Drilling in end grain

[Ray Gardiner]

Hi All, This is my first post. I am a retiree woodworker hobbyist, located in Victoria, Australia. Mostly I do a bit of everything. Turning small bits and pieces (been doing peppermills lately). I make a few of my own tools, a dovetail saw and I'm making a bow saw at present, and of course furniture for family and friends and having a good time doing it.

Anyway, here is my question, A friend who makes gun-stocks posed this question about a year ago and I still don't have a definitive answer.

How do you drill long holes accurately through end-grain, especially wildly figured end-grain.

The problem becomes more urgent when you realise that these pieces of walnut are worth a small fortune (up to $1000).

To just re-cap, when you drill end-grain with a twist drill the center of the bit tends to wander alarmingly. Highly figured grain is worse.

Shell augers are supposed to ride on the outer edge of the bit and should be more stable, but last time he tried it ran off just as badly as the pointed twist drill. He was able to save the job by recutting down the hole with a very long vary small gouge and re-cut the sides of the hole to get it back on track.

Most of the info on shell augers and the like seem to refer to turning standard lamps and musical instruments of various types, where the work
is turning and the drill bit is run through a hollow tailstock. Can't do that
with a gun stock unfortunately!..

The next thing he will try is a gun-drill (soon as he can get one).

So, does anyone here have some suggestions to try?



Ray Gardiner

[Jim Becker]

Could you split the gun stock blank, route a channel slightly undersized on both halves, reassemble and then clean it out with the long drill?

BTW, welcome to SMC!

[Prashun Patel]

Is a 'shell auger' the same thing as a bradpoint bit? If no, then I'd use one of these. The cutting wings around the edge produce cleaner holes than a twist and the brad point (should) keep the bit centered.

Before I (too a newbie) discovered BP's, I used to use a scratch awl to punch a pilot dent into which the twist bit would go. Worked fairly well.

A third approach (if there's enough clamping space) would be to clamp a door hinge over the hole (or shelf pin drilling jig) and then using a vix (self-centering) bit to make the hole.

All this is assuming you don't have a drill press.

[Greg Hines, MD]

Hi All, This is my first post. I am a retiree woodworker hobbyist, located in Victoria, Australia. Mostly I do a bit of everything. Turning small bits and pieces (been doing peppermills lately). I make a few of my own tools, a dovetail saw and I'm making a bow saw at present, and of course furniture for family and friends and having a good time doing it.

Anyway, here is my question, A friend who makes gun-stocks posed this question about a year ago and I still don't have a definitive answer.

How do you drill long holes accurately through end-grain, especially wildly figured end-grain.

The problem becomes more urgent when you realise that these pieces of walnut are worth a small fortune (up to $1000).

To just re-cap, when you drill end-grain with a twist drill the center of the bit tends to wander alarmingly. Highly figured grain is worse.

Shell augers are supposed to ride on the outer edge of the bit and should be more stable, but last time he tried it ran off just as badly as the pointed twist drill. He was able to save the job by recutting down the hole with a very long vary small gouge and re-cut the sides of the hole to get it back on track.

Most of the info on shell augers and the like seem to refer to turning standard lamps and musical instruments of various types, where the work
is turning and the drill bit is run through a hollow tailstock. Can't do that
with a gun stock unfortunately!..

The next thing he will try is a gun-drill (soon as he can get one).

So, does anyone here have some suggestions to try?



Ray Gardiner


Welcome to the Creek.

I have no experience with gunstocks, but I would think that the most accurate way to drill it out is to first, have a very stable drill press, and to have your workpiece securely clamped in place. I would think that drilling out short segments would be most accurate, drilling out the 4-6" of your drill press depth, then adding extensions to your drill bit. I have seen lamps and such drilled out like that using first a large diameter twist or brad point bit, followed by a spade bit and extender once the hole has been established. Beyond that, my Shopsmith can do horizontal drilling, which would also work, but you have to use what you have already.

Doc

[Ralph Barhorst]

Ray,

I would like to be the first to welcome you to the "Creek". You can obtain a lot of useful information here. I actually spend more time here than I do in the workshop.

In answer to you question, I usually use extra long brad point bits. I have a set that is 18" long.

You might also look at this website. Their "Timber" bits might also work.

http://advantage-drillbits.com/woodworking.html

[Ray Gardiner]

Could you split the gun stock blank, route a channel slightly undersized on both halves, reassemble and then clean it out with the long drill?

BTW, welcome to SMC!

Thanks Jim, that would work, and definitely solves the drilling problem, but would leave a glue line, which would probably be undesirable.

[Lee Schierer]

As others have said, Bradpoint bits are the way to go. Keep the Rpm fairly high and the bits will wander less. Back the bit out frequently to clear the chips when drilling long holes.

[Ray Gardiner]

Is a 'shell auger' the same thing as a bradpoint bit? If no, then I'd use one of these. The cutting wings around the edge produce cleaner holes than a twist and the brad point (should) keep the bit centered.

Before I (too a newbie) discovered BP's, I used to use a scratch awl to punch a pilot dent into which the twist bit would go. Worked fairly well.

A third approach (if there's enough clamping space) would be to clamp a door hinge over the hole (or shelf pin drilling jig) and then using a vix (self-centering) bit to make the hole.

All this is assuming you don't have a drill press.

Hi Shawn, The shell auger is a bit different to a brad point drill,
it's more like a tube with an angled tubular cutting surface, I think the idea is that the already drilled portion of the hole acts as a guide to the angled cutting head. And yes we have tried brad point bits, but you need to grind down the center pin a bit, otherwise it tends to follow the point.

Brad points with a reduced (or removed center) are close to what is needed.

And yes we are using a floor standing drill press, and the jig is all set up
with laser alignment etc. One problem with the drill press is the quill travel is only 6", and being vertical makes chip removal problematic.

[john bateman]

Maybe glue a piece of non-end grain wood on so that the bit can establish a straight path. Then saw off this extra wood when finished.

[Mike Henderson]

Welcome to the Creek!

I don't have a solution but I've had the same problem. No matter what type of bit I've used, and no matter how the drilling is done and the work held, the bit wanders. I assume the tip of the bit begins to cut more in one direction, and the shaft of the bit bends to allow the bit to go "off axis". To help people visualize the problem, think of drilling with a flexible shaft bit - because the shaft of a long bit is flexible.

Whenever I've drilled these long holes, I've used a drill press and clamped carefully but I still get "off axis" holes.

I've also tried drilling from both ends to minimize the drilling length but that has it's own problems (getting the holes to meet in the center), and often the resulting hole is not straight, in any case.

I have heard that a gun-drill will hold it's axis better but I've never used one. Please report on how it works for you.

Mike

[There's no reason this would work any better, but I have had a bit more success drilling long holes on the lathe, drilling through the tailstock. But I cannot see why turning the stock instead of the bit would make any difference. I've probably just been lucky in my trials on the lathe.]

[Ray Gardiner]

Ray,

I would like to be the first to welcome you to the "Creek". You can obtain a lot of useful information here. I actually spend more time here than I do in the workshop.

In answer to you question, I usually use extra long brad point bits. I have a set that is 18" long.

You might also look at this website. Their "Timber" bits might also work.

http://advantage-drillbits.com/woodworking.html

Thanks for the welcome, I have just been and check out that website,
looks pretty good, I can understand why you spend a lot of time here, the
depth of knowledge is amazing. What did we do before the internet?

[Ray Gardiner]

Welcome to the Creek!

I don't have a solution but I've had the same problem. No matter what type of bit I've used, and no matter how the drilling is done and the work held, the bit wanders. I assume the tip of the bit begins to cut more in one direction, and the shaft of the bit bends to allow the bit to go "off axis". To help people visualize the problem, think of drilling with a flexible shaft bit - because the shaft of a long bit is flexible.

Whenever I've drilled these long holes, I've used a drill press and clamped carefully but I still get "off axis" holes.

I've also tried drilling from both ends to minimize the drilling length but that has it's own problems (getting the holes to meet in the center), and often the resulting hole is not straight, in any case.

I have heard that a gun-drill will hold it's axis better but I've never used one. Please report on how it works for you.

Mike

[There's no reason this would work any better, but I have had a bit more success drilling long holes on the lathe, drilling through the tailstock. But I cannot see why turning the stock instead of the bit would make any difference. I've probably just been lucky in my trials on the lathe.]

Thanks for the welcome, and yes, you have understood the problem perfectly. I haven't seen any of the gun-drill literature refer to drilling in timber, and they seem to rely on compressed air or cutting fluid channels to remove chips.

Drilling flutes, bagpipes, standard lamps etc are all drilling in relatively straight grain materials (as far as I can see) and the work is turned rather than the drill bit. I think this helps because the work is more rigid than the
drill bit and the drill bit would need to flex back and forth sideways. But
maybe someone here knows the real answer.

[Ray Gardiner]

Maybe glue a piece of non-end grain wood on so that the bit can establish a straight path. Then saw off this extra wood when finished.

Good suggestion,
I have seen this method used, you start off with a supporting block, as long as the drill bit less a few inches, and as you drill down you replace the support block with shorter ones. The idea is that any flex in the unsupported
section of the drill bit is minimized. I think it's worth exploring further.

[Ray Gardiner]

As others have said, Bradpoint bits are the way to go. Keep the Rpm fairly high and the bits will wander less. Back the bit out frequently to clear the chips when drilling long holes.

Hi Ralph,
Consensus seems to be converging on brad point bits, I like the ones with little or no center point, albeit that a starter hole might be needed. http://www.morriswoodtool.com has some interesting brad point and variants, including a fishtail version that might we worth exploring.

[Jim Holman]

The best way to drill gun stocks for ammo tubes and the like is to drill the stock blank before it is shaped. Then you use the resulting hole at each end to insert a holding fixture for shaping the stock. I have had the most success drilling long holes with a piece of drill rod of suitable length with a small step ground in the end that looks kind of like a flat single flute bit. No center points. Drill a starter hole slowly and use it to guide the homemade long bit, feed very slowly and remove often for cleaning out chips.

[Chris Padilla]

What about a lathe? For metal working, they have a nice 'drill bit holder' piece/thingy (sorry, don't know the vernacular for it) that you use to drill holes on a metal lathe. The center of the chuck lines up with the center of the lathe's spinning head. I don't see why something like that couldn't be adopted to work on a ww'ing lathe.

What say ye all you metal workers out there?! :)

[Peter Quinn]

Hi Ralph,
Consensus seems to be converging on brad point bits, I like the ones with little or no center point, albeit that a starter hole might be needed. http://www.morriswoodtool.com has some interesting brad point and variants, including a fishtail version that might we worth exploring.

Ditto Ray. Morris makes brad points with a geometry for end grain drilling that was recommended to me by ANOTHER manufacturer at a wood working expo for drilling deep dowel holes in door styles on a horizontal borer. Have you checked out this page?

http://www.morriswoodtool.com/ToolTips.htm

[Dick Strauss]

Possibly some of these Dewalt "Pilot" bits would work for your endgrain issue. They aren't too expensive, stay sharp, and seem to work pretty well in many situations...

http://www.dewalt.com//ProductImages/PC_Graphics/Photos/DEWALT/ACCESSORIES/LARGE/1/DW1916_3.jpg

[Pat Germain]

Isn't this just the thing a horizontal boring machine does well?

[Eddie Darby]

In the Amazon rain forests when making a blow gun, the natives burn out the hole since the Drill Press needs too long of an extension cord.:D

[Ray Gardiner]

Thanks for all the suggestions, there are a couple of stocks coming up to be drilled next week, I will pass on all the comments and advice to my friend.

Some observations/conclusions so far...

1. The morristool endgrain brad point bit has minimal spurs also the fishtail
bit from morris seems promising.

2. I wish I understood how gun drills work!... The cutting edges seem to
be counter-intuitive.

3. Drilling/Boring on a lathe, there is something fundamentally different happening when the work is turning, rather than the drill bit.

I think we are going to be trying a gun drill, however I have some ideas for building a home built horizontal boring machine........ more later.

Thanks folks.

[Prashun Patel]

Possibly some of these Dewalt "Pilot" bits would work for your endgrain issue. They aren't too expensive, stay sharp, and seem to work pretty well in many situations...

I agree they're good workhorses, but I can tell you how many a hole I've torn to shreds because of this bit. I've only be successful in using it for rough work.

[David DeCristoforo]

An interesting "read" on a related subject....

http://www.mcgee-flutes.com/making.html

[Mike Henderson]

An interesting "read" on a related subject....

http://www.mcgee-flutes.com/making.html
That's really interesting. I spent way too long on his site. Thanks for posting, David.

Mike