drilling in pine

[John T Barker]

I'm drilling a ton of holes in pine and I am using a brand new forstner drill bit on my drill press. I get tear out on entry. Anything I can do to eliminate this? RPM's? Nothing?
Thanks

[John Lankers]

Interesting, my first guess would have been a dull drill bit but when yours is new and of good quality that eliminates this possibility.
Have you tried starting the cut very slowly to give the spur time to score the perimeter of the hole? If you only had a few holes to drill you could sandwich the workpiece between two sheets of hardboard or scrap to eliminate tearout.

[pat warner]

Would clamp the work before the drill hits it.
And if the cutter is >7/8, I'd drill at <250 rpm.
And it would not hurt to enter slowly, then feed at the cut rate of the tool.

[Keith Westfall]

If it's not clamped somehow, it may move a bit causing a bit of tear out before it gets deep enough to stay in place. (only guessing...)

[John McClanahan]

Even though the bit is new, it sounds like it is not as sharp as it could be.


John

[Lee Schierer]

Take a piece of scrap and bore a hole through it. Then clamp that piece directly over the location for the hole in your finished piece. The scrap piece will prevent any tear out.

[John T Barker]

Appreciate the suggestions. Unfortunately I have to drill 4700 holes so clamping or use of scrap would slow me down too much. I'll try the slow feed...I hate pine.

[Brian Tymchak]

Even though the bit is new, it sounds like it is not as sharp as it could be.


John

My guess as well. Or the entry of the bit to the wood is too fast. Go slow for the bit to cut its first edges.

[Brett Luna]

You might also try starting the hole with the drill running in reverse, allowing the spurs to more gently score the perimeter.

[Bradley Gray]

You could make a pattern with an index hole under each hole you need to drill that fits over a pin in the drill press table.

This holds the work almost as well as a clamp but is much faster.

[Erik Loza]

I don't have a suggestion beyond than what others have posted but am curious. What is the project that requires 4,700 holes?

Erik

[John K Jordan]

I'm drilling a ton of holes in pine and I am using a brand new forstner drill bit on my drill press. I get tear out on entry. Anything I can do to eliminate this? RPM's? Nothing?
Thanks

This may not be practical for a "ton" of holes, but when I want an absolutely clean entry I clamp another piece of wood on top and drill through it. (Another piece on the bottom too if I want a clean exit.)

And make sure the bit is sharp even if new.

I haven't tried this, except on the lathe where tearout was a problem and when chip carving, but I'm wondering if a coat of thinned sander sealer before drilling would help.

JKJ

[william watts]

We do not know what size holes your drilling. My set of LV brad point bits has cutting spurs that are way sharper than my forstner bits, but they are under 1/2". LV my have larger available. You could hold the work steady against a fence if it's shape allows. 4700 holes at 15 seconds per hole equals 19.5 hours :eek:

[Frank Pratt]

How about making all the pieces just a little bit thick & then bring them down to final thickness after the holes are drilled, thus removing the torn out layer. Something to try if nothing else works.

[Myk Rian]

You might also try starting the hole with the drill running in reverse, allowing the spurs to more gently score the perimeter.
On a drill press?

[John T Barker]

I got this job on craigslist and it sounded like an easy (though time involved) way to make a few bucks. Information was to drill ten holes (1-1/4" deep) in 8" long 1-1/2" x 1-1/2" pieces of pine. I tweaked up a jig, modified it a bit and still have the problem on occasion. My biggest problem is that my jig set-up works those dimensions...as it should. The pieces I have are different in thickness and length and I really don't know how to approach that as far as my hold down is concerned. I'm thinking of adding a complete cover over the bit entry point to reduce tearout but I'll still have problems with the thinner pieces.
I'm thinking the fact that the holes are 5/8" and 3/4" apart center to center is really the biggest part of my problem.

[Brett Luna]

On a drill press?

Well, there's that to consider and I totally didn't.

[John T Barker]

I've come to realize I need to design a fence featherboard that can hold a piece of stock on top of the workpiece to prevent the tearout. I'll dream it up tonight.

[pat warner]

250-1000 lb destaco clamps would hold the work, and in seconds.
Notwithstanding, you're at constant risk (exit & entry tearout) without clamping and precise indexing.

[Rich Riddle]

I am with you on hating pine but also oak.

[Alan Schwabacher]

What if you made a carrier to fit your piece, using cam or destaco clamps to hold it tightly between two pieces? You could have countersunk alignment holes drilled in the bottom piece to fit over a pin sticking up from the table in line with the bit. Clamping the workpiece into the carrier would do all your alignment, and then you could position accurately for each hole by putting the carrier on the pin. The top part of the carrier should minimize tearout, and could be replaced without compromising accuracy because alignment is controlled from below. Of course bit sharpness and speed would remain relevant, and depending on the accuracy you need, the pin and alignment hole could be anything from a dowel fitting into a hole drilled in wood, to a drill rod fitting into a steel bushing.

[michael langman]

You need to make a jig like a die set. Take two pieces of wood with the correct holes drilled through them inline at their correct locations.
Then press two long dowels into the bottom piece of wood and put two springs over the dowels so that the two pieces of wood separate when you remove the clamp that holds them together, with the part being drilled in between. The top piece of wood has slip fit holes for the dowel pins.
Place a stop on the lower piece of wood to l;ocate the piece you are drilling.

[Bill Orbine]

I never had a tearout problem using a forstner bit in pine or any other wood...clamped or not. Clean holes are one of the features of forstner bits!

Whose forstner bit are you using? And how much runout do you have on what make/model drill press?

[Myk Rian]

Well, there's that to consider and I totally didn't.
;) That's OK. We all have our moments. Mine seem to be getting more often.

[John T Barker]

I never had a tearout problem using a forstner bit in pine or any other wood...clamped or not. Clean holes are one of the features of forstner bits!

Whose forstner bit are you using? And how much runout do you have on what make/model drill press?

It's a Freud bit. I haven't checked for runout but visually it doesn't seem bad.

[John T Barker]

I appreciate the input on jigs but truth be told I can't visualize what you're describing.
Thanks though.

[Terry Beadle]

One other possible cut improvement is to drill a test hole in a piece. Mark drill bit with ink line so as to be able to recognize rotation position #1.
Then mark hole in piece as cut #1.
Unclamp the bit in the chuck and rotate it 1/4 turn.
Drill another test hole and mark #2....ect.
Check which of the 4 holes has the least tearout ( if any ).

This will reduce any tear out due to chuck run out issues.

This is a technique recommended on this site several years ago.
Being an old fart, that's past my refresh rate of memory....go figure...hoot!

Enjoy the shavings.
Good Luck and when you have all the holes drilled, get a beer and grin!

[Keith Westfall]

It seems like you already have enough holes to drill without having to drill alignment holes all over the place!

Set your fence, mark the center point of your hole, and maybe set up a suitable toggle clamp and stops and away you go.

As previously said, if you have a good sharp bit, it should be a non issue.