TD Limb Alignment

[khardrunner]

I'm building a riser for a set of limbs that I already have. How the heck do I get the limbs to line up correctly? I heard the bingham jig is terrible.

They are a simple 1 bolt, 1 pin design. I need to drill for the bolt and put the pin in the riser as well.

[NormanDale33]

I think Bradfors showed a way of using the Bingham jig that really made it do a pretty good job of aligning the limbs. It worked well for us. Are your pin and bolt the same distance apart as the jig?

If so, I would try drilling the bolt first. Once the bolt is drilled and your bushing installed, I would line the jig up on the riser pad and screw it down, as close to center as possible. From there use a long 5/16" bolt to screw your limb through the jig and into the bushing on your riser. You can then line up the pin into the pin hole. I would tape the belly of the limb and draw a center line down the limb, before attaching it to the riser.
Check the limb for allignment using a string clamped to the limp tip and run it down the  belly of the limb through the center line drawn on the riser. Adjust the (undrilled) point end of the jig to make sure your line runs down the center line drawn on your limb and riser. Measure twice before drilling. Repeat on the other limb.

I hope that makes sense and if you have any questions let me know. If your point and bolt don't line up with the jig I am not sure the best way to handle it then. The bingham jig isn't inherently square because of its adjustability. IF you realize that it can still be helpful lining things up. Once again I hope that helps, and I am not an accomplished bowyer or nearly as talented as others on here so hopefully someone else will have some advise.

Good luck and take your time!

[khardrunner]

I don't even have one of those jigs... I've also heard about a grizzly jig but I don't know where to find that one

[NormanDale33]

I guess that was an incorrect assumption on my part, sorry about that. The Bingham jig is expensive for what it is, but it has helped us/me in bow building. Check grizzly tools out online at  www.grizzly.com  and see what they have for jigs. Not sure what would be helpful.

Good luck.

[Jim Rocole]

DO a search for drilling jig. Kenny M had a post on here not to long ago and it looked great. Grizzly also sells one call a self centering drilling jig. I am not a fan of the bingham's and have had to redrill several pinholes in the riser to align the limbs. I now draw centerlines on the limbs,drill the bolt hole in the riser and limb, align limbs with long straight edge( though you can use a lazer)remark the riser center after align limbs then drill pin hole in riser.

[NormanDale33]

I have had to redrill as well with the Bingham jig, definitely not something you can pop on and assume square. Definitely need to make sure you mark center (on everything) with the jig. LEt us know what you find for jigs out there.

[khardrunner]

Thanks guys for the help! Anything else you think of would be great!

[kennym]

Wasn't my jig, but looks very good. Wish I had more time in the day!!

 http://tradgang.com/cgi-bin/ultimatebb.cgi?ubb=get_topic;f=125;t=006244

[Sixby]

The Binghams Jig is garbasge. Go to Harbor Freight or to a tool store and get a self centering jig. Locate your main bolt hole where you want it and drill in the riser and install your insert.
Now have both limbs profiledthe same/. I grind mine to 1.500. Use the jig to drill your 5/1/6 hole and your 1/4inch pin holes on the limb where you wnat them placed.

Now attach both the limbs and either with a long level , laser or string center theentire bow up withthe limbs attached/. I always work from center and most times use a string ,. I clamy the string on the center line of both limbs and make cure it is centered all the way through the entire bow. Tighten the bolts down good and tight ,. Check alignment again./

Now drill through the pin holes in the limb into the riser for your riser pins. This gives you instant perfect alignment/

Take the limbs off and install the pins ,. they only need tostick up about 3/16 of an inch or so/

The limbs should fit on perfectly and be in perfect alignment now/

Problem, Unless you are lucky the limbs will not interchange.; You need right now to profile the limbs and put on tip0 ovelays and determing top and bottom by putting lightest limb as top limb.

Option if you want interchangablelimbs is to have a machines make you a pair of jigs. One for the riser and one for the limbs./ Cost about 500.00 average..


God bless and hope this helps some.
Steve

[Bjorn]

You just can't get more accurate than this!
 
My first 2 pce    

[joquiver]

I use a mic and measure the holes in the limbs. find center of the riser block and draw a line down center, measure with a mic off both sides of block, limb angles already cut and block still square .then determine where the bolt hole is going to be and carefully measure, I measure 4 or 5 times and use the mic to scribe the lines across the center line of the riser block.use a center punch or icepick to mark the bolt hole then put one of the mic points in the bolt hole indention and scribe across the center line with the other point of the mic,now mark with center punch.I have had good luck with this.I have built risers for pronghorn and horne limbs .

[giff]

ho about this  http://www.harborfreight.com/self-centering-doweling-jig-41345.html

[johnny girardi]

Self centering jigs work well dowl-it comes to mind.Made in Michigan. measure how far apart at center hole.