A woodturning student today brought with him some turning tools. He has just bought a second hand lathe and they were included in the deal. They were unbranded, and extremely blunt. We did some sharpening and immediately realised that they were carbon steel.
Carbon steel turning tools nowadays are almost entirely confined to cheap sets sold to beginners. This is not to say they are no use, I still have a number of carbon steel tools that I bought in my early turning days, and more that I have made since. They all work, though I tend to keep most for light duty only. We finished the sharpening and decided to give them a try in the lesson.
We put a piece of softwood in the lathe and started work with the roughing gouge. After a short time Marc seemed to be struggling a bit. The gouge was bouncing and leaving a poor surface. After more grinding, the same thing happened again. On inspection, I found that the edge was not just blunt, it was bent back, forming a heavy burr. This damage was done by a small knot in the wood. A quick re-grind at a more obtuse bevel angle helped, but it was clear that these tools were not going to be a lot of use. We changed back to my own high speed steel gouges and soon made better progress. I am pleased with how quickly Marc has learned to roll beads with the gouge.
Although they did not appear discoloured, it is possible that the tools had been overheated by their previous owner. If so, it should be possible to grind back to sound metal and give these tools a new lease of life.