Are Parabolic fluted drill bits the best for drilling pen blanks?
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Drill bits for pen turning
- Thread starter Ed Jarvis
- Start date
I don't know anything about pen blanks, but parabolic flute drill have the largest depth to diameter ratio of any common drills.
I've been turning pens for over twenty years. Frankly I have found that no bits are better than others and I have been very successful with the bit set from HF. The key is slow drilling with frequent withdrawal to clear the flutes.
If you are working with plastics, use soapy water as a lubricant. Specialty plastic drills are available, they have a steeper angled point. Again slow and steady, You dont want to heat the drill up.
If you are working with plastics, use soapy water as a lubricant. Specialty plastic drills are available, they have a steeper angled point. Again slow and steady, You dont want to heat the drill up.
For pens I’ve found it best to use a slightly smaller drill bit before using the finished size. Drilling in one go you can end up with oversize holes.
You need some space for the adhesive but not too much. I’ve only ever used standard twist drills, but I’d be interested if there’s something better?
You need some space for the adhesive but not too much. I’ve only ever used standard twist drills, but I’d be interested if there’s something better?
Roger Wiegand
Beta Tester
I've wondered about using a size smaller than called for followed by a reamer. Seems to work very well for accurate holes in metal. I've had problems with inaccurate holes in some expensive resin-impregnated blanks despite using high quality bits.
Using a reamer sounds a bit over the top for pen blanks but it might work well? The problem is getting reasonable price reamers in the correct size.
I’ve found some pen blanks require some odd size drill bits in the past.
The last time I made a couple of pens I made note of the recommended drill size but luckily did a test first in some scrap wood. The hole was slightly over size so I went down I think .1 or .2 of a millimetre to get a better fit.
I’ve found some pen blanks require some odd size drill bits in the past.
The last time I made a couple of pens I made note of the recommended drill size but luckily did a test first in some scrap wood. The hole was slightly over size so I went down I think .1 or .2 of a millimetre to get a better fit.
Per Google and my experience:
"A parabolic flute drill typically has a depth to diameter ratio of around 15:1; meaning it can effectively drill holes up to 15 times its diameter deep, particularly when used on softer materials like aluminum, copper, and mild carbon steels."
What that means is a 1/4" drill can drill to 15 times .25" or 3.75" depth without pecking. That assumes accurate alignment in the drill holder which is not likely in many wood lathes.
Anyway, yes, they are the ultimate drill for deep holes.
"A parabolic flute drill typically has a depth to diameter ratio of around 15:1; meaning it can effectively drill holes up to 15 times its diameter deep, particularly when used on softer materials like aluminum, copper, and mild carbon steels."
What that means is a 1/4" drill can drill to 15 times .25" or 3.75" depth without pecking. That assumes accurate alignment in the drill holder which is not likely in many wood lathes.
Anyway, yes, they are the ultimate drill for deep holes.
I too have been turning pens for almost 25 years and the single thing that made the drilling portion of pen making was when I purchased the Nova Viking drill press. It allows me to set the perfect speed for drilling whatever type of material I'm using. And with perfect speed for drilling pen blanks I have found that any bit I use drills the best hole for that pen blank. Have not lost a blank since getting it.
I just drill on the lathe with a set of pen jaws and a Jacob's chuck. This too allows me to control drill speed (I have a Nova Nebula) and saved me the cost of a drill press.
I mostly use 7 mm, and I've always used a Brad point bit. Our club turns slimlines for military personnel overseas. I've done 110 in the last few months. The Brad point bit has always worked well for me.