Making holes in wood

While waiting for Hurricane Charley's windy demo, I found an old 'palimpsest' of my notes re making holes in wood. (the real reason for this post is to use that sporty word ) Anyway, I thought to offer some thoughts on making holes for beginners to consider and for others to disagree with or offer a better way.

  1. Drilling requires more power than boring with a 'turning cut'
  2. Spinning the wood against a fixed bit produces a truer hole than spinning the bit. I don't know why, maybe the set-up is stiffer.
  3. Consider making true long holes with other than twist drills and Forstner bits.
  4. D-bits and gun drills will enter and straighten a hole that began true then wandered with the grain. If you don't force.
  5. Consider making long holes from both ends. They will meet if both are started with a center bit in the same punches the spur & center used in roughing out.
  6. Usually replaced turnings between centers run truer than those replaced in a chuck.
  7. For making short holes in metal or very hard open grain woods, use an end mill. Ex: drilling angled holes for inserted bits.
  8. The accuracy and precision of reaming and lapping are rarely necessary for holes in wood. Good for us to know about, but reamers cut along their length and have no drilling point.
  9. Drill bits are turning tools that are usually neglected compared to the grinding, sharpening and using of gouges and chisels.
  10. Long bits will spring off center. Work out the spring by repeatedly running through with the same size bit. Consider drilling with a series of undersized bits and cleaning up with a final D bit.

  1. Wow! I better stop here and resume later. Wind is really picking up. Sorry no time to review this mess. To be continued..... Arch

Fortiter,

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Arch
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Related to both of these points is the core drill. I used core drill extensively in an earlier life as a machinist to straighten and enlarge holes. As with a reamer they cut along their length. I used them primarily to enlarge holes to their final size.

Reply to
Kevin

Use a center drill to start the hole. It is extremely rigid and, except under extreme provocation, will not flex over the length of the fluted portion. Use one large enough to make a hole larger than the web of the next drill to follow. If needed, walk through a progression of drill sizes (keeping the web size in mind) to get to the final size. Drive each drill bit except the final one only about 3x the diameter deep. If you start a hole true and follow the progression, you have a much greater chance of the drilled hole running true.

Consider the final use of the drilled hole. Carefully. Many holes do not need to run particularly true. Fer instance, if you are drilling a hole to take a threaded insert, it can be just about any shape and (within reason) headed off in any angle. After all, the threaded insert will correct the hole when it is threaded in. If you are running lamp pipe just 6-8", just do your ordinary best and it will come 'close enough'. If you are making a wooden pattern for a machine tool to trace over, you'll need to do a whole lot better ... but then you'd already know the steps you need to take to assure the needed precision.

If you have to drill a deep hole, consider setting up in the drill press. That way gravity won't be working against you, pulling the bit down sideways. I have an 18" x 1/8" bit and yes, gravity sucks.

Bill

Reply to
Anonymous

Forgive my ignorance.

What's a D-bit?

Gord>While waiting for Hurricane Charley's windy demo, I found an old

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Gordon Clarke

mike

Reply to
mike

I escaped Charley so I'm trudging on:

Thanks Kevin and Mike for the upgrades. I hope for more.

Gordon, I hope someone, perhaps our resident D bit person Leif, will pitch in with further info for you. He will suggest lubricating the bit with LDD, which may not be a bad idea. Anyway, to add a few more iffy tips that some woodturning beginners may not know...... or not want to know:

  1. To provide rigidity. the web of some twist drills thickens along the shaft's axis. Sharpening with an automatic drill sharpener or a fixed jig can lead to a thicker chisel edge as the bit shortens. This may reduce the cutting edge and increase the rubbing surface.
  2. Oversize holes may be caused by forcing the bit, or the drill's tip being off center. Beginning without a pilot hole or shallow and smaller than the web may not allow the bit to follow and might drill an oversized hole.
  3. Warning! Some new cheap twist drills are neither accurate nor precise. Some have dull edges with unequal edge lengths and eccentric points. Often the edges are too backed off for drilling wood. Shaft diameters vary and some aren't even straight. Woodturners can often get by, but examine them before buying used or bargain twist drills.
  4. Failing to withdraw the bit often in order to clear the chips might cause them to pile up to one side. This can wedge the bit eccentrically and force it to cut oversize or to seize up in the hole.
  5. When withdrawing a bit held in a tapered Jacobs chuck, hold on to the chuck, not the tailstock. A drill & chuck that has just exited the tail spindle and is flying around is a fearsome thing,

Feel free to rub off these jottings from my 'palimpsest', :) Arch

Fortiter,

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Arch

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