All right folks, I'm in the prototyping phase again. I'm developing a shorter D/R, forward riser, three piece longbow. I'm thinking 58" nock-nock. I drew up a riser that is 14" long. The bow will be built with 1.5" stock. My limb wedges are 8.25" long. I roughed out a pine riser this morning, but forgot to take any photos. I'll get you guys caught up tonight! I've got one of the pirate riser/limb drilling jigs. I plan to lay the mock-up riser on a piece of butcher paper and start drawing limbs until I hit on what I think is right. I'm thinking around 3" deflex, and bring the string nocks back to just above the back of the riser in reflex. I don't know what my limb pad angles are, because I just drew it out until I thought it looked right. I will know more tonight when I start drawing limbs.
1. What kind of limb pad angle are you guys thinking on this? I'd like to be able to make recurve limbs for this model as well.
2. The holes in my drilling jig are spaced 2.5" on centers, but I was thinking of going 2" between the insert and alignment pin, since the longer spacing is crowding my grip area. What are your thoughts on 2" spacing?
3. How short can I go on the limb pads?
4. The riser will be action-wood from Kenny. I plan to lay up the riser with a 3/16" phenolic I-beam. The riser depth will be 1.25" where the limb bolt insert will be. Is this enough depth?
5. Any good tips in general regarding this project?
I should get me riser block, wedges, and take-down hardware today from Kenny, so I will probably answer some of my own questions when playing with the parts. I'll post some photos of my riser tonight.
sounds like a worthwhile endeavor. wish i could help but ive never built a takedown. im sure reverse engineering one will help you though, then from there you can change things to how you like them.as far as limb pad angle i think ive read most are 20 degrees, although someone who knows better can probably give you absolute specs. good luck and keep us updated on how it goes. looking forward to some future pics.
Marty,
Do you have the binghams pronouned LB plans? I can dig mine out and take some coparative measurements if you would like. The 2" separation between limb bolt and pin doesn't sound like an issue to me. The locking bolt should easily handle the torque. The only "downside" I see is the decreased accuracy for lining up the limbs. With your craftmanship abilities I see no issue there either. good luck.
pete
I think I am in somewhat uncharted seas here Pete. The overall length I am aiming for is not common. Isn't the Bingham plans for a much longer bow?
Allright folks, this is where I'm at. I scrapped the 14" riser in favor of a 15" one. More room for grip and sight window. I have 10 degree limb pads. Here is a rough riser with the critical elements only.
(http://i121.photobucket.com/albums/o203/Apex-Predator/Bow%20Building/Riser-3-1.jpg)
(http://i121.photobucket.com/albums/o203/Apex-Predator/Bow%20Building/Riser-1-1.jpg)
Using the jig hole locations that I have ruins the asthetics of the riser. I refuse to make the ends any deeper. I think I can just shift the hole jig over 1/2" and have enough meat for the insert. Here is the jig location, and the modified insert location. What do you guys have to say about using two bolts, instead of a bolt and a pin?
(http://i121.photobucket.com/albums/o203/Apex-Predator/Bow%20Building/Insert-1.jpg)
(http://i121.photobucket.com/albums/o203/Apex-Predator/Bow%20Building/Insert-2.jpg)
(http://i121.photobucket.com/albums/o203/Apex-Predator/Bow%20Building/Insert-3.jpg)
Here is my first limb drawing. The limb deflexes 1" behind the limb pockets and then reflexes 1/2" beyond the back of the riser. That's 5" of curve. The black line will represent a 60"AMO bow. I plan to build a 58" as my mainstay on this form, so it will have the string grooves even with the back of the bow.
(http://i121.photobucket.com/albums/o203/Apex-Predator/Bow%20Building/Limbprofile-3.jpg)
(http://i121.photobucket.com/albums/o203/Apex-Predator/Bow%20Building/Limbprofile-2.jpg)
(http://i121.photobucket.com/albums/o203/Apex-Predator/Bow%20Building/Limbprofile-1.jpg)
That is a lot of curve to my eye, but what do you guys think?
i think for looks one bolt would be easier to make nice than two, however im sure it wont hurt overall to have two bolts. you could always build your prototype and change later to suit your needs based on your first one.as far as the limb reflex/deflex if its not far from any other bow you build it should be ok, far as i figure it wouldnt be much different from building any other bow aside from the bolts holding it together rather than it being one piece. everything ive seen you post has turned out great im sure no matter what you decide it will be fine. thanks for taking us along with the build.
Marty,
I love the design of your new bow. Very interesting that you've chosen to have the limbs secured on the 'belly' of the riser instead of the back. What was the reason for this? If it is just for looks, then you've made a good move!!!!!
As far as the bolts are concerned, (and this is from a very inexperienced bow builder) I would put the 2 in. My reasoning is leverage. Maybe I'm wrong and maybe a engineer could clarify this for us, but if you only used 1 bolt, in my mind it would have to be the one closest to the riser end. I'm not sure you have enough material at the end of the riser, so I would put both in. Thats just my opinion! Other than that, I'll be watching this with interest, as I love the look!
Pete
It's been recommended that I make the limb pads shallower, to avoid having a 9" brace height. I am sort of leaning that way, since it will be easier to make a recurve limb around the same riser. Let's see what I can come up with.
PZee, the forward riser design is unique in looks, but also makes for a very easy shooting bow. They also point very well. The design challenge is getting good early draw weight, and not winding up with too much brace height. Everything is a trade-off between shootability and performance.
Here is the latest. I have incorporated several good suggestions into this third riser/limb profile. I cut 6 deg limb pads on this one. I left the limbs straight for a good portion, turned the reflex into a tighter radius, and reduced the net reflex by one inch. The black line represents a 58" amo bow. Here are the two risers side-by-side.
(http://i121.photobucket.com/albums/o203/Apex-Predator/Bow%20Building/Riser3-1.jpg)
(http://i121.photobucket.com/albums/o203/Apex-Predator/Bow%20Building/Riser3-2.jpg)
(http://i121.photobucket.com/albums/o203/Apex-Predator/Bow%20Building/Riser3-3.jpg)
(http://i121.photobucket.com/albums/o203/Apex-Predator/Bow%20Building/Riser3-4.jpg)
Top profile is prototype #1, and bottom is #2.
(http://i121.photobucket.com/albums/o203/Apex-Predator/Bow%20Building/Limbprofile2-1.jpg)
I can see you have put lots of thought in this!
I would use the 2 bolt also on a bellymounted limb. I would think less vibration and noise. Just think about all the posts of backmount limbs that squeak,pop etc. Those are pulling against the riser.
I agree on the foward handle being easier to shoot.
Marty,
how about using a pair of lugs or T nuts that are counter sunk in to the belly of the limb and then covered. In other words the bolt would go through the riser in to the limb. this would make the mounting hardware disapear.
pete
I'm still taking belly steps Pete! Next thing you will want is a carbon riser, and 90% let-off! :)
That is a fancy system you describe, and I'm sure I'll be looking at a better way down the road, but right now I want to build my "first" three piece. I may pick your brain later, but right now mine is about to explode.
I am by no means as experienced as the guys who have already replied (it took me about 3 visits to this thread to figure out what a limb pad was! lol) but I must say that 10 degree pad sketch above the 6 degree one looks like it would draw smoother. maybe it's the more gradual bend of the limbs but it's also just appealing to the eye.
I would also recommend going with 2 anchors per pad than one for this engineerical (I make words as i need em!) reason:
Moments. You are going to creat a very big moment (which is a rotating type of stress found at your connection in the direction of your load) with one connection, and being that it is on the belly side i'm afraid you'll shear your inserts right out of your riser one day. With two anchors you're obviously dispersing the load over two connectinos per limb, greatly reducing your moments affected area.
On a side note, have you considered what your brace height would be? maybe that can help you decide which limb pattern you like?
Otherwise thanks for taking us along Apex!
The brace height is driving the shallower angled riser pads. I fear that the 10 deg pads will require a 9+" brace, which I want to avoid. I think the 6 deg will work much better in getting near 8", which is more acceptable to me. This is all conjecture until I strap a pair of real limbs on her though. The shallower angle will also make it easier to fit some recurve limbs to this riser. Most forward riser recurves have 0 deg limb pads.
Apex, I've yet to try a takedown myself but I will give you my opinions though. I like two bolts too. Bob Lee and Palmers both do it and in my subconscious mind it just seems sturdier, of course they are bolting to the back which is opposite your design but I think it makes even more sense on the belly anyway. If you don't you will need at least three inches of pad from the bolt toward the center of grip for leverage. On the net reflex thing, I don't think it is correct to measure from the back of the riser as much as measuring from the back of the imaginary line as if you were to draw the arc from the pad angles through the grip. That apex point, pardon the pun, is the true back location. If you try to go all the way out to the back of the riser you will get a little radical in reflex.
Good points Jason.
:thumbsup:
:thumbsup:
I took a few hours today, in between the two other builds I have going on, and worked on my proto-type riser. Ive got two layers of glass laminated in the riser and I plan to laminate at least two more on the risers back. She has 1/8" phenolic limb pads. Hopefully my drilling fixture will be done soon. It will have three holes for drill inserts, so I can go with either two pins and one bolt, or two bolts and one pin.
(http://i121.photobucket.com/albums/o203/Apex-Predator/Bow%20Building/7-11-10-1.jpg)
(http://i121.photobucket.com/albums/o203/Apex-Predator/Bow%20Building/7-11-10-2.jpg)
(http://i121.photobucket.com/albums/o203/Apex-Predator/Bow%20Building/7-11-10-3.jpg)
What drilling jig are you getting Apex? Custom?
Looking good. Chuck
I've having one built by a local machinist buddy of mine.
Looking good! I'll be real interested in your experience with the bolts and pin setup. I have the jig for it, but haven't even begun to build up the nerve to try it. As you know, I opted to play with the hinges first.
Looking good so far. Can't wait to see more.
I've been waiting for this one Marty, ever since you posted your intial design thoughts about this take down. Its looking great.
I have to say that your not making this first attempt an easy one. Limbs on the belly introduces a lot of issues that are potentially harder to deal with. Looking at the website of arguably the most famous of the belly sided take downs, Black Widow Bows, especially the pch model shows one limb blot in the center of the pad with 2 pins, one on either side. The grip extends further back than the limb pad, which really looks sweet and allows the riser to be shorter without your hand touching the limb. I have always found it easier to copy a bow and add refinements, than to start from scratch in uncharted territory. Looks good so far!
Marty,
I know nothing about take downs, but I applaud your willingness to experiment and share it with us.
In trying to understand why you designed it this way, i get the reduction in the degree of angle on the limb pad to reduce brace height. what about the limb profile now though. does it change to reduce stress in the area that would be the fade if it was a one piece?
Now i think that the reduction from 10 to 6 will give you a better string angle also, or are you changing that with limb profile and length?
The tighter curve on the limbs will allow me to increase the pre-load on the limbs without going too high on the brace height. The straighter section of limb will be easier to manipulate the bend on with wedges, if necessary.
Something new to ponder... you are looking for a lower brace with (higher) load in the first 4-6" of draw... Have you concidered redesigning the limb and making it static recurve limbs?
I'm gonna get the longbow figured out first. I won't know any more until I get that first set of limbs on her.
I made one of those once, that looked like the staighter of the two. With the forward riser, that will point well. Mine shot very well. I just couldnt get used to the look and sold it. Mine was longer than that, maybe 62" I cant remember for sure. There very stable with that big riser. Mark
looking forward to how this unfolds, your posts are always very informative.
Marty,
After looking at the limb profiles on page one of this thread, I think you will have string slap problems on the back of the limb. This is my take-down hybrid, it is 1.5" wide x 64" long and uses .002" taper per inch, with a 16" riser and 8" wedges and 10 degree limb pads. My first 2 prototypes used a tighter radius at the tip and both had string slap.
(http://i818.photobucket.com/albums/zz110/greginmalad/back%20yard/100_0619.jpg)
(http://i818.photobucket.com/albums/zz110/greginmalad/back%20yard/100_0618.jpg)
If you are intrested in the numbers, this bow will shoot 9 gpp @ 28" in the 190 fps range with a solid anchor, hold, then release. And in the 200 fps range with a pull through flight shooter release.By the way, this is my fishing bow, thats why its wearing a no-glove.
Great looking bow Greg. My initial plan is in motion Greg, so I will have to modify if mine has string slap. I do want to avoid that.
Had a little time yesterday and this morning to work on my form. Plywood doesn't measure what it's supposed to, so I bought a sheet of MDF. Three 1/2" pieces measure the 1 1/2" width I need. I figure if I put a finish on it, the thing should hold up well enough. Lot's of forms made out of this stuff. We'll see!
This form is longer by 2" than I plan on needing for usable limb. I've found that the last inch or so always needs to be cropped due to trouble getting good glue lines at the very end.
(http://i121.photobucket.com/albums/o203/Apex-Predator/Bow%20Building/7-20-10-1.jpg)
(http://i121.photobucket.com/albums/o203/Apex-Predator/Bow%20Building/7-20-10-2.jpg)
Marty,
I use 1/8" or 1/4" masonite in the middle of my plywood forms to get the correct width.
Marty
As with all your bows, I am impressed once again. Great looking design and as it has been said, looks as though you put alot of thought into this.
Good luck with the rest of the process and looking forward to the finished product.
I love that riser design. I just have trouble with short bows. I would like to see that type of riser in a 64" or 66" bow. I think that riser coupled with a mild r/d style longbow limb in longer lengths would be the ultimate in shootability for a long draw guy like me. Can't wait to see how it turns out.
Marty, can't wait to see your bow when it's finished. I'm sure it's going to look fantastic. You make me wanting to try a take down myself.
BTW Greg your bow is absolutely awesome.
----------
Andy
I got my form finished, my wedges built, and my lams cut to size and prepped. I'm gonna glue up one limb in the am. My drilling jig should be finished tomorrow.
Here is the wedge on top of one piece of black glass and two edge grain red elm lams. Another piece of black glass goes on top, as seen in the other photos. Each red elm lam is tapered .015 each, for a total of .003 limb taper. My total lam stack is .316, which is a little more than most recommended, but I tend to need a little more than most others. Besides I had them on hand already ground. It's a W.A.G. at this point anyway.
(http://i121.photobucket.com/albums/o203/Apex-Predator/Bow%20Building/7-22-10-1.jpg)
With a little hand pressure the lams draw down nice and tight. I think the glue up will go very smoothly!
(http://i121.photobucket.com/albums/o203/Apex-Predator/Bow%20Building/7-22-10-2.jpg)
(http://i121.photobucket.com/albums/o203/Apex-Predator/Bow%20Building/7-22-10-3.jpg)
(http://i121.photobucket.com/albums/o203/Apex-Predator/Bow%20Building/7-22-10-4.jpg)
Do you guys glue anything on your limb pads for sound dampening, or is it best to avoid that if possible?
Apex, for whatever reason I try to avoid fiberglass limb to fiberglass piece on the riser contact (just me personally). I usually have phenolic on the from of the riser and then laminate a thin piece of hardwood to the limb. I've put cork (gasket material from autozone) in between and that works well, but to me doesnt look all that great. I have also used some stick on, thin felt circles and I think that works best and looks good too. I have a Cascade bow that has a very thin felt lining on it and I think that is the best I have seen yet..I haven't looked to hard for a place to get it though.
Your bow is looking great!
Got my new drilling jig delivered this afternoon. I will take down the riser and limbs until my jig fits snuggly, clamp and drill. That will be right at 1.400". The hardened inserts can be removed and/or swapped around depending on whether I am drilling alignment pin holes, limb bolt holes, or limb bolt threaded insert holes.
I still haven't decided whether or not to go with two bolts and a pin, or one bolt and two pins.
(http://i121.photobucket.com/albums/o203/Apex-Predator/Bow%20Building/Drillingjig-1.jpg)
(http://i121.photobucket.com/albums/o203/Apex-Predator/Bow%20Building/Drillingjig-2.jpg)
Marty,
I prefer wood or phenolic for limb pads, glass to glass seems to be a bit louder. I have tried cork, felt, and plastic spacers between the limb and riser but none worked better than Remington dri-lube, a dry teflon spray.
The drill jig looks good, I had one built last year, it was money well spent. I hope everything works out well.
very cool so far im excited to see your finished results as you always post great stuff.
Marty, I am not a TD guy,but this one is cool!!
Your form is looking great Marty, the wingnuts on the side washers is a great idea that I am going to try. I have been using MDF for years now because it is so much easier to work with than plywood. I do have the heat tapes so the forms don't go in a bow oven. Thats going to be a great looking takedown!! Bob
Got one limb cleaned up and the other in the oven. This thing is starting to look like a one limbed bow now! I think it may draw 80# though! :)
My jig worked out well. I drilled the riser and limb seperately and they fit right together. The idea is to build a set of limbs without the bow, but there is a problem. See down towards the bottom of my photos where I sanded the limb into the riser, so it all flows well. That is where the riser needs to be in my possession in order to make it look good.
(http://i121.photobucket.com/albums/o203/Apex-Predator/Bow%20Building/7-24-10-1.jpg)
(http://i121.photobucket.com/albums/o203/Apex-Predator/Bow%20Building/7-24-10-2.jpg)
(http://i121.photobucket.com/albums/o203/Apex-Predator/Bow%20Building/7-24-10-3.jpg)
(http://i121.photobucket.com/albums/o203/Apex-Predator/Bow%20Building/7-24-10-4.jpg)
(http://i121.photobucket.com/albums/o203/Apex-Predator/Bow%20Building/7-24-10-5.jpg)
(http://i121.photobucket.com/albums/o203/Apex-Predator/Bow%20Building/7-24-10-6.jpg)
Really looking forward to seeing how this turns out. Looking nice. Really like how the drilling jig is working for you.
Well, I've learned alot today! My jig would be the ticket if I had a drum sander to square up my riser block and limbs before drilling. Everything lined up fine, as far as pins and bolts go, but the limbs are not quite straight! I think I can work out the twist. Another issue is my wedge bending at the end of the riser. Doesn't look good to me, and I'm not sure how to avoid this shy of going with two bolts. My wedge is 3/8" thick. The hook in the limbs is too much, in my opinion. What I have here is a semi-recurve, and will surely get some string slap. There is no tip wedge. My total stack has a .003 taper. She is gonna finish around 54@28, but that is at 60" NTN, and I was shooting for 58". The full draw photo looks kinda hingy, but she will probably be fast. She seems to have very good early draw weight. The limbs are kinda noodly at brace. You can move them easily with your hand in the string direction. Is that vertical instability? What are your thoughts?
(http://i121.photobucket.com/albums/o203/Apex-Predator/Bow%20Building/7-25-10-1.jpg)
(http://i121.photobucket.com/albums/o203/Apex-Predator/Bow%20Building/7-25-10-2.jpg)
(http://i121.photobucket.com/albums/o203/Apex-Predator/Bow%20Building/7-25-10-3.jpg)
(http://i121.photobucket.com/albums/o203/Apex-Predator/Bow%20Building/7-25-10-4.jpg)
looks pretty cool for a prototype :thumbsup: wish i could help with the technical stuff, but my area is all wood so far. as for the limbs not being straight on the wedges is it an issue with the form or is it the wedges themselves not being square? you could always make a rubber bushing to mount between the two to help dampen vibration, i hear of people using innertubes to help soften up production takedowns all the time. looking at the pictures it looks like the area of the limb that mates with the wedges might not be quite long enough before it transitions into the taper, i held a credit card up to the computer screen against the edge of your phenolic strip and its pretty straight, however the limb side of it just barely curves away from it.maybe overbuilding the flat mating surface of the limb by a little bit then trimming after glue up would help relieve some of the tendency of this area to bend slightly with the rest of the limbs on the form. just my $.02,hope it helps a bit.
The flat section of the wedge is flexing. It's perfectly flat un-braced.
Marty,
I think one limb bolt will work if you move it closer to the end of the riser, there is a lot of leverage on that bolt. A 1/2" thick wedge will help, can somebody measure the wedge thickness on a Black Widow take down?
To eliminate the string slap and noodle limb, straighten out the last 8" of the limb. Leave some reflex just not so much. Using .004 taper per inch will also help, as would making it 1.5" wide.
For a first prototype it doesn't look bad and it will be fast. Just a few minor changes and it will be fine.
if the wedge itself is flexing the only way to really combat that is probably either move the bolt closer to the edge or to make the wedge thicker so it doesnt flex.
Hey Marty,
That is looking great! Seeing my recent mishaps, you can always send that one east over the Atlantic to the UK. I will put it to good use :)
Pete
Well I cropped this riser on each end back one inch. I got rid of the outer alignment pin because it was in the way of my cut! :o I drilled out the inboard pin hole and installed another insert. So now I have two bolts and no pin. I'll take some photos a little later after my latest laminate on the back of the riser sets up good.
And so goes experimental bows! :D
I'm bettin you get her whipped into shape! :thumbsup:
I'll get her shooting Kenny, but definitely have different plans for the next generation design.
Marty
I had the same issue with the limb not laying on my riser with the bow unbraced (my limbs are on the other side.). When I braced it, it closed the gap but I wasnt happy with it. My problem was in my form. From the but end of my form it started bending too early so I adjusted my form by sanding and filling with bondo untill I got a nice flat form just enought so the limb layed flat on my riser. For your setup I would think the two bolt system would work better and eliminate the gap just by the pressure of thightening the bolts.
Good luck.
Terry
I'm learning a lot with this one. Here is my new limb. And the new shortened riser. I got some epoxy in my inboard inserts that I have to clean out, and then I'll show you some new photos. I'm sorry I'm updating so slow, but have another build I'm in the middle of as well.
(http://i121.photobucket.com/albums/o203/Apex-Predator/Bow%20Building/7-27-10-2.jpg)
(http://i121.photobucket.com/albums/o203/Apex-Predator/Bow%20Building/7-27-10-3.jpg)
(http://i121.photobucket.com/albums/o203/Apex-Predator/Bow%20Building/7-27-10-4.jpg)
You're learning a lot with this one and teaching us in the process.
From your discription of the "Hingy" looking and the pictures it has the appearance of a Bingham's limb design whereas the limb starts bending out from the riser in a locallized place. Bingham's recurve design makes me think of a longhorn steer when braced. Yours isn't as extreme as those, though.
I am looking forward on how you plan on shaping the riser to fit the hand.
Good work, Marty.
Alright, it's starting to come around. I'll shoot her at first light, and then lot's of sanding. After I finish my other build that I'm working on, I'll finish this one out.
(http://i121.photobucket.com/albums/o203/Apex-Predator/Bow%20Building/7-28-10-12.jpg)
(http://i121.photobucket.com/albums/o203/Apex-Predator/Bow%20Building/7-28-10-13.jpg)
(http://i121.photobucket.com/albums/o203/Apex-Predator/Bow%20Building/7-28-10-1.jpg)
(http://i121.photobucket.com/albums/o203/Apex-Predator/Bow%20Building/7-28-10-18.jpg)
(http://i121.photobucket.com/albums/o203/Apex-Predator/Bow%20Building/7-28-10-17.jpg)
(http://i121.photobucket.com/albums/o203/Apex-Predator/Bow%20Building/7-28-10-16.jpg)
(http://i121.photobucket.com/albums/o203/Apex-Predator/Bow%20Building/7-28-10-15.jpg)
(http://i121.photobucket.com/albums/o203/Apex-Predator/Bow%20Building/7-28-10-14.jpg)
Marty
Looks awesome - looking forward to the finished product!
><>
Glenn
Wow! This thing has a couple of issues, but shoots better than anything I have built so far. This thing has excellent potential! I was stacking arrows at 28 yards. The forward riser is the most pointable bow I have handled. Both limbs on this one are twisted, due to my hard-headedness in relying on my drilling jig. I can hardly wait to glue up another and drill it properly. I will finish this one out and hunt with it. She has wonderful manners, except for a slight limb buzz. I attribute that to the string lying on the edge of both limbs. No recoil, and as quiet as the quietest recurve I've ever owned. Less noise than my pronounced R/D longbow. If you can tell, I'm quite excited.
Now to finish Dennis' bow! Got her stringed up this morning buddy!
Glad you are finding all the work is worth it. I've enjoyed my belly mounted bows for their manners too.
:thumbsup:
Hell yeah Apex! Love what you got going on bro. That's a sick stick for sure. Such a distinctive character to that bow.
Did some performance testing this morning, and I am very pleased. With this riser set so far forward, it's got to be robbing me of 1-2" of real draw length on the string. I'm gonna compare it to one of my others and see if I can measure the difference. Any way, shooting 10.14 gpp, drawing 28" (as measured 26 1/4" to deepest part of the grip), with a 12 strand D97 string, and a three fingered release, I am getting an average of 182 fps. That's with an 8 1/4" brace height! :o She gains three pounds an inch out to 30", and gains four between 30-31". Not bad for a 60" bow! More testing is definitely in order here.
That's good speed for sure.