Shopsmith Forums

I hate when that happens.

A long time since I've turned a bowl, but I have watched quite a few videos. So I could be wrong, but it seems to me that once the blank is balanced, turners try to keep the speed as high as possible to achieve a smoother cut.

Yep. I had it up around 2000 rpm when it decided to take a cruise of the neighborhood. What I meant by going slow was the cutting angle/depth. The trouble with bubinga is that you get a nice shearing action on the long grain and then as the end grain comes around the situation changes and you can't keep up that depth of cut even with a razor sharp chisel. So you try to keep the cutting angle high so when it hits that end grain it allows the chisel to pass through it and not dig in. But then you make one little itty bitty mistake and pow. Very unforgiving wood. It is so hard it is brittle. The end grain is like concrete with a wood grain in it. I have turned it once before so I knew I was in for a treat. It's hard to even cheat and use abrasives because it doesn't sand real well on the end grain. Beautiful wood for furniture though. The next time I decide to turn bubinga I will make it a segmented bowl which makes life a lot more pleasant.
Paul

Well the roughed out bowl had sat around enough and I decided it was time to finish it. To prevent any more grabs I finished it with various size straight and round nosed skews. Interesting that the big grab I had on this bowl was back in Sept. It bent the SS arbor so bad it was not usable. I ordered another quill assembly back then and have still not received a new one. They have been on back order for 8 months now. Wow.
Paul

Unless you are using them as a scraper, it is not a good idea to use skews on a bowl, for the same reason you shouldn't use a spindle roughing gouge on a bowl. When turning a bowl, the grain is constantly switching from face grain to end grain, and the end grain is perfect for grabbing a skew or roughing gouge. Since bowls are normally larger and heavier, a catch can do some real damage to the tool or the machine, and if it comes off the lathe, to the turner.

Skews work great, however, when used in scraping mode on a bowl.

Mike

Very nice.

Pretty!

In normal situations you are correct Mike. Unfortunately bubinga is about the hardest wood I turn. Although technically harder even ebony is easier to turn. The entire bowl was done using a set of modified screws which gave me a happy medium between shaving and scraping. Bowl gouges are too difficult to deal with when turning wood this hard. Fortunately it is a very shallow vessel so they worked. Any deeper of a bowl would probably prevent the use of them on the inside. I have been resisting carbide tools but if I ever turn anything this hard again I think I will give them a try.
Paul

Now you've piqued my curiosity. I've never turned bubinga, so I'll have to give that a try.

I know you have a lot of skill, but I wanted to give a warning to others that don't have your experience, or who happen to be turning something softer.

Your work is always beautiful and inspiring.

Mike

The trouble with bubinga is it is enticing due to the amazing color and grain but it’s like turning concrete with wood grain in it. It polishes to a metal like finish with that amazing red color. More like grinding than turning. I have only turned it once before and it was a large platter which was the same challenge. That bowl was the last of it so it will be a long while before I turn it again.
Paul