(As asked about in another thread about finger tops: http://www.sawmillcreek.org/showthre...91#post2755391)

------------------------------------------------------------------------------------------
To friction-burn lines on a slope on a turned wooden object.
JK Jordan, 12/13/2015

I developed this technique about 15 years ago. Maybe others do the same thing but I've never seen it nor have any of the many people I've shown over the years.

Basically, I interrupt the finishing cut partway down the slope to form a groove, friction burn the line, then continue the finishing cut. For example, suppose we want to burn two lines on a slope like in this photo:

Tops00_small.jpg

We want to create the two lines on the left slope as shown in the profile in this sketch. The black dots on the profile represent the desired burn marks.

FrictionBurn_slope_sketch_revised.jpg

Step A: Leave the surface a little bit higher than the desired profile as shown by the green line. I never measured, certainly less than 1/16", doesn't need much.

Step B: Cut the final profile down to where you want the first burn line. Hold the wire in the little valley and burn the line.

Step C: Continue cutting the final profile down to where you want the second line and repeat the burn.

Finish: Continue cutting the to the end of the profile.

NOTES:
- Since the top part of the burn mark will be cut away you may have to burn a little deeper than you would on a normal friction burn.

- When continuing the profile cut as in step C be careful not to cut into the burn mark or you may cut it away!

- I often make just a whisper of a cut over the line if I want the line to be thinner (less deep) but this requires a careful cut to keep from removing the line entirely and having to start over.

- Sanding too much will remove the groove! Sharp tools and a careful hand on good wood should require little no sanding. (I usually hit it with a touch of 600 grit.)

- Most of the wires I see used to friction burn lines are too thick for my taste. I have a stash of thin galvanized wires made to attach tags to valves. I don't know the gauge. Without measuring I'll guess they are 0.2 or 0.3 mm.
------------------------------------------------------------------------------------------

JKJ