I've been playing around using forstner bits on a drill press to face rod stock and delrin with little success so far. I've not used a forstner before so I guess I don't fully understand how they cut. Maybe it's the speed or the placement of the stock with respect to the cutting blade? In the picture below, I assume the only relevant cutting blade for facing is as shown. So, do I make sure that that blade is at least as wide as the rod stock and center the blade over the piece to be faced. Should I get forstners closer to the diameter of the stock I'm facing z(i.e. close to the ebonite diameter and a very small one for delrin).? 'I've seen videos where it looks like they put the forstner exactly in the middle of the rod stock but that definitely isn't working for me and I don't like what the center point does to the part (its too big). What is the proper placement of the bit over the part to be faced? I did grind off the center point after a few failed attempts. Did I ruin the bits ability to cut properly?
Also, I've tried speeds from about 600 RPM and up to about 1200 rpm on both ebonite and delrin and I'm still not satisfied with the quality of the surface. I want it to be smooth and somewhat shiny. I'll play with other speeds tomorrow but any recommendations would be greatly appreciated.
You may have to sand on a flat surface after the cut to achieve a smoother surface depending on your cutter. The problem with vulcanite is that it will dull your blade almost immediately. If you can sharpen your bit easily, you may be able to achieve a smooth cut.
You need to slow way down....like 300 rpm to drill and face. It seems slow, but you will get better results on the ebonite and on briar that way. Very small cuts work best and clear your chips often. Make sure whatever vise setup you are using is quite substantial in size and very stable.
As far as the bit size, I used a 1.5" almost exclusively. Instead of buying a set of different sizes I went to Woodcraft and bought 3 of the same size and used them just for facing. That way I knew I could face anything that I needed to. It also makes achieving a flat (which you can then modify), and perpendicular to the chamber, rim pretty easy on the drillpress.
You might also check your forstner bit....mine all have a top rpm of 800 stamped on the side. Momma doesn't want any of her boys getting hurt.
Am I Calamity Jane or Annie Oakley??...depends on the day. www.ladybriar.com
I've practically given up trying to get good results with Forstner bits. They do okay when they are brand new if they are high quality precision Forstner but, like Premal said, they dull very quickly and sharpening them and maintaining a precise, flat cutting edge is very difficult in my experience. You'll be a lot happier once you graduate to a lathe and pin gauges or a metal lathe.
wdteipen wrote: You'll be a lot happier once you graduate to a lathe and pin gauges or a metal lathe.
I know I will and I plan on getting a lathe someday. I just haven't made enough pipes to justify it. I want to make sure I'm going to stick with pipe making before I invest in a lathe. So, I'm stuck with the drill press for at least another year or so as I'm just making pipes in my spare time.
I bolted my drill press to the basement floor today and that did help. It is a substantial press I got at a good price from a gunsmith but it is what it is. I now know fully what George was saying about a drill press that is rock solid/steady. Even with the press bolted down, there is flex in the column/pole and some vibration. It will work for now and I'll adapt. But, it's obvious that a serious pipe maker needs a lathe.
I made the same mistake of cutting the spur off when I was new.you will need a new bit. I use a 1" forsnter. Sharpen with a diamond hone, just a few strokes per facing and go slow. The cutting edge should be planing off an almost transparent brown ribbon of ebonite. The hole created by the spur will be the pilot for airway.
I still use forstner bits in my lathe to do some facing.
Invest in a metal lathe as soon as possible. Although great for pipe making they are tools that can be used for so many other things as well. I've fabricated many parts for golf carts, my motorcycle and also even parts for other machines using my 9x20 metal lathe.
