Drilling a blank

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dozuki

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I haven't made a pen in several years and when I was making them regularly i was using a drill press. Since i moved I no longer have a drill press. I have been trying to use my new lathe and it seems to push the blank deeper into the chuck before it starts to drill. Then it pulls the blank out of the chuck when I try to remove the bit, very frustrating. I'm using the blank holding jaws for my chuck and I tighten it down as much as i can and it still seems to push and pull the blank. The lathe is running at around 800RPM. To slow or to fast? All help greatly appreciated.
 
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dozuki said:
I haven't made a pen in several years and when I was making them regularly i was using a drill press. Since i moved I no longer have a drill press. I have been trying to use my new lathe and it seems to push the blank deeper into the chuck before it starts to drill. Then it pulls the blank out of the chuck when I try to remove the bit, very frustrating. I'm using the blank holding jaws for my chuck and I tighten it down as much as i can and it still seems to push and pull the blank. The lathe is running at around 800RPM. To slow or to fast? All help greatly appreciated.
Click to expand...
You do not say what type chuck it is and what the jaws look like. The blank may not be square so if you are using a 4 jaw chuck not all jaws maybe hitting the blank. Next is the jaws may not be tightening square down on the wood or blank. There are times when chucks and jaws get stretched and the back end may clamp down but the front end does not. My suggestion is to get a dedicated pen blank chuck. I can not talk about the PSI one because not sure if they improved it. But I had problems with theirs. I spent a little more money and got an excellent one. https://www.timberbits.com/vicmarc-pen-blank-chuck You maybe can find cheaper but these are excellent chucks. others may have ideas for you. With this type of chuck you can chuck up any type blank no matter if it is square or not because you clamp onto two opposite corners of the blank. Even round blanks work very well. Good luck.
 
I have the nova pen jaws and they are excellent. Can you post a photo of your setup? It might help us see what it looks like.
 
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How sharp are your bits? What kind of bits are you using? On occasion, I buy a set for normal drilling into 2x4 or similar, and I am finding that mediocre sets are not as precise as the size says and not a straight as a good set either. And not as sharp as a good set. When I am drilling on the lathe for pen making, I do NOT use mediocre or inexpensive bits.

If you are pushing the blank into the chuck, it is not cutting effectively. If pulling the bit out pulls the blank out, then your bit is probably bent slightly.
 
It doesn't seem to matter if the blanks are square or round. I was using a Brad point 10mm bit. I will in vest in a new one just to be sure. Here I thought those were pen blank jaws. Will look for appropriate jaws as well. Thanks to everyone for all the advice.
 
Brad point bits are intended to drill cross grain rather than end grain (pens). This is more pronounced when drilling in exotic "hard" woods. They are difficult to sharpen and need more force to cut cleanly. Start very slowly to establish a good center hole.
Instead use standard 118° drill bits from a good manufacturer. Many years ago I scored a full set of Chicago-Latrobe bits.
 
Hi Paul,
You may have said what material you are drilling but I have not been able to pick up on that. The type of drill bit matters in my opinion. Here is a link to the bits designed for acrylic Link to Acrylic Drill Bit and I have had the best luck with Brad Point for wood blanks. I also do not have a drill press or drill exclusively on my lathe. Here is the chuck I use Link to Drill Chuck I think there is one that opens up wider than this one as well.

Also I rarely drill through to the end of the blank mainly because of blowout chances. If I am drilling a double-barreled pen then I drill one end to the depth of the brass tube then flip the other end around and drill to the other end. Then I cut the center part out which many times is only 1/4 to 1/2 inch of material depending upon the length of your blank.

I drill around 800 RPM just like you have set but I also make sure I clear the material out from the drilling process maybe two or three times which is a pain in the neck because the tail stock throw moves slowly. One of the reasons I moved to the new Turncommander lathe is that it has a 3" throw on the tail stock and with the Acrylic bits they are designed to really move out the drilled material nicely and I can do one run at the drilling without removing the bit.
Happy turning,
Andy
 
The jaws you have in there aren't for square blanks, but they will work on round ones.

These are what I have for my Oneway chuck. I only use two of the jaws, so that they will hold blanks that are not perfectly square.

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These are the ones that Nova puts out.

1720440474971.jpeg
 
Generally, I am not a fan of PSI tools. They are OK, but in penturning we are dealing with pretty tight tolerances demanding equipment that can handle them. PSI tools seem to go from good to not so good because their overseas manufacturers sometimes have a good day and sometimes not, but they seem to ship everything no matter what. I have a Nova like darrin1200 showed in this thread and they work really well. Lately I have moved to resin blanks and do my own casting, so the blanks are round to begin with, so have increasingly used a collet chuck and I find that to be the best so far of anything. Changing bits, varying your feed, etc will all help, but if the chuck isn't holding properly that will prove to be more of the issue.
 
I also use the Nova with pen jaws as Darrin has pictured. It works well for me. There's a lot more contact to hold the blank even without any "teeth". Make sure your drill bits are sharp and clear the swarf often. Don't let the bit get too hot, which happens especially quickly with really hard woods. I've not tried it, but PSI does have a chuck specifically dedicated to blank drilling. I'm sure it would at least work better than your current setup.
 
sorcerertd said:
I also use the Nova with pen jaws as Darrin has pictured. It works well for me. There's a lot more contact to hold the blank even without any "teeth". Make sure your drill bits are sharp and clear the swarf often. Don't let the bit get too hot, which happens especially quickly with really hard woods. I've not tried it, but PSI does have a chuck specifically dedicated to blank drilling. I'm sure it would at least work better than your current setup.
Click to expand...
I just saw that PSI have a set to fit the OP's chuck. I can't see why these wouldn't work as well as the others.

1720528941492.png
 
So you are using the so-called 'pin' jaws (shown in the upper right corner of the picture on the box in your post), and the blank is coming out of the jaws as you are withdrawing the tailstock-mounted drill chuck. That just doesn't sound right. I have also been away from pen making for a while, but just drill a blank this morning and the process worked fine for me. I used the so-called 'No 1) jaws (aka 'stepped jaws' - lower left corner in the picture on the box).

You said that it doesn't matter whether you grip the blank on the flats or the corners. I agree that with those jaws, it shouldn't matter. But the fact that it does suggests a couple of questions:
1. How tightly are the jaws gripping the blank? It may be that your blank is too small for the jaws, and the jaws close completely before getting a firm grip on the blank. Are the jaws actually leaving 'bite' marks on the blank? Have you tried the 'No 1" jaws - they can close around much smaller items, and may work better if the problem is that you blank is smaller than the minimum capacity of the 'pin' jaws.
2. Are you stopping the lathe before trying to back out the drill bit? That can be a problem because the bit can stick in the blank. Have you tried backing out the bit with the lathe still running. That approach might work better.
 
Hmm. $22.95? What series/brand of chuck is referred to in the ad? PSI? That might be the problem.
Something's not right here. monophoto has some valid points to consider. I have the Nova pen jaws and never had any problem. In fact, I put the chuck on the lathe, lining up to drill a bunch of pen blanks tomorrow. Not necessarily an assembly line but I figure all I have to do is change bits. Will wait for the bit to cool if doing more than one size, too.
 
Woodchipper said:
Hmm. $22.95? What series/brand of chuck is referred to in the ad? PSI? That might be the problem.
Something's not right here. monophoto has some valid points to consider. I have the Nova pen jaws and never had any problem. In fact, I put the chuck on the lathe, lining up to drill a bunch of pen blanks tomorrow. Not necessarily an assembly line but I figure all I have to do is change bits. Will wait for the bit to cool if doing more than one size, too.
Click to expand...
It is PSI's own chuck.
 
I've found the chuck listing in the PSI on-line catalog. The description includes this information on the included jaws:
1720723343213.png

The picture Paul provided suggests that he is trying to use the 'Pin Jaws'. According to the description, these jaws are intended to grip mortises (internal, expansion), although I'm sure that they can be used to grip a tenon. However, the important point to note is that there is a minimum tenon size; when the four flat sections of the jaw base (the flat plates that are screwed onto the sliders in the scroll chuck) come together, the exterior of the jaws form a nearly perfect circle that is about 1" in diameter.
1720724129333.png

At the same time, the interior of the jaws form an interrupted circle. The PSI specification doesn't state the diameter of that circle, and because I don't own those jaws, I can't measure it. But whatever that interior diameter is determines the smallest tenon that the jaws can grip.

So my suspicion is that the blank that Paul is attempting to grip at, or slightly less than, that minimum dimension. Hence, the base of the jaws close completely before the jaws can firmly grip the blank.

PSI used to publish a really handy full-page table in their hard-copy catalog that specified the gripping range of all their jaws and chuck combinations. Ah, the good old days!
 
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