Rotated pegs

Mark Arnold

Mark Arnold

Well-known member
I just made a slew of doors that have pegged m&t joints. I drilled 1/4" holes and used 1/4" square pegs with chamfered ends. As I drove the pegs in, almost without exception they would rotate a few degrees clockwise so they are no longer parallel to the stiles. I don't mind the result since it makes the doors look handmade, but I was wondering if anyone knows why this occurs. The doors are cherry as are the pegs. The grain runs out slightly to the right on some stiles and left on others, but the pegs rotate in the same direction. Is it a hammer issue? If I were left-handed, would they rotate counterclockwise? Any thoughts?
 
Mark,
Maybe it's the Coriolis effect? If it is consistent and you want the pegs to line up with the doors then start with the peg offset in that direction so you end up closer to square.
Mike
 
Mark,
        Is it possible the drill bit going through the wood made marks like in a gun barrel and causes the pegs to rotate?  Just a thought.
                                                                Mike A. 
 
Mark,

I think it most likely has to do with how consistent the tapers are on the pegs. If they are not perfectly balanced, they could exert pressure on the hole differently. Or, you might just want to hold on to the peg until the square part begins to engage the hole/stile because that's when the final resting place of the peg becomes established. All that said, sometimes the pegs just "want" to go askew.

Chuck Bender
 
Mark,

I don't have this problem.  But I do, as Chuck says, hold onto the peg until the square portion firmly engages into the wood.  Perhaps this is the trick to straight pegs.

Dennis Bork
 
Thanks for the replies.

Mike, I did try moving my bench to the southernmost wall of my shop to lessen the Coriolis effect, but no luck!

Chuck, the tapering was done with a chisel so it wasn't consistent. I knocked about 3/16" of the corner of the square off where it met the end of the peg (about 30 degrees, I'd guess), which created a square on the end of the peg, rotated 45 degrees from the square of the peg itself.

Michael's post did make me think of a  possible cause. I used a brad point bit to drill the holes at the drill press and because I had so many holes to drill, I went at a rather brisk pace. I noticed tearout at the two points where the bit made an uphill cut (10 o'clock and 4 o'clock), but didn't think much of it since it was in the hole and wouldn't be seen. Now I am thinking that the missing wood fibers resulted in areas that are less dense than the surrrounding wood and when the pegs were driven in, the points naturally gravitated to these softer areas. Does that sound logical?
 
Anyone know if the pegs rotate in the opposite direction in Australia?

I have noticed this happening with wire nails as well. For a lot of the things I have built for my shop, I have used wire finish nails and flattened the heads to resemble cut/wrought nails. When driving these round nails, they like to twist their way in (only noticeable because of the flattened head) so I have to use needle nose pliers to hold them while driving to keep them from twisting. I think maybe that drilling the pilot hole causes the wood fibers inside the hole, especially the end grain, to spiral around the inside of the pilot hole in the direction of the bit rotation and that this would cause an effect similar to rifling in a gun barrel, causing the nail/peg to rotate as it was driven through the hole.
 
I am thinking the drilling of the hole makes perfect sense. I must try this with a spoon bit as it can turn in either direction.
Mike
 
Mark,

I've drilled the peg holes with both a drill press and with a hole shooter and notice to difference, i.e., no rotation.  Perhaps I'm just lucky or simply live in a different time warp.

However, I also do Rev War re-enactments (as a merchant) and when setting up my tent I do notice that when I pound in the round iron tent stakes with my left hand they do rotate in a CW direction.  If I use my right hand they will sometimes rotate CCW. 

The mystery conintues.

Dennis Bork
 
Mark,
        Sometimes when I have a lot of holes to drill such as you did in the doors I will set up a jig on the drill press and use a spiral upcut  router bit as opposed to a bradpoint because of the tearout. Makes a nicer hole if your drill press shaft is not worn out and doesn't wobble any. Turn it up to 3500 rpm or so. 
                                Michael Armand
 
Mark,
Did you never hear the idiom about square pegs and round holes?
The gods are talking to you.

-Chuck
 
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