View Full Version : D bits out of drill rod
12-05-2003, 12:16 PM
Anybody have some good tips on making D bits out of drill rod? (No pun intended) What I do, is take my drill rod, grind halfway through the rod about 1" down using the side of my grinder. Then I grind the tip at an angle across the top and bevel off the back. I then harden and temper the steel. But with all my efforts, I still don't think it cuts as cleanly as a common twist drill bit or a gun-drill. Although, it doesn't wonder like the twist drill bit. I'm wide open for suggestions on how to make a better D bit.
12-05-2003, 12:52 PM
Jake , it sounds like you are on the right track. I made mine very similar. You might try making the front a bit more "gundrillish" :confused:
grind around an inch back from the tip removing a quarter of the dia, like a quarter of a pie looking down the drill. Then grind the front with a bit of an angle to present a wider cutting edge. Then grind the rest of the rod with a flat in line with the cutting edge. I use this on long bores without too much drama.
:D I just read that lot back and I am confused :D Give me a buzz on 0044 7703 176222
and I will try to describe it better.
Wulls. PS remember the time difference!!! :thumb:
12-09-2003, 09:27 AM
Have you ever made a gundrill?
12-09-2003, 01:00 PM
Try an Arkansas stone, lightly across the "flat", you may have a bit of "burr" on the side. A little bees-wax and mineral oil every couple of inches worth of bore help too. I have been using Davey Stephenson's method, very simple, very quick (to make), and have had excellent results. Here is a link to his instructions.
boring long holes (http://www.bagpipeworks.com/drills.htm)
12-09-2003, 07:00 PM
Originally posted by Ceannt:
I have been using Davey Stephenson's method, very simple, very quick (to make), and have had excellent results. Here is a link to his instructions.
boring long holes (http://www.bagpipeworks.com/drills.htm) That looks interesting. How long would it take to bore a 3/16" hole down the length of a chanter stock with that type of tool. My guess is that it would take longer than a gundrill.
12-10-2003, 01:07 AM
Originally posted by Jake M.:
Have you ever made a gundrill? Yes, they are not that difficult as long as you are not doing hard or abrasive materials. The problem here is old skills are dying out as material technology gets better. I can buy off the shelf a twist drill in TCN coated material which will last for ever on delrin and AB and produce straight holes. Using a gun drill from behind the tailstock was the way all pipemakers used to drill drones, now -a-days I have seen this less and less.
12-10-2003, 05:25 AM
Happy, your assumption is correct, it is SLOW . It takes less time if you cut slow, less time spent allowing the bit to cool off! With larger diameter bores, the time is exponential because you have to drill a small pilot hole, and then enlarge a couple of times to get your final diameter (run-out is a function of diameter). It's a lot of fun though, and kind of cool to use such an old technology. Besides, when I looked into modern gun-drills, (thinking I could jury rig an old shop-vac for the air) I clutched my chest and collapsed when I read the quote! I purchased enough drill rod for every bore I would ever need for a quarter of one gun-drill.
12-16-2003, 09:52 AM
The point of D drills is to bore slow and concentric. I cut ~1" and pull out, blow off the little half log of chips, dip the bit in raw linseed oil and cut again. Patience gives you a nice straight bore and the linseed oil polishes it beautifully.