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