I understand that angle grinders are considered (really) bad for cutting wood.
Would a variable speed angle grinder be any better?
A 10,000+ RPM machine will obviously get caught and go out of control if the line of cutting changes even a bit. Will a machine going at 3-4000 RPM be easier to manage if something goes wrong?
The golden rule in Woodworking is, know where your fingers are before you start to cut, so you don't have to start looking for them afterwards.
That goes double when using the wrong tool. Put the grinder down, walk away, and buy the correct tool for the cutting you propose to do. Even the cheapest saw at Harbor Freight would be a more appropriate solution.
Youtube poster "Stumpty Nubs" had a serious accident using an angle grinder with a saw blade. The blade grabbed and the spinning grinder was instantly yanked from his grip and rotated into one of his hands. He describes this incident in online videos.
Woodworking instruments (including disks that can be mounted on an angle grinder) generally have teeth that in some circumstances can "grab" a piece of wood and fail to cut it trough. Wood has variable and anisotropic properties (and in some cases it also contains long-forgotten nails) that promote such events.
In this case, the instrument with its motor and mainly with its inertia exerts a great deal of force and torque on its support.
When the support is steel or cast iron bolted to a heavy table or to the floor - good. The worst that could happen is that the instrument breaks or some wood piece could fly at considerable speed across the workshop.
When the support is the carpenter's hands, the instrument itself gets wild.
Lower RPM does not in itself make things safer.
At lower RPM the instrument is more likely to fail to cut some harder part and kick back, at the same time the kickback is not much safer.
What can be considered safe, then?
The only thing I personally do with an angle grinder on wood is to cut something small and well-fixed using a disk for metalwork. It has no teeth so it can't easily "grab" something and it also makes the whole process quite inefficient. The disk actually burns its way in the wood.
Will a machine going at 3-4000 RPM be easier to manage if something goes wrong?
The actual question implies that the act of managing an adverse action may become an easier task. That should tell you the the choice of machine probably was not made wisely.
This begs the question of why? Why is the grinder the tool of choice?
What needs to be accomplished?
What other tools may be a better choice to complete the task.
To answer your question:
Yes, it may be technically easier to handle at a lower RPM, in the event of something going "wrong".
That meaning the bodily injury and accompanying damage to equipment, materials, furnishings, etc. may be to a lesser degree than that experienced if the tool was used at higher RPMs.
** My question to you:**
Is lessening the damage to your body and collateral materials the goal here?
OR
Is it cutting some wood?
If it is the latter, please tell us what you are trying to accomplish.
Angle griders with abrasive blades are fine for cutting wood so long as everything is well secured, and you're not in a hurry.
If you start using cutters in them that can bite into the wood then you're into widowmaker territory.
3000 RPM makes no difference so long as the blade edge is moving faster than you can it's the torque that will get you into trouble, a 3000 RPM angle grinder will probably have more torque and get you into bigger trouble.
