Setting the speed of the burr while power carving is something that you will develop as your personal work flow develops. Speed control is different for everyone. I can offer some thoughts and general guidelines, but as your personal carving style develops over time your use of speed control will probably change. – Mine has.
Also, an underlying factor in understanding speed control is developing good tool control.
TOOL CONTROL comes with time and practice. There is no shortcut here. Tool control will allow you to take advantage of speed control, and knowing at what speed you want to run your tool.
When it comes to speed control there are several things you need to consider while you are power carving. These are:
- Are you doing a roughing operation?
- Are you doing a refining operation?
- What burr are you using, and how aggressive a cut does it make?
For most of my roughing operations I am using an aggressive carbide such as a Saburr-Tooth burr. I am removing the bulk of the wood that I don’t want on my carving. This type of operation I typically run my Mastercarver Pro Flex Shaft machine at full speed.
I am not being aggressive with the cut, but letting the tool do the work. The wood comes off very fast at this stage.
The faster the speed of the burr the more control I have, and the less the burr wants to grab the wood.
During the refining steps of my carvings I find that I use the widest range of speeds. That really depends on the type of burr I am using, how aggressive the cutting action of the burr is, and the size of the burr itself.
Tool control is extremely important here. A general guideline is: The faster the burr is spinning the smoother the cut it will make. However, the faster the burr is spinning the easier it is to run off course. Again, tool control during this step is extremely important.
Some refining operations are completed with my Mastercarver Pro flex-shaft machine while others are completed with my Mastercarver Micro Pro Champion. This depends on the level of refinement I am working at. As the detail increases I move to working exclusively with the Micro Pro Champion.
What burr are you using, and how aggressive a cut does it make?
The more aggressive the burr is, the more it will want to grab the wood and run off course at low speeds.
The finer the burr is (diamond, ruby, stone) the easier the burr will run off course at high speeds.
This really has to do with friction.
But, at the same time neither of these statements are true. It all depends on the type of cut you are making, and how much tool control you are exercising.
That is why I say that these are just general guidelines, and as your skill, tool control, and work flow develop you will find the right answer for you.
Of note is when I am using my high-speed engraver for power relief carving, or other power carvings I keep the air pressure set to a constant 40 psi. I never vary the speed of this tool, and do ALL of my work at this speed I rely on tool control exclusively for completing my work with this tool.
So, to really answer your question I will say that working with the speed of the tool, and figuring out at what speed you can complete what operation will help you develop as a power carver.
But, ultimately the speed you decide on may be slightly different that the speed I decide on. However, following the general guidelines I have outlined will give you are head start on figuring out your own personal work flow, and developing your tool control.
Let me know your thoughts. Does this help? Please post your comments below.