newbee question about Bubinga

[malc75]

I have been given an eight inch Bubinga bowl blank and am having difficulty turning it. It seems so hard, could this be the angle of my gouges, I only have a Clarke's cheap set which I have ground to 40 degrees, is it my lack of experience, or is Bubinga a puppy to turn? This is only my third turning.
Malc.

 

[finneyb]

Malc,

The short answer is that I have no idea - however searching on the web it maybe that silica is dulling the tool edges.

Workability: Easy to work overall, though depending upon the species Bubinga can have silica present, which can prematurely dull cutting edges. Also, on pieces with figured or interlocking grain, tearout can occur during planing or other machining operations. Gluing can occasionally be problematic due to Bubinga’s high density and natural oils. Turns and finishes well.

http://www.wood-database.com/lumber-ide ... s/bubinga/

Brian

 

[Silverbirch]

Hi Malc
You said it was only your third turning. Is it only the third time you have applied your tools to a piece of timber on the lathe, or have you done some practice on scrap?
I`m not sure what timbers you have turned previously, but if they have been softish, you would find Bubinga hard by comparison. However, it is not normally a terribly hard timber to work. It may be that your tools are not as sharp as they could be. Learning to sharpen your tools goes hand in hand with learning to turn. Also, IMO a 40 degree angle is a bit shallow for a bowl gouge especially in hard wood. 45 degrees and upward would probably be better.
My suggestion would be to put the Bubinga aside until you have had a bit more practice under your belt with an easier timber such as sycamore or beech. You would then be more able to do it justice. (Another thing you will want to start doing as a turner is to put aside nice pieces to use at a later date when a suitable project comes up).

Ian

 

[KimG]

Your tools might be a bit suspect too, they sound as though they are likely to be Carbon Steel rather than High Speed for one thing, if that is so, they will lose their edge much sooner for a given amount of work.

I don't think Clarke are known for good quality tools in the same way that Crown, Henry Taylor or Robert Sorby are, if you can, replace your tools with HSS by these makers, you are sure to find a world of difference.

 

[Robbo3]

If these are your tools, then KimG beat me to it,
- http://www.machinemart.co.uk/shop/produ ... chisel-set

If you join your local woodturning club & often a kindly member will offer you some free tuition.

 

[mattyts]

Clarke tools aren't made from HSS,they are made from general steel and will not hold an edge for more than a few seconds

 

[Paul Hannaby]

Bubinga is quite dense and harder than many other woods but with a sharp tool it can be cut well. Is your problem evident from the first cut after sharpening ? If so, you may not be sharpening the tool as well as it should be.

If the cut starts well and gradually gets worse, that is due to the edge becoming dull. Better quality tools will extend the life of the edge.

Problem three might be technique. If you aren't presenting the tool correctly, you won't get the best cut and the edge will deteriorate faster.