drill problems

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joe004

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I've been using the lathe to drill my blanks with great results until recently. I've been drilling some plastic blanks and when get finished I have a perfect hole on one side and a hole about 1mm off on the other. Here are some pics of my setup with a 10.5mm bit. I end up with a void where you can see the epoxy. Is there a way to adjust the tail stock or align it?
 

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walshjp17

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Have you checked your headstock and tailstock for alignment? Put a spur drive (or dead center) in your headstock and a live center (with a point) in the tailstock. Bring the tailstock up to the headstock and see how closely the points align. You may have to adjust one and/or the other of the head or tailstock.
 

monophoto

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I have the same lathe and have had some experience with alignment.

As John said, the first step is to check for alignment. That's easy - put a spur drive in the headstock, bring up the tailstock with a live center. It's important to lock down the tailstock because if it is not locked down, it can move, giving you incorrect information about alignment.

You must check for both vertical and horizontal alignment. I would expect that there will be some horizontal misalignment because the headstock must be mounted on the bed when you set up the lathe. To correct for a horizontal mismatch, find the allen keys that came with the lathe, loosen the four allen head bolts that attach the headstock to the bed, twist the headstock to cause the spur drive to be exactly in line with the tip of the live center, and then tighten the bolts.

I found that my Turncrafter lined up perfectly in the vertical axis. That's a good thing because correcting a vertical alignment problem requires shims - that's more fiddly.

It's also helpful to remember that a small misalignment will be amplified with a long spindle. As a check, I put my MT Jacobs chuck in the headstock, and mounted a brad-point bit to emulate a longer spindle, and then checked the alignment of the point of the bit with the point of the tailstock.

But back to the original problem - what do you mean when you say the hole is centered on one side and off center on the other side? If you mean that you are getting a 10.5mm hole on one side, and a slightly larger hole at the other end, that sounds more like the blank is moving as you are drilling so that you are getting a hole that is conical rather than straight.
 

joe004

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Feb 6, 2014
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Cabot, ar
I have the same lathe and have had some experience with alignment.

As John said, the first step is to check for alignment. That's easy - put a spur drive in the headstock, bring up the tailstock with a live center. It's important to lock down the tailstock because if it is not locked down, it can move, giving you incorrect information about alignment.

You must check for both vertical and horizontal alignment. I would expect that there will be some horizontal misalignment because the headstock must be mounted on the bed when you set up the lathe. To correct for a horizontal mismatch, find the allen keys that came with the lathe, loosen the four allen head bolts that attach the headstock to the bed, twist the headstock to cause the spur drive to be exactly in line with the tip of the live center, and then tighten the bolts.

I found that my Turncrafter lined up perfectly in the vertical axis. That's a good thing because correcting a vertical alignment problem requires shims - that's more fiddly.

It's also helpful to remember that a small misalignment will be amplified with a long spindle. As a check, I put my MT Jacobs chuck in the headstock, and mounted a brad-point bit to emulate a longer spindle, and then checked the alignment of the point of the bit with the point of the tailstock.

But back to the original problem - what do you mean when you say the hole is centered on one side and off center on the other side? If you mean that you are getting a 10.5mm hole on one side, and a slightly larger hole at the other end, that sounds more like the blank is moving as you are drilling so that you are getting a hole that is conical rather than straight.


Thanks for the info, and yes you are correct about getting a conical hole. I have made sure that the blank was tight in chuck several times during drilling and still get these results. Its getting to be an expensive problem!
 

joe004

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Cabot, ar
Try drilling with a smaller drill first. Then, run your 10.5mm through the pilot hole.

This has worked, for me.


This may sound stupid but since its a brad point bit wouldnt that create a vibration since the point has nothing to dig into?
 

monophoto

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Joe

Whether a pilot hole is really helpful depends on the kind of bit that you will be using when you 'follow' that hole, and also on the size of the pilot hole.

Ordinary twist bits center better if you are enlarging holes in small increments. So if your target is a 3/8" hole, then starting with a 1/8" bit, and then using (successively), 1/4" and 3/8" twist drill bits to enlarge the hole should give good results.

However, if the final bit you will be using is a brad point bit, then there is a problem. Brad point bits work reasonably well with no pilot hole, and they also work well with a very small pilot hole, but they don't work well at all if you are enlarging a hole that is only slightly smaller than the brad point bit - for the reason you mentioned. A brad point bit needs either virgin wood, or at most a hole that is smaller in diameter than the wide end of the brad point to keep the bit aligned. If the hole is larger than the wide end of the brad point, the bit will wander around, and it would be random chance if the hole lines up with the pilot hole. The same thing is true with forstner bits.

But if you are getting a conical hole, then I suspect that your problem is something different. One possible cause is that the blank is shifting as you are drilling. The picture indicates that you are using pen blank drilling jaws on a scroll chuck - I don't have drilling jaws, but I know that if I use ordinary pin jaws on a scroll chuck I can get a conical hole if there is a way for the blank to shift from side to side as i am drilling.

Another possible cause is that your drill bit is flexing. I've made a lot of 'cheap' pens using Bic refills that require a 5/32" hole, and one of the problems is that a small bit like that can flex if it is pushed too hard. An important point is that the lathe has do the work - make sure the bit is sharp, and run the lathe at a speed such that the bit cuts its way into the wood. If you advance the ram faster than the bit cuts the wood, the bit will attempt to follow the grain boundaries inside the wood, and if the blank is tightly held, that can lead to a conical hole. Fortunately, a 10.5mm bit is pretty beefy and I wouldn't expect much flexing.

The other possibility is that your bit is bent.
 
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KenV

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Juneau, Alaska.
Joe -- If you have been using that brad point bit, odds are that it is duller than it was when you began using it. Brad point bits are hard to sharpen for most of us, and a duller bit will flex and drift more than a really sharp one.

When brad point bits are sharpened on grinder by hand, by a drill doctor, or on the jig with a tormek, they end as a more standard twist drill bit instead of a brad point.
 

ELA

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One more thing to check. See if the brad point itself in slightly off center on the drill bit. I have a large brad point bit that the point is sligthtly off center and it drills a conical hole just as you describe.
 
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Some good advice above. Also, since you say that you were doing ok until recently, I'd think about what has changed. Yes, check your lathe for alignment. Good practice anyhow. I'd also suggest sharpening your bit or getting a new one. LOML got me a Drill Dr last Christmas and sharp (really fresh sharp) bits seem to have eliminated the issues I was having (much the same as yours but on a drill press). And, frankly, I don't like using brad point bits on acrylics, etc. Seems to "prime" the blank for a blowout.
 

joe004

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Cabot, ar
Thank you all for the information. I've probably drilled 20 or so blanks with this bit and may be time to change. I'm not a fan of brad points but it was the only 10.5 mm I could find. Just out of curiosity about how many plastic blanks can you drill with a bit? Just ballpark I know there's no exact number.

Thanks again to all the men and women on this sight for helping a dummy like me!
 

KBs Pensnmore

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Thank you all for the information. I've probably drilled 20 or so blanks with this bit and may be time to change. I'm not a fan of brad points but it was the only 10.5 mm I could find. Just out of curiosity about how many plastic blanks can you drill with a bit? Just ballpark I know there's no exact number.

Thanks again to all the men and women on this sight for helping a dummy like me!

Hi Joe, about 20 would be a good average for acrylic blanks, with a brad point bit. A standard Jobber would be around 40-50 on acrylics, it seems to be quite harsh on HSS. Ask SWMBO and family for a drill doctor for Christmas :biggrin:
If anyone in the States, has trouble getting metric sized drill bits, let me know and I can chase them up for you.
Kryn
 

79spitfire

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They have a 10.5 at Penkits.biz, that is not a brad point, but a "standard" pointed bit. Also, if you have been making a variety of pens in acrylic and wood, 20 would easily account for a dull bit. Many woods are very hard on HSS bits. Your real solution may be to invest in a Drill Doctor, or become good at hand sharpening drill bits.
Brad point drill bits aren't the best for plastics. All those tiny sharp points are dulled quickly by synthetic materials, they don't dissipate heat very well.
 

PenPal

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My best way is to bring two accurate points together with a thinnish feeler guage between you can SEE 360 degrees of misalignment instantly. Always clean out carefully the morse tapers first ant the ways and as has been said lock up the tail stock. Good luck.

Peter.
 

t001xa22

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Arlington, TX
Joe, I will throw in my 2 cents worth: I have been drilling with my lathe for 8 years and would not do it any other way. I switched over to using all jobber twist bits with a Drill Doctor backing me up. I found that I can control my penetration a lot better with twist bits. I lost way too many blanks with a brad point. My most crucial lesson learned was aligning a blank, wood or acrylic, in the scroll chuck. Many blanks are not cut fully square, so when #1 and #3 jaws grab the blank, there might be a space at #2 and #4. When I hand-align these two jaws before final tighten, I get a much better drill start. The proof will be when the drill bit goes through, it will not vibrate the blank. If vibration starts, I will likely see a wobbled exit hole on the other end. Anyway, you have been getting some great advice from turners much more learned than I. Good luck.
 

farmer

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Drill bit

You could roll the bit on a piece of flat glass to see if the bit is bent.
I use this band of drill bit. no pilot hole and have had the best luck with them staying centered or not walking.
That being said I change my drill bits out every 2 years and I don't drill anything but wood with them.
My next set will be carbide bits and just certain sizes.
Dewalt Drill Bit Set, 29 PC DW1969 | Zoro.com

Features: Backtaper Design With Acute Cutting Edges and Enlarged Flute Chamber To Eliminate Walking, Minimize Friction and Maximize Chip Removal

PS I am using taig based lathes that have been modified, I do all my drilling with the lathe.
 
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79spitfire

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You could roll the bit on a piece of flat glass to see if the bit is bent.
I use this band of drill bit. no pilot hole and have had the best luck with them staying centered or not walking.
That being said I change my drill bits out every 2 years and I don't drill anything but wood with them.
My next set will be carbide bits and just certain sizes.
Dewalt Drill Bit Set, 29 PC DW1969 | Zoro.com

Features: Backtaper Design With Acute Cutting Edges and Enlarged Flute Chamber To Eliminate Walking, Minimize Friction and Maximize Chip Removal

PS I am using taig based lathes that have been modified, I do all my drilling with the lathe.

These are my favorite bit for sheet metal, (believe it or not), they make nice round holes. I have not tried them in wood or plastic. I will have to locate some.
 

farmer

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Drill bits

Dewalt Drill Bit Set, 29 PC DW1969 | Zoro.com


These are my favorite bit for sheet metal, (believe it or not), they make nice round holes. I have not tried them in wood or plastic. I will have to locate some.




For making pool cues drilling the joint pin hole I normally can get 0.0015 run out .
One in a half thousands for a 3.250 deep hole is not bad for a three dollar and fifty cent Dewalt drill bit.
But I have noticed that I have to replace the bits every two or threes years because they start to walk.

I drill on using my lathe and to be very honest the big bore spindle 1.385 is so nice turning square wood to round wood with the 4 jaw chuck and a live cutter.

I don't use plastic very much, Cue ferrules and paper wrapped phenolic .
and normally never use acrylic.
My point is I don't know how the Dewalt drill bits will hold up drilling acrylic.

Drilling a blank on a drill press I would think a pen blank vise would be a must and the chance of bending a bit in acrylic would easy if the operator allow the bit and blank to get hot while drilling.

Actually acrylic is water proof and a person could use some kind of lube or water to cool the bit if that is a problem.

Are you in Reno ?
 

79spitfire

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Messages
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Dewalt Drill Bit Set, 29 PC DW1969 | Zoro.com


These are my favorite bit for sheet metal, (believe it or not), they make nice round holes. I have not tried them in wood or plastic. I will have to locate some.




For making pool cues drilling the joint pin hole I normally can get 0.0015 run out .
One in a half thousands for a 3.250 deep hole is not bad for a three dollar and fifty cent Dewalt drill bit.
But I have noticed that I have to replace the bits every two or threes years because they start to walk.

I drill on using my lathe and to be very honest the big bore spindle 1.385 is so nice turning square wood to round wood with the 4 jaw chuck and a live cutter.

I don't use plastic very much, Cue ferrules and paper wrapped phenolic .
and normally never use acrylic.
My point is I don't know how the Dewalt drill bits will hold up drilling acrylic.

Drilling a blank on a drill press I would think a pen blank vise would be a must and the chance of bending a bit in acrylic would easy if the operator allow the bit and blank to get hot while drilling.

Actually acrylic is water proof and a person could use some kind of lube or water to cool the bit if that is a problem.

Are you in Reno ?

Yes, I work in Reno. I like my quiet so I live east of town.

I drill on the lathe. I find I can control where I drill the blank much more easily. I often wish to drill a strait hole off center, to get to where I think the best figuring is. On the lathe I set the piece up on my 4-jaw independent chuck and carefully set it off center. Whenever I do this on my drill press (granted it may be the fact I have a cheap drill press!) something just doesn't line up and I blow out the side of the blank. On long holes in acrylic or similar materials I will use a bit of olive oil. It seems slick enough to to the job, and is easily cleaned with soap and water.
 

farmer

Member
Joined
Jun 16, 2012
Messages
807
Location
NV
Offsset holes

Dewalt Drill Bit Set, 29 PC DW1969 | Zoro.com


These are my favorite bit for sheet metal, (believe it or not), they make nice round holes. I have not tried them in wood or plastic. I will have to locate some.




For making pool cues drilling the joint pin hole I normally can get 0.0015 run out .
One in a half thousands for a 3.250 deep hole is not bad for a three dollar and fifty cent Dewalt drill bit.
But I have noticed that I have to replace the bits every two or threes years because they start to walk.

I drill on using my lathe and to be very honest the big bore spindle 1.385 is so nice turning square wood to round wood with the 4 jaw chuck and a live cutter.

I don't use plastic very much, Cue ferrules and paper wrapped phenolic .
and normally never use acrylic.
My point is I don't know how the Dewalt drill bits will hold up drilling acrylic.

Drilling a blank on a drill press I would think a pen blank vise would be a must and the chance of bending a bit in acrylic would easy if the operator allow the bit and blank to get hot while drilling.

Actually acrylic is water proof and a person could use some kind of lube or water to cool the bit if that is a problem.

Are you in Reno ?

Yes, I work in Reno. I like my quiet so I live east of town.

I drill on the lathe. I find I can control where I drill the blank much more easily. I often wish to drill a strait hole off center, to get to where I think the best figuring is. On the lathe I set the piece up on my 4-jaw independent chuck and carefully set it off center. Whenever I do this on my drill press (granted it may be the fact I have a cheap drill press!) something just doesn't line up and I blow out the side of the blank. On long holes in acrylic or similar materials I will use a bit of olive oil. It seems slick enough to to the job, and is easily cleaned with soap and water.


Sounds like you have a nice lathe, I am normally in reno at least one every other month.
I do my normal VA hospital stuff and then hit the wood store, and sometimes I will play pool for a day or two.

I miss the wood crafter store that closed Reno.

On my Mid American cue lathes or modified taig based lathes the tail stock can be adjusted sideways and I have a indexer on my spindle.
I made a pilot that fits in my tail stock for my cordless drill.

Making it really easy to make a 6 shot cylinder for a home made wooden toy revolver or wooden wagon wheels I made for a scaled down wooden wagon .

The index and the off set to be able to drill holes opens a whole new world of stuff to make .



I make my grand children wooden toys, I make a pretty mean YoYo .

Anyway pleased to have met you .
 
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79spitfire

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Sep 19, 2010
Messages
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Location
Nevada
Those Taigs sound great. I have 2 a cheap HF 8X12 and my Dad's old Rockwell 46-111 modified with a variable speed sewing machine motor. I've modified a tool rest to cover the gap bed. I am going re-mount the motor as it does vibrate a bit. It's a bit of a work in progress, but it's very capable. Dad made hundreds of various projects on it over the years, I intend on doing the same.
 
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