Help - Need 1"Dia rod with 3/8" center hole full length

[Thomas Canfield]

I have been asked to make a 2 piece staff, nominal 1" diameter, with candle holder on top. Both sections need to have hole for electric cord full length. Lower section is 39" long and top section is about 24" long with 4" diameter candle holder at top. I tried to drill a 1" dowl with lamp auger and got about 19" before blowing out side. Any secrets for drilling deep/long holes in slender rods? I was drilling at about 350 rpm with steady rest at end and drive end in chuck. Should I drill at faster or slower speed? go with light force on auger feed? Help.

Trying for solid wood, but other option seemed to be use a router to cut half core in two half sections and then glue and turn round.

[Steve Jenkins]

Start with a piece about 1-1/4or so square and a little longer than you need. Rip down the center then with either a router or dado blade cut a groove in both pieces. Glue it back together and turn it round. If you are careful with ripping and re-gluing the joint will be nearly invisible.

[Brice Rogers]

Steve probably gave you the best advice and the easiest to implement.

The brute force method would be to use a "gun drill". The gun drill was invented about 150 years ago to be able to drill a hole through the center of a chunk of metal to make a rifle barrel. They had the same problem that you had. If you google it, you'll see some examples. Gun drills are used for high L (length) to D (diameter) ratios of perhaps 300 or more. The cutter is shaped kind of like a letter "D". That makes it much stiffer and the body of the drill helps to keep it from wandering very much. Many gun drills also include a channel through drill bit for either pressurized air or fluids to help clear the chips. You can buy a gun drill (bit) on ebay for 10 or 15 bucks.

Drilling through wood is more difficult than drilling through metal because the grain can make the drill wander more easily.

Another approach would be to start with a significantly larger diameter shaft of wood, let the drill bit wander a bit and when done, put it on the lathe between hole centers and turn the OD to the desired size. That will make the hole roughly concentric with the "bore" of the shaft.

But Steve's approach seems easier.

[Brice Rogers]

BTW, "drill pecking" is a technique where you advance the drill bit in bursts. So, you are kind of "pecking" at the piece that is being drilled. It tends to reduce the typical wander a bit. Will it be good enough? I don't know. Google drill pecking.

[Leo Van Der Loo]

Thomas If you want to drill the hole, rather than the sawing and glueing, you can make yourself a Drill to do that.

The Gun drills you find on Ebay are almost all only a foot long , if that, longer ones are rather expensive and made to drill metal, though some will be able to drill wood.

Got 2 pictures here, one that shows some gun drills, and the other the info for making a D drill, you do need a longer piece of steel and grind/file to the shape and dimensions shown.

When using it, start with a drilled hole and then use the D bit, you will have to retract the bit often, as the swarf will quickly fill that small space on the bit, good luck if you want to go that way.

342760 342759