Countersinking screws in G10/Micarta

MDQBox

MDQBox

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Hi, can anyone give me tips on how to countersink screws in G10/Micarta. The counterskink bits available at my local hardware store countersink but at an angle/bevel. Looking for something or someway to create a countersinked screwhole which is terraced or stepped down flat instead of a tapered countersink hole.

In this illustration, the screws are tapered or beveled. This is what I DO NOT want to do, but have the bevel or countersink 90 degrees to the flat surface. The one in the gree circle is what I would like to achieve.
ipd4c4.jpg


Any and all help is appreciated.
 

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d_clark said:
Drill the larger hole first to the correct depth of the screw head, then drill the rest of the way through for the screw.
Click to expand...

I countersink holes in wood scales (for Chicago bolts) this way, but I use standard drill bits in my drill press. Actually I drill the smaller hole first then use the larger bit to create the countersinks. The bottoms of the countersinks are not flat, they are tapered a little bit, but it doesn't matter. Plus for putting scales on fixed blades everything is epoxied so it all ends up very solid. I think countersinks are very touchy, you need to be very careful with the depth. I go slowly and use the stop on my drill press for trial and error so I don't drill too deep.
 
Yes, thats the way I counter sink some of mine on G10 as well. But he's doing them the manner as a blind cutlers bolt is done. Which is ok too. If your not experience on counter sinking go slow and be careful working G10. I don't care to work with it any more. Wear respirator and eye goggles, tightly. DM
 
Thanks for the info and tips. I've tried countersinking with regular drill bits going VERY slowly (like 5-10 rpm on the drill) and there is a point where the bits will "bite" into the G10 and want to push it's way through to the other side and I end up with a large hole instead of a countersink or more often times than not, I get a delamination on the surface.

I think I will give d_clark's suggestion a try and use a Forstner bit, only "problem" there is there expensive bits. But you gotta use the right tool for the right job or risk a Mickey Mouse job.

I should mention that I am working on scales that are between 1/8 and 3/16 of an inch in thickness for folders. So nut much room for error. I've actually completely ruined 2 sets of half-finished scales because of the countersink issue.

Thanks for all the info. and tips fellas.

:thumbup:
 
" I go slowly and use the stop on my drill press for trial and error so I don't drill too deep." As quoted by BDMICARTA.

I think this is the answer to your problem if (and that is a big IF) you have a drill press that you can set the depth or stop on. You can get one fairly cheap from HF if you don't expect too much. It will work, as long as you don't expect it to be a heavy duty drill press. A good investment if you are planning more such projects down the road.

Omar
:rolleyes:
 
OHALLUM said:
" I go slowly and use the stop on my drill press for trial and error so I don't drill too deep." As quoted by BDMICARTA.

I think this is the answer to your problem if (and that is a big IF) you have a drill press that you can set the depth or stop on. You can get one fairly cheap from HF if you don't expect too much. It will work, as long as you don't expect it to be a heavy duty drill press. A good investment if you are planning more such projects down the road.

Omar
:rolleyes:
Click to expand...

Yes, I've thought about investing in a drill press. I used a diamond coated barrel rotary bit this morning which actually worked nicely for creating a pocket hole.
 
Would a step drill work? This would give you a square shoulder, and let you choose the diameter pretty easily?
 
Actually I've been using diamond coated rotary tool bits. They works really efficiently and I can control the diameter of the hole I'm making which comes in handy. Something that is rather hard to do with brad point bits and forstner bits. Plus I had a really hard time finding small sized forstner bits. The diamond coated bits are serving me well.

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Actually, there is a specific tool for this application - it is called a "counterbore bit". It is like a countersink bit, but it will drill a clean, square bottomed shoulder on the outer hole. The Counterbore bits have a guide, which is smaller than the counterbore and helps you keep the holes lined up and concentric. Do some searching at your usual tool sites and you'll find lots of different types - and unless you go for a fancy carbide bit, they are relatively inexpensive for regular HSS (which is fine for G10 and micarta).

The other option is to buy one of the "stepped drill bits from some of the knife supply stores. These are regular drill bits which have been trimmed down on the last half-inch, so that you get a nice flat-bottomed counterbore hole. Relatively expensive though...

TedP

counterboring.png
 
phillipsted said:
Actually, there is a specific tool for this application - it is called a "counterbore bit". It is like a countersink bit, but it will drill a clean, square bottomed shoulder on the outer hole. The Counterbore bits have a guide, which is smaller than the counterbore and helps you keep the holes lined up and concentric. Do some searching at your usual tool sites and you'll find lots of different types - and unless you go for a fancy carbide bit, they are relatively inexpensive for regular HSS (which is fine for G10 and micarta).

The other option is to buy one of the "stepped drill bits from some of the knife supply stores. These are regular drill bits which have been trimmed down on the last half-inch, so that you get a nice flat-bottomed counterbore hole. Relatively expensive though...

TedP

counterboring.png
Click to expand...

Yes, I've actually considered using that but the problem is finding small sized ones. Something from 1/16 on up to 3/8 of an inch. I will keep looking and thank you for the info.
 
Stepped bits, meant for Corby-type bolts, may be your answer if you find the appropriate sizes. I've drilled hundreds of stepped holes for Corbies into G10, micarta, plain and stabilized woods and CF, and I just use two bits. One brad-point for the shaft and one angled metal-cutting bit for the head. (larger brad-points and Forstners are difficult to center in a smaller existing hole, but you may have good success drilling the larger counter-sink hole first and then centering the smaller bit in it, as they will leave a center-point at the bottom... it will depend on your accuracy in laying out where the holes need to be.)

MDQBox said:
I've tried countersinking with regular drill bits going VERY slowly (like 5-10 rpm on the drill) and there is a point where the bits will "bite" into the G10 and want to push it's way through to the other side and I end up with a large hole instead of a countersink or more often times than not, I get a delamination on the surface.
Click to expand...

That's way too slow. G10 is tough as well as both fibrous and layered, so it will want to grab any bit turning that slowly, and that's going to cause big problems. Sharp bits and moderate speeds (600-2000 RPM) have always worked for me.

Having said all that, there's not a heckuva lot of wiggle-room in a 1/8" scale. The rotary burrs may indeed be the best option (especially without a drill press), and if they're working for you, stick with 'em. :)
 
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