Broken bit in aluminum...any ideas???

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Brooks803

Brooks803

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Sep 13, 2009
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for the pen I made for my 1000th post I had made this nib to attempt a fully kitless pen. Well...in drilling out the backside of the nib to allow the refill to fit properly the bit broke off inside. I didn't clear out the bit as I should have but now faced with this. The nib has been completely drilled through but it's in there good and tight. I was looking to see if the expertise of my fellow IAP members could help salvage this peice. Here's a link Pete (Curly) gave me: http://www.chaski.org/homemachinist/viewtopic.php?f=4&t=89129. Before I go out looking for this stuff I wanted to see if there was a more simple way first. I know just starting over is the easiest way but I like how this came out so I want to try to fix it first before putting it on the ever growing "dummy, why did ya do that" table to remind me of past mistakes. Thanks in advance for any assistance!
 

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How much is in there?

Based on the picture, I assume you still have to trim off the end where the drill bit is ... can you carefully cut this off and expose more of the bit so you can get a hold of it so it could be twisted out? Or maybe you'll get lucky and have it come out with the trimmed piece.
 
Put it in a frame and hang it above your lathe as a reminder. When they're in tight like that I've never been able to salvage the piece.
 
Andrew_K99 said:
How much is in there?

Based on the picture, I assume you still have to trim off the end where the drill bit is ... can you carefully cut this off and expose more of the bit so you can get a hold of it so it could be twisted out? Or maybe you'll get lucky and have it come out with the trimmed piece.
Click to expand...

Right, the part the bit is poking out of will be cut off. I'm used it to hold the peice in my collet chuck. The bit is probably 1/3 the way in there.

TomW said:
You cant grab the protruding piece with vice-grips?
Tom
Click to expand...

I tried that already. That's what all the tool marks are on the back of the peice.
 
I'd say put it back in your lathe, and cut off the section taking light cuts until you are though the aluminum and expose the drill bit (the tip should stay stuck on the drill bit) ... you should then be able to twice the bit of aluminum off and expose enough of the drill bit to be able to attach vise grips or similar to it, then just twist her out (hopefully at least)!
 
Your three biggest friends are:
  1. Heat,
  2. Cold, and
  3. Penetrating Lubricant.
First of all, spray a good penetrant, such as PB Blaster in both ends and let it sit for a while. If that doesn't loosen the bit, put the piece in your freezer until cold. If you still can't budge the bit, warm the nib in an oven (or carefully with a torch) and try again.

If working the bit free by wiggling it from the back gets nowhere at all, you can try knocking the broken bit out from the other end (provided you have a punch small enough).

Good luck,
Eric
 
This happens to me more frequently than I'd like to admit, but I do it in stainless steel. But irrespective of what metal you use, I do what Bruce has already suggested..... Bin it and start again.
I have a bucket load of 'nib blanks' with 2.5mm drill bits stuck in them:redface:

You may be able to 'unscrew' the broken bit, but the damage is done. If you were drilling to suit a rollerball refill then the hole is probably already too deep and you'd still need to clean up the hole and risk snapping another bit.

What really intrigues me is why you didn't drill all your holes before turning the nib to shape?

Nice shape though!!:biggrin:
 
I'll second PB Blast.....it works great! Be patient as you'll have to let it work for a day or so.

Turn down the end to expose the broken bit and give it a good shot of PB Blast and let it sit.....nib down. Give it a hit several times during the day....it'll come out.


Barney
 
I used to work in a machine shop as a deburrer, not a machinist. I don't know what it's called, but there's some liquid, maybe an acid (?), that dissolves the steel drill but, but not the aluminum. I didn't look over the link you originally posted, so I'm not sure what that says, but that's how they handled broken bits at the shop I worked at. Good luck with whatever you do!
 
I'd chuck it back in a collet, part down half that area on the back to reveal a longer length of broken bit, then grab it with some vise grips and twist it out. it's rather interesting that you drilled this after you spun it and it's also interesting that you tried to drill all the way through with that bit. I would have only drilled in half way with the tiny bit, then all the larger holes in from the back side. But..kudos to you for making the attempt, failing on round 1, looking for tips and solutions so you can try and fix this and learning for the future!
 
I would do as others have mentioned. Turn down the backside abit to expose the bit more, grab with a pair of vicegrips and work the bit back and forth. I would not try to twist back out all at once. Maybe even a shot of WD40 wouldn't hurt. You may surprise yourself. I also don't think all is lost if you get the bit out. Don't give up on it just yet. What do you have to lose???
 
It's interesting how the whole thing was planned out. As I sit and stare at it, I change my mind about parting away more material off the end to reveal more bit because you are really looking down to the wire as it is as far as materials to hold on to. You can't chuck on to the nib anymore because it is shaped to an odd form that won't fit safely in a collet. You need now to keep as much material on the scrap end as you can now, because you still need to drill the back end larger and will need to be able to hold on to it to accomplish the drilling. I'm thinking now, chuck it in reverse so the nib faces into the lathe and bring in a triangle cutter with one face square to the bit and cut in to the end so you remove some inside material without any outer material being removed..kinda like boring out a bowl. That will get you some room and more material to grab on to. Hopefully the bit isn't broke right off as long as the whole inside of the nib or it's likely to just snap off where you grab and twist on it. Framing that nib and starting fresh might be the best option..rethinking your entire approach at the same time. I also don't know if you were going to thread the end to screw into the pen..which would be a good idea, but impossible to accomplish with this approach. Next time drill your holes before you turn it. Don't drill the small bit all the way through. If you are threading it, do that after you drill but before you shape. If threaded on the outside, grab the nib from the inside and use the tailstock for support during shaping. You'll get there.
 
skiprat said:
This happens to me more frequently than I'd like to admit, but I do it in stainless steel. But irrespective of what metal you use, I do what Bruce has already suggested..... Bin it and start again.
I have a bucket load of 'nib blanks' with 2.5mm drill bits stuck in them:redface:

You may be able to 'unscrew' the broken bit, but the damage is done. If you were drilling to suit a rollerball refill then the hole is probably already too deep and you'd still need to clean up the hole and risk snapping another bit.

What really intrigues me is why you didn't drill all your holes before turning the nib to shape?

Nice shape though!!:biggrin:
Click to expand...

Thought you might like that part, since I had the inspiration from your guild pen :wink:

To be honest, this was a first attempt and I never even thought to drill first ask questions second. Makes sense now though :redface:

workinforwood said:
It's interesting how the whole thing was planned out. As I sit and stare at it, I change my mind about parting away more material off the end to reveal more bit because you are really looking down to the wire as it is as far as materials to hold on to. You can't chuck on to the nib anymore because it is shaped to an odd form that won't fit safely in a collet. You need now to keep as much material on the scrap end as you can now, because you still need to drill the back end larger and will need to be able to hold on to it to accomplish the drilling. I'm thinking now, chuck it in reverse so the nib faces into the lathe and bring in a triangle cutter with one face square to the bit and cut in to the end so you remove some inside material without any outer material being removed..kinda like boring out a bowl. That will get you some room and more material to grab on to. Hopefully the bit isn't broke right off as long as the whole inside of the nib or it's likely to just snap off where you grab and twist on it. Framing that nib and starting fresh might be the best option..rethinking your entire approach at the same time. I also don't know if you were going to thread the end to screw into the pen..which would be a good idea, but impossible to accomplish with this approach. Next time drill your holes before you turn it. Don't drill the small bit all the way through. If you are threading it, do that after you drill but before you shape. If threaded on the outside, grab the nib from the inside and use the tailstock for support during shaping. You'll get there.
Click to expand...

I think you give me too much credit Jeff, thinking I had a plan....I wish! I just chucked up a peice of alum rod and started turning to see if I could do it. Once it started to look like something I'd use I started to think about drilling. So I might give your idea a try and bore from the inside out so I don't lose my waste part for chucking.

Thank you to everyone who has given advice! I do appreciate it. Like John said "what have you got to loose". Even if I don't get the bit out I learned tons and have a better idea of how to do it right the next time.
 
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Just an ol' man idea, how about heating the nib and chilling the bit after taking off a bit of aluminum around the bit as suggested above. Aluminum has a huge expansion ratio to steel so if the nib expands and the bit shrinks even a little bit, it might allow the bit to break loose. Just a hope, not even qualifies as an idea.
Charles
 
Brooks803

In the other thread, I was, without knowing the steps you had taken, mentioning that a small carbide centre cutting end mill will cut out the HSS drill bit if done correctly. Then I remembered the thread about dissolving the bit out with the alum so never mentioned the end mill.

I think getting some alum at a local health food store would be cheaper than buying a good carbide end mill and risking breaking it too. :eek: Ultimately it's your call.:befuddled:

Hoping for a good outcome no matter which way you go.
Pete
 
You say that it is already drilled all the way through,any chance of getting a small
(1/16)punch and knocking it out?Like Skippy said though,the damage may be done!One thing I do when drilling on the lathe is to tighten the chuck by hand enough to drill but not to tight that if it catches that it wont spin in the chuck,if it does catch then I STOP the lathe and back out,works for me.
 
I did try to punch it out, won't budge at all. Pete, I did find some alum in my grocery store yesterday. I picked some up but I want to try some other methods first and if all else fails I'll do the alum. One of the first things I tried was the freezer. We shall see...thanks everyone for the tips. Hopefully others can learn from my mistakes!
 
Many great ideas already posted!

Here is my idea, turn to expose the broken bit enough to drop a nut down nut on to the bit, weld a nut on the end of the broken drill bit.

Apply heat and gently twist to remove bit. The larger nut head allows you to apply more torque and remove the bit.

There is not easy right answer...I hope this helps...or gives you an idea
 
If you did not lube the bit before you drilled, then the aluminum could be stuck on that bit like glue and if so, no amount of force will release it because you are talking about a considerable length of material, when you calculate the two flutes in the bit circling around at the same time..1" of length could equal 3" of frozen on surface length.
 
I say rechuck the nib, push the jakob chuck back to the piece, and weld the bit back tOgether! Since it will not stick to aluminum, you might be able to twist it out.
 
Just wondered have you tried heat... not tooo fearce. I'm guessing the aluminium will warm quicker than the bit so the alloy might expand enough to unwind under applied heat.... problem is the"spiral" might defeat it I guess. I normally drill metal with a drip feed coolant to the bit
 
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