3 piece takedown question

[Sigmazxcs]

Hi gang,
I've returned with yet more questions for all the bowyers out here.

Recently I was met by some questions on limbs and limb alignment.

1) How do you guys align and drill your limb locking parts (bezel bolts and pins)? Are the any jigs to recommend?

2) Is it safe to reshape aftermarket limbs?
I am thinking of reshaping (reduce overall limb width) aftermarket limbs to fit a hybrid longbow riser that is not ILF-compatible.

Do let me know your suggestions and advices!
I'd really appreciate all inputs!
Thanks gang!

[Dimondback]

I use a jig from bingham's projects. The jig gets bad reviews but if you take your time you will get great results with it. I actually called Bingham's concerning the jig reviews and they said it is CNC machine milled and is accurate to how ever many thousanths of an inch. I have had no issues other that the drilling holes being a little tight on some drill bits initially. Good luck!

[Sigmazxcs]

I see, thanks dimondback!

The drilling jig is suitable for one pin one bolt designs right? What drill bit sizes does it fit?

[Trux Turning]

That jig is one pin one bolt and uses 1/4", 5/16" and 27/64"(riser) drill bits

[strungstick]

When I started about 20 years ago I paid a machinist about $75.00 to make a set of jigs out of UHMW and drill bushings.  I just patterned it after a jig table Jim Brackenbury was using.  5/16 and single pin alignment.  I bolted the jigs in the center so they would pivot to allow for any slight variations in cut angles of the riser.  I cut the riser to finish dimensions and leave the limbs wider until they are mounted and cut accordingly.  There were some past posts with some photos of jigs similar to mine and someone may be able to repost those.

[Sigmazxcs]

Hi truxturning,
Thanks for letting me know! Any idea what bit sizes would it be in metric units? I'm in Singapore and we just can't work in inches it seems. Brits got the better of us.

Hi strungstick,
I did consider that, but I'm pretty tight on budget now. Gotta give my girlfriend some money so she can go overseas to enjoy herself.
I have seen some jigs by other tradgangers though. Looks pretty neat to have it fixed for 2 sided drilling. Saw the one by KennyM I recall. But I doubt Singapore has any machinists for hire, at least not for small jigs like these. Any alternatives?

[kennym]

I suppose with a 2x2 block of HARD wood and a drill press and a little luck, you could make one that would do a few bows before it got sloppy.  ?

[LC]

Well count me in the crowd that thinks the Binghams jig is junk. Actually it's not junk I'm sure it's CNC to the thousandths but installing it on a limb or riser eyeballing it on a "center" line you drew with a pencil thats 2 1/4" long,  you can throw those CNC thousandths out the window. Actually CNC is for duplicating exact parts a machinest works in thousandths every single day. I actually had my FIL who is a machinest make me one, now looking back I'm sorry I wasted his time. Actually it's the second most worthless thing he ever gave me!  lol Just kidding I got the best wife in the whole wide world! Partner for life. He did end up making me a jig "system" that works. If time allows I'll post pics of how I do it. I'm sure there are better ways though and I'll be watching this thread.

You actually can buy harden inserts sized for certain drill bits to makes jigs out of wood much like Kenny mentioned if thats what you want to do though.

[talkingcabbage]

I made one similar to Binghams out of corian.  It works, but is a real bugger trying to get everything to line up.


Joe

[rmorris]

If you want to make your own look into drill bushings. Used in the machining world to make jigs that will ware out a drill bit way before the hole gets sloppy. they run about $12 each ( last time I purchased them)

[Sigmazxcs]

Now that you guys get me thinking, maybe I should make a jig. I'm thinking of solid aluminium block or acrylic block lined with aluminium. I have a milling machine back in school so I guess it should come in really handy. I'll probably draw up a plan for the jig and get advice from here.

And any tips on drilling? Gonna drill action wood and phenolic, I don't experience with those so I guess I can use some help.

And oh, any idea on reshaping aftermarket limbs?

[Dimondback]

Originally posted by Dimondback:
I use a jig from bingham's projects. The jig gets bad reviews but if you take your time you will get great results with it. I actually called Bingham's concerning the jig reviews and they said it is CNC machine milled and is accurate to how ever many thousanths of an inch. I have had no issues other that the drilling holes being a little tight on some drill bits initially. Good luck!

Also note that I have not used this jig more than a couple of times yet but initial results were acceptable (or lucky) don't know yet     Having a self centering system like some other drilling jigs would be a vast improvement or at a minimum finer threaded thumb screws. For building a few takedowns it should be fine for me though assuming future builds yeild the same results. Good luck!

[Sixby]

diamond, I think you got lucky. one of the locate pins is drilled off perfect center/ You do one limb the turn the jig the other way to do the bottom limb and voila you have limbs out of alignment , every single time. the
Binghams jig is literally junk.
Either have a set of custom jigs made or you can work out something with a self centering jig set or you can drill the limb locate holes where you want them through the limbs. mount the limbs on the riser and string line the limbs to perfectly center the riser bolts and center of the limbs and then drill through the mounted limbs and take the limbs off and put the pins in the riser. This will give you perfect results every time. Only problem is that you now have to put on overlays on the limbs and drill through the overlay from the bottom for your riser bolt hole. Its an extra step that to me is worth while.

God bless and good luck , Steve

[Sixby]

there is one other system that works fantastic. Mill the components through your drum sander to diminsion. Riser and limbs. lay on a flat table with jigs attached to the table and drill the limbs and riser with the same jigs.  everything auto lines up and makes everything interchangeable. Pretty much works for only one type of riser and one pad angle though unless you figure out how to move the jigs.
God bless you all, Steve

[savage1]

LC I posted a few weeks ago trying to see what people are using and only got one hit. "Limb Alignment". I see now that it has been covered here.
Can you post pics of how you are doing your drilling?  Anyone else? I plan on building some contraption eventually. We are not all craftsmen but we all need decent alignment.

Lou

[Mad Dog]

Would a self centering doweling jig like this work?
 http://www.harborfreight.com/self-centering-doweling-jig-41345.html
You can drill 2 holes at the same time using drill bushings with 3/4" center to center spacing if using smaller bits.

[LittleBen]

I heard one guy who clamps the limb to the riser, aligns it, drills both holes straight through the limb, fills the alignment pin hole with an oak dowel to fill the extra depth, then add an overlay of black glass with a limb bolt hoel in it to cover up the alignment pin hole.

That becomes a problem though if you want a second set of limbs and nothing is standardized.

[Sigmazxcs]

Hi guys.

Thanks for the input so far! I figured I'll need to shelf the drilling aside for now. Ran out of proper glue for the inserts.
By far, I think I'll make my own jig for drilling. Since my school's workshops has some great hardened steels, aircraft grade aluminiums and a CNC machine! Looking good I'd say!