Drilling limb bolt hole on a three piece takedown.

[Sharp Shooter]

I may have asked this question before. I've been using a brad bit to drill the holes for index pins and limb bolts, they seem to work best for me, but I still damage the glass when the bit goes through. I use masking tape, it helps but doesn't stop it. What do some of you do? Thanks Tony

[kennym]

I either use a brad and just drill the point thru, then drill from other side or use a backer block clamped to the far side of limb.  Wish I knew a sure way to not get little splinters....

[MoeM]

I haven`t have built a 3piece jet but an overlay on the base shall solve the prob- drill smaller through it from the back and then desired dia from belly- I guess nothing can splinter then...

[carpin'mark]

I use an extra piece of tape or two where the bolt hole will come through, and a backer block like kenny said to support the glass. The extra tape seems to help hold the fibers down a little better, if I do get a tear, it tends to be small and usually easily fixed with a little dab of thin CA to wet it out.

[Sharp Shooter]

Thanks everyone!! Tony

[Crooked Stic]

If you do get little frizzy edges on the hole- I use a 45 degree grinding stone in a drill to chamfer it back a bit. And don't force the drill bit through.

[talkingcabbage]

I've started using a cobalt bit instead of a regular hss. It stays sharper longer and seems to not do the fray thang quite so much. But like crookedstic says, you can't force the bit. Go slow.

[Sharp Shooter]

Thanks everyone! I experimented a little, added a 1/16" phenolic to the face and belly worked good. Tony

[LittleBen]

I've never tried to drill through glass but I'd guess that a tapered grinding stone in a dremel or drill would do the trick ...

I'd proibably try drilling a small pilot hole, then opening it up wiht the grinding stone through both layers of glass, then finish up with a drill bit of the desired size through the ramainder of the limb, through the pilot hole.

[Saskquach]

I use these with a hardwood backing. Use less pressure as you exit thru into the backing

 http://www.leevalley.com/en/Wood/page.aspx?p=42352&cat=1,180,42240

Dean

[Sharp Shooter]

Thanks Dean!!