Metal Spinning How to, Part 3-- Spinning Tool
Metal spinners use a variety of tools when executing a metal spinning project or product. The first and most important is the metal spinning tool. Your first metal spinning tool should be a combination tool. A combination tool is fabricated from chromoly steel and has a handle made of hard maple of oak. This kind of tool is ideal for nonferrous metals such as aluminium, pewter, and red metals such as copper, brass, and bronze. The tool is called a combination tool because it is used for both spinning and planishing.
There are three parts to the combination tool, the steel rod, hardwood handle and ferrule. There are many different types and shapes of metal spinning tools; I am going to describe the tool that I use the most. The tool is fabricated from a Ø19mm (¾”) 4140 alloy steel rod cut to 415 mm (16”) in length.
One end of the rod is prepared in such a way to have multiple radii and a planishing surface. The first step is to prepare the tool is to machine or grind a 38mm radius 30mm down the shaft.
Now add a 3.5mm radius to the tip of the rod and blend to the R 38mm surfaces. Now machine or grind a flat onto the tip of the tool. Start at the center of the rod and extend 30mm down the shaft. Now blend the perimeter of the flat planishing surface in such a way that there is a smooth transition between the spinning surfaces and the planishing surface. This transition area will start with a small radius at the tip and have a larger radius as it moves down the shaft 30mm. Now it is time to polish the first 500mm of the tip to a mirror finish.
The second part of the combination spinning tool is the ferrule that is inserted onto the handle to resist hoop stresses that could result in the handle splitting while in use. This ferrule is simply a piece of metal tubing with an I.D. ≅ Ø 35mm x 1.25mm thk x 50mm long.
The ferrule can be made from almost any metal but brass and stainless steel is the most common. These ferrules are usually polished to a nice finish simply for aesthetic reasons. Once the spinning rod is inserted into the tool handle the ferrule is installed. The ferrule should be a tight fit onto the handle and be installed with the aid of a wooden mallet.
The last part of the metal spinning tool is the handle. We alternate between using hard maple and oak depending on availability, but any hardwood should work just as well. The handle is made from a Ø50mm x 500mm long dowel rod.
These are generally available at specialty lumber yards. The first step is to drill a Ø19mm (Ø¾”) hole 100mm deep in one end on the centerline of the handle; it would be best to do this in a lathe. After drilling this Ø19mm hole turn the Ø50mm O.D. down to Ø35mm x a distance of 50mm. This feature is to accommodate the installation of the ferrule.
On the opposite end of the tool handle, what we refer to as the butt, turn or sand a 13mm radius onto the end of the tool. At this point you would have a perfectly functional tool handle; however, most people like to undercut the diameter in the middle and add some grooves and other embellishment for aesthetics. These tools can be made to look and function quite beautifully.
Before you start to assemble the tool, check to see if the unpolished end of the tool has any burrs left from the saw. If so, file a small chamfer around the diameter to make it easier to insert the rod into the handle. Start the blank end of the rod into the 100mm deep hole as far as possible by hand, it should be tight. Now while holding the rod and handle vertically pound the butt of the tool onto a concrete floor. The rod will move into the handle some distance with each blow. You will know when the rod is seated all of the way into the handle by the difference in sound and feel. Place the ferrule over the handle and start it onto the handle by hand and then pound the butt of the tool onto the concrete floor. This procedure is unlikely to result in the ferrule being completely installed onto the handle, you will need to finish the installation using a wooden or plastic mallet.
The tool is now complete.
While I didn’t discuss the part tolerance with regard to the three parts, the tutorial does give a detailed description of how to manufacture a metal spinning tool. While you have read through this fabrication procedure, I would also hope that you have realized that the purchase of one of these tools for $144.95 would a real value.
This completes this post on the metal spinning tool. Future posts will describe how to
use this spinning tool.
This is the 3rd post on my series of metal spinning. If you missed the first 2 post a link is below: