Celtic Knot – #1 The Start, Design & Material Selection

Over the years I have borrowed designs from one medium to another like from Native American pottery and Oriental Bronzes into wood turning or Frank Lloyd Wright style textiles into stained glass.

I have always liked the Celtic designs that run from fairly simple to really complex and had thought about trying to incorporate one as an inlay into a piece.  The drawing on the left looked like a possibility and after seeing examples (right) where that design had been incorporated into a pen turning, I decided to explore how it was done.  After seeing a short live stream from Record Power out of New Zealand and a little research it looked like a project to tackle.  First to give me a better understanding of how the 13 different pieces interact to make the completed design I did some 3-D drawings varying some different parameters to see what I liked the best.  The bottom rendering is what I settled on or at least what I am shooting for.

Next is to pull out the possibilities for the various pieces to be used.  For the body cherry, mahogany and mesquite were considered.  I decided on using the mahogany as it’s a good turning wood whose grain will not compete with the Celtic knot.  The light banding wood will be maple and the dark center piece between the maple banding is walnut.  I want a really dark wood for the center and walnut may not be the best choice.  As I get into the build and some mockups get done, I should get a better idea of what looks the best.

First is to cut a piece off the mahogany board.  Here it’s set up on the chop saw ready to go.  In this photo you can see a red arrow that indicates the diagonal grain direction in the piece I want to use to make the pen blanks. 

To get straight grain blanks the piece gets cut on the bandsaw at an angle matching the grain direction.  I will get two blanks out of this piece with each of them long enough for two pens.

Ripping the blank using the bandsawn edge against the table saw’s rip fence for reference gives me a good straight generally parallel edge to the bandsawn edge.  That’s because the bandsawn edge is a rough and not perfectly straight.

To get straight parallel edges the newly cut edge is put up next to the rip fence and the bandsawn edge gets trimmed enough to remove the bandsaw blade’s rough surface.  This cut edge gets flipped and the first face gets a skim trim cut.  Usually this is enough to bring both faces parallel and flat but if not, the process can be repeated again.  Last is to rip the blank so its width is the same or a shade wider than the thickness of the blank.  The top photo shows that completed while the bottom two photos show the bandsawn edge before and after trimming on the table saw. 

While the width and thickness of the piece is close it’s not close enough.  To make the finished knot look right those two dimensions need to be very, very close which is done with the thickness sander.  The photos below show that after being run through the thickness sander the width and thickness only differ by two thousandths of an inch.

Working on the three-layer maple/walnut stack is next and it’s at this point a change is made.  Looking at the walnut piece I was worried that it may not be dark enough to provide the desired contrast between it and the maple.  So, it was back into the wood stock to see what other dark material was available.  In addition to the walnut (bottom sample in photo below) four other woods were potential candidates, Mesquite, Katalox, Wenge and Ebony.  Rather quickly I narrowed it down to the Katalox and the Ebony either of which will work better than the walnut.  I decided to go with Katalox because when finished it goes almost black with just a tinge of dark red which should work well with the mahogany body of the pen.  It is also already the width and is just a little thicker than I need.

Starting with the maple which it is just a little wide and thick.  Once it was ripped to the correct width it gets cut in half to make the two outer layers.  Because the piece is just a tiny bit longer than the piece of Katalox I have rather than use the chop saw to cut it in half a Japanese pull saw it used since its kerf is much thinner than the chop saw blade.  To get a square cut a reference block is clamped to a jig.

The two pieces start out at a little over 1/8” thick and are brought down to 3/64” which is closer to the final thickness.  Here the photo shows one of the initial pieces ready to go.  The carrier it’s on does a couple of things.  First, it provides for a solid larger supporting base as the piece gets thinner and thinner.  Second, the piece of cherry on the right end of the carrier gives a positive stop that keeps the maple piece from slipping while being sanded.  Because the pieces are so thin, once sanded to thickness I clamped them between two ¾” thick pieces of oak to keep them from curling and set them aside.

Next up is to start thinning the katalox using the thickness sander to bring it down near to its final thickness.  Just as I got ready to make its first pass through the sander it occurred to me that before I go through the process of getting the maple and katalox to their final thickness and gluing them up into a three-layer stack it would be a good idea to do a simple proof of concept to see if the process would work as planned or not.

Next Up – Proof of Concept & a Problem