# Help me drill on center



## Fish30114 (Feb 28, 2018)

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!!


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## Charlie_W (Feb 28, 2018)

Sorry you are having difficulties...no fun.

The only suggestion I have at this point is instead of using a center bit, just use the point of your skew and make just the slightest dimple for the 7/64” bit to start in. If you need to make the dimple a hair larger, account for the length and just shorten the end after getting your hole drilled.
The steel skew is harder than the copper and should work as long as you have a true sharp point. Of course you will touch up your skew afterwards.
Also, a point tool or a corner of a square carbide cutter may work here as well....see what you have that may work.

Good luck and keep us posted.


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## Curly (Feb 28, 2018)

Copper can be difficult to machine. Lubrication is important. If the headstock and tailstock are not perfectly aligned you will break the tips off the small centre drill. You could try to very lightly grip the end of the centre drill with the chick jaws so it can wobble and let it find centre. Better than a centre drill for starting holes is a spotting drill that matches the angle of your drill bits. No tip to break off and the cone marked matches the end of your drill bits so starts better.


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## dogcatcher (Feb 28, 2018)

When drilling are you using a drilling fluid?   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.


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## Gary Beasley (Feb 28, 2018)

I was told copper is pretty grabby with a standard bit and that the bit should be reground at a shallower angle, maybe 70 degrees or more to work better. I had the same problem drilling the tips of solid copper bullets to make nibs.


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## KBs Pensnmore (Mar 4, 2018)

I've answered this in the metal lathes section.
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


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## monophoto (Mar 4, 2018)

Is there any play in the tailstock of your lathe?  If so, you could be locking the tailstock down with it very slightly out of alignment.

My suggestion is to start by facing off the blank, and then following Charlie's suggestion to use a skew or point tool to create a small divot in the center of the blank.  

Then, with the center bit in your jacobs chuck, bring the tailstock up and center the bit on that divot before locking it down.  That will assure that you are starting the hole exactly on-center, and should prevent the problem you are having with breaking the center bit.  After using the center bit to start a hole, replace it with the bit you want to use, and then repeat the process - center the bit in the hole before locking down the tailstock.


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## walshjp17 (Mar 4, 2018)

Fish30114 said:


> 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....



If you are concerned about the quality of center drill bits, look at the Little Machine Shop's bits.  Very high quality and not all that expensive.  Here is one set.  https://littlemachineshop.com/products/product_view.php?ProductID=4859&category=  They have several others in various sizes.


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## Woodster Will (Mar 4, 2018)

Try using a spotting drill instead of a centre drill, it’s the best tool for the job.


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## Fish30114 (Mar 5, 2018)

Thanks for the feedback folks, several ideas I will try--I do have some spotting drills, so I will try that straight away---making a center point with my skew or other tools is OK I just am not sure I would get that centered. 

Thanks for all the input though!!


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