Celtic Knot inlay - any science?

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TomW

TomW

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I've got the Celtic knot bug.

I'm somewhat frustrated by my current method, which is cut the kerf (have several blades with different kerf widths). then trial and error to try to find "something or some combination" that "might" fit (and be pleasing colors).

This weekend I ended up with A) plastic pic guard surrounded by wood veneer, b) pvc sheet surrounded by 4 layers of wood veneer.

What I'd like to do is plan a knot, not just take what fits. I dont mind buying an assortment of stuff, and even an additional saw blade, but I'd like to have some assurance the materials/thicknesses/colors will work.

Does anyone have a solution they might be willing to share?
Thanks in advance
Tom
 
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I've done some celtic knots, not a bunch though.. I don't use the kerf method myself... I cut all the way through, glue whatever I'm using for the knot to the end, let the glue set, then make the next cut, glue and let dry, then put the end back in place, glue etc.... it's probably not the best way, but works okay for me... more of my celtic knots have been in pepper mills rather than pen, although I've done one or two pen blanks this way.
 
I've used the cut-through method and found that aligning the pieces after can be tricky. I prefer the kerf method and to make this easier, I made a "test block" from a piece of 2x4. I cut a kerf in the block on the bandsaw and on the tablesaw. Then I can set up these saws to cut inlay pieces and use the block to test the fit. This way, I can cut several inlays with one setup and have them ready when I need them.
 
TomW said:
I've got the Celtic knot bug.

I'm somewhat frustrated by my current method, which is cut the kerf (have several blades with different kerf widths). then trial and error to try to find "something or some combination" that "might" fit (and be pleasing colors).

This weekend I ended up with A) plastic pic guard surrounded by wood veneer, b) pvc sheet surrounded by 4 layers of wood veneer.

What I'd like to do is plan a knot, not just take what fits. I dont mind buying an assortment of stuff, and even an additional saw blade, but I'd like to have some assurance the materials/thicknesses/colors will work.

Does anyone have a solution they might be willing to share
Click to expand...
Hi Tom; I've done maybe 4 or 5 Celtic knots with reasonable success. One rule that is imperative in my estimation: The width of the material used for the knot must equal the width of the material (kerf) removed by the saw blade.

It makes no matter whether you cut all the way through or use the kerf method!

Cutting all the way through presents a problem in lining the pieces up when reglueing, but it's not an insurmountable one.
Click to expand...
 
Tom -- I have only been able to figure out two ways to control the cuts to get a knot that does not distort.

The easy way is to use the cut and replace. You can make any thickness cut as log as what is removed is replaces with some precision.

The hard way is to fix the control on a centerline (control line if you decide to an asymetrical assembly) of the segmented assembly and build it from the center control. I took this hard/difficult process far enough to confirm it works -- but after two pieces decided it was more effort than I wanted to spend.

The gage block shown in the tutorial in the library is a good way to prepare the inlay pieces to match. Error in thickness multiplies as you add cuts. Half as much with a 4 segment assembly as with the 8 section assembly that Ron Sardo did a few years back.

Be sure to allow a tolerance for the glue thickness.
 
I've only made 3 or 4 but I like the plastic shim stock and a Freud Diablo 7.25" circular saw blade on the table saw. The Diablo kerf is ~ 0.06" and I build the inlay from the various shim stock material. My favorite is a simple white (0.025") - black (0.0125") - white (0.025") sandwich to fill the kerf. The shim stock is a little pricey but a 5" X 20" sheet of each thickness makes several inlays. Each thickness is a different color, too, which makes it great for pen inlays IMO. I bought mine from Amazon but Google "plastic shim stock" shows some other places a little cheaper:

http://www.amazon.com/Plastic-Color-Coded-Shim-Assortment/dp/B00065UYKU/ref=pd_sbs_indust_1
 

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A few knot tips

I've done quite a few knots. I cut the slots on the band saw using a jig I made for the purpose. I match my material to the kerf. I use sandwiches of edge banding that I buy at the local Borg. I remove the glue by soaking it in water and it peals right off. The banding tends to curl but I press it dry and it holds it's shape. The red oak type is easy to ebonize with the vinegar and steel wool method. And I can get it in a white plastic variety if I want that.

When I use metal strips, I've had some issues with the CA not wanting to hold on waxy or oily woods. I've found that swabbing the kerf with acetone before gluing solves the problem. I think the most important step is to get the hole perfectly centered so that the knot will be even.

It's also worth noting that I had my share of failures when I first started doing them. I still have failures from time to time. Especially if I get too aggressive when turning.
 
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No science at all. Match the material used to the kerf of the blade. Plenty of info in library.
-animated-pen-knot-good-file.gif




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Hey Tom -- got the e-mail from one of the mags - one of the gallery pictures was rolling pins made with the celtic knot -- with the insets about 3/8 inch --

the rolling pins were a nice job and regardless of size -- what goes out is the same thickness as what goes in. Just plan for the thickness desired.
 
Wow, I have not seen those pens. They are awesome! So is the animation!
Is there a library entry that explains how to insert the different colors?
 
Linarestribe said:
Ok, how did you make that animation?
Click to expand...


Animation is done using photoshop

MarkD said:
Wow, I have not seen those pens. They are awesome! So is the animation!
Is there a library entry that explains how to insert the different colors?
Click to expand...


No secret with the colors. I shown these quite awhile ago. Here is a photo of the blanks so that should explain the colors. Hope this helps and good luck with the knots. They are fun to make in any style pen.


penXblanks-1.jpg
 
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