Blank Drilling Problem Revisited

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imagine

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Hi folks,
After reading about problems drilling a centered hole I got to thinking about a problem I run into sometimes. While drilling some woods with a 7mm bit, particularly BOW, the bit will flex a bit upon entering the blank and continue to wander so the the bit comes out off center on the other end. I have been correcting for this by starting the hole and then loosening the vice a bit to allow it to center itself and then continue drilling. Any way to prevent the wander?
 
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One thing I have done at times is to use a center drill first. These are short little bits used to start holes when drill metal. Sometimes called a combined drill and counter sink. A #3 size is 1/4" diameter.
 
I have had this lately too. I took my brad point bit and ground off the tip and drill doctored it to a standard shape. It seems to help quite a bit. I was going to post when this happened and ask if there is a more rigid bit out there for this smaller size.
 
I will sometimes use a bulelt point bit or lately I have been taking a scratch all and using it as a centre punch (by hand) to put a starting point. Has worked a lot better and I don't use the bullet point nearly as much.

Edit: I should say that in order to do this I first have to find the centre of the blank. I don't have my vise clamped to my drill press becasue I use my drill press more regulary for other things than drilling blanks.
 
I usually lower the bit down to the blank and just lightly touch the blank with the tip of the bit and just let it slowly make a starter hole and go very slow until I am about a 1/2" in. Hope this makes sense.
Andy
 
I use the over size bullet tip 7MM bit from Woodturningz and drilled thousands of blanks with it and wonders very little. I never worry about trying to drill the very center of the blank.
 
Yes, a pilot hole whether drilled or made with a punch, awl, or nail is the proper way of preparing to drill. A spinning bit is just like a top and will follow irregularities in the surface till it finds some place to sit. A pilot hole gives it a place to sit. When drilling wood, a bit can walk along the grain lines which are harder till it finds a soft spot to bite into. Also, be very sure your bit isn't bent. A bent bit will drift off center while drilling. Easiest way to check is to roll it on a piece of glass. You'll know if it is bent! Also, be sure that your DP table is square to your chuck. A quick and easy way to check this is to take a coat hanger, cut and rebend till you have a piece that will reach near the edges of the perimeter of the table after it has been tightened up in the chuck. Spin the chuck by hand and watch the 4 sides for variance in clearance. Adjust table appropriately so that there is an even clearance all around. Too many times drilling off center is blamed on things other than an unsquare table..

Other things to remember: a bit will get the blame when too much pressure is used. Even with wood, to much pressure can cause a bit to seek the path of least resistance and wander.

Rule of thumb, small bits, small pressure.

Dull bits will wander.

When problems persist, try a new bit.
 
Greg offers the best advice above. First be SURE the DP table is square in all directions. Second, don't force it, let the bit do the work. And by all means keep the bit and all cutting tools sharp. If you can't sharpen it, a new bit is in order.
 
I find drilling the hole the hardest part of making the pen. I tried the center drill and still will drift. I find the best practice is go slow little bits at a time
 
I use brad points as much as possible. My practice is a slow speed on the drill press, put the point of the bit into the center of the wood and apply a little pressure, then turn on power. Your bit "flexing" is a sign you are doing something wrong. I would suggest, that if you aren't using brad points, you start the drill press and bring the bit down slowly to the wood, let it find it's own starting point, then bring down into the wood. Is the bit properly sharpened? That could be a big factor.
 
My solution for economy,accuracy and speed is to only use DeWalt extreme 2 7mm drills sometime called bullet point,pilot point.No wander,no splitting,great for burl and Corian,care near the end and no breakout.Peter
 
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