# Drill Bit Size



## Tony's Pens (Aug 8, 2010)

I have learned that if your pen kit come from Craft Supplies it needs a hair bit small hole for the brass tubing than what is suggest. If it says to use a 7mm drill bit you will find that the pen blank and brass tube has more slack than what you want. I use a size "I" drill bit for all of my pen kits that require a 7mm hole. This is just under sized so the brass tubing will have a better fit. Of course you don't want it tight because you will split the pen blank when you press the kit together. Mine slides in and out with just a tap on my hand. Example: Craft Supplies instructions says to use a 25/64 drill bit for their Cigar pen kit. I use a size "W" drill bit. This makes the brass tubing have a little better fit. I have placed a link below of a Drill Bit Size Chart. You can use it to know what size drill bit to go down to for a better fit for your brass tubs. Scroll down about half the page and you will see the size 7mm and then look right above the previous size and you will see a size "I" bit. Hope this helps and not confusing. 

http://www.carbidedepot.com/formulas-drillsize.htm


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## EBorraga (Aug 8, 2010)

This sounds o.k. until you paint the tube or inside of the blank for an acrylic pen. Then you might have a very tight fit. Just some food for thought.


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## Tony's Pens (Aug 9, 2010)

I haven't got into a situation to paint the tubes.  I guess I don't know why you would paint your tube unless the blank is really see through.


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## ldb2000 (Aug 9, 2010)

Tony's Pens said:


> I haven't got into a situation to paint the tubes. I guess I don't know why you would paint your tube unless the blank is really see through.


 
Most Acrylics are best done with painted holes and/or tubes . Acrylics are by nature transparent and nothing will ruin the look of a beautiful pen faster then seeing the brass tube through the thin parts of a blank . Also what is a perfect fit in one material is sometimes terible in another , remember glue starvation will cause the bond of blank to tube to break with very little heat so you want enough glue to really bond the tube to the blank .
We have a great chart here in the library for drill sizing , if fits perfectly printed on a standard size piece of inkjet paper http://content.penturners.org/misc/hutdrills.pdf . I have one copy over my lathe and another copy over my work bench .


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## Smitty37 (Aug 9, 2010)

*Bit size*



Tony's Pens said:


> I have learned that if your pen kit come from Craft Supplies it needs a hair bit small hole for the brass tubing than what is suggest. If it says to use a 7mm drill bit you will find that the pen blank and brass tube has more slack than what you want. I use a size "I" drill bit for all of my pen kits that require a 7mm hole. This is just under sized so the brass tubing will have a better fit. Of course you don't want it tight because you will split the pen blank when you press the kit together. Mine slides in and out with just a tap on my hand. Example: Craft Supplies instructions says to use a 25/64 drill bit for their Cigar pen kit. I use a size "W" drill bit. This makes the brass tubing have a little better fit. I have placed a link below of a Drill Bit Size Chart. You can use it to know what size drill bit to go down to for a better fit for your brass tubs. Scroll down about half the page and you will see the size 7mm and then look right above the previous size and you will see a size "I" bit. Hope this helps and not confusing.
> 
> http://www.carbidedepot.com/formulas-drillsize.htm


 
If you are using a drill press, I wonder if you might have hit onto the solution for the slight wobble in the bit that a lot of us (using lower priced drill presses) get when drilling. I know it sometimes makes my holes feel a little too loose when I insert the tubes.


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## Tony's Pens (Aug 9, 2010)

With my method of using the next few thousandths smaller drill bit (and I mean a few) the brass tube fits correctly every time. I always use my lathe to drill my pen blanks. I mark the center point on one end (I use a center finder and you must mark all four corners). I then put the other end in the chuck and tighten it just a little snug. I then pull the tale stock up with drill bit in and slowly turn the lathe with my hand. If the center point wobbles compared to the drill bit position then I adjust the end with the center point to stop the wobble. Once everything lines up I tighten the chuck. With this method you should never have a run out with your pen blanks. I drill Corian with the lathe and have never had run out. Corian does not have enough room to allow for run out. Of course I am new to pen turning and what I do may not be what others are having success with.


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## snyiper (Aug 10, 2010)

Smitty I have found if you choke up too much on the bit you get that wobble. By that I mean I would push the bit too far up into the chuck and the teeth would tighten on the drill lands or spaces and cause a wobble. So even on long bits I tighten at the top of the bit.


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## Russianwolf (Aug 10, 2010)

I have one of the 100+ drill bit sets. I use my calipers to measure the tube, then use them to select the bit for the hole. Less chance of being disappointed that way.


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## randyrls (Aug 10, 2010)

ldb2000 said:


> Most Acrylics are best done with painted holes and/or tubes . Acrylics are by nature transparent and nothing will ruin the look of a beautiful pen faster then seeing the brass tube through the thin parts of a blank . Also what is a perfect fit in one material is sometimes terible in another , remember glue starvation will cause the bond of blank to tube to break with very little heat so you want enough glue to really bond the tube to the blank .
> We have a great chart here in the library for drill sizing , if fits perfectly printed on a standard size piece of inkjet paper http://content.penturners.org/misc/hutdrills.pdf . I have one copy over my lathe and another copy over my work bench .




One thing to remember is that the same drill bit will drill a bit larger hole in acrylic than in wood.  I believe the wood expands away from the drill bit and then shrinks a bit.  The difference isn't a lot, only a few thousandths or so.


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## sgimbel (Aug 10, 2010)

I just made come cigars from Craft USA using the 25/64th bit. I drilled it on the lathe and I use Gorilla glue and everything slide together just like it's suppose to.


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## ed4copies (Aug 10, 2010)

The hole in cocobolo (and many other species) will "close a little" after drilled.  Maple doesn't do this.  

Acrylics also drill differently from wood and the hole and brass are frequently painted.

Moral: Drill your favorite size hole and test with the tube you plan to use.  IF you are using wood, think about waiting a day or so to put the tube in.  You may be surprised at how much the hole "closes" as air hits it.

OR, get used to your pens cracking days after they are made.  If the fit is too tight, when the brass gets warm and expands, the wood will give up.

Crack!!


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## Smitty37 (Aug 14, 2010)

*Thank you*



snyiper said:


> Smitty I have found if you choke up too much on the bit you get that wobble. By that I mean I would push the bit too far up into the chuck and the teeth would tighten on the drill lands or spaces and cause a wobble. So even on long bits I tighten at the top of the bit.


 
Thank you...I do sometimes choke up a bit...I also learned that my quill is less than perfect...not quite sure about taking on replacing it though looks like a time consuming job that can easily be screwed up...lots of junk on that shaft from the pullies to the chuck.


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## Smitty37 (Aug 14, 2010)

*Didn't know that*



ed4copies said:


> The hole in cocobolo (and many other species) will "close a little" after drilled. Maple doesn't do this.
> 
> Acrylics also drill differently from wood and the hole and brass are frequently painted.
> 
> ...


Thanks. I didn't know that....of course that could be because my holes are rarely tight and not due to any concious reasoning they have usually been drilled a couple of days before I glue in the tubes.  Sometimes a couple of weeks or even months.


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