Dang those are expensive. I bet they work good though!
Yes, they cost more than other bits. However, you can drill a long click with one (or any other long bodied blank) and they cut very fast and clean out well. I have individual bits, not the set, as I'm buying mine as I need them. That allows me to spread the cost out, and I keep them in the plastic tubes that they came in, so that they don't get dinged up.
Now, let's look at a couple of scenarios about the cost of these bits. Let's say that you've decided to make the one-piece slimline
http://content.penturners.org/articles/2009/one_piece_slimline_pen.pdf, and it's going to be the slimline that you sell, and that you're going to charge $20.00 for it. It takes a 7mm bit and those cost $10.00.
Scenario 1: You buy the bit for $10.00. Then you make one pen and sell it for $20.00 and basically burn the profit from that pen (and some of your labor cost) to pay for the bit. Then after that, the bit is paid for, and you don't think about the cost of the bit anymore.
Scenario 2: You prorate the cost over the life of the bit. You buy this bit for $10.00, and then you make 100 pens with it before you get it too hot, or drop it, or lose it or it gets borrowed or whatever. That equates to 10 cents per pen for bit cost. Now the bit doesn't seem to cost so much, does it? Now let's say that you allow double that cost for the bit (20 cents). After the 100 pens, you've paid for your original bit AND you've set aside the money to buy a replacement bit. It works for me :biggrin:.