RR drill points

[Dan Herda]

Speaking specifically about ram rod drills,what is the best point geometry to use? Conventional ,(118,135)
Or a brad point.I have an extended twist drill with a badly ground point, and have means to put whatever point I want on it and am just wondering what is best.
Thank you for any input.

[P.W.Berkuta]

I like the brad point bits - for me it tracks true and stays on course. I back it out often, try not to force it and clean the chips out after about 1 inch of drilling depth. I can change drill bits on my long drill rod because I threaded the drill rod (female threads) and threaded my drill bits (male threads). I have 135 deg. twist drill bits that I use to clean up the hole after the brad point if necessary. Hope this helps.

[snowdragon]

I use standard points, because they are easy for me to re-sharpen on my fine wheel bench grinder. They are welded to steel rods. I use some guides that I've made and haven't had one drift off at all yet. I do about 1/2" at a time, clean out the chips, and then another 1/2". I try not to get the wood very hot, as I warped a stock once due to overheating. Takes me about 1/2 hour after set-up to drill a ramrod hole. I will do one complete ramrod hole without re sharpening, but I will re-sharpen the next time I use the drill.  Bill

[bedbugbilly]

I use either a 5/16 or 3/8 brad point drill on mine.  I had them made up years ago and they have always worked well.  I take my time, back out often to clear chips and have never had one wander on me (knock on wood   ).  On full stocks, I make up guide blocks that help guide the bit as it lays in the ramrod channel - nothing fancy but so there is something around the bit for 360 degrees. 

I've never used anything else than these two bits.  I've seen ramrod drills that are sold by some of the suppliers but have never tried them - have often wondered how well they work.

[flehto]

Before drilling my first 3/8 dia. RR hole, the question arose...what drill point would cut straight and be uneffected by hard and soft spots. Thought how an end mill cuts very cleanly and decided on a flat bottom drill point. The first hole came out perfect because the drill's  flat bottom cuts like an endmill.  The next 4 RR holes were a repeat of the first.

Some years later visited Fred Miller and looked at the drill points on his RR drills....they also were flat bottomed.

A brad point drill should also work well, but are more difficult to sharpen VS a flat bottomed drill which is very easy to sharpen....Fred

[Dphariss]

Gun drill.
Never seen a brad point or twist drill that did not cause a problem sooner or later an this is across several makers over several decades. They are to flexible and cut far too well on the SIDES.
Gun drills are call this because the are deep hole drills. Drilling gun barrels.
For rod drills I make them like this.

Try to drill more than 1/2 to 1"? It just stops cutting.  Push too hard? I don't think it matters unless the shaft of the drill is flexed out of line this might make it run out. I have made them of mild steel and not even hardened them though casehardening is best for mild steel though.
However. If its pointed top the wrong place it WILL go to that place. So I start them carefully and use them carefully.
If then go astray, once, it was because I forgot  something I had learned years previous but was out of practice in doing 1/2 stocks....
I used to really sweat rod holes and holes for through bolts in brass suppository guns is REALLY bad if to runs out. This was why I made the first gun drill. To drill the buttstock on a Peabody.

No Bill, I am not at the Laundromat this time. Airports have wifi too. Hope to be in Montana by afternoon. May kiss the ground....

Dan

[Darrin McDonal]

I totally agree with Dan. I have both types but I know my gun drill bet will not let me down as long as you start off by sending it in the right direction. I have used the gun drill, oh approx 10-1 to by brad point bit so maybe thats why I am so comfortable with it. I have had any problems with either however.
Darrin

[whetrock]

Great picture, Dan. Thanks. I have made bits for this purpose, but not made gun-drill style. Does the angle of the ground edge matter much? What angle would do you recommend?

[Brian Jordan]

Check out this link:

http://www.sterlinggundrills.com/nose_grind_contours.shtml

These are the basic grind configurations for just about any material. The N8 grind listed here  is probably the most common used in machine shops. This will work well in hardwood. I made one of these drills in 3/8" a few years ago. I never have used it yet. I will be making one in 5/16" for my current (and first build) that I am working on.

The important parts of a gun drill doing it's job properly is to get the D/4 dimension (refer to drawing) correct. This is simply the 30° cutting edge is one forth the width of the diameter. And the proper relief angles are equally as important.

[Dphariss]

Great picture, Dan. Thanks. I have made bits for this purpose, but not made gun-drill style. Does the angle of the ground edge matter much? What angle would do you recommend?

I mill the slot then grind the point to something that looks like it will work. About like the photo shows. I think pointer would be better than flat since it would be easier to start. But suspect that a flat end will 
I also tend to burnish a slight burr down the leading side of the groove so it cuts very slightly larger than the shaft. This makes the rod a slightly looser fit in the hole and reduces the heat generated.

Dan