Custom Shoulder Bolts = Perfect Alignment?

[Standswittaknife]

Was wondering if anyone uses custom shoulder bolts that would allow the bowyer to drill a 27/64 hole in the limbs and riser, therefore using one self centering jig for alignment?  I use a double limb bolt design and am thinking this could be the answer I need for perfect limb alignment. I'd buy a custom bolt that would have a shoulder of 27/64 and a 5/16 thread. Just a thought.  Thanks,

[fujimo]

explain for a metric dummie   :D  
so a 27/64 hole thru limb into riser, tap riser hole and glue in insert.
bolt has a shoulder to match limb thickness at wedge.
sounds perfect.
would you needbolts with different length shoulders further up or down the wedge.

what about a sleeve made from micarta or phenolic, 27/64 od and 5/16 id, that could be glued into the limb hole after drilling- would still line up perfectly, and would finish nicely.

[Standswittaknife]

I'm thinking of two different methods.  Use a bushing that is 27/64 wide with a small 1/2" ring at the top, tapped with a 5/16 smooth hole.  This bushing would then be inserted and glued into each limb hole (in my case 4 bushings per bow.)  OR get a 27/64 shafted shoulder bolt that was threaded down to 5/16.  The shaft would then match up with the 27/64 limb hole and be as wide as the riser inserts. Therefore, I could use my self centering dowel jig (bought from Grizzly and modified) only once.  I currently have it drilled exactly like the bingham's drill jib, but with 2 27/64 holes and 2 5/16 holes.  This new method would mean that I could use the same drill holes for limbs and riser, therefore there would be no way to get the limb holes off (assuming the limbs are sanded parallel.

[Standswittaknife]

Oh and the length of the shoulders would be same as I use a parallel wedge design that fades after leaving the riser. I think my jig I had made up is slightly off (I think the 5/16 holes are slightly caddywampus...) creating limbs that are twisted.

[fujimo]

i think it sounds like a great plan. would be easy to take some 27/64 size bolts turn the ends down and tap new threads on- engineering shop probably would not charge very much for that, but the bushing sytem might be the cheapest- i dunno.
but if i build a take down again- i will follow your example and do this- seems so much simpler!!

[Standswittaknife]

Got a quote for the bushings and they would be too expensive to have built at almost 6 a piece.. Going to try the shoulder bolt route...

[fujimo]

i was thinking more a brass rod, or phenolic rod turned with  a bore turned down the center, cut slightly oversize, epoxied in place, and then sanded flush. i dont know if the shoulder would actually hold much anyway- i would rely on the bezel to increase the pressure applied surface area.
but then again it might not cost very much to turn an existing bolt down, and to tap a thread- you could just have the bolt turned , and then tap the threads  yourself to save costs-

but might be quite affordable for them to just to thread it on the lathe while they have it chucked up!

[BigJim]

Why not use two alignment pins and save yourself a ton of fuss.

bigjim