Engraving Bits

Several people have commented on the radius arm for my ball turner and asked what the engraving bits are. I call them “D” bits as they are a half-round in cross-section. They are also called “V” bits based on the profile. You can buy them in lots of different angles and coatings. I tend to buy the cheap bits from ebay or Amazon in packs of 10. However, specialist milling tools suppliers have parts costing £10s each.

For the lines on the brass ruler I used the following parameters:

  • 60° carbide D bit
  • 1/8″ diameter bit
  • 0.25mm single cut depth
  • 2000rpm (maximum speed on the Sieg SX2.7)
  • Feedrate ~ 20mm/minute

As I say, it is best buying a box of 10 of these bits as they easily chip.

You can buy them from places like:


tool holder and radius arm

Free Hand and Ball Turning Tool

A free hand and ball turning tool designed to work on the Warco WM240B lathe. I’ve done some free hand turning before and although it was ok, I used a wood working technique and this is a bit dangerous with metal. With the need to turn the curve on the smokebox door of the Burrell traction engine I also need a ball turner.

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