Need help drilling metal rods on center

[Fish30114]

OK folks, I am wanting to continue turning some pens from metal, Aluminum, Copper, Brass--I have been able to make several I am pleased with using pieces of Cigar Pen kits to finish them--where I am running into trouble is with getting a dead center hole drilled for a small bit-i.e. 7/64" for the tip of a refill.
I have been through about 6 small center drills, the tip of them keeps breaking off in the metal piece I am attempting to drill, so far only copper. These center drills are of questionable quality, I bought several sets through Amazon and they were all cheap in price...but having said that I have tried several speeds and in all cases I was feeding the bit in very slowly--I have only been successful in getting one hole drilled dead center, and on that one the center drill didn't break-so maybe that's the key, but I just can't seem to get one of these center drills for a small bit not to break, and once that happens I have to scrap the entire bar of copper I was working with! My headstock and tailstock are aligned beautifully, but if I just try to drill a hole with just the drill bit, they are hideously misaligned.
I would like to be able to achieve this without having to go to a metal lathe, I have been satisfied with the shaping I have been able to achieve on the several I have built, but on all these, I installed a brass tube in a larger hole I drilled through the middle of the bar stock and then trued the pieces up to match the bushings for the pens. I am really trying to figure out how to get the center drilled for now!!

Any help/info is appreciated!!

 

[Penultimate]

Instead of a center drill try a spotting drill. They don't have the tip lie a center drill.


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[thewishman]

A collet chuck in your headstock would hold the blanks better and more precisely.

 

[bmachin]

Mike is right. Spotting drills are the way to go, but you aren't going to walk into Home Depot or Lowes and pick one up.

What you are trying to do is to locate the center of your piece with a non-flexible drill for the bit that is going to drill your hole. (I know you already know this). In reality all you need is just a shallow divot for the tip of your 7/64 bit to engage. That said, try using just the tip of the center drill (the very short wide angled part before the straight section) which is, in effect, a very small diameter spotting drill.

As far as drilling copper itself goes, if you google it, advice on practical machinist and other sites is all over the place. I've got nothing for you on that score other than to say that I believe that copper is a real bear to machine.
This is not based on experience, only from reading online. I think that I would move to a free machining (or even non free machining) aluminum or brass. I really think that your material is a big part of your problem.

http://www.onlinemetals.com/app_groups.cfm?step=2&id=2

Hope this is worth what you paid for it.

Bill

 

[Terredax]

When I was researching Beryllium I found that 145 Tellurium copper alloy is a free machining alloy. I didn't purchase any because of the price.
Maybe you could look into it?

 

[mredburn]

Breaking drill bits and problems with holes that are not centered are usually an alignment problem. Put a dead center in your head stock and tail stock, a live center will do in the tail stock. push the tail stock up to close to the head stock and see if the points are perfectly aligned. Put a used credit/gift/debit card or thin wood 1/8 or less between the points and put a little pressure on them by advancing the tailstock quill slightly. Does the card remain straight up and down perpendicular to the lathe bed and does it remain straight across or does it tilt or angle in any direction when viewed from the top and side? That will tell you if they are really aligned or not. Most breakage is from misaligned tail stocks, you may have to hold yours left or right as you lock it down.
Make sure your drilling with the rod in as close to the jaws as you can. If the rod is bent slightly it could wobble enough to break the drill bit. A collet chuck would be better than a 3 jaw chuck for this.
If there is any slop in your quill travel the copper rod may be grabbing the drill bit and breaking it.
Drill chucks have different tolerances for repeatability and alignment. Its not likely the issue but it may be a cumulative problem. What are you using for cutting Oil when you drill?

 

[Terredax]

Breaking drill bits and problems with holes that are not centered are usually an alignment problem. Put a dead center in your head stock and tail stock, a live center will do in the tail stock. push the tail stock up to close to the head stock and see if the points are perfectly aligned. Put a used credit/gift/debit card or thin wood 1/8 or less between the points and put a little pressure on them by advancing the tailstock quill slightly. Does the card remain straight up and down perpendicular to the lathe bed and does it remain straight across or does it tilt or angle in any direction when viewed from the top and side? That will tell you if they are really aligned or not. Most breakage is from misaligned tail stocks, you may have to hold yours left or right as you lock it down.
Make sure your drilling with the rod in as close to the jaws as you can. If the rod is bent slightly it could wobble enough to break the drill bit. A collet chuck would be better than a 3 jaw chuck for this.
If there is any slop in your quill travel the copper rod may be grabbing the drill bit and breaking it.
Drill chucks have different tolerances for repeatability and alignment. Its not likely the issue but it may be a cumulative problem. What are you using for cutting Oil when you drill?

Sometimes this doesn't work.
The points might align when pushed together, however, when the tailstock is pulled away from the headstock, there could be misalignment. This could be cause by alignment of the headstock to the ways, the ways not parallel, slop in the tailstock, and even alignment issue of the tailstock to the ways.
My neighbor has a piece he places in the headstock with a perfectly aligned center spot/tiny dimple, and he puts a morse taper fitting with a laser in it to check headstock/tailstock alignment from time to time, at any distance apart. It works very well.

 

[bmachin]

Don,

Can you describe the part you are trying to make and the procedure you are using here? I understand that you are trying to drill the hole for the tip of a ballpoint or rollerball refill to come through, but what is the whole part? Is it a separate grip section? Is it one piece with the pen barrel? Is it just a 3/8 or 1/2 inch long tapered cone?

I'm not sure what you're trying to align. I sounds like multiple setups with a woodturning chuck.

It may be easier in terms of alignment to drill it from the inside. That might require fabricating a special bit or fixture to hold one. However that shouldn't be too difficult if you go ahead and get the ER collet chuck you were talking about.

FWIW
Bill

 

[randyrls]

I have been through about 6 small center drills, the tip of them keeps breaking off in the metal piece I am attempting to drill, so far only copper. These center drills are of questionable quality, I bought several sets through Amazon and they were all cheap in price...but having said that I have tried several speeds and in all cases I was feeding the bit in very slowly

Don; Turn at High Speed (1000 RPM or more) and use lubrication (tapping/cutting oil).

Peck drill and use lube with each peck.
Don't buy them from Amazon, Little machine Shop has good ones and they sell individual sizes, not sets of various sizes.

 

[dogcatcher]

I found that I can buy plumber's thread cutting oil locally and it works good on steel. I have also used Dexron II auto trans fluid. In my limited experience the latter is as good as the higher priced cutting oils.

 

[Dieseldoc]

Drilling metal rods on center

What you have described sounds like you chuck has excessive run out.
Check the run out by putting drill bit backwards into the check, tighten it up on the non flute end, put dial indicator on and check run ont.

 

[Paul in OKC]

Chuck run out is not the cause in this issue, there is still part of the material that spins true to the axis. Tail stock alignment on wood lathes is questionable for drilling metal, IMO, due to a bit of slop between the base and the ways. You can spot drill with a larger center drill by just dimpling the face. Also is the face of the material been trued up? That can make all the difference in the world. Like has been said, higher rpm and lubrication is a must on the small center drills. When you bring the tip up to start drilling, try to just touch the face and see if it is making a small circle, if so try adjusting the tail stock position and try again. Good luck!

 

[eharri446]

I read an article that was referred to in a machinist group about drilling copper. What they said could be causing the problem was heat build up causing the copper to grab the drill bit.

It sounds like you are trying to handle the heat issue already.

One thing I was going to ask was would a 1/8 inch hole work without permitting to much slop. If it would, try getting a step drill, they have them that start at 1/8 and go up, and if you drilled from the back of the item, each additional step would allow for more efficient waste removal which could also cause a problem.

 

[philipff]

drilling

OK folks, I am wanting to continue turning some pens from metal, Aluminum, Copper, Brass--I have been able to make several I am pleased with using pieces of Cigar Pen kits to finish them--where I am running into trouble is with getting a dead center hole drilled for a small bit-i.e. 7/64" for the tip of a refill.
I have been through about 6 small center drills, the tip of them keeps breaking off in the metal piece I am attempting to drill, so far only copper. These center drills are of questionable quality, I bought several sets through Amazon and they were all cheap in price...but having said that I have tried several speeds and in all cases I was feeding the bit in very slowly--I have only been successful in getting one hole drilled dead center, and on that one the center drill didn't break-so maybe that's the key, but I just can't seem to get one of these center drills for a small bit not to break, and once that happens I have to scrap the entire bar of copper I was working with! My headstock and tailstock are aligned beautifully, but if I just try to drill a hole with just the drill bit, they are hideously misaligned.
I would like to be able to achieve this without having to go to a metal lathe, I have been satisfied with the shaping I have been able to achieve on the several I have built, but on all these, I installed a brass tube in a larger hole I drilled through the middle of the bar stock and then trued the pieces up to match the bushings for the pens. I am really trying to figure out how to get the center drilled for now!!

Any help/info is appreciated!!

Look at a film on Utube on this very subject. It will show you how to do it, exactly. Philip

 

[KBs Pensnmore]

I think half the problem is the drill bit, it's best to dub off the cutting edges of the drill bit, so they have zero or even positive rake. I suppose that's akin to using 0 or positive rake for turning brass. From memory the cutting lubricant should be kerosine, Tallow or Lard can be used also.
Kryn

 

[Fish30114]

Thanks for the great feedback folks. I am confident in my headstock/tailstock alignment---I will try a spotting drill straight away as I have a few--the part I am attempting to make is the bottom half of pen, so I intend to drill the center to allow the tip of the refill to protrude, turn the taper down for the tip from the larger stock piece--so I am trying to drill the 7/64" hole in the dead center of a 5/8" piece of copper, and then I would drill the larger body of the refill sized hole from the other end of the piece. I am holding the copper rod in a collet chuck, for lube I am using Blade Coat--which has worked well for me in other applications as far as drilling, just where I didn't need this type of accuracy.

I am going to order some better quality center drills from LMS as well.

Ya'll have given me some good ideas to try, so I will keep on working!

Thanks for the input!

 

[frank123]

Breaking drill bits and problems with holes that are not centered are usually an alignment problem. Put a dead center in your head stock and tail stock, a live center will do in the tail stock. push the tail stock up to close to the head stock and see if the points are perfectly aligned. Put a used credit/gift/debit card or thin wood 1/8 or less between the points and put a little pressure on them by advancing the tailstock quill slightly. Does the card remain straight up and down perpendicular to the lathe bed and does it remain straight across or does it tilt or angle in any direction when viewed from the top and side? That will tell you if they are really aligned or not. Most breakage is from misaligned tail stocks, you may have to hold yours left or right as you lock it down.
Make sure your drilling with the rod in as close to the jaws as you can. If the rod is bent slightly it could wobble enough to break the drill bit. A collet chuck would be better than a 3 jaw chuck for this.
If there is any slop in your quill travel the copper rod may be grabbing the drill bit and breaking it.
Drill chucks have different tolerances for repeatability and alignment. Its not likely the issue but it may be a cumulative problem. What are you using for cutting Oil when you drill?

Put a high precision metal rod (such as drill rod or, better, a roller taken out of an old printer) and use a dial indicator to measure the run out along different points of the length of the rod. Increasing run out along its length indicates a misaligned head stock. adjust accordingly so that there is none then realign (if necessary) the tailstock.

 

[Fish30114]

Frank 123, I can do that--thanks for the input sir!

 

[MIBrian]

When drilling copper or brass the drill will grab so you need to put negative rake on the drill tip. That basically is dulling the cutter part of the tip on a grinding wheel, you want to scrape the hole not really drill it.


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