Building a metal bow riser

[WTK]

I was out in the garage yesterday sketching out a new riser to get a set 65 lb takedown longbow limbs down to 55 lbs or lower. So I'm going to build another angle iron riser. It will be 21" end to end and will have adjustable limb pads so I can change the draw weight and tiller. I removed an angle iron frame that direct tv used to mount the dish on my sister-in-laws flat roof after she moved. So I am cutting it up for the material to build this with. Going to be fun. Here's a picture of the cad sketch side profile. I'll add pictures as I get it further along. I got the metal cut yesterday so I'll try and get it layed out today.

Here's the 16" zombie riser that this will resemble

[bronco611]

if this is not a joke, then it looks like a cool idea. how did you blend all the joints together (bondo)? it looks good but could you post the stress calculations so we can determine if your design will expose the inside of our cranium at full draw if it fails due to fatigue failure over a period of time.

[WTK]

LOL, no joke. No bondo just bolted together. I've been shooting the original for almost a year and its solid. I used a piece of scrap maple for the grip on it so it might look like bondo. I'll be pulling the new one on my tiller tree with a rope and pulley system to check for twist or bending but I don't expect any.

[chackworth3]

Very cool. what is the range that you can adjust your angles?

[A.J.]

Very cool and interesting.

[60 Deluxe]

You probably would have gotten along quite well in Cuba. I love watching guys use their brains and build things out of next to nothing.

Please let us know what brace height works best at each angle.

Looks like a Hoyt!

[AJMag]

It's deja vu. Just saw this on another trad site. Cool project

[WTK]

Chris I'm not sure yet on how much I can change the angles. I'll have to set it up and try and see how much the pad can go and still be stable. I'm thinking I'll add a lock down bolt near the end of the pad to secure it against the main frame.

[WTK]

Finally getting some work done on this. Sketched out the design and drilled holes along the lines then used my grinder to rough out the parts. Taking longer than I like as been fighting some health junk.

[WTK]

Finally healthy enough to get back out to the shop and have fun. Picked up some new stronger steel and started over. I'm trying it before putting on the adjustable limb pads to be sure it would stay straight. But its at 52 lbs now which is right where i wanted so now I'll have to think about whether or not I want to put the adjustable pads on because it will raise the draw weight. Anyway it spits out arrows so I'll play with it some more tomorrow and I think I need to make a little longer string for it too.

[Draco]

I built this one last year but it is an ILF handle. It's a little different than yours though.

[froghunter]

Very interesting! I have had an idea for a riser design for some time now. I just need to get around to building it. Keep posting progress!

[WTK]

Like that Draco, looks lean and mean

[WTK]

Here's the Force Draw curve and chrono data for the bow. 525 gr arrow at 182 fps at 28" 52.03lbs at 28"

[WTK]

Here are some more numbers from different arrow weights. 52.03 lbs @ 28"
672 gr arrow @ 161 fps
476 gr arrow @ 189 fps
388 gr arrow @ 203 fps