Drilling holes into partially turned workpieces without shredding or tearout?

[Jon Rista]

I'm turning two-piece coffee scoops. Something I've wanted to do for a while. I want two-tone woods, one type for the handle, another for the scoop. I've therefor been putting little tenons on the handles and drilling little holes into the scoops. The tenons are fine, its the drilling that's a problem. I've tried strait drilling with the final bit (1/4" usually), and also tried starting with a smaller bit and progressing through a few up to the final size. So far, every attempt results in shredded wood around the edge of the hole. I think its partly because where I am having to drill, there is a bit of curvature. I thought about drilling before I turned, but, that makes it a lot harder to judge how deep I really need to drill, and then there are often issues still, as turning over a hole often doesn't leave the best edge either (at least, not with my current skill level, maybe there is a technique that can avoid the issue.) I've tried starting slow, which seems to pretty much guarantede that chunks of wood will be ripped out. Starting faster, its then hard to control where the drill contacts (and I have no jigs to help me drill into a piece still on the lathe...I've been drilling by hand.)

I do try to leave a bit of material that still needs to be turned off, so that once the hole is drilled, I can do that...but, these drill bits really shred, and even leaving a bit of wood on that still needs to be turned off, usually a chunk on the side with the highest curvature still gets ripped out and there is no repairing it.

Wondering if anyone has any tips for drilling into a piece still on the lathe, with some shape/curvature to it, without any chipping or shredding.

 

[Doug Freeman]

Here is a pic of how I do mine, drilled and epoxied while still square. I use epoxy to not have air gaps. I started making them in 2 pieces, whether matched or not, to save on wood. Can generally get 4 handles out of the spindle blank size for the scoop.

Turn a sphere at the large end and turn the handle, then put in a scoop chuck I made to hollow.

I’m going to make some with larger tenons and bandsaw in 1/2 to get 2 scoops per blank one of these days.

For drilling I use brad point bits, which are a bit like forstner bits, they have cutters on the OD for a clean cut.

 

[robo hippy]

I am wondering if you do some hollowing first and then drill? If so, drill into the solid wood, then hollow. As with turning tools, bits need to be sharp.

robo hippy

 

[Rick Moreton]

I've only done a few of these but drilling into side grain with a brad point bit before hollowing may help. I got more tear out and the bit wanted to wander on end grain. Also aim for a press fit with a slightly mushroomed end of the tenon can help cover up small gaps.

 

[Jon Rista]

I am wondering if you do some hollowing first and then drill? If so, drill into the solid wood, then hollow. As with turning tools, bits need to be sharp.

robo hippy

I've only done a few of these but drilling into side grain with a brad point bit before hollowing may help. I got more tear out and the bit wanted to wander on end grain. Also aim for a press fit with a slightly mushroomed end of the tenon can help cover up small gaps.

I've been hollowing first, so I know how deep NOT to drill. I don't want the wood of the handle appearing internally. So I do hollow first, then rough turn the outside. Then drill, its shallow but enough for the handle to hold well.

 

[John Whitley]

It might also be worth trying a 1/4" forstner bit for this application. A brad point bit is a good idea, but brad points generally work best into side grain and are less effective entering end grain. A forstner bit will be more forgiving depending on your intended grain orientation, and is certainly what I'd reach for first when trying to create a clean mortise hole for a project like this. It would be easy enough to test this on a piece of scrap/practice turning with any forstner bit (or brad point)!) you may have lying around, before purchasing one in the size you need.

 

[Jon Rista]

Here is a pic of how I do mine, drilled and epoxied while still square. I use epoxy to not have air gaps. I started making them in 2 pieces, whether matched or not, to save on wood. Can generally get 4 handles out of the spindle blank size for the scoop.

Turn a sphere at the large end and turn the handle, then put in a scoop chuck I made to hollow.

I’m going to make some with larger tenons and bandsaw in 1/2 to get 2 scoops per blank one of these days.

For drilling I use brad point bits, which are a bit like forstner bits, they have cutters on the OD for a clean cut.

View attachment 81387

Does this approach require any manual carving? How are you able to turn the scoop fully round without hitting the handle with the tool?

 

[Jon Rista]

It might also be worth trying a 1/4" forstner bit for this application. A brad point bit is a good idea, but brad points generally work best into side grain and are less effective entering end grain. A forstner bit will be more forgiving depending on your intended grain orientation, and is certainly what I'd reach for first when trying to create a clean mortise hole for a project like this. It would be easy enough to test this on a piece of scrap/practice turning with any forstner bit (or brad point)!) you may have lying around, before purchasing one in the size you need.

It would be side grain, really. I have both bradpoint and forstenrs, although I'm not sure I have a 1/4" of either... Most of my bradpoints are in millimeters, so I may have one that is close enough. I think my smallest forstner is 5/8".

 

[Richard Coers]

I've been hollowing first, so I know how deep NOT to drill. I don't want the wood of the handle appearing internally. So I do hollow first, then rough turn the outside. Then drill, its shallow but enough for the handle to hold well.

If you don’t allow the handle tenon to go through the scoop wall, you really have very little strength at that thin of joint. I think the Shakers cut a slot in the tenon to make it a wedged mortise and tenon joint for more strength.

 

[Jon Rista]

If you don’t allow the handle tenon to go through the scoop wall, you really have very little strength at that thin of joint. I think the Shakers cut a slot in the tenon to make it a wedged mortise and tenon joint for more strength.

Well, its a coffee grounds scoop. It shouldn't need a ton of strength. That said, I am putting the handle a little lower on the scoop, where the wall is thickest. The tenon is probably around 1/4" long on its own, so as long as it is around. Stylistically, I just don't want the tenon visible from the inside of the scoop...

 

[Jamie Zietak]

Maybe the Star M F-Style bits will do a bit better for tear out. Chris Schwarz has recommended these for chairmaking purposes, in particular handling off 90 degree holes. He speaks a lot about the clean exit, but I would imagine it would have a clean entry as well. His biggest complaint is the usable lifetime, but in the context of a coffee scoop, it may not be an issue?

Here's one of many posts he's made about them: LostArtPress - Bits

I've purchased them from here before: TayTools StarM bit

 

[Jon Rista]

Maybe the Star M F-Style bits will do a bit better for tear out. Chris Schwarz has recommended these for chairmaking purposes, in particular handling off 90 degree holes. He speaks a lot about the clean exit, but I would imagine it would have a clean entry as well. His biggest complaint is the usable lifetime, but in the context of a coffee scoop, it may not be an issue?

Here's one of many posts he's made about them: LostArtPress - Bits

I've purchased them from here before: TayTools StarM bit

Well, I remember now why I was just using a jobber bit. All the other types, poke a hole into the scoop...forstner, bradpoint. I suspect these StarM bits, which look really cool otherwise, would do the same thing. The jobber is able to get me just deep enough, without punching all the way through....

I have an idea here, though, that I'm going to try. I have some hole punch bits, for cutting out plugs. They normally cut a plug and a ring around the plug, so you can pop the plugs out with a small screwdriver or something. However, I THINK the rim of these bits, is the exact same size as whatever size plug you are cutting. So if I use these, just to get a starter circular cut going, then maybe...assuming I can center the actual 1/4" bit inside that circle...that might prevent the chipping that the jobber bit has thus far been causing...

Centering the jobber inside the cut ring, though...is not going to be fun...

 

[Dave Landers]

I drill shallow 1/ 4” holes using a straight router bit. Doesn’t have a point like a brad point or forstner bit to go too far though.
I drill on the lathe. Might work if secured at the drill press. But without the center point it might be challenging to get started without drifting if drilling by hand.

 

[John K Jordan]

I drill shallow 1/ 4” holes using a straight router bit. Doesn’t have a point like a brad point or forstner bit to go too far though.
I drill on the lathe. Might work if secured at the drill press. But without the center point it might be challenging to get started without drifting if drilling by hand.

There are metal "drill guides" that can be held securely or clamped to flat work. They keep the drill bit from drifting.
For either a drill bit or an end mill I think it might be reasonable to make a custom drill guide curved to fit the work (if I understand the problem correctly). I'd use a hard, fine-grained wood, perhaps lignum vitae which is self-lubricating. Using the wood lathe and with the help of someone with a milling machine could help to make the drill guide.

To avoid making the hole larger with use I might round over the peripheral cutting edges of an end mill (up the sides of the flutes) except close to the cutting edge at the tip.

I'm not sure I'd worry so much about drilling turning the outside first, drilling, then hollowing. It might be easy enough to measure carefully to avoid cutting into the hole (especially if the hole were a flat-bottomed end mill.

But I admit I've never made such a thing and know not of what I speak...

JKJ

 

[Larry Copas]

While the Star M bits do an excellent job on the entry and exit side they won't work for this application because the center spur is too long and will go through the scoop. I use them frequently building chairs and stools.

A plunge router would do an excellent job with a standard router bit. Just don't know how you would get it in place to do the deed.

 

[Doug Freeman]

I've been hollowing first, so I know how deep NOT to drill. I don't want the wood of the handle appearing internally. So I do hollow first, then rough turn the outside. Then drill, its shallow but enough for the handle to hold well.

The handle tenon shows inside the scoop with my method. I want it to in order to have max length contact, and not worry about “breakingthru” when hollowing.

Does this approach require any manual carving? How are you able to turn the scoop fully round without hitting the handle with the tool?

No manual carving (other than some cleanup of where the center points locate at each end).

The glued blank is set between centers, turned round, turn the handle/scoop joint down some while turning a sphere at the scoop end, then finish turning the handle. This allows “flaring” the handle/scoop joint, vs a 90* attachement.

Its then placed in a “scoop” jaw set I made, which allows the handle to pivot down to allow the the protruding top of the sphere to be cut off and then hollowed. When the handle is held level, the far end of the scoop is below the handle. The top of the scoop is at an angle to the handle. It actually scoops stuff better bs the top of the scoop beings level with the handle.

 

[John K Jordan]

The glued blank is set between centers, turned round, turn the handle/scoop joint down some while turning a sphere at the scoop end, then finish turning the handle. This allows “flaring” the handle/scoop joint, vs a 90* attachement.

Its then placed in a “scoop” jaw set I made, which allows the handle to pivot down to allow the the protruding top of the sphere to be cut off and then hollowed. When the handle is held level, the far end of the scoop is below the handle. The top of the scoop is at an angle to the handle. It actually scoops stuff better bs the top of the scoop beings level with the handle.

Perhaps post diagrams or photos of each step so everyone can understand better the steps of your process, the order of assembly, and the orientation of the assembly on the lathe, more about the scoop jaw, etc. Diagrams would be better or at least useful accompaniment to the photos. For example, I don't understand completely why the outside of the bowl can't be turned first. (I prefer to turn the outsides of things first since that shape is what people see first, maybe measure and drill,then turn the insides as needed for wall thickness, clearance at hole, etc. I, for one, would appreciate your reasoning on the order of things.

That is, unless you want to keep some things secret!

Nice looking scoops, well done - nicer that many I've seen. Good attention to detail and an interesting variety!

JKJ

 

[robo hippy]

An old wood shop trick, if you are drilling through some thing, you need "backing" otherwise you get bolw out/tear out. On the drill press, this means you have a board under what you are drilling through, and the piece you are drilling needs to be clamped down, or at least held down firmly. Maybe leave the cup part thicker than final thickness so you can turn the tear out away. Not always a guarantee because some times the tear out can go pretty deep. After you insert the handle, then trim off the waste. Good sharp bench chisel or carving chisel.

robo hippy

 

[Walter Mooney]

It would be side grain, really. I have both bradpoint and forstenrs, although I'm not sure I have a 1/4" of either... Most of my bradpoints are in millimeters, so I may have one that is close enough. I think my smallest forstner is 5/8".

Jon, sounds to me like an opportunity to buy a new tool!
I agree with @JohnWhitley about using a Forstner bit, and I also understand the small hole that might protrude into the scoop part after using it for full depth. So how about this — start the hole with a Forstner bit (6mm or 1/4”) then finish the hole to the required depth with a twist bit?

Best of luck to you. Be sure to post some photos of the finished products!

 

[Jon Rista]

There are metal "drill guides" that can be held securely or clamped to flat work. They keep the drill bit from drifting.
For either a drill bit or an end mill I think it might be reasonable to make a custom drill guide curved to fit the work (if I understand the problem correctly). I'd use a hard, fine-grained wood, perhaps lignum vitae which is self-lubricating. Using the wood lathe and with the help of someone with a milling machine could help to make the drill guide.

To avoid making the hole larger with use I might round over the peripheral cutting edges of an end mill (up the sides of the flutes) except close to the cutting edge at the tip.

I'm not sure I'd worry so much about drilling turning the outside first, drilling, then hollowing. It might be easy enough to measure carefully to avoid cutting into the hole (especially if the hole were a flat-bottomed end mill.

But I admit I've never made such a thing and know not of what I speak...

JKJ

This sounds like the likely solution. The scoops are still on the lathe (from 2z2xY or 2.5x2.5xY blanks, jaw number marked for proper reattachment.) I've been using the indexing wheel to lock the scoop angle in place, then resting the bit on the tool rest as I drill. I haven't been turning all the scoops the same, each one is different and unique. I'm wondering here if I could just find a way to attach a drill guide to each, once locked into place with the indexing wheel, and use either a router bit (I have a 1/4" strait), or end mill.

Its a tricky little problem... I guess I could just drill all the way through and make things simpler, but, it really breaks the appearance I was going for.

 

[Jon Rista]

An old wood shop trick, if you are drilling through some thing, you need "backing" otherwise you get bolw out/tear out. On the drill press, this means you have a board under what you are drilling through, and the piece you are drilling needs to be clamped down, or at least held down firmly. Maybe leave the cup part thicker than final thickness so you can turn the tear out away. Not always a guarantee because some times the tear out can go pretty deep. After you insert the handle, then trim off the waste. Good sharp bench chisel or carving chisel.

robo hippy

Thus far I have been trying to avoid drilling all the way through. My problem is the corner of the bit is biting into the wood on first contact, usually the part that curves away, and ruining the scoop. I do wonder if I can clamp a flat piece of wood over the outside surface of the scoop to get the bit started, and if that will prevent the problem or not. I suspect for that to work, I would probably have to turn a custom fit piece for each scoop, all of which have been different and unique (and destroyed) so far, so that the full profile of the outside surface of the scoop was in contact with this waste block.

I guess the other possibility is I just leave more material on the outside and drill earlier than I have been, and just turn off any wood that chips out. Well, hopefully this afternoon I'll have some time to test out some of all these ideas!

Thanks all! Will report on how well these ideas work.

 

[Jon Rista]

I drill shallow 1/ 4” holes using a straight router bit. Doesn’t have a point like a brad point or forstner bit to go too far though.
I drill on the lathe. Might work if secured at the drill press. But without the center point it might be challenging to get started without drifting if drilling by hand.

This is definitely something I'll be trying. I do have a 1/4" router bit. I am not sure if I could use a router bit like this, with a drill guide (thinking the cutting edges might prevent that), but, maybe if I also pre-score the outer edge of the hole with my hole punch bit, then drill. Even the jobber bit, leaves a depression in the middle of the hole, but a pen mill or router bit would leave a flat bottomed hole.

 

[John K Jordan]

The scoops are still on the lathe (from 2z2xY or 2.5x2.5xY blanks, jaw number marked for proper reattachment.) I've been using the indexing wheel to lock the scoop angle in place, then resting the bit on the tool rest as I drill. I haven't been turning all the scoops the same, each one is different and unique. I'm wondering here if I could just find a way to attach a drill guide to each, once locked into place with the indexing wheel, and use either a router bit (I have a 1/4" strait), or end mill.

Its a tricky little problem... I guess I could just drill all the way through and make things simpler, but, it really breaks the appearance I was going for.

Others make them by drilling through, but I don't like the look as much.

IF they were all close to the same OD, I think a drill guide could be made by drilling and/or turning wood to fit (still thinking of lignum vitae or some hard wood like sugar maple, dogwood, guatambu, ebony, etc), turn the OD, fasten the guide to one side with clamps or big rubber bands, make a stop for an end mill, and drill. Shouldn't be any tearout that way. then turn the inside (with careful measurements.

Turn the outside. Even with a bit of tearout on the outside, and handle with a wider flange at the join could hide the tearout. Turn the inside. I'm then thinking of a 2-part handle, the flange shaped to fit the curvature, slide onto the handle, glue the handle in place, slide up the flange and glue. May be too much effort.

Oh, or turn the handle dowel, flange and all, then flatten a spot on the outside of the bowl as needed and glue the combo into place.

Might have to try one.

JKJ

 

[Brian Gustin]

Thus far I have been trying to avoid drilling all the way through. My problem is the corner of the bit is biting into the wood on first contact, usually the part that curves away, and ruining the scoop.

here's an idea.. start the hole the first 1/16" depth with your brad point bit, but first run the drill bit in reverse so the cutting "corners" of the brad point bit will score the circle , cutting the most vulnerable exterior wood fibers , and then start drilling normally with very very light pressure until you're down that first 1/16 inch or so, and then finish your blind hole with the regular twist drill bit? I often do the drill in reverse trick when drilling flat work so as to minimize or eliminate (when all works perfectly) tearout.

 

[Jon Rista]

here's an idea.. start the hole the first 1/16" depth with your brad point bit, but first run the drill bit in reverse so the cutting "corners" of the brad point bit will score the circle , cutting the most vulnerable exterior wood fibers , and then start drilling normally with very very light pressure until you're down that first 1/16 inch or so, and then finish your blind hole with the regular twist drill bit? I often do the drill in reverse trick when drilling flat work so as to minimize or eliminate (when all works perfectly) tearout.

About to head out to see what works. I think, this is going to be my first attempt. I have been using an awl to prick the center point where I want the drill to start. Starting off with a bradpoint in reverse should be pretty easy once that starting center hole is in place. This should do what I was planning to do with the hole punch bit as well, but I think it'll be easier and more consistent since I can use the starter hole and guarantee proper centering.

 

[Jon Rista]

Others make them by drilling through, but I don't like the look as much.

IF they were all close to the same OD, I think a drill guide could be made by drilling and/or turning wood to fit (still thinking of lignum vitae or some hard wood like sugar maple, dogwood, guatambu, ebony, etc), turn the OD, fasten the guide to one side with clamps or big rubber bands, make a stop for an end mill, and drill. Shouldn't be any tearout that way. then turn the inside (with careful measurements.

Turn the outside. Even with a bit of tearout on the outside, and handle with a wider flange at the join could hide the tearout. Turn the inside. I'm then thinking of a 2-part handle, the flange shaped to fit the curvature, slide onto the handle, glue the handle in place, slide up the flange and glue. May be too much effort.

Oh, or turn the handle dowel, flange and all, then flatten a spot on the outside of the bowl as needed and glue the combo into place.

Might have to try one.

JKJ

I'm just getting started with these, so my first couple handles here have been fairly modest, but, the intent was for them to be a bit more interesting than just a rounded dowel shape. This was the very first handle I turned, i think. The tenon is larger than 1/4" smaller than 3/8", I think I used one of the letter bits that fit it closest, and that larger bit did seem more problematic. I may try and whittle the tenon on this down to 1/4". Anyway, this is a lilac branch, and I have a bunch of that which I was going to use for some of the handles. I want to make them a bit more interesting, but, all should have something near the scoop side that would hide the interface with the hole to some degree:



This one, despite that ball on the end, still wasn't able to hide the chipout on the first few scoop attempts. I also had wall thickness issues on the first couple. This scoop is much simpler, I'm mostly trying to figure out wall thickness so I can actually attach the handle at a reasonable position: