The hows and whys of power tools.
If you’ve decided to carve a bonsai you’ll need tools. There are two types of power tools you'll use, saws and rotary tools.
As far as saws go, I’ve tried reciprocating and chain saws. Forget the recipros, they vibrate the tree massively and are hard to control. If you don’t believe me then google HarborFreight.com. You can get one for 15 bucks, or so. When you throw it away you’ll have wasted a whole lot less money. Chain saws, on the other hand, are very useful. Buy a cheap electric one with a 12” bar. The secret for carving is controllability. In the center of the bar, about 3” from the tip, drill a ¼” hole. When you bought your electric drill it probably came with a useless handle. Bolt that handle through the ¼” hole. With one hand on the saw and the other on your new handle you have ultimate control. Naturally, you’ll use caution; make sure the handle is securely attached to the saw and your hand is securely attached to the handle. As long as you don’t let go while the saw is running, you are perfectly safe.
Useful rotary tools are Dremel tools with ⅛” collets and die grinders with ¼” collets. Dremels cost anywhere from $30 to over $100. I’ve bought knockoffs and they just don’t have the power. Dremels are great for detail work. Buy carbide bits, they last longer and are worth the cost. You can get good carving burrs (bits) from www.MicroMark.com. Just don’t try to do major carving with your Dremel. For the big jobs use a die grinder which is a Dremel on steroids. A lot of people use Makita die grinders. I am not a fan, they’re expensive, too light weight, and I’ve had bearing problems. Here’s a case of cheaper is better. Go to HarborFreight.com. Theirs are about $40, and on sale, about $30. You’ll use ¼” shank router bits. Carbide core box router bits in ¼”, ⅜”, and ½” are useful. Carving burrs with ¼” shanks in various shapes are handy; google router burr bits for sources. With rotary tools faster is not always better. Use only enough speed to make clean cuts. Your bits will clog with wood particles. Clean regular bits manually. Burrs are cleaned with a propane torch, just burn the crud away.
You don’t have to chuck bits all the way in, but, if not far enough in they may come out of the collet and become a flying object. Some bits are available with long shanks. These will give you the length you need for deep carving.
I've been doing bonsai since the late 70's. I'm passing on what I've learned in those 35+ years. These are real life techniques and tips that worked for me, but, may not for you. Remember, this is free advice and worth every cent of it.