Someone had posted a link to a page that showed how to grind your own 'd' bit (?)for drilling deep holes. I seem to have lost my link to that page, and can't seem to ask the right question to get what I want. playing around with a few ideas on a possible black powder rifle, any help appreciated. Thanks
I hate to be so pessimistic but if you are thinking of actually making a rifle barrel then it is a really long process.
You would need to located an oil tube which is a tube with a vee rolled into one side. Then make a single edge drill bit and solder that into the oil tube. Drill a pilot hole and then use the full length oil tube mounted drill which is stationary. You will need an oil pump to force cutting oil down the tube, which flows back out through the carrying the cuttings with it.
Once you get the hole drilled you will need to make a single edge reamer to ream the hole to size.
Once you get that finished you will need to rifle and then finish lap the bore.
In short a LOT of work.
If you are just interested in building a black powder rifle you can purchase rifled barrels with a twist suitable for either round ball or bullets from most of the larger barrel makers. Douglas, for example stocks 36 inch twist 44 and 50 cal barrels.
I have pre-drilled piece of drill rod. w/ a .250" bore, all it needs is a nice clean hole in it. As the one that is there is badly lobed. It's more about playing around w/ what I have. The P&T mills are shut down in our area, so between fire season and no place to ship wood, I need something to hide in the shop with ;) what I would really like is a pedersoli frontier carbine in .32, but $600 is a lot to spend on zero income....
You really aren't talking about "drilling" a hole then, you are talking about reaming, or enlarging, an existing hole.
Assuming that your drill rod is not hardened then you can do that with a series of single edge reamers or by making a deep hole drill and boring it to nearly finished bore diameter and then reaming. But, you still have the problem of how to get the cuttings out. The problem that all deep holes have. That is the real problem.
You might try making a single lip drill from drill rod and use a round oil tube and hope that the cuttings wash out the further end of the hole.
Generally barrel drilling is done at high rotational speeds and very fine feeds to give the finest chips possible so that they do wash out easily and the drill/reamer is fairly long for its diameter with very little clearance - to keep the hole as straight as possible.
However, if you expect this thing to shoot at all accurately you still have the problem of rifling the barrel after you get the hole to size. You can make a smooth bore but it won't be accurate at all. I once made a double barrel derringer with smooth bores and "across a card table" it shot good groups but try it at 25 yards and you were lucky to hit the paper.