Engine Turning Pt 2

As I discussed in my last post about engine turning, I am using a straight line engine in my work.  This post will cover how an straight line engine works in more detail.

Pattern Bar Holder

There were many variations of engines built, however, they all follow the same basic principles in their operation.  There needs to be some sort of headstock to hold the work piece, and there needs to be a tool slide to secure the graver and the guide, which controls the depth of cut.  As the head stock and piece are moved down, the graver is pressed into the material and cuts a line.  A basic engine such as this is typically called a bordering engine, and was used for creating borders on picture frames.  The variation in the patterns that a bordering engine can produce is very limited.

Most straight line engines have a few other critical features that allow them to create an infinite number of patterns.  The first is a pattern bar holder.  Pattern bars can be bolted in place, and using a few adjustments, can be changed to alter the final pattern that is engraved.  It is important that the pattern bar holder is very sturdy, that it allows multiple bars to be held at the same time, and that the bar can be moved up and down independently from the headstock.  My next post on engine turning will discuss the variations created through this important feature.

The tool slide on the Plant straight line engine has several important upgrades.  The first is an index system for moving the graver from left to right.  Using a ratchet and pawl system along with an adjustable stop, the cutter can be advanced by a known amount between each cut.  Because the human eye is excellent at picking out flaws in repetitive patterns, it is critical to keep the spacing consistent from cut to cut.  A radial adjustment is also a useful addition to the tool holder.  If the work has a curved surface on the edge, such as the side of a case, it is important to keep the graver perpendicular to the surface that it is cutting.  If the graver isn't perpendicular to the surface, one side of the cut will be deeper than the other.

The most important upgrade to the headstock is the radial adjustment.  The most common system to allow radial adjustment of the piece is through a worm gear.  The worm provides very fine control over how many degrees the piece is turned from one cut to the next.  A further improvement is to add a ratchet and pawl system to allow indexed fine control over the radial movement.  In the case of the 14" Plant, each notch on the ratchet wheel moves the piece 1/4 of a degree.  The sunburst patterns created using this upgrade were very popular on cigarette cases and picture frames.

The next post on engine turning will discuss what pattern bars look like, and how variations in their use can lead to an infinite variety of patterns.

Engine Turning

Engine Turning, or Guilloché, is a form of decorative engraving that is accomplished with the assistance of an engine. Its origins are rooted in the 18th century when artisan jewellers modified ornamental lathes, or rose engines, to cut metal using a fixed cutter. Rose engines used for ornamental turning typically use a live, or spinning, cutter to cut soft materials such as wood or ivory. I will be discussing rose engines and ornamental turning more in a later post. 14" Plant

The evolution of engine turning eventually led to the invention of the Straight Line Engine. The photo on the left is of the 14" Straight Line Engine that is in my shop. It was produced in the early 20th century by G. Plant & Son in Harborne, England. The 14" refers to the maximum length of cut that the engine can produce. Unfortunately G. Plant & Son closed up shop in the 1950's.

Through the use of different shaped pattern bars, the engine allows the operator to create a series of parallel or radial lines. Adjustments allow precise changes to each cut, creating stunning interference patterns. When combined with transparent enamel, pieces that have been engine turned truly come to life.


Welcome to Silver Hand Studios.  Through this blog I'm hoping to keep everyone updated with what is new and upcoming at SHS, as well as help inform you about the processes and materials I use for making my pieces.  If you have questions concerning any of the pieces, materials or techniques, please contact me.  I am always happy to talk about what I am working on.  There is an RSS feed of this blog available, as well as a mailing list to help keep up to date. I attended the LA International Pen Show for the first time this year.  Besides enjoying the wonderful weather, it was a pleasure to be able to meet everyone who stopped by my table.  I am looking forward to attending again next year.  Throughout the year I will update my show schedule.  If you at a future show, please be sure to stop by and talk pens.