Easy Washer Setup
By Miles Partridge
Ron Geppert wrote a tip on holding a washer in a lathe to reduce its OD (CLICK HERE to view this tip). I have another suggestion that helps to fix the problem of maintaining concentricity in the setup.
If you want the ID and OD concentric and you have a washer that is already concentric, the threaded arbor will not ensure the OD runs true. My solution is to put an undersized threaded rod or bolt through the washer, with a nut and a smaller washer on each side of it, and tighten it all up on the washer you want to turn down.
Chuck the threaded rod in the lathe and put a flattened piece of copper pipe between a flat part of a tool holder and the OD of the washer. Rotate the chuck in a slow gear in reverse and use the cross slide to push the copper against the washer OD so the high spot touches the piece of copper. It will push the high spot down until it is running true; within a thousandth or so if you are careful. You can then turn the washer down with light cuts.
Some Depth of Cut Tips
By Roger Thomas
People are always asking me about depth of cut when turning. First of all, the machine will tell you if you are taking too large a cut – you will get severe vibration and possible tool breakage. Normally, you can take depth equal to the width of your insert or carbide tipped tool IF you have the horsepower to do it!
On indexable inserts I tell people to take at least three times the nose radius for depth of cut. You must go deep enough to engage the chipbreaker that is common on most current carbide inserts to take advantage of its chipbreaking benefits. Of course, a lot of other factors have to be considered: machine size and condition, material, grade of insert, and the most important factor – the operator! Call your local cutting tool distributor for more information; they are a great source of information.