Timbo
Member
The following was written with drilling on your lathe in mind.
If you're like me, you've run into problems when trying to drill a centered hole into pen blanks which are spalted, highly figured, or segmented. The problem is that there is a lot of uneven variability in the density of the wood, including at the entry point, this causes the bit has a hard time finding and staying centered. Even if the bit is perfectly aligned after locking down the tailstock, harder or denser areas of wood causes the bit to want to wander towards the softer, or less dense areas. This will manifest itself as wobbling or vibration of the bit.
My solution is to provide a good entry for the bit, and a guide to help keep it on track throughout the drilling process. Corian to the rescue! I found that gluing a 1/2" thick piece of Corian to the end of the blank prior to drilling eliminates most of the problems with drilling these types of blanks. Here's my process:
1 - Get a piece of that 1/2" thick Corian you will never use for a pen because the color is just yuck. Cut it into strips slightly narrower than your pen blank. Cut little squares from that. Use medium or thick CA to glue the little square of Corian to the end of your blank. Make sure the edge of the Corian square do not overlap the edge of the blank. Why...Later we will want to cut the Corian away, we'll want our blank to still sit flat for sawing. Here's what mine sample looked like:
View in Gallery
2 - This is a blank for a cigar pen which requires a 10mm bit. I use that bit to drill into the Corian a little more than 1/2", until I just start entering the wood. This is what it looks like (sorry about the over-exposure).
View in Gallery
View in Gallery
3 - Next I replace the 10mm bit with a smaller bit, then finish drilling through the blank. The smaller bit is only used to clear the way for the larger bit, reducing resistance, lessening tear out, lessening the chance of a blowout, and makes it easier for the Corian block to act as a guide for the bit shaft.
View in Gallery
4 - I then replace the smaller bit with my 10mm bit and redrill the hole to the correct size.
View in Gallery
5 - The last step is to slice off the Corian block using whatever method you prefer.
I've used this method with a lot of success. Give it a try if you think it could help you.
Tip 1 - If you don't have any Corian you could substitute a piece of fine grain hardwood, like Sugar Maple, acrylic, or a scrap Tru-Stone.
Tip 2 - This method will also work for longer single barrel pen blanks that you might want to drill from both ends. Glue a piece of Corian to both ends of the blank. Make sure the blank is square prior to drilling so that when you reverse it in the chuck, the drill holes will line up.
If you're like me, you've run into problems when trying to drill a centered hole into pen blanks which are spalted, highly figured, or segmented. The problem is that there is a lot of uneven variability in the density of the wood, including at the entry point, this causes the bit has a hard time finding and staying centered. Even if the bit is perfectly aligned after locking down the tailstock, harder or denser areas of wood causes the bit to want to wander towards the softer, or less dense areas. This will manifest itself as wobbling or vibration of the bit.
My solution is to provide a good entry for the bit, and a guide to help keep it on track throughout the drilling process. Corian to the rescue! I found that gluing a 1/2" thick piece of Corian to the end of the blank prior to drilling eliminates most of the problems with drilling these types of blanks. Here's my process:
1 - Get a piece of that 1/2" thick Corian you will never use for a pen because the color is just yuck. Cut it into strips slightly narrower than your pen blank. Cut little squares from that. Use medium or thick CA to glue the little square of Corian to the end of your blank. Make sure the edge of the Corian square do not overlap the edge of the blank. Why...Later we will want to cut the Corian away, we'll want our blank to still sit flat for sawing. Here's what mine sample looked like:
View in Gallery
2 - This is a blank for a cigar pen which requires a 10mm bit. I use that bit to drill into the Corian a little more than 1/2", until I just start entering the wood. This is what it looks like (sorry about the over-exposure).
View in Gallery
View in Gallery
3 - Next I replace the 10mm bit with a smaller bit, then finish drilling through the blank. The smaller bit is only used to clear the way for the larger bit, reducing resistance, lessening tear out, lessening the chance of a blowout, and makes it easier for the Corian block to act as a guide for the bit shaft.
View in Gallery
4 - I then replace the smaller bit with my 10mm bit and redrill the hole to the correct size.
View in Gallery
5 - The last step is to slice off the Corian block using whatever method you prefer.
I've used this method with a lot of success. Give it a try if you think it could help you.
Tip 1 - If you don't have any Corian you could substitute a piece of fine grain hardwood, like Sugar Maple, acrylic, or a scrap Tru-Stone.
Tip 2 - This method will also work for longer single barrel pen blanks that you might want to drill from both ends. Glue a piece of Corian to both ends of the blank. Make sure the blank is square prior to drilling so that when you reverse it in the chuck, the drill holes will line up.