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View Full Version : Boring Holes with a brace -- poor results



Denis Tranchemontagne
03-23-2009, 2:00 PM
I am building a bench, and have been doing it with the tools I have available. A combination of hand and powered.

For drilling out the mortices on the legs I use a brace, and the holes weren't perpendicular. So I am guessing bad form. So I tried to be more careful when drilling the holes for drawboring, they may have been better not positive. However I had another noticeable problem, the top of the holes where not perfect circles. I don't think this is going to affect the performance of the pegs but they look a bit sloppy. I used spiral bits for both of these tasks.

Is there some trick/technique that I am missing or is it just a matter of practice.

Denis

David Keller NC
03-23-2009, 2:04 PM
Mostly a matter of practice. Assuming you were using Jennings-pattern spiral auger bits, not holding the bit perpendicular to the surface will result in an oval hole. It can also happen if the bit has been dropped and one of the spurs has been bent out - you can easily check this with a caliper, or just eye-sight.

One tip to learning to bore with a brace and bit - set a square on your work (two are better - set perpendicular to each other to give you a two-axis reference), and use it as a reference for 90 degrees. Hold the top of the brace with your left hand, and put your chin on top of it - it will help to hold the top of the brace in-line as you use your right hand to swing the brace handle around in a circle.

Richard Magbanua
03-23-2009, 2:11 PM
Did you sharpen your bits? I used a brace a bit for my bench and I did learn a few things. It really was easier than I thought. I found a better brace to use and it was noticeably easier than the rusty one I used first. I also learned to sharpen my bits I got on Ebay with a fine file. I couldn't find any step by step instructions but I pieced together a few I found. I guess sharpening is pretty straightforward. To drill better holes I just took it slow and checked my angle often. I think it was better to not push down so hard if at all since the tip of the bit does that for you.
As far as the big mortises, it was a PITA. I had much better luck hogging out the waste with the brace an bit and then using my router with a straight bit and edge guide to clean it out. You get to a point where you really need to get the darn thing done.
I did drill the holes for the dogs with the B&B but had to take the router to a few because the bench dog wouldn't pass all the way through.

Good Luck!

Here are some pics if you're interested:
http://www.flickr.com/photos/magbanua/sets/72157610497536990/

Bruce Page
03-23-2009, 2:38 PM
I guess you've learned this the hard way, but twist drills, if fed too fast can give you a triangular shaped hole.

Wilbur Pan
03-23-2009, 3:30 PM
Do you have a drill press? One way to deal with this is to take a scrap piece of wood 2-3" thick or so to your drill press and use the drill press to put a hole the size you want through the scrap. Then take the scrap to your workpiece, clamp it to the workpiece so that the hole goes over the spot where you want to drill, and use it as a guide to keep your brace straight.