Friday, January 27, 2017

Wood Lathes and Their Tools

This Article is talks about the evolution of wood lathes and the tools used with the modern lathes.  Each of the tools have special uses depending on the shape and how they are sharpened.

Wood Lathes date back to about 1300 BC.  Egyptians first developed a two person lathe where one person would rotate the wood with a rope while another would shape the wood with a sharpened tool.  Romans later improved the lathe by the use of a Turning Bow.  Later in the Middle Ages a Foot Pedal replaced the Turning Bow and allowed one person to operate the lathe, the Foot Pedal is still used to some extent in Third World Countries.

Lathes continued to evolve through the ages; using animal power, water power, steam power and electric power.  Today we are fortunate to have a variety of variable speed lathes and sizes from small bench lathes to the larger lathes that will turn objects up to 24” in diameter and still bigger but these are special use, usually for commercial application.

When a lathe size is mentioned say as a 14 inch than means there is 7 inches between the center of the Head Stock and the lathe bed or Ways; 14 inches is the maximum diameter.

Tools for the Wood Lathe, there are many but they all fall into six tool groups. They are the Gouge, Scraper, Skew, Parting Tools, Specialty Tools and Carbide tools.  The numbers of these tools are greatly multiplied when you consider different sizes as in thickness, width and length. The many different profiles and shapes that also increase the number of tools.  After you have turned for a few years it is easy to have 20 or 30 different tools. 

Gouges, there are several profile shapes that have specific uses.  Spindle Gouge is used for shaping square wood into round spindles and because of its high sides it should never used on bowls.  Bowl Gauges have many different profiles that make bowl gouges very versatile and are great tools.  Detail Gouges have their purpose.  Gouges require practice to understand different methods of use and how to sharpen the tool.  If you take the time to learn how to use the bowl gauge you’ll never be without one in your tool chest.

Scrapers are used to smooth your turning, sharpened correctly they are very good.  Many experienced turners leave a burr on the edge, this will cause to scraper to cut very fine.

Skews have a double edge bevel and are normally shaped at about a 30 degree angle. With the double bevel edge the chisel can be turned over and used both left and right, some have a rounded edge.  Skew can be used for smoothing and special angels.

Parting Tools are used for parting off (removing) the turning from the waste block.  There are a number of other limited uses.

Specialty Tools are texturing tools, chatter tools, Chinese Ball Tools, and etc.

Carbide Tools and gaining a lot of use because of their hardness and ability to stay shape longer.  The carbide cutter is attached to the shank of a tool that can only be used for that purpose.  Different shapes are cups, flat round, square, diamond and etc.  They are a good tool and have their place in the wood turner’s tool chest.  The only drawback is the cost of the replacement cutters.

Beginning turners can purchase tool sets in a number different sizes depending on the size of the lathe. The sets will have one of each of the tools described above except the specialty and carbide tools. I hope this article helps those that are just learning this wonderful craft.

Tuesday, January 10, 2017

Green Wood With Natural Edge

A  few Natural Edge Bowls turned from green wood.  The light colored bowls are Oregon Myrtlewood (Umbellularia californica) and the red colored bowls are Coastal Redwood (Sequoia sempervirens), both old growth and second growth.

Select the wood that you want to work with and cut it lengthwise.  I always over cut the length so that I can avoid the end checks.

A small diameter log will produce a bowl with high ends and low sides. A larger diameter log will have a more uniform edge

Use a circle pattern cut from plywood to locate and position the bowl on the log and then trim the excess with a chainsaw.  Be sure to locate and mark the center of the circle.
Following the circle pattern cut the log round on a bandsaw
Remove the pattern and attach faceplate.  I wrote a blog called "Reverse Chucking"
This will help to understand how to attach the bowl blank to the lathe.

Always use the tailstock to support the work.  Some of these green bowl blanks are very heavy.                                                                                        

Turn and shape the outside profile and create sipot with dovetail to attach the work to a chuck.
Turning has be reversed on the lathe.  The dovetail has a greater holding strength than a straight spigot.
Support with the tailstock.
Remove the inside.  Leave the thickness at about 1 inch uniformly
around the bowl.  If the thickness is uneven there is a greater chance the wood will crack during drying.
After the inside has been removed and the turning is lighter use a large Forstner bit to remove the center.

 Finished bowl ready for drying.  After the bowl is dried re-chuck the bowl and finish.

I wrote another blog on drying bowl in a Kiln, check it out.
This is a unique piece. You don't find these very often.  I finished this bowl and gave it to a friend for wedding gift.  He complained that it wouldn't hold soup and she threatened him with divorce if he messed with it.