I use either mild steel or stainless steel for the round bars, and mild steel for the square (they're so fat stainless isn't needed). Mild steel is just cheaper than stainless, and it works fine unless you're hanging the tool way out over the rest.
I can sell these just as bare shafts at reduced cost, or as complete handled tools, your choice. Handles will be made from laminated hard-maple unless otherwise requested. I can also make the shaft as long or as short as you like.
I recommend 6" to 8" for the 3/8" round and square bars (beyond the handle, you will have apprx. 3" in the handle itself), and about 10" to 12" for the 1/2" square, though you can go shorter if you like.
I also make another "general purpose tool" that uses a 5/8" round steel shaft with a 1/4"x1/4" HSS cutting bit in the end. These come with a sharpening block to hold the insert while sharpening, and I normally grind a radius on one end of the insert and a flat on the other.
This is the best general purpose tool I have ever used, period. And I've used a LOT of different tools. It will do just about anything you ask as long as you have a sharp insert ground to the proper shape. I use it for hollowing, roughing, bowl and faceplate work, spindles, fine finish cuts. Pretty much anything that one could use a general purpose tool on.
The inserts are very inexpensive at around $3 each, so you can keep several on hand and grind them to specialty shapes whenever the need may arise. And they last a long, long time. I've been using the same 3" insert for my round and square profiles since I made the tool over a year ago, and even though I use it all the time, it's still about 2.5" long.
If you are turning pipes and stems on a wood lathe, or turning any kind of acrylic, and you haven't tried either carbide tools or a HSS cutting bit tool like I'm making, you're missing out! And I'm not just saying that because I'm selling these tools. Whether it's my tool or a commercial model, you should really try one out.
The square carbide inserts make it super easy to get a straight tenon with a square shoulder on your stems. And the carbide inserts stay sharp for a long, long time while cutting acrylic. And the radiused square inserts work very well for shaping stems. If you need a bit more "curve, the 3/8" round will cover it. And if you're roughing in stummels, one of the carbide tools or my general purpose tool will make quick work of it, and leave a sweet finish behind.
And unlike a gouge or skew, there is very little learning curve. Just hold the tool flat (or nearly so) and let it do all the work. It's pretty simple!
I will make and attach a PDF price list in the hear future giving all the prices and options for these. But just for a general idea, my prices will start at about $20 for a basic mild steel 3/8" round bar with insert and go up to about $60 for a handled stainless steel tool with 3 inserts.
I will also have custom order handle options available using some specialty laminated blanks made from various domestic and exotic hardwoods.
Below is a picture of one of my 3/8" stainless steel round bar tools with a custom laminated handle and quick-change ferrule. The handle is still in the finishing process (needs to be sanded again and have the final finish applied), but you get the idea of what I'm making. (there is no insert in the bar)
