Basket weave pattern

#1
This basket weave pattern uses a sine wave to generate the basket weave. The exact same pattern can be used on a sawtooth pattern bar or rosette. A basket weave can also be made using a dedicated basket weave pattern bar, but I won't talk about that here.

There are a few more variables you'll need to figure out with this pattern versus the barley corn pattern I wrote about previously. At the heart of this basket weave is a barley corn pattern (if you compare the diagrams from the previous pattern, you'll see the same black and red lines form a barley corn in this pattern). In between those two cuts are a series of cuts to create the basket weave effect. I've illustrated it with two extra cuts, however, depending on the pattern bar or rosette, you could make more cuts (at a certain point additional cuts are going to be lost).

So we have four cuts that will be repeated to make the pattern. This is the setup for straight line work.

A=0.1"
P=0.6"
Ph1=0" (our starting point for the pattern bar, the black line in the diagram)
Ph2= (P/2)/3 = 0.1" (the second cut, the blue line in the diagram)
Ph3= Ph2*2 = 0.2" (the third cut, the green line in the diagram)
Ph4= P/2 = 0.3" (the fourth cut, and the red line in the diagram)
X=((A/5)+A)/3 = 0.040" (we are dividing the distance between the barley corn cuts by three)

Set the pattern bar to 0. Make the first cut.
Set the pattern bar to 0.1", advance the cutter X, make the second cut.
Set the pattern bar to 0.2", advance the cutter X, make the third cut.
Set the pattern bar to 0.3", advance the cutter X, make the fourth cut.
Set the pattern bar to 0.2", advance the cutter X, make the fifth cut.
Set the pattern bar to 0.1", advance the cutter X, make the sixth cut.
Set the pattern bar to 0, advance the cutter X, make the seventh cut.
Repeat as necessary.

For the rose engine, I've used a 48 lobe sine wave as in the barley corn pattern.

A=0.1"
P=7.5º
Ph1=0º
Ph2=1.25º or one notch on a 288 count crossing wheel, or 60º
Ph3=2.5º or two notches on a 288 count crossing wheel, or 120º
Ph3=3.75º or three notches on a 288 count crossing wheel, or 180º
X=((A/5)+A)/3 = 0.040" (we are dividing the distance between the barley corn cuts by three)

Make first cut at 0º, advance X.
Make second cut at 1.25º, advance X.
Make third cut at 2.5º, advance X.
Make fourth cut at 3.75º, advance X.
Make fifth cut at 2.5º, advance X.
Make sixth cut at 1.25º, advance X.
Make seventh cut at 0º, advance X.
Repeat as necessary.

As with the barley corn pattern, you may need to adjust X to suit the pattern bar, and depth of cut.

Edit:
Looks like the forum has mangled my images. Let me figure out a better way to get them in the post.
 

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#2
The actual engraved output of Chris' recipe for the straight line pattern would look better than the picture. There is a slight offset in the drawing that doesn't reconcile with the numbers. What's important, though, is an intermediate goal to the pattern that leads to the final illusion of "basketweave" and that is precise alignment of generated line segments. The generated line segments are those formed by the repetitive stringing of the flatter portions of the wave. Actually, the more angular the wave, the better effect. You can also do this pattern with other ratios 5:1, 4:1, and some experimentation will be necessary to get the proper overlap. The photo shows a relatively angular wave pattern.

I sketched up what I mean by the alignment of generated line segments. I hope you can see that the blue lines lie on top of the pattern in such a way to suggest the weave angle. If there is deviation as shown in the "mismatch" then the ultimate effect suffers a bit. Minor adjustments may need to be made from the recipe depending on the actual shape of your pattern bar or rosette, the size of the rubber, and for rose engines, the diameter of the circular engraved pattern. Even Daniels says do what you need to do. Those without good eyesight or a good loupe are in bad shape :)

Έλληνες πάντα
Rich
 

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#3
Here's an example of a basketweave attempt on a rose engine that I made some time ago and it shows some artifacts illustrating some of the things said. The piece is the size of a quarter. First, you cant see a lot of the issues with the naked eye. Second, the alignment is not too bad. Third, the waviness of the curve causes all those little squiggly overlaps and those get worse the bigger the pattern. Fourth, the cuts are not deep enough.

You can see that alignment stays with the diameter of the pattern.

Cheers,
Rich
 

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#4
Rich,

Minute experimentation is necessary, to be sure. While the formula works, I've tried it many times with different rosettes/pattern bars etc. Where the trouble comes is with the sine wave. Frankly, despite what we think, we seldom get a true sine wave and the adjustments about which you speak are, infact, to make up for that. The closer you are to a true sine wave the easier the set up will be.

Thanks to both of you for the illustrations. At the moment I'm too buried to have done them myself, and likely my old method paper and pen would have been much more cumbersome and not worked as well anyway.

I can't tell you how pleased I am that this information is getting out and also to see this forum being used.

David
 
#6
Rich and David make an excellent point that I should have spoken about in the initial post. Every pattern bar/rosette is going to be a bit different, and some experimentation is required to get the best looking pattern. Another thing that will affect the pattern is depth of cut. If you have working on a larger piece, you may choose to use a deeper cut than something small like a watch dial.

The information that you find here is a good starting point, but you will need to experiment. It is worth keeping a notebook beside your engine to write down what you did on different pieces to get the look you wanted. You never know when you will want to replicate that in the future. It is also worth experimenting with different pattern bars using the same patterns that you've had success with before. I recently started using a drapery pattern from my sine wave bar with a basket weave bar and it looks great.

And most importantly, let us know what works, and what you are struggling with. Someone may have use for a pattern you've made, or have the answers to issues you're experiencing.
 
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