Takedown alignment pin location Ideas

[T Folts]

Talking 3pc takedowns here. Typically I see the bolt hole near the center of the riser and then one or two alignment pins from the bolt hole spaced out going to the tip ends. Ive also seen one pin used in this fashion, also two bolts on each end of the riser pad and a pin in the middle. So here's my situation, Ive built bows with the one bold two pin configuration and while explaining this to my machinist who is going to help me desing a jig for drilling the riser and limbs he stated the the best alignment would be keeping the pins as far apart as possible suggesting having the boldt in between the two pins. Also making the jig as long for a better alignment from riser to limb tip. Any thoughts on this for you 3pc bow builders?
Terry

[jess stuart]

I guess that your machinist friend is technically correct.  I don't think it makes to much difference in a practical sense.  I have always just used one bolt and one pin.  I can't think of any alignment problems that could be traced to the spacing of my bolt and pin.

[GREG IN MALAD]

Terry,
This is what I designed for my drill jig. It uses one bolt and two pins per limb and will locate all 6 holes within .002 of centerline.
The outer pin is 1.125" from the end of the riser, the bolt is 3.125" from the end of the riser, and the inside pin is 3.875" from the end of the riser. There are holes in the baseplate to adjust for different length risers, and the jigs will rotate for different pad angles.
 

[GREG IN MALAD]

And this is the jig for the limb.

[GREG IN MALAD]

To make this system work you need a drum sander. The riser and limbs must be the correct width, and the same width, this jig is for a 1 1/2" wide bow. I start out by sanding the riser and limbs to 1.5" wide, then clamp the riser in the jig and drill all 6 holes with a hand drill.
Now for the limbs, on the right side of the jig there is a small step, this is to locate the end of the limb against. I stand the limb on it's edge then c-clamp it to the jig. Because the limb is 1.5" wide it's entire length it is in perfect alignment.
Hope this helps.

[T Folts]

Wow Greg that is a great help, I will print this and show him how you are doing it, you rock.

Terry

[michbowhunter]

I kind of use the same setup.  Drill through one side for the limbs and the other for the riser.
I use the stop blocks so each riser and set of limbs come out the same....justs makes interchanging limbs a breeze!

[T Folts]

Looks good, I like it thanks.
Terry

[jess stuart]

Those are some nice jigs.  Did you have them made at a local machine shop.  Need to think about getting me one.

[GREG IN MALAD]

Yes, I had a local shop do the machine work. I wish you could buy these.

[T Folts]

I have a question about your jig and bow width.
What width materials are you starting with for your limbs to end up at 1 1/2 inches. I built my form for 1 1/2 and when I get them cleand up I am under that and my machinist needs to know my width befor he can start. I was thinking 1.4 inches but is that to narrow?
Thanks
Terry

[Apex Predator]

I believe Jared (michbowhunter) uses 1.4", as do I.

[T Folts]

Thanks Apex

[GREG IN MALAD]

I start with 1 3/4" to end up at 1 1/2"

[T Folts]

I kinda figured that. If I need to work on my form I may change it. I think it would make cleanup of the limbs easier.
Thanks
Terry