Recurve Build #3, 64" I-beam (tutorial)

This bow came from an idea I had based on my limited experience shooting recurves.  I had been wondering why I don't see many long 1-piece recurves commercially available anymore. Bear used to make lots of lengths, but now it seems that 60" is the longest bow that I commonly see at the sporting goods stores or in catalogs, unless you go to a longbow design. Maybe it's because the longer bows were for the target shooters and that market went to take-downs. I'm not sure, but I still like them. The longest Bingham's Project, Inc. plans is also 60". These are great shooting bows, but I am tall and have a long draw and I really like the pull of the longer bows that I have tried. In fact, I have been shooting a 66"/44# Bearcat in a traditional 3D league and it is working really well for me. So, I was thinking about what it would take to alter the plans to make a longer bow, like maybe a 64" version. What I was contemplating was how to scale the design. 

I have a few bows that I measured to see how they are laid out. I measured the limb from tips to fadeout along the belly. I measured the riser from fade to fade in a straight line along the side of the riser. I know these are not exact measurements as it's hard to see where the fade ends and not all string grooves are in the same location, but its close enough. I wish I had a bigger sample size.

It appears that the Tigercat adds one inch to each limb to get its 62" size, but the other bows seem to have added length mostly to the riser, creating room for a longer sight window and more mass. I was surprised how short the limbs were on the Tamerlane. It is such a smooth bow to draw and a pleasure to shoot. I wish they had made one at 50# or so.

Since I will have to spend time and $$ to build a new press to test this out, I wanted to decide which way to go. I could just find a source for a 4" longer riser (or build one), leaving the limb design alone, or I could try to put 2" more into the riser and 1" into each limb. After talking with the good members of the TradGang forum, I started to lean toward the idea that the riser was the place to make the length increase, while using the 60" limb design without change.  The longer riser will change the geometry of the pull to produce that "longer bow" feel that I like.

I found out that Bingham's had once developed and sold a 68" "Target Bow" recurve plan.  I even got a copy of this plan from one TradGang member so that I could research the design.  I really enjoyed seeing these old plans and comparing them to their current 60" plans.

(click any picture for full-size image)

I took some shots of the 60" patterns laying next to the 68" drawings. I noticed that the lower half of the riser template for the 60" bow has changed a bit. It looks like they moved the grip angle down a bit more in the current version (slants toward the lower limb more quickly), maybe to make it more comfortable.

The 68" pattern is basically the 60" limb design with a longer riser (30"). However, as you can see in the lower photo, the angle of the fades is different as well. It is closer to angle of the Tamerlane and other target bows I have seen. Also, there is a wider sight window and rest/shelf. Those types of details are personal preferences and are easily changed to have more/less wood in the riser. Overall, I think this info makes putting a 64-66" design together a lot easier. 

After getting a lot of info on 64"- 69" recurve designs, I began making a plan to build one. I decided to start with a 64" bow. I made a plan for a press by modifying the Bingham 60" plan to handle a longer riser and adding some minor changes from some other designs. It's not too difficult, but does require all the work that goes into building a new press.

I also decided to build my own hardware for this press. The Bingham product costs about $25/set (plus S/H & taxes) and 2 sets are required. It cost me about $30 to make these with stuff from the local hardware store. After the cutting, drilling, heating, bending, welding, and grinding, there will be an hour or two invested in production, so you will have to decide if it's worth it or not.

Because I will have to make my own riser block for a longer bow, I decided to use what I could find locally for my first bow. I think it will be expensive to buy a 2x3x26" block of exotic wood. Plus, I have had a hard time finding a block that size. It seems that thinner wood is easier to find.

At a local place, I got a nice piece of walnut with some figure in it. I think its beautiful.

I had a piece of maple that I decided to sandwich in the middle.

I glued up the block with smooth-on, then trued it up and cut the initial shape.

Then I added a couple strips of black phenolic with a thin piece of bocote in the middle.

This is the riser shape I am thinking about doing.

I decided to go with black glass on the back and clear glass on the belly, with birdseye maple visible. All the rest of the core lams are hard maple.

I finally got it in the press and into the oven.

I put my "beater" blade on the bandsaw to cut the limbs and got them roughed out. Bingham's says that a 4 TPI, skip toothed, neutral rake blade will last the longest, even though it will smoke and squeal a bit. So I keep one blade just for this chore, which keeps my other blades sharper for wood. The template I used is the same as for the 60" pattern recurve limbs. Then I use the drum sander to finish the shaping, just like the other builds.

I also got the front profile and grip area roughed out.

After smoothing out the front profile with a sanding drum, I glued on some maple and walnut detail strips. This is where I learned just how thin wood needs to be to bend correctly. The phenolic strips, though thicker, bend easily compared to this wood. But I wanted to try using wood accents this time, so I messed around until I got it right.

Next, I took a piece that was cut from the front profile and glued it on to help build up the heel of the grip. 

After some cleanup:

I also cut out the sight window and did a bit of shaping on the drum sander. I still needed to take more wood/weight off, but it's starting to feel comfortable when gripped. 

The front detail strips hide the maple line down the center, but they also blend nicely into the curves as I shape them. I think it makes it looks nicer.  The grip heel piece also works nicely to shape the handle and add detail.

After finish sanding with 100, 120, and 220 grit paper, I wiped it all down with mineral spirits and let it dry.  Then I started applying coats of Tru-Oil, sanding between each until a smooth surface was achieved. Then I began applying coats of Minwax Wipe-on Poly, which I feel leaves fewer lines and other problems in the finish.  These are some pictures in full sunlight, showing the details.

Here is the figured maple sight window and walnut side grain with black glass.

Walnut and maple front covers that hide the middle stripe.

The middle layer shows in the back and the birdseye maple limbs are beautiful.  This is my first time using clear glass and I like how well is shows the wood pattern, especially on a 2" wide limb.

The black-bocote-black sandwich and walnut grain shows well on the side.

This shows the grain on the grip area.

And here is one shot of it strung and one at full draw.

OK, so I feel like I need to put in a final results section along with my impressions of this bow.

Here are the stats for this bow:

- target stats: 64", 45# @ 28", 2" wide

- achieved stats: 65", 53# @ 28", (58# @30")  205fps with a 378gr arrow (at my 30" draw)

- .040"  ULS black glass for the back

- .043"  ULS clear glass for the belly

- .070"  hard maple parallel lam for back 

- .100"  birdseye maple tapered lams for belly (taper: .001/1") (visible thru glass)

- .253" stack height: 

- riser: 2 x 3 x 26", walnut with maple i-beam 

This bow is fun to shoot.  I like the feel and dimensions of this bow a lot more than the 58"-60" bows of the same style.  This one draws and shoots very smoothly and it sure puts some speed on a shaft.  I still need to take it to the range and chrono the speed, so I will add that data when I get it.  I can tell that it will be over 200 pfs for sure. The riser is quite dead in the hand and comfortable to shoot.  I'm sure the heavier riser has something to do with that.  I will try some anti-vibration measures on the limbs to see if it offers any improvements. 

This bow would be great for shooting longer distances and for hunting.  I think I need to try another one that hits closer to my target stats of 45# or less, so I think I will try .010" less stack height next time and see how it comes out.   One thing about this style of bow, compared to the r/d longbow that I built, is that it takes longer to shape the large riser section to remove weight and slim it down for fit. Still, it is a great design to shoot, especially now that I have a longer version that fits me better.  I also like the wider limbs when showing fancy wood.

Reflex / Deflex Longbow Build #1 (tutorial)

After I got some experience by building a couple 1-piece recurve bows (Build 1, Build 2), I wanted to expand my knowledge and test my abilities some more. So, I started researching how to build a longer recurve ( more than 60"), and also how to build a longbow.  I will put the results of the longer recurve design in another blog.  I really like the looks of the reflex-deflex  (r/d) style longbows.  There are great examples from commercial builders as well as hobby builders like the ones I have connected with on the Trad Gang forum and other archery forums.

These r/d longbows are not cheap to buy, so I assume there is significant work that goes into them. Still, I decided to build one to see if I can pull it off.  I spent a couple weeks just looking at all the bow designs, asking questions, looking for supplies, and reading build tutorials.  At this point, I could easily have gone back to Bingham's for a complete kit and instructions. However, I like the curved style risers that I see better than the flat ones like Bingham's.  So, I started looking at how to get started into building one of those, which meant building my own 'kit'; no instructions.

I contacted KennyM on the TradGang forum, who is a supplier of laminates (lams) and other bow building materials.  He is great to work with and gave me a lot of help.  He has a web site which shows a nice r/d form; one he has been developing for years.  He is nice enough to sell the pattern to newbies like me, saving a lot of time on developing a pattern. Also, since I wanted to build a 66" bow on a 64" form, he helped with that.  I also wanted to try the power lam and tip wedge design ideas on this bow.  A tip wedge is supposed to stiffen up the tip section of the limbs and the power lam is supposed to stiffen up the area just past the fades. Kenny can make a "super lam" that combines both of these elements into one lam, making the assembly less complicated and less costly.


Here are the stats for this bow:
- target stats: 66", 47# @ 28", 1.5" wide
- achieved stats: 66", 47# @28" (53# @30"), 192fps with a 378gr arrow (at my 30" draw)
- black ULS glass: .040 x 72" (2)
- maple parallel lam: .055 x 36" (4)
- maple super lam (belly power lam + tip wedge combo), .060 x 36"  (2)
  (.060" for 2" past fades, then taper .001/1", then fade thicker at tips, .042" in center)
- maple taper lam: .115 x 36, (taper: .002/1" on back) (2)
- riser: 1.5 x 2 x 18", zebra

KennyM was very helpful with the specs.  He took the stack height for 45# limbs (.355"), added .010” to it to compensate for the extra 2” of  length, added another 2#  from the super lam effect: so it should be around 47# (if the S/L has as much effect on a 66” bow). And as we can see, it was right on the money!

The main issue with building a new design is that there is a significant up-front effort required to build a new bow press for each design.  I don't mind building presses, but they are not as much fun as building an actual bow.  Also, there is cost associated with each form.  To save a little $$, I decided to build my own press hardware for this new press.

(click any picture for full-size image)

The form has to be 1 1/2 inches wide for this style of bow. I had to calculate what layers of ply would get me that thickness.  I ended up being over by 1/32, so I made sure all the screws were sunk deep and ran it thru the planer. Perfect thickness.

The KennyM form is easy to use. It's 1/2 of the pattern and you just have to lay it out on both sides of a center line and 1 " off the bottom.

I cut it out with a bandsaw as close to the line as possible.

Then, I used the template to flush up the edge. I used a 2" flush cutting bit from MLCS Woodworking that works beautifully.  The upper or lower bushing rides along the form/template and the blades create a perfect surface.

I had some Formica laying around from when we did our counters, so I ripped a strip on my saw and used it on the form.  It helps create a nice, square surface that is more non-stick than just the plywood.Before glue-up, I wipe a thin coat of grease on it.

After I figured out the lower part of the press, I needed to create a template for the riser so that I could cut out the top of the press correctly.  I started by cutting and sanding on a block of ply until it would fit nicely on the press with the lower 2 lams under it.  Here it is being tested.  It has to be tweaked until there is no light under the curve. Then I know it will glue up nicely.

With the back of the riser curved to fit, I had to figure out a nice curve for the belly-side.  It is not easy because there are only a few guidelines and a diagram to follow.  I guess the exact curve is not that critical as long as it is the same on both ends and has the required taper at the ends (1/8" at 2" from tip, 1/16" at 1" from tip). Before glue-up, the tips have to be faded to paper-thin to blend with the lams correctly. I use a board behind the wood to keep if from breaking while I create these fades.  I didn't take a picture of it, but it's shown in my other build.

Also not shown is the detail added to the riser.  I cut the riser lengthwise and glued in a piece of hickory.  Then, I also cut a curve on the bandsaw, sanded it smooth, and put a strip of black phenolic in there. I am not as creative as some builders are, so this will have to suffice for now.  I hope it looks good when finished.

With the riser done, the top of the press can be finished and hardware installed.  It takes a lot of time to get the press setup correctly so that the bows will come out right. I was surprised how much tweaking I actually did. 

After a "dry run" test of the glue-up, everything looked good for the real thing.  I decided to put a few little blocks of wood on the edges of the press to keep the layers from sliding around during the "squishing" process of the glue-up.  The hose is inflated to 60psi and really puts a lot of pressure on all the layers.  Since the longbow has 2 more lam layers that a recurve, there is more that might move around.  I had to deflate and re-inflate the hose a couple times to get everything the way I wanted.  Finally, it went into the bow oven for 4 hours.

Info on building an oven and using it are in my other bow building blogs.  I did have to modify my oven to accept this  longer form and the hoses sticking out of the ends.  My wife says it looks like a long casket now.

Out of the oven, the bow is removed from the press and cleaned up from all the tape, plastic, and glue.

Based on directions from other bowyers, I drew my profile lines on the taped-up limbs.  About 2" from the fade-outs the limbs are 1 1/2" wide.  From there it tapers straight to the tip, leaving it 5/8" wide at the string grooves. 

I switched the bandsaw to my "beater" blade for sawing glass.  Bingham says that a 4 TPI, skip toothed, neutral rake blade will last the longest, even though it will smoke and squeal a bit.  So I keep one blade just for this chore, which keeps my other blades sharper for wood.

After sanding down to the line with the drum sander, I used a long sanding block to remove any wavy bumps from the limb sides that were created during the sanding process.

Then, using an angle finder, I marked 55 degrees at the grooves.

The grooves are cut with a  3/16" chainsaw file.

I forgot to take pictures because I was in a hurry before work.  I used a piece of maple lam, black phenolic, and a thin piece of Zebra wood to add detail to the tips.

 After they heat cured (smooth-on epoxy), I finished cutting the grooves and sanding the tips. I also shortened the tips, as recommended by some bowyers. I think it will look good when finished.

Another step that I didn't show was adding details to the riser.  I put some maple and a black strip across the back side of the riser.

I also put some maple, black, and zebra strips on the belly side above and below the grip area.  I was trying to build up the heel area of the grip a bit.  I hope it comes out nice when I do the final shaping.  This picture is of the rough cut out of the riser shape and sight window.

After some time on the shaping drum w/ 80 grit .

And also some filing.

And lots of hand-sanding with paper from 100 to 220 grit.

For a finish, I have to do a hand-rubbed method, since I am not setup to spray one on. It takes a lot longer and sometimes it can be frustrating dealing with flaws and dust, but it will eventually come out looking nice.  I have been learning patience. I used several coats of Tru-Oil, sanding between coats to remove high spots. After the surface was smooth enough, I put on several coats of Minwax Wipe-On Poly to finish it up.

OK, I got back from the range last night, where I setup and tested the bow. I got final measurements on pull weight and arrow speed as well (posted at top).  I have to say that I am very pleased with how well this bow shoots.  It is faster than I expected and very smooth shooting.  I have a Flemish string coming and I may try some string dampeners.