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Main Boards => The Bowyer's Bench => Topic started by: beachbowhunter on December 28, 2012, 10:58:00 AM

Title: Tips on drilling clear glass needed!
Post by: beachbowhunter on December 28, 2012, 10:58:00 AM
I just finished my first set of TD limbs and one of the difficulties I had was chipping/splintering around the drill holes. I use a great jig and the holes are nicely aligned.  How do you avoid the chipping?  Do you drill fast or slow? Drill press or hand drill? Any recommendations on drill bits?

thanks!
Title: Re: Tips on drilling clear glass needed!
Post by: psychmonky on December 28, 2012, 07:09:00 PM
Never built a glass bow, but could you use masking tape? Put it on the spot to be drilled and then drill through it and remove after your holes are there? Might be worth a shot.
Title: Re: Tips on drilling clear glass needed!
Post by: Sharp Shooter on December 28, 2012, 08:18:00 PM
I have the same problem, masking tape helps, also use a drill bit that scores the outside edge of the hole. I think their called a brad point bits. They work better for me. Tony
Title: Re: Tips on drilling clear glass needed!
Post by: Bradford on December 28, 2012, 09:27:00 PM
going in the glass usually is not the problem..it is coming out the other side.  I make sure there is a piece of wood tight to the bottom of my limb..and i go slow.. i still get a splinter now and then but that is what super glue is for
Title: Re: Tips on drilling clear glass needed!
Post by: D on December 28, 2012, 11:01:00 PM
I had the same problem. My fix...drill with a small bit first to get an alignment hole then drill through the glass with the drill in reverse, then when your in the wood drill in foward then use the small hole as a guide on the other side so you can reverse drill through the glass on the other side.  I hope that makes sence.  Has anybody tried Forsner bits??  I've never tried them on glass
Title: Re: Tips on drilling clear glass needed!
Post by: perry f. on December 29, 2012, 09:31:00 AM
Bradford, how do you fix it with super glue?
Title: Re: Tips on drilling clear glass needed!
Post by: Sharp Shooter on December 29, 2012, 11:17:00 AM
Another thing I've discovered the hard way, once you drill the holes through the limb, use a reamer an bevel the holes and apply super glue to the bevel. This will help prevent the glass from splitting farther down the limb. Hasn't happened a lot but can. Tony
Title: Re: Tips on drilling clear glass needed!
Post by: Bradford on December 30, 2012, 08:48:00 PM
Just like sharp shooter... Most of the time the splinter is still there.. I apply a small amount of superglue under the sliver.. or just around the hole if there is no splinters and let it dry.  It holds it all together and seals it up.
Title: Re: Tips on drilling clear glass needed!
Post by: D on December 30, 2012, 10:15:00 PM
I just tried a forstner bit on a scrap piece I had that I cut off the limb when I glued it up and it didn't splinter bad at all.  I didn't clamp it down or anything just pressed it down against my bench.  The exit hole didn't even splinter much either.
Title: Re: Tips on drilling clear glass needed!
Post by: beachbowhunter on December 31, 2012, 01:07:00 AM
I used masking tape and had a piece of wood beneath and tight but still had splintering. I did seal everything with super glue.  

I have heard of something called "pilot bits". Anybody know what those are. I don't know what a Forstner bit is.
Title: Re: Tips on drilling clear glass needed!
Post by: Crooked Stic on December 31, 2012, 05:28:00 AM
Use sharp bits. Clamp a hardwood piece underneath and dont force it. Countersink the hole on each side with a grinding stone mounted in a drill.
Title: Re: Tips on drilling clear glass needed!
Post by: D on December 31, 2012, 09:57:00 PM
Drilling with the drill in reverse just to get through the glass gives the cleanest how I've found yet.  I'm sure its not good on the bits but they are cheeper than glass.
Title: Re: Tips on drilling clear glass needed!
Post by: kennym on January 01, 2013, 09:33:00 AM
The best bit I ever had , and don't know if they still make em, was a black and decker from the department store called a bullet point(I think)

It was kind of like a brad point, but for metal (or glass) , had a  lil point in center and then the edges cut first, worked lke a champ.

They may not still be the same, but I found some here..

 http://www.amazon.com/dp/B000PIVM9U/ref=asc_df_B000PIVM9U2324474?smid=AM0TJKCE8MD21&tag=sdcbing4-20&linkCode=asn&creative=395105&creativeASIN=B000PIVM9U  

You cant see the end of the bit, but the pic on the package kind of shows it better.
If anyone tries em, let us know how they work...
Title: Re: Tips on drilling clear glass needed!
Post by: 4runr on January 01, 2013, 09:48:00 AM
Norb, a pilot bit is just a smaller bit than the one used as the final bit.

For example, if your finished size hole is going to be 3/8, first drill a hole with a 1/8 bit.

HOWEVER, if you're using a Forstner or a brad-point, don't drill a pilot hole. Both those bits have a center "point" which the bit uses as a pilot.
Title: Re: Tips on drilling clear glass needed!
Post by: Sigmazxcs on January 01, 2013, 11:06:00 AM
Haven't dealt with glass yet, but I've quite a bit of experience dealing with similar materials.
A pilot hole is a good solution, but be sure to align the surface parallel to the drilling platform, otherwise, god have mercy on you.
Title: Re: Tips on drilling clear glass needed!
Post by: D on January 01, 2013, 07:56:00 PM
Hey Kenny Lowes has those pilot point bits.  I bought a whole Dewalt kit of them.  Pretty cheep too.  But I used one of them and it splintered the glass. Ya know I never thought about it til now they actually make a drill bit for glass.  To drill in mirrors to hang on walls.  They actually look like two blade broadhead on a shaft.  I've never tried them.  I knew they had them but never even thought about them.  I've seen them at Lowes but I can't remember what size they were.  Heres an example
http://www.amazon.com/Vermont-American-13310-4-Piece-Glass/dp/B000ETWIKM/ref=sr_1_7?ie=UTF8&qid=1357087929&sr=8-7&keywords=glass+drill+bit
Title: Re: Tips on drilling clear glass needed!
Post by: Roy from Pa on January 01, 2013, 08:18:00 PM
Ifin you boys made real bows outta wood, ya wouldn't haf ta worry about such trivial things   :laughing:    :archer2:    ...
Title: Re: Tips on drilling clear glass needed!
Post by: kennym on January 01, 2013, 09:52:00 PM
But Roy, we would haf to make so danged many to get just one.  :laughing:    :laughing:  

Hmm, were you drilling just the glass, or a glued up limb?  I always just drill slowly til it turns white on the back side then drill from the other way. This is on limbs glued up tho.
Title: Re: Tips on drilling clear glass needed!
Post by: beachbowhunter on January 02, 2013, 01:25:00 AM
They call them lip and spur bits or brad points according to Wikipedia. Are those the ones you have tried?  The description of how it Cuts fibers is interesting.
Title: Re: Tips on drilling clear glass needed!
Post by: beachbowhunter on January 02, 2013, 01:27:00 AM
Definitely not like the Lowes link from D. Can't post a picture from my phone.

Like these?

http://www.traditionalwoodworker.com/COLT-5-Star-Brad-Point-Bits-Inches-HSS-Germany/products/725/
Title: Re: Tips on drilling clear glass needed!
Post by: D on January 02, 2013, 11:26:00 PM
Dang thats a pretty cool looking bit.

Roy thats just not nice. lolol

Kenny I've never tried those glass bits on a bow.  The thought about them just hit me when I was typing.  I have no clue how they would do on a bow.  As far as the drilling backwards it was when the bow was glued up.  You have built way more and way better bows than I have and your knowledge is way way way more experienced than me so whatever you suggest is probably the best idea.
Title: Re: Tips on drilling clear glass needed!
Post by: Kauz on January 02, 2013, 11:52:00 PM
Hello,
Lee Valley sell Carbide-Tipped Lipped Brad-Point Drills. I think this would be the best option, as steel will dull on first contact with glass. Furthermore, I noticed that the diameter of steel bits (even HSS) diminishes just enough so that bushings won't get through.
regards
Title: Re: Tips on drilling clear glass needed!
Post by: kennym on January 03, 2013, 06:53:00 AM
Hey D, probably not!! LOL  I'm just fishing for info all the time!

Kauz, will have to look at those, you are scorrect on glass dulling stuff! Thanks.
Title: Re: Tips on drilling clear glass needed!
Post by: D on January 04, 2013, 12:11:00 AM
Ok so I brought one of those glass bits home from work I was talking about and tried it on a piece I cut off a limb and.....it was a terrible idea lolol.  Do not use that style of bit. lol  It splintered really bad. Putting a butterknife in a drill probably would have done a better job. lol
Title: Re: Tips on drilling clear glass needed!
Post by: Roy from Pa on January 04, 2013, 12:45:00 AM
I've never had to drill a hole in a BBO Bow or an Osage Self Bow:) I think you boys are worken with the wrong materials.    :saywhat:    :laughing:
Title: Re: Tips on drilling clear glass needed!
Post by: D on January 05, 2013, 12:29:00 AM
Roy I've never worked for hours and hours and hours on a glass bow only to have it lift a splinter and ruin it. lolol...I sure do like the looks of a boo bow though.
Title: Re: Tips on drilling clear glass needed!
Post by: Roy from Pa on January 05, 2013, 12:43:00 AM
Ya I like BBO's too, but they can drive a man to drinken:)
Title: Re: Tips on drilling clear glass needed!
Post by: D on January 05, 2013, 12:55:00 AM
They drove me to spiking a bow on the floor of my shop like a football when the boo lifted a splinter.  Stupid bow. lolol
Title: Re: Tips on drilling clear glass needed!
Post by: Roy from Pa on January 05, 2013, 01:38:00 AM
LOL, don't feel bad, I have gone bezerk too on a few bows myself after a splinter blew up.

All the Kings Horses and all the Kings Men, couldn't put Humpty Dumpty together again. LMAO
Title: Re: Tips on drilling clear glass needed!
Post by: Dimondback on January 09, 2013, 02:24:00 PM
There are plenty of opportunities for what I call "adult temper tantrums" in both types of bow building.....and sometimes fly fishing in the winter as well...I have been so "hot" I am pretty sure I melted the ice some in my rod guides  :)