How to accurately drill into end grain of a 20 inch table leg

Question

I have a table leg that was connected to the table top with mortise and tenon and tenon broke off. As part of the repair I'd like to put in a dowel through leg and table top and wood glue the whole thing. Leg is maybe 2 inch in diameter.

My question is how can I make I make my dowel hole centered and perfectly straight. I don't have a drill press tall enough to accommodate a leg this long.

Another idea is to use Drillmate like this https://www.leevalley.com/en-ca/shop/tools/jigs-guides-and-fixtures/73237-drill-guide?item=46J8370 but I am unsure on how to secure the table leg to a vice that would house the drillmate on top of the vice?

Am I overthinking this and should drill it by hand?

Thanks!

Answer 1

I'm going to suggest two very different methodologies, both of which won't require the purchase of any new bits or any awkward changes to the setup of your drill press (although the first suggestion does make use of the press).

Make a drill guide, use that
Essentially follow the technique from this Answer to an old Question here, How do I drill a hole exactly in the center of a circle?

Note you don't need a 2" Forstner/other bit to use this method.

Although it would be great if you had a suitable 2" bit of some kind you can instead drill the bottom of the block for a few guide rods that will slip over the outside of the leg, or, chisel a shallow square mortise that the leg is a reasonably tight fit into.

Going with either of these if you happen to end up with a sloppy fit to the end of the leg don't worry, there's no need to scrap it and make a new one. As surprising as it sounds simply packing out the end of the leg with paper towels and then forcing it into the jig will still result in good alignment..... and the hold is much firmer than you might guess¹.

Drill by hand, with the aid of a helper
As you probably know it's quite easy to gauge tilt to left/right when drilling, especially with a long straight piece of wood to guide your eye, but much less easy to know if you're leaning a little forward or backward.

So have your Temporary Workshop Assistant™ stand 90° to you and tell you when your drill is aligned left/right to them (your forward/backward). This can be more accurate than it sounds² and presumably you only need to drill a fairly shallow hole here (I'm visualising a 3/4"-1" hole ~1" deep).

Note on the other stage of the operation
As I mention in a Comment above, if this leg is not mounted vertically the drilling of the corresponding hole in the tabletop might actually turn out to be the more challenging part of this!

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¹ I regularly use this method during restorations of swing braces to hold the heads on an undersized dowel/round piece of wood (in my case an old chair stringer or a small branch) for much of the sanding and all of the refinishing work.

² This was actually a standard workshop technique back in the day so was widely used in production workshops.

Answer 2

I'd find the center and make a good accurate divot (~1/2" deep or so). Then find a long drill bit -- at least 12". Clamp 3 or 4 narrow strips of wood to the leg so they come up 6-9" above the top of the leg where you want to drill. You'll be able to hit the divot and visually keep yourself in the middle of the sticks. If this isn't clear, respond and I'll either sketch or snap a pic of what I mean.

Answer 3

See if you can unbolt the drill press body from the base and turn it so that the drill faces over your workbench unimpeded by its base. Then measure the accurate center, make a small hole with a thin nail, and use a brad point bit (so it doesn't skip around on the end grain surface) to drive into the nail hole. Make sure to secure your drill press carefully so it doesn't tip over. See if you can have a friend help.