Issues drilling the blank

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Infinity76

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So I'm new to pen turning and having issues drilling the blank.
I'm using the correct size drill bit as stated in the instructions and I also checked the size of the brass tube.
However, I have used a drill press and drilled another one on the lathe. But I'm finding that the tube will go in half way and then becomes stuck, it goes in the other way ok, but then gets half way and gets stuck again.
I used the drill bit a number of times, but nothing is making the brass tubing go all the way through.
Any ideas?

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randyrls

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Stuart; Check the drill bit and see if it is bent. Roll it on a flat surface like a table saw top.

The wood used must be dry. Wood will bend and warp as it dries. The hole the drill bit makes may cause the wood to change dimensions. If you are in AU, it is summer there and that may cause wood to move and bend. Don't use a wood piece with the pith in it. The pith is the center of the wood. If you can see concentric rings around a center spot, that is the pith.


Hope this helps
 
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pianomanpj

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Second what Randy said. Also watch your drill speed and feed rate. Acrylics and other plastics can soften or even melt if either is too high.

There are some "recommended" bits that will be awfully close to the brass tube size, so you may want to either sand or ream the hole, or use the next size larger bit. This is where a detailed bit chart will help.
 

Infinity76

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Thanks Randy,
Drill bits are new and I believed the blanks are dried out, as I imported them from the UK months ago.
But in regards to weather.... it's been very hot here over the last few weeks, between 95f - 109f.... roll on Christmas as it's predicted to be just as hot.

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WriteON

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What size bit are you using. If it's 3/8 or larger...pre drill first with a 7mm bit. When you are finished drilling let the blank&bit cool off and drill through again to clean/clear the hole.

You should be able to drill straight through...not 1/2 and flip to other side...that does not work. Take small bites and withdraw. Slow speed rather than fast. Fast speed heats up quickly.
 
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ed4copies

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Instructions are important for laying out the parts and assembling correctly.


When you are drilling, if the hole is too tight in the middle, use a SLIGHTLY larger bit. Some wood will contract, don't be afraid to sand the hole larger if the next bit size is too big.
 

monophoto

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Stuart

One point is not clear - are you drilling from one end, and going all the way through, or are you drilling half way from one end, and then fiipping the blank and completing the hole by drilling from the opposite end?

You should always drill all the way through from one end. If you try drilling half way through from one end, and then flipping the blank end for end to drill the rest of the hole, you will get a hole through the entire length, but the axes of the two holes may not be exactly aligned. That means that there is a discontinuity half way through the hole - the hole won't be perfectly straight for the entire length. But the tube is straight, and will bind when it encounters that discontinuity.

Don't worry about centering the hole on both ends of the blank. The hole must be straight to accommodate the tube. But its OK for the hole at one end to be off center as long as there is enough blank material around the hole to turn the body of the pen.

This is a common problem when drilling on a drill press - the throw often isn't long enough to drill the entire length. Rather than flipping the blank end for end, the correct way to handle the problem is to drill as deep into the blank as is possible for your drill press, and then elevate the blank with the bit in the hole to drill the rest of the way through the blank. I keep some scrap 3/4" thick lumber that I can slip under the drilling vise to elevate the blank without having to change any of the setup on the drill press.
 
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jttheclockman

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I would like to see your answer to Louie question because doing this for over 10 years I have never heard or had it happen where the center of a drilled hole shrinks. We are talking a pen blank most possible 1" square. I have been woodworking and drilling holes in wood alot longer than that too and never seen this phenomenon. I believe you are drilling from both ends and they do not match up and that is always possible. As mentioned you need to drill from one side only. :)
 
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Stuart

One point is not clear - are you drilling from one end, and going all the way through, or are you drilling half way from one end, and then fiipping the blank and completing the hole by drilling from the opposite end?

You should always drill all the way through from one end. If you try drilling half way through from one end, and then flipping the blank end for end to drill the rest of the hole, you will get a hole through the entire length, but the axes of the two holes may not be exactly aligned. That means that there is a discontinuity half way through the hole - the hole won't be perfectly straight for the entire length. But the tube is straight, and will bind when it encounters that discontinuity.

Don't worry about centering the hole on both ends of the blank. The hole must be straight to accommodate the tube. But its OK for the hole at one end to be off center as long as there is enough blank material around the hole to turn the body of the pen.

This is a common problem when drilling on a drill press - the throw often isn't long enough to drill the entire length. Rather than flipping the blank end for end, the correct way to handle the problem is to drill as deep into the blank as is possible for your drill press, and then elevate the blank with the bit in the hole to drill the rest of the way through the blank. I keep some scrap 3/4" thick lumber that I can slip under the drilling vise to elevate the blank without having to change any of the setup on the drill press.
This was an issue I was having when trying to do longer drilling into a blank. What I've found is exactly what Louie has stated above. You can't start from one end, flip it to the other end and have a straight non-binding hole. If you're bit isn't long enough, go as deep as you can, turn off the DP and loosen the chuck, let the bit slide down into the tube further and then tighten the chuck and start drilling. It works for me and I haven't had a tube stick since I started using this method. One caution though, the drill bit will be hot so let it either cool down or wear gloves.
 

magpens

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In my opinion, the best technique (for me) is to round the blank before drilling and then drill on the lathe. . If you have to drill in from both ends, the fact that the blank is already round gives you pretty good assurance that the two holes will meet accurately in the middle.

Stuart, I have indeed experienced the problem you are having when drilling wood, where the hole is smaller in the middle than on the ends. . I don't know the reason.

My solution is to use a rat-tail file a little smaller in diameter than the smallest part of the hole ... but you have to be careful to not enlarge the two ends of the hole. . I know this is not an elegant solution, but ... hey ... you have to do what works sometimes.

Bear in mind that the recommended drill size is not always the best size to use, depending on your material. . I have found it very worthwhile to have a variety of drill bit sizes close to the size you want to drill. . You can then enlarge holes when necessary. . I know that it's expensive, but I have never regretted buying complete sets of jobber drills in Fractional, Metric, and Letter sizes. . And I always keep a drill size chart handy in the shop.
 
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monophoto

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Stuart, I have indeed experienced the problem you are having when drilling wood, where the hole is smaller in the middle than on the ends. . I don't know the reason.
There are two possible reasons:
1. The drill bit is bent.
2. The drill bit isn't centered in the chuck, so that the axis of the bit isn't coincident with the axis of rotation.

In either case, the bit drills a conical hole that can have a smaller diameter in the center than it has on either end.

But remember Occam's Razor - the simplest explanation is most likely to be the correct explanation. That's why I'm gravitating toward drilling from both ends, with the two holes not lining up exactly in the middle. I know that's a simple explanation because I've done it that way and have seen the consequences.
 

magpens

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Louie,

I am quite sure there must be more possible reasons. . I say that because I am confident in my equipment and techniques and am sure that the drill bit axis coincides with the lathe axis of rotation.

Part of the on-lathe-drilling technique is to ensure that the blank is quite accurately round and that the ends are turned square to the axis before drilling. . If the ends are not square, then it can indeed happen that the drilling goes off-axis.

Just my two-bits based on my experience in my shop.
 

Dehn0045

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Sandpaper is your friend, as Roger and Ed already suggested.

I have found that I have this issue when I don't clear the chips from the flutes frequently enough. The bit gets hot, wanders, and the blank warps a little when it cools off (this is my theory anyway). Keep the bit cool by cleaning it often, it depends on the wood but I usually clean it every 0.5 inch or so. Also using denatured alcohol on a rag works for cooling, or apply a little wax to the bit (this has some potential drawbacks).
 

ed4copies

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I have experienced the phenomenon you describe when I have drilled from only one end. Indeed it CAN happen.


I don't know why, I just know what I did to "fix". I speculate the wood is oily and somewhat wet so it expands to fill the hole--in any event, making the hole SLIGHTLY larger solves the problem.



YMMV
 
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If it's being drilled all the way through with one pass and it's still sticking, wouldn't just running same drill bit down through it again take care of this? It shouldn't be that much of a problem. I agree with Louie, and this is the first time in a long time that I've seen Occam's Razor actually come into play. With all things being equal, it should be the simplest explanation.
 

Dale Allen

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Hopefully the OP will fill in some of the answers presented here. Some pictures of the blanks and pictures of the setup would help.
As for drilling from both directions, if the blank is turning true to center both ways and the drill bit is aligned with the blank center, it can be done. I've done it and you cannot tell it was done that way as opposed to all in one direction.
 

StanBrown

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I would like to see your answer to Louie question because doing this for over 10 years I have never heard or had it happen where the center of a drilled hole shrinks. We are talking a pen blank most possible 1" square. I have been woodworking and drilling holes in wood alot longer than that too and never seen this phenomenon. I believe you are drilling from both ends and they do not match up and that is always possible. As mentioned you need to drill from one side only. :)
I will admit to being a newbie here and as such perhaps not so well versed in the art of pen-making and have only turned around 100 pens or so. However, I have had this same experience 5 or 6 times. Every time it was with a different species of wood, some angle cut and some straight (with the grain) cut blanks. And, by the way, I always drill completely through the blanks from only one end with sharp, straight bits. I have never drilled half way and then flipped the blank end-over-end to finish the hole as I could see the problems involved in trying to align the two shafts.

Without bothering to analyze the problem in depth, my solution has been to insert the tube into one end of the blank until it sticks, then use the tube to mark the sticking point on the outside of the blank. Then I do the same thing from the other end of the blank. This gives me a very accurate picture of where the sticking point is and how long it is. Then I wrap a piece of sandpaper around a dowel and ream out the suspect area of the hole. It usually doesn't take very long for the tube to slip through the entire blank as it is supposed to do.
 

jttheclockman

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hey if you and Ed Brown and others have seen this phenomenon then I guess it is possible and so be it. I tell you I have drilled my share of wood blanks in many different species from domestic to exotics.and wood in general and never have I ever seen a blank close up in the center and probably will never see it. I never let my drill get so hot and always clear the hole. I guess going in and out of the hole to clear the hole helps in this case. I guess I am the exception to the rule:):):) Have at it guys and drill those holes a couple times before taking off the lathe. Man a 3/4" to 1" blank drilled out leaves about what 1/4" space on all sides and it moves that much to close up and only in the middle, is a head scratcher for me for sure. :):):):):):):):):)
 
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Infinity76

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A huge thank you for taking your time to reply.
Just to confirm, I used both a verable speed lathe and verable drill press, both set on the slowest speed. Also I only drilled all the way through it, lol wouldn't trust drill half way and holding my breath hoping the holes meet.

Drill bit is straight (checked) and brand new. However, over here in Australia it states to use a 10.5mm bit for Sierra pens and this is where the problem is... I think. Reading instructions from the States, it states to us a 24/64 drill bit, which in mm's is slightly larger then 10.5mm.

I could sand them, however I ordered a 24/64 drill bit online and hopefully this will work. I have also brought some flexible CA glue, read this helps also.... but I think my original CA glue was already flexible, as it was brought from a pen turning store.

I will take on board to leave the blank to cool down. After drilling the blanks, I did go to the glue up.

To all, again a huge thank you for your input and knowledge. Thank you and have a safe and enjoyable Christmas with family.

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geoffholden

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I'm going to suggest something else as a possibility. Have you checked to make sure the tube itself is straight? It most likely is, but if there's a bend in the tube it would certainly bind up in a straight hole.

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pianomanpj

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The 10.5mm tube is snug in the prescribed hole size. I've had more than one get bound up about halfway through as well. And I also drill from one end only. I typically sand the hold larger and all is good. The next size up bit would work without all the the fanfare.

Though I can't claim empirically what causes this, perhaps one side of my bit is a little sharper or ground at a different angle than the other (with a Drill Doctor this should not be the case), or there is a small ding in one of the flutes. Or perhaps I have a little runout on my quill that causes the bit to drift. Any way you slice it, there is still little room for glue even in a perfectly drilled hole so opening it up one way or the other isn't a bad idea.
 

jttheclockman

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I hate to belabor this topic and beat to a dead pulp but could it be possible all you people that seem to think the wood shrinks in the middle be seeing some runout in the blank, drill bit or lathe itself. When you start a bit in a blank many times the bit will wander some till it grabs and when it gets about half way into blank it now is drilling straight to the size the bit truely is. That is why you see the hole slightly larger on the ends than the center. The center is drilled to basically what the drill bit measures. I believe the bit is just too tight for the tube to begin with. I still do not believe the wood is shrinking especially that thin. This is one reason it is suggested to use a starter bit all the time. Because if the wood shrinks in the middle than why does it not shrink on the ends too.??? Even if there is a flaw in the bit that flaw passes all parts of the inside the blank as you advance. If there is a problem in one area it would show up throughout the blank. As I said it is a head scratcher for me. Happy turning.:):):)
 

pianomanpj

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I hate to belabor this topic and beat to a dead pulp but could it be possible all you people that seem to think the wood shrinks in the middle be seeing some runout in the blank, drill bit or lathe itself. When you start a bit in a blank many times the bit will wander some till it grabs and when it gets about half way into blank it now is drilling straight to the size the bit truely is. That is why you see the hole slightly larger on the ends than the center. The center is drilled to basically what the drill bit measures. I believe the bit is just too tight for the tube to begin with. I still do not believe the wood is shrinking especially that thin. This is one reason it is suggested to use a starter bit all the time. Because if the wood shrinks in the middle than why does it not shrink on the ends too.??? Even if there is a flaw in the bit that flaw passes all parts of the inside the blank as you advance. If there is a problem in one area it would show up throughout the blank. As I said it is a head scratcher for me. Happy turning.:):):)
And now to set the dead pulp on fire... :rolleyes:

I don't think there is any "shrinking" in the middle at all. I think it's a combination of imperfect tools, possibly imperfect techniques and the nature of the materials being drilled. Does this occur more often in materials with end grain? How about plastics, both soft and brittle? Tru-Stone?

I would think that if the bit drifts a little in a given direction, then the blank would tend to remain straight (in relationship to the hole) as it is being supported by the bit running through it. The off-center drilling would continue and get worse the deeper the hole is drilled. Once the bit is removed, the blank returns to its natural state, possibly with a non-straight hole. This would be on a small scale, of course, but you get the idea. :)
 

dogcatcher

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It is not runout, runout causes a larger hole, not a smaller hole. Same with the bent drill bit theory, a bent drill bit will act as a "boring bar" and bore a larger hole than the bit size.

Pool cue makers have a reason for not turning a pool stick in one sitting, they remove a little wood each time over days for a reason. As you remove wood, you remove or change internal stressors inside the wood. The same reason as some of the professional duck callmakers drill their blanks one day with a 5/8" drill bit and then wait a few days and ream them with a 5/8" reamer. The "pressure stressors" at the end of a blank are different than on the center of the blank.
 

pianomanpj

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It is not runout, runout causes a larger hole, not a smaller hole. Same with the bent drill bit theory, a bent drill bit will act as a "boring bar" and bore a larger hole than the bit size.

Pool cue makers have a reason for not turning a pool stick in one sitting, they remove a little wood each time over days for a reason. As you remove wood, you remove or change internal stressors inside the wood. The same reason as some of the professional duck callmakers drill their blanks one day with a 5/8" drill bit and then wait a few days and ream them with a 5/8" reamer. The "pressure stressors" at the end of a blank are different than on the center of the blank.
That makes sense. Now I'm even more curious as to how this applies to different materials. (Wood, acrylic, antler, etc.) Amboyna burls have historically given me grief on a 10.5mm tube. Always had to sand the hole.
 

monophoto

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Stuart (the OP) posted an update on his problem earlier today that contains some information that may help clarify what is happening:

"Also I only drilled all the way through it, lol wouldn't trust drill half way and holding my breath hoping the holes meet."

And - - -

"However, over here in Australia it states to use a 10.5mm bit for Sierra pens and this is where the problem is... I think. Reading instructions from the States, it states to us a 24/64 drill bit, which in mm's is slightly larger then 10.5mm. "

Obviously, there is no 24/64" bit; 24/64 is actually 3/8", and that is far too small. That may just be a typo.

The actual recommendation for the US version of a Sierra is 27/64 which is just a hair larger than a 10.5mm bit. And there is an assumption here that the pen kit he purchased in Australia labeled 'Sierra' is the same as the kit by the same name in the US.

He doesn't actually state which bit he is using, but I would assume that since he is in metric-land, its 10.5 mm. In that case, the hole he is drilling is slightly undersized. My suggestion would be to try the next larger standard metric size - 10.8mm.
 

magpens

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John (and others),

Don't let it be a head scratcher or a head shrinker.
Wood has elasticity just like every other material.
When you force a bit through it, it expands.
When you back out the bit, the wood contracts ... it is not shrinking, per se.
At the ends you don't experience the same expansion and contraction because the bulk is not there ... also, the elasticity is not isotropic but has different effects in different directions (across the grain, parallel to the grain) partly because wood is not a homogeous material. . On top of that, the elasticity is temperature dependent and the there is more frictional heating as the drill approaches the longitudinal center of the blank, partly because there is more wood surrounding the bit and partly because there is less cooling for the business end of the drill.

Therefore you expect different behaviour near the center as opposed to the ends. . Perfectly normal when you consider the physical properties of the materials involved.

This will happen even with a "perfect" drill bit, with perfectly centered drilling which is aligned perfectly with the axis of rotation.

Of course, it would be extremely complicated for even a person with a PhD in materials science to write down an exact equation for the process and solve it mathematically, or even numerically. . There are just too many factors to consider and too many unknowns for any material (eg. wood). . But in spite of the fact that we can't do a complete quantitative explanation we can understand the principles involved. . Ask any qualified mechanical engineer and I have no doubt he would agree.
 
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monophoto

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Wood has elasticity just like every other material.
When you force a bit through it, it expands.
When you back out the bit, the wood contracts ... it is not shrinking, per se.
At the ends you don't experience so much expansion and contraction because the bulk is not there ... also, the elasticity is not isotropic but has different effects in different directions (across the grain, parallel to the grain) partly because wood is not a homogeous material. . On top of that, the elasticity is temperature dependent and the there is more frictional heating as the drill approaches the longitudinal center of the blank, partly because there is more wood surrounding the bit and partly because there is less cooling for the business end of the drill.
And I would expect this problem to be aggravated if the hole is snug to begin with, as OP has suggested.

So Mal is correct - it may not be rocket science after all.

However that does suggest another question - how long is OP waiting between drilling the hole and attempting to insert the tube. I would expect that dimensional changes associated with heating would change over time after the hole has been drilled.

So is it better to insert the tube quickly, while the wood is still warm, or wait until it has cooled down?
 
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Hi Stuart,

That happened to me just last week on two pens ! The problem is the wood itself, cherry burl, very hard. I drilled straight thru taking my time, no heat, the wood still moves after drilling. Tube seemed to fit right after drilling, but come glue in time not even close ! I let it sit and drilled again with a tiny bit larger bit. don´t give up

Irv
 

jttheclockman

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Mal I have been wood working for over 40 years. I know how wood moves. I know how heat creates problems. I know how temp from the outside can affect wood and also finishes. I know how water within has a great effect on wood. I know all that but again you are talking 1/4" at best all around the internal stress is so minimal the pool cue thing was brought up again the diameter is 3 times that of a pen blank. They work with balance to their end product. We do not. Why is it I never encountered this problem?? That is why it is head scratching. I have done exotics that are known to be prone to movement such as pink ivory, holly, ebony, burls of all kinds, and such and not once has a tube gotten stuck in the middle of a 3 inch long piece of wood. Heck i have used pens with blanks longer than that. I do drill and also glue the same day so maybe there is something to that . When I drill I usually start with recommended bit size. If I need to step up the tube does not go in right from the end and I make note in instructions to step up the bit for next time. I think theories are being thrown around here an there is something more to the operation of the OP then wood shrinking.

Love for someone to give me an example of a wood that they found prone for this to happen. I may have some and will give it a try. Also explain your operation of drilling the blank and when you notice the tube does not go all the way in. :):):):):) Hope that is enough smileys.
 

MRDucks2

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Well, I’m not gonna put a dog in this fight, but suggest why some folks may see it and others do not. The largest portion or my background is industrial Maintenance and Reliability.

Based on what I read on here and knowing much of our equipment and materials are mass produced in manners to keep cost down, I reference the “recommended” bit size, measure the diameter of the tube I plan to use and the drill bit I plan to use. Decide if I like the “fit” choosing a different bit if I think it is too tight or too loose and drill with that bit.

If anyone happens by choice or coincidence to drill a hole the size of the the tube, that tube will stick. It has to have a slip fit to work, when everything it cooled and in it’s “normal” state.

Is it possible that is the problem?


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