Steel is an amazing material. It comes in an array of types, from stainless to high speed. The distinct structure of each variety makes it optimal for different applications. M42 high speed steel has been used for centuries in shops of all kinds, from enormous factories to your personal woodturning shop.
M42 high speed steel has a unique structure, allowing its trademark durability and edge sharpness. A 10% additive of cobalt is responsible for M42's toughness. Cobalt allows heat-treatment up to 64-68 HRC. This provides M42 with outstanding edge durability. Furthermore, M42's composition is unusually tight, meaning it can be honed to a fine edge.
In addition to a fine edge, it is the heat-treatment process that makes M42 the industry standard for hundreds of applications.
Steel is shipped from suppliers to machine shops around the world in an annealed state. Because this is the steel's softest and most relaxed state, machining the steel in this form is much easier. Heat-treatment always takes place on annealed steel. Once a steel has been heat-treated, it can be returned to it's annealed state. Steel cannot be re-heat-treated without first being annealed.
Once the steel has been machined, it moves onto heat-treating. Different types or grades of steels can be heat-treated to different harnesses. Because M42 has a 10% cobalt content it can be heat-treated harder than most high speed steels, to 68 HRC.
After the hardening process, the steel is very brittle and pressured. This is why tempering is the next step. Tempering reduces the internal stress of the steel and increase robustness.
Once the steel has been tempered it is ready for use in a huge warehouse, machine shop or at your wood lathe.
Questions? Call our metallurgists at (206)878-7672. Happy turning.
Downed trees are a plentiful source for woodturning blanks, however, before you turn on the saw it is important to understand the best practices for cutting and storing your own blanks.
Inspecting the Tree
As you inspect a fallen tree, make sure to distinguish between limb wood and trunk wood. Generally, trunk wood includes fewer knots and irregular growth, features that add uniqueness to your piece but tend to warp and crack.
Storing Before Cutting
Until you are ready to cut your log into blank sized chunks, store the wood in long pieces to limit the number of open ends at risk for cracking. Using a sealer, such as this one offered at Packard Woodworks, will guard against checking. Don't worry about removing tight bark, it will actually slow moisture loss and protect against splitting.
Cutting the Log
When you are ready to cut the log into blanks, it is helpful to understand that the middle of the log is called the 'pith' and is the tree stem. This area is very unstable, tends to dry unevenly, and should not be included in your turning blanks. Following the diagram below will allow you to cut two bowl blanks from a log while avoiding the volatile pith area.
Once you've cut your blanks don't forget to mark, seal and store them in a dry area until you are ready to mount them on the lathe.
Information drawn from this helpful Wood Magazine article. And this informative video.
Performed by lifelong turners, spindle turning appears simple. Mount the wood, a few strokes, and voila, a beautiful piece. In reality, there are many fundamental principles that will allow you to approach spindle turning with ease. Professional Nick Cook shares a few of these concepts.
A full article by Nick Cook including more spindle turning tips can be found here.
- Always cut downhill, from large diameter to small diameter on spindles. Attempting to cut uphill on some woods will produce disastrous results—expect a lot of catches.
- Adjust the height of the tool rest to match the tool you are using. You should cut above center for most lathe tools. If you switch from a thick tool (like a spindle roughing gouge) to a thinner tool (like a skew) you will need to raise the tool rest.
- For additional support and better control of your spindle turning, wrap your index finger around the tool rest.
- Never drive the blank onto the spur center while it is mounted in the spindle. This can damage the Morse taper and stress the lathe bearings.
- Never drive the spur center into the blank with a steel-faced hammer.This will damage the Morse taper, preventing it from fitting properly. Always drive the spur with a wooden mallet, dead blow, or other soft-faced hammer.
- Position the tool rest parallel to the blank and as close as possible— 1/4" is adequate clearance. Be sure to lock the tool rest to the support and the support to the lathe bed. Always rotate the workpiece by hand before turning on the machine. No matter how many times you have seen it done in demos, never move the tool rest with the machine running. Always move the tool rest closer after removing the corners from the blank—excessive overhang of the tool will cause chatter.
In the midst of how-to videos and articles, Nick Cook offers a different type of insight.
Find more insightful tips from Nick Cook here.
- Too big. Start by mastering crucial techniques on smaller, shallow bowls.
- Too hard. Start with green wood, it can be found inexpensively and will provide smooth, easier cuts.
- Big gap at the tool rest. If the tool extends more than an inch over the tool rest it's time to stop the lathe and adjust the tool rest.
- Wrong direction. For face grain bowls cut uphill. On the interior of your bowl, cut downhill or from rim to center.
- Wrong tools. Remember to never use a roughing gouge on bowl work. A 1/2" or 5/8" bowl gouge makes great beginners' bowl gouge.
- Rushing into finishing. Don't worry about finishing a piece, focus on basic shape and confidence. Practice pieces are most important as you begin turning bowls.
- Lack of body movement. Notice how most turners move with their work. This allows them to produce fluid curves.