me is accomodation for commercial, triple vaned crossbow arrows. This prod has enough upsweep in the tips to allow for a generous slot to be cut for the cock feather. The bolt track is made from two brass angle sections, screwed and epoxied to the stock halves before they were glued together.

 I thought the plate of Laurel on the butt of the stock looks particularly nice. I played with the idea of making the stock hollow for keeping spare strings and batteries and wax and whatnot, maybe I'll try that on version 2.0

 Here's where it gets a bit weird. I wanted the light weight of a cord binding, but I also wanted to be able to mount and unmount the prod quickly and with basic or no tools. This is what I came up with, given the materials I had on hand. It works pretty well, but I'm not in love with the look of it, and I'll need to do some field testing to see if it is sturdy and durable enough for long term use. If not I may convert to a more standard and permanent cord binding.


Gnome

Thanks, Orien!
Here are some photos of a mockup of the type of front sight I have in mind. That is actually a piece of clear 1/8" plexiglass, printed and digitally router cut and touched up on the edges with a sharpie. Looks nice, but is way too fragile for the real world. It's a quick way for me to see if I'm on the right track with the design before I start cutting metal.
 

The rear sight I have has two different size aperatures that toggle, so I figured I'd try two rings on the front, as well, to match them for different ranges.
Also evident is the mounting solution I pondered over for weeks- the ends of the bolts on the prod irons that were right there in front of me the whole time.

 
The real deal will be made of aluminum, steel, or possibly PVC, and be a bit more massive. I'm going to try to find some tiny colored beads I can glue to a wire running through drilled holes top and bottom of the aperatures. Too bad this one is so fragile, it works really well, though I didn't get the size of the rings quite right- they both need to be larger. Didn't get the pips in quite the right places either, but that's what mockups are for.
Gnome

This part took a lot longer than I thought it would. After messing around trying to make my own cross hair type aperature front sight, I gave up and bought a nice fiber-optic enhanced product from Excalibur for about $25. Then all I had to do was come up with a sturdy and attractive mounting solution. I must have made at least six seperate attempts at that, mostly from aluminum, and mounting it correctly from the side, before reverting to my original idea of steel to match all the rest of the steel up front, mounted centrally on two pillars.
 
 Those of you with real metal working equipment, as well as real metalworking skills, would cringe at the effort it took me to make this single bit of steel the right shape. I started with a 3/8" mild steel rod, figuring that if I started big I'd have more material to grind off later to true everything up and clean up the curves. Didn't bother to think that It would have been easier to get it right with heat and hammer if I started with a thinner bit of steel in the first place. Live and learn.
 

 
Here it is in place, sorry the photo is so dark. I had to have those posts curved just right both for esthetics and to provide plenty of clearance for the string.

 
Since the Excalibur front sight was a bit smaller than what I was planning for, I needed to move the rear sight up as far as I could so the large aperature was a good match. It is, and having the rear sight further from my eye is much easier to see, as well.

 
Now all I need is enough free time and clear weather to take it out and dial it in and see how well it works.
Gnome

Every time I check in this thing gets cooler.  Love the irons, and that front sight is just fantastic!  Well done, Gnome! 

Hey Scottty, Thanks!
I got a chance to get some better pictures today:





I bolted the original stirrup on for bench tests, which I still need to get out to a range and do, and now I'm thinking about reshaping it into a removable bipod. I have to do something with that bolthole in the stock... I really did a 180 on this one, starting with trying to keep it light up front and now bolting on every bit of steel I can manage.


Here you can get an get an idea of the sight picture:


Front and rear aperatures match up really well in size leaving a nice open image. The front sight is mounted 90 degrees from it's intended usage so the two posts could be used as additional range adjustment references, but I've seen seen them jury rigged up this way as well. It's supposed to be adjustable with a fixed rear peep, but of course I fixed it and have an adjustable rear sight. The front is centered about 3/8 inch lower than the neutral position of the rear aperature, If I can't dial that in for 20 yards I'll adjust the mount.
Gnome

Geezer here:  I've gotta say, this has turned out a pretty snazzy looking bow, with lots of interesting ideas.  In retrospect, I think the wrist-section, between the lock and butt looks rather weak.  I wonder if you were doing it over again, it might have been better with a thumb-hole stock, so you'd have extra strength in that narrow spot, where the grain could well be in the wrong direction.  Still it's a very handsome piece and the sights in particular are very snazzy.  Good work!

Gnome,
   Very creative and marvelous ............. only as a suggestion how about using acorn nuts and all thread
where you have regular nuts and bolts ...... may look a tad more finished

Chaz

Thanks guys.

Geezer, I know what you mean, though I think it looks weaker than it actually is. The stock is two halves glued together, and there's an oak dowel running all the way through the grip, and at it's narrowest it's still over an inch and a half thick. I'll probably end up carving quite a bit of wood off the stock, both for esthetics and ergonomics. I think that will help consolidate the design, so it doesn't look so much like a burly fore end and a burly butt stock with a flimsy grip between.

Chaz, acorn nuts... great idea! To the hardware store!

Gnome

Duhhh, I forgot you said the stock is laminated.  That, paired with a solid peg through the center should be sufficient to keep it together.  And no worries about the looks- it's a fine looking piece just the way it is.  I just wondered about the connection between butt and body.  I had an old 91 Mauser carbine years ago that had been dropped from horseback.  Somewhere along the line, somebody reinforced the narrowest part of the stock with a large rivet... in fact, I've seen a lot of 91 Mauser carbines (Argentine) that had been rebuilt that way.  It just made me think you might run into similar problems.  But if the stock is laminated and already reinforced, you should be good to go.  I don't recommend dropping it from horseback just to see.... Geezer.

Latest build, finished! (knock on wood)


I reshaped the shoulder stock, mainly to make it more comfortable, but I think it looks a lot better, too.



also reshaped the original stirrup into a bipod that can be pivoted out of the way. It can be taken off entirely, of course, but it's fairly handy to have on there.
Also got some nice brass end cap nuts, thanks Chaz!



That space on the lock was an accident of design calling for embelishment, which led me in a roundabout way to settling on a maker's mark:
A Susan B. Anthony dollare embedded in the stock. This crossbow has two, but since doing this one I've installed one coin on all my builds.









zeroing in the sight was just a couple of clicks, I guess it paid off that I was so particular in getting everything straight and level in the first place. My battery was dead in my Chrony so I don't have any hard data on velocity yet, but shooting both commercial aluminum arrows and bolts I made out of oak or fiberglass of various sizes and weights, I'm pretty pleased with the energy delivered to target and the accuracy. I compensated for different projectiles intuitively, of course if I settled on a particular type for a target session or hunting I'd zero in for that type.
Gnome

Looks fantastic, a work of art. You did good!

Todd

Elegantly done, Gnome.  Elegantly done.

Beautiful lines and curves. Love the front sight bridge. Awesome work.

Thanks, all. Often times things don't go as planned, it's nice when they actually turn out better than planned. Now that I've finalized this design, I wonder what it would look like with a walnut stock...
Gnome

Walnut would look a lot like that Laurel butt cap.  Give that cherry a year or so and it'll dark quite nicely by itself...