Trouble Drilling Holes on Lathe

[Dragnet]

Hello everyone -- long time lurker here, finally found a good reason to post as I've had some trouble drilling holes for my segmented blanks that remain centered throughout. I've recently transitioned to using my lathe for drilling and I've been using a Nova G3 chuck with Pin Jaws in the headstock and PSI 1/2" drill chuck in the tailstock. I invested in some fantastic flute bits as well, which do much of the work themselves of clearing dust as I move the bit forward (I go pretty slow and typically only have to back out a few times to clear).

As you'll see in the photos attached, I don't have any problems starting on-center.. the issue is getting out the other end centered, and I'm not sure why I'm getting so much drift. I have noticed a fair amount of wobble on the drill chuck as I move forward, but I wasn't sure if this could be causing the problem. I should add that my lathe is a Delta 46-460, and I typically drill at 1350 rpm.

Any thoughts?

 

[Gary Beasley]

The bit is flexing and following the grain of the wood. 1350 is a bit fast for drilling, have you tried a slower speed?

 

[Dragnet]

The bit is flexing and following the grain of the wood. 1350 is a bit fast for drilling, have you tried a slower speed?

Thanks for the quick response Gary! I have not tried going slower, as I would need to change the pulley... I can certainly do so however. What RPM would you suggest? and assuming the bit is flexing, would that alone fix the issue?

 

[montmill]

It helps me to back out and clear the chips often, makes a nice clean hole. Slow down and let the bit work, just like your gouge.

 

[tomtedesco]

For what it's worth, I drill around 500 RPM and back out often to clear chips and allow for cooling.

 

[monophoto]

In my experience, the keys to getting a hole centered include all of the following:

1. Start with the blank between centers. This will create centered dimples on both ends of the blank. Turn a tenon on one end, and then remount the blank in either a scroll chuck, or better yet, a collet chuck, that grips that tenon.
2. When remounting, make sure that the tail stock centers on the center dimple in the end of the blank before tightening the chuck to fix the blank in position.
4. After mounting the drill bit in the chuck and bringing the tail stock up so that the bit touches the wood, make sure that the bit is centered on the dimple before locking down the tailstock. Many small lathes have a bit of 'wobble' in the tailstock that can cause the bit to be misaligned if you don't take this step.
3. Use a center bit to start the hole. A center bit is a very short bit that tapers to a narrow point that is normally used by machinists to start drilling holes, and that can also be used as a countersink when drilling wood. Because it is very short and relatively thick, it won't flex very much so it allows you to start the hole exactly on center.
4. VERY IMPORTANT: There is a balance between rotational speed, and the speed at which the bit advances into the wood. The lathe should be rotating fast enough for the bit to cut a hole in the wood before you advance the bit into that hole - if you advance the bit faster, so that it is forcing its way into the wood, there will be a tendency for the bit to follow the natural grain lines that represent boundaries between softer wood (summer growth) and harder wood (winter growth) which then causes the bit to flex as the bit deviates off the rotational axis. But as noted below, you don't want (or need) excessive rotational speed - 500 r/min is fine, but anything about 1000 r/min is too fast. In general, advance the bit slowly.
5. Periodically, back the bit out of the wood to clear the swarf that collects in the flutes of the bit. If swarf completely fill the flutes, it will cause additional friction inside the hole, and the additional heat can cause the blank to crack. How far you can drill in each pass depends on the size of the bit and the dimensions of the blank - you can drill deeper with larger bits that have deeper flutes. Note that excessive rotational speed will aggravate the tendency for friction to cause heat.
6. If the hole that you are drilling is fairly large (say 1/2" or larger), drill the full depth with a small bit, and then come back to redrill to the final diameter with a larger bit.
7. So the bottom line is to be patient and drill slowly - it's better to take a bit longer and get the hole right than it is to slam the bit into the wood and find that the bit has deviated off center or have the blank crack.

 

[turnit2020]

I find drilling at about 450RPM is best. I drill about 5 turns of the tailstock wheel at a time and then stop and clear the debris before going back to trilling. If you are drilling acrylics let the bit cool before going for another cut, especially at the very end to avoid blow out.
Another way might be to use PSI 1" capacity pen blank drilling chuck. Gives accurate drilled holes consistently. Just my thoughts.
turncrazy43

 

[Curly]

Before you go any further, are the headstock and tailstock in alignment with one another? The simplest method is with good centres put the points together and make sure they are tip to tip when looking from the side and above. Do it with the tailstock quill/ram retracted and fully extended. If they aren't things need to be corrected. Try push the tailstock away from you when clamping it down, again when pulling it towards yourself, twisting it clockwise, then counterclockwise and finally just letting it find its own spot. Doing so will show you if there is any best positions to align it. A dead conical centre and a conical live centre are usually better than the ones that come with most bench top and cheaper lathes.

 

[MillerTurnings]

Hard to tell from the pic, but it doesn't look like the drill bit has a point on it- but has a pyramid tip? I find these tend to drift, especially since the blank is laminated with different hardness of woods. I personally use regular twist bits, sharpened each blank, and as noted go slow and clear out often.

 

[jttheclockman]

You got alot of good info already such as slow speed down to 500 to 600 RPM. Let the bit do the work. Do not force it. Check alignment of head and tailstock. But what I would like to add is when drilling, I like to just barely tighten the side holding lever which helps steady the drill chuck. Also to help steady I keep my left hand on it while turning in the tailstock handle. I do this both going in and out. Next when you chuck up your blank in the pin jaws make sure it is sitting square and then turn the lathe on and you should see the blank spin on center and not wobble. If it does then there is a problem with either the chuck or the blank not being true.

 

[Dragnet]

You got alot of good info already such as slow speed down to 500 to 600 RPM. Let the bit do the work. Do not force it. Check alignment of head and tailstock. But what I would like to add is when drilling, I like to just barely tighten the side holding lever which helps steady the drill chuck. Also to help steady I keep my left hand on it while turning in the tailstock handle. I do this both going in and out. Next when you chuck up your blank in the pin jaws make sure it is sitting square and then turn the lathe on and you should see the blank spin on center and not wobble. If it does then there is a problem with either the chuck or the blank not being true.

Great info guys -- a few questions/concerns I can check off, like the head/tailstock alignment, which I've checked and is on point. Also I do hold the chuck with my left hand when moving forward. For the question about the bit - I think it should be fine, though I attached an image of the exact bit I'm using for reference.

It sounds like I need to:

1) Slow the lathe down to around 500 RPM
2) Advance the bit slower than I have, perhaps backing off more frequently that I have
3) Consider using a center bit to begin process

I will test this in the next few days and report back. Thank you to everyone!

Also, in case anyone was curious, I've attached photos of a few of my recent segmented pens.

 

[magpens]

One other thing, Joshua ...

I find it important to square the ends of the blank before I start drilling. . The center drilling is also important.

BTW, I use only jobber drill bits which work perfectly fine for me after the center drilling.

 

[magpens]

@Dragnet

Beautiful segment work !!!! . Thanks for showing !!

I especially like the "random one" on the left !!!!

 

[jttheclockman]

Lots of work in those segmented pens. I like the Panache pens the best

 

[Warren White]

My only comment beyond what has been offered thus far (all excellent suggestions!) is that in my experience the pen jaws on the G3 chuck were not closing in parallel. Nova sent me a new set of jaws (which had the same problem); a new chuck with new jaws (which had the same problem). I purchased a Vicmarc chuck and pen jaw set and have not had a problem since. I have also noticed that it is easy to over tighten the jaws on the blank and that can cause problems in drilling.

 

[Charlie_W]

In addition to all the above suggestions, I see as you said your bit has flutes to pull chips/swarf out. I found these bits to have too much flex for my liking. This bit you show also has a tiny center point. If you use a center drill to make a divot for the bit to start in, most likely the edges of the bit will contact the wood before the center point and can cause the bit to lead off center. For this bit, a tiny centered mark in the wood is best to the bit can start with the point in the wood first. Also on the standard Brad point bits, I found that some of the bits were not ground precisely and the center point was not even in the center.

My go to is a standard twist bit which is stiffer and I either use a center bit or the point of a skew to make a starting point for the bit. I also bring the bit up to the wood with the tailstock loose and with the lathe running, I let it "find" it's center in the divot then lock the tailstock and begin drilling......advancing very slowly at first.

In my experience, the best drilled hole is achieved by turning the blank to fit a Collet Chuck instead of using the different pen or pin jaws.

Good luck!

 

[eharri446]

My only comment is that the chuck you used may not be the right one. You may need to switch to the Pen Plus set of jaws which provide more length to support the blank.

 

[dogcatcher]

Try using a center bit and drilling with a jobber drill bit.

 

[Mr Vic]

My eyes might be off but it looks like the blank is 4 layers of different wood. If the larger piece is harder the the others the drill might drift into the softer woods.

 

[KenB259]

Probably gonna ruffle some feathers here but something just doesn't ring true about this thread. Drilling a straight hole through a pen blank is pen making 101. We all learned rather quickly when we started out how to accomplish this. The OP is struggling, but then posts very advanced segmented pens they have made. Just an observation.


Sent from my iPad using Penturners.org mobile app

 

[jttheclockman]

Probably gonna ruffle some feathers here but something just doesn't ring true about this thread. Drilling a straight hole through a pen blank is pen making 101. We all learned rather quickly when we started out how to accomplish this. The OP is struggling, but then posts very advanced segmented pens they have made. Just an observation.


Sent from my iPad using Penturners.org mobile app

I questioned that also. How is he building these type pens?? Now they all are stackable so could be drilling individual layers and stacking and gluing on tube. But if he is building and then drilling then why the problem now?? More info is needed.

 

[Dragnet]

Probably gonna ruffle some feathers here but something just doesn't ring true about this thread. Drilling a straight hole through a pen blank is pen making 101. We all learned rather quickly when we started out how to accomplish this. The OP is struggling, but then posts very advanced segmented pens they have made. Just an observation.


Sent from my iPad using Penturners.org mobile app

Really? Everyone has been extremely helpful and I am especially grateful, but your comment is indicative of why so many forsake participating and contributing to forums like these. Since you asked, and since I now feel the need to defend myself to inscrutable ends, here goes..

I began turning 3 years ago with my father, who had ALS and for whom I lived with and helped care for. He has a rather large workshop in his basement, and this is where I worked up until his death, some months ago. In that workshop all of my drilling was done using his tools -- drill press, bits, vise, etc. While it did the job, I was never fully satisfied with the results I obtained from drilling on his press, so when I moved out and bought many of my own tools, I decided to begin drilling on the lathe. I've now been doing so for a short while and have been having the issues noted in the original post. Anything more and I'd be happy to provide details via a personal message or email, as I see no reason to bore the kind individuals who have contributed or may be following this thread.

 

[Dragnet]

I questioned that also. How is he building these type pens?? Now they all are stackable so could be drilling individual layers and stacking and gluing on tube. But if he is building and then drilling then why the problem now?? More info is needed.

Most of the blanks I've made are sandwich style, with thin 0.15-0.35" cuts of 2-3" x 6-10" woods, glued together with gorilla glue. Once they are fnished and after drilling my hole, I use the table saw to cut small segments (typically around 4mm) which I then sand individually and glue, one by one on the tube. This process was exactly the same when I used the drill press, with the only exception being that I did not turn the blank round prior to drilling. Some photos for illustration.

 

[mick]

I have to agree with John, that Panache is gorgeous! This is one of my favorite ways segment, so many different ways to orient the blanks. One question I didn't see asked. Are you tightening down the tailstock and advancing the quill or pushing the tailstock forward by hand? Sometimes I've noticed if try to just push it forward it can grab at times and with an aggressive bit like you show it can wander or follow grain. To me that type bit isn't suitable for segmented work.

Sent from my SM-G955U using Tapatalk

 

[Dragnet]

I have to agree with John, that Panache is gorgeous! This is one of my favorite ways segment, so many different ways to orient the blanks. One question I didn't see asked. Are you tightening down the tailstock and advancing the quill or pushing the tailstock forward by hand? Sometimes I've noticed if try to just push it forward it can grab at times and with an aggressive bit like you show it can wander or follow grain. To me that type bit isn't suitable for segmented work.

Sent from my SM-G955U using Tapatalk

Thank you . The panache I think you're speaking of is a mix of unused segments left over from other projects. Once I have enough, it's nice to throw something together, not knowing the what end result will be and have it turn out well .

For the question, I am tightening and advancing the quill. The flute bits were recent purchases, but I still have my brad point bits. I prefer the flutes because of how well they clear the swarf (learned a new word today!) but if some of the other suggestions fail, going back to the brad points is always an option.

 

[Dehn0045]

I use a G3 with pin jaws for my drilling and also turn round prior to drilling. Like you, I had some struggles at first, but was able to find success after some tweaks. I drill at 500 on my Jet 1013 (belt, so that is my slowest speed). I believe that VS lathe will lose torque at slower speeds, so something to consider (not sure if yours is VS). I find heat and clogging of the flutes to be my biggest enemies, I clear chips often and cool the bit (with DNA). I also turn off the lathe when removing/inserting the bit to reduce heat buildup. Obviously starting on center is key too. I find jobber twist bits work fine as long as they are sharp. Best of luck

 

[jttheclockman]

OK Joshua let me first say many times when people ask questions they forget sometimes we were not standing there with them when something went wrong. We rely on photos a great deal because it helps tell the story. No one knew you because you are new here and we had no idea you were drilling and working your pens with a different set of tools and methods so when you show us rather sophisticated segmented pens we have to think you have been at this for some time and now the questions get different than for someone who is just starting out. Your explanation makes sense now.

Drilling on a lathe is more accurate for many reasons but you need to start at the beginning. That chuck you are using and those jaws do not support the blank all that well. You have quite abit of material unsupported and you are trying to drill a hole dead center. I will ask is that blank square?? The reason I ask that is a 4 point chuck you are using and if it is not square then it will find its own center when tightened. I prefer a chuck that has 2 points of contact because no matter what way you put it in the chuck it finds dead center. When you had blank chucked up did it spin true or did it have a wobble?? Spinning at a lower rpm will help you see this better and for drilling you should drill slower which you acknowledge.

Now I know those are suppose to be aa new version of pen blank drilling bits but I prefer standard twist bits. Stay away from brad point bits!! These are similar in that they have a point that can follow a grain pattern more easily that standard twist bits. I say this because standard twist bits have a bevel on each side and the point is part of the bevel as opposed to those where it is the leading part of the bit. You may want to try a standard twist bit in place of those and see if that helps.

Backing out and clearing the swarf is important and also keeping the bit cool is as well. Need to drill slowly. I try not to extend the quill too far out when drilling. I rather move the tailstock and repeat procedure. To do that just recoil the quill and push the tailstock forward and then the bit is pushed in hole. Now restart lathe but make sure you are not pushed in too far where the bit is hitting the bottom of the hole or else it will grab on you and could break the blank. Hold the drill chuck as normal and continue drilling. Rinse and repeat as many times as needed. Many times when drilling long blanks like that it is better to do it from both ends. That is what I do.

Segmented blanks such as what you are doing have different woods used which have different hardness and grain patterns so extra care is needed and going slow will help. Good luck. You will find that sweet spot for sure.

 

[Dragnet]

OK Joshua let me first say many times when people ask questions they forget sometimes we were not standing there with them when something went wrong. We rely on photos a great deal because it helps tell the story. No one knew you because you are new here and we had no idea you were drilling and working your pens with a different set of tools and methods so when you show us rather sophisticated segmented pens we have to think you have been at this for some time and now the questions get different than for someone who is just starting out. Your explanation makes sense now.

I understand -- I was speaking to KenB's post, which was, point blank, a snide and unscrupulous remark that held no merit. He's a schuck. In my original, unedited thread opener I say that I've "recently transitioned to using my lathe for drilling". I'll leave it at that as it doesn't justify additional discussion and every other member, including yourself has been remarkably gracious and helpful.

Drilling on a lathe is more accurate for many reasons but you need to start at the beginning. That chuck you are using and those jaws do not support the blank all that well. You have quite abit of material unsupported and you are trying to drill a hole dead center. I will ask is that blank square?? The reason I ask that is a 4 point chuck you are using and if it is not square then it will find its own center when tightened. I prefer a chuck that has 2 points of contact because no matter what way you put it in the chuck it finds dead center. When you had blank chucked up did it spin true or did it have a wobble?? Spinning at a lower rpm will help you see this better and for drilling you should drill slower which you acknowledge.

Yes, you are right about material unsupported. As you probably have figured, I need quite a bit of length to begin with in order to make segmented blanks such as these. When you're cutting some 15-20 different 3mm segments, much is lost to blade kerf. If you know of longer jaws or a better alternative, I'd be glad to hear. As for the blank being square, I'm not sure I understand. The ends should be square, yes, but if you're asking if the diameter of the circular blank is consistent along the entire length of the blank, I think not. While I take pride in my turning skills, I am not so precise and I wouldn't know how to accurately test this. I do have the PSI pen chuck, which is a 2-point chuck though it appears to be primarily intended for square blanks. Perhaps I could try using this, though I wonder if it would suffice with a round blank? For the wobbling I'm not certain and that will need to be checked again once the RPM is lowered.

Now I know those are suppose to be aa new version of pen blank drilling bits but I prefer standard twist bits. Stay away from brad point bits!! These are similar in that they have a point that can follow a grain pattern more easily that standard twist bits. I say this because standard twist bits have a bevel on each side and the point is part of the bevel as opposed to those where it is the leading part of the bit. You may want to try a standard twist bit in place of those and see if that helps.

Backing out and clearing the swarf is important and also keeping the bit cool is as well. Need to drill slowly. I try not to extend the quill too far out when drilling. I rather move the tailstock and repeat procedure. To do that just recoil the quill and push the tailstock forward and then the bit is pushed in hole. Now restart lathe but make sure you are not pushed in too far where the bit is hitting the bottom of the hole or else it will grab on you and could break the blank. Hold the drill chuck as normal and continue drilling. Rinse and repeat as many times as needed. Many times when drilling long blanks like that it is better to do it from both ends. That is what I do.

Segmented blanks such as what you are doing have different woods used which have different hardness and grain patterns so extra care is needed and going slow will help. Good luck. You will find that sweet spot for sure.

Will stay away from the brad point bits. I don't have any standard twist bits, but I can check at my father's workshop. I would hate though to give up these flutes, as I've purchased many sizes at significant cost...

For the other tips, I've already written them down and intend to put into practice.

Thanks again, your help (and many others here) has been invaluable. I simply need to experiment a bit, which I hope to do in the next few days. I'll report back with what I find.

Best,
Josh

 

[Dehn0045]

A collet chuck might offer a little bit more support and better precision, I have a set that I use from time to time. It's a little more trouble because you have to hit a specific dimension when turning round to drill. IMHO the pin jaws are your best bet for the G3 - they have "pen jaws" but they are designed for square/rectangular blanks and only have 2 jaws, I'm thinking 4 shorter jaws is better than 2 longer ones (but I don't think it is a huge difference either way). These are the only options for the G3 that I've seen.

 

[jttheclockman]

Lots info there. First let me say that you can hold a round blank in those pen chucks very easily. Have done it many times. I also use a collet chuck sometimes too. I originally bought that PSI pen chuck and it was a piece of junk. https://www.amazon.com/PSI-Woodworking-CSCPENCHK2-Dedicated-Drilling/dp/B07CKTCX4W Went through a ordeal to get new jaws because they would not close evenly and the guy from the parts dept suppose to have sent them to me but never got them He supposibly did this twice. They knew they had a bad run on them. Gave up with PSI garbage and bought Timberbits Vicmarc pen chuck and have not looked back. Very well made and yes pricey but you get what you pay for. http://www.timberbits.com/vicmarc-pen-blank-chuck

You maybe able to make those drill bits work if you do some of the changes. You will see. I see you make the long blanks for that type segmenting but there is no reason to not be able to cut in half to drill. Use a bandsaw or scrollsaw to get a thin kerf. You will not lose much material.

When I say blank being square I did not realize you turned that round before you drilled it. A collet chuck would work better than if it were round. With a chuck like the one I shown from Timberbits it does not matter because any 2 corners will work and put it on center.

 

[Dragnet]

Just checking in, having finished some tests using the tips provided. I think I can conclusively say the problem is wobble. When I turned the RPM down to 500 or so, this became clear as I noticed the hole punch on the end I'd be drilling into would move quite a bit, failing to remain stable in one spot. This was on a new blank I turned, however when I put the original blank back on (the one shown in the original post), I noticed even more wobble, so no wonder it came out the other end so off-center. Of note, I also mounted these same blanks on the PSI pen jaws (2 jaws) and there was no noticeable difference.

I guess the question now is, what is the easiest way to correct this? Perhaps I'm off here, but it seems that if the blanks are turned more uniformly round, they will have less wobble than those that may have more variation in diameter across their length. If true, I could simply take more time when rounding to ensure more precise/uniform diameter across the length of the blank. As I alluded to previously though, this can be difficult and I don't know how to accurately measure anything other than the ends.

What else may be causing this? Is the blank length an issue?

I bought a center-bit set, which hasn't arrived and may help, but I still don't think I'll get me to where I want, which is a perfectly centered hole.

Thanks,
Josh

 

[jttheclockman]

Josh, do you need to turn the blanks round before drilling holes?? Length is a problem that I see. As I said too much unsupported material. Now what you can try is if you need to turn round, maybe get more accurate with this. If I have to turn round I always turn the ends down first and slowly take the middle down using a straight edge to keep an eye on the straightness. If both ends are the same diameter than it should be easy to see. Now I use a collect chuck alot of times with round rods which helps in support.

But with what you have I am assuming you turned round between centers using some sort of dead and live centers. This required a center hole or center dimple. So what you do is chuck the blank up in your chuck you have and put a center in the tailstock. Not before you really tighten the blank in the chuck slide the tailstock up to blank and line up the center with that dimple and keep it there. Now slowly lock down your chuck. Now spin the lathe by hand and it should be centered. If it wants to jump out of that dimple than that blank is truely not true. If it spins true then try drilling slowly as mentioned before. Best I can do for you.

 

[Dragnet]

Sorry for the delay updating and replying. After testing a number of different strategies, I had a sort of A-HA moment. I am a bit ashamed, but it turns out the problem is one of my own creation... and I failed to realize it for some time. I have attached photos and as you can see, I replaced the original tailstock spindle lock handle with a screw made for other purposes. I did this because I noticed the factory lock handle would often interfere with my dust collection hood when moving the tailstock forward some distance. I thought the circular head of the new lock handle would reduce this interference (and it did), however it came at the cost of inadequate spindle stabilization, most prominently when I was drilling. With the replacement lock handle, the spindle was either 1) completely loose or 2) too tight to move forward. After going back to the factory lock handle, I realized it could be tightened such that the spindle was both stabilized and allowed to move forward..

I want apologize to everyone that offered support and help. While the guidance may have not solved the issue, I learned a great deal and it absolutely has and will continue to prove beneficial in my drilling endeavors.

Thank you to all!