Thread: Drilling straight dog holes... how??

It's sort of a chicken or the egg problem, of course. First, you need a hole already square to a surface, to hold a large/stout rod (approx. maximum chuck capacity), to clamp in the chuck. Attach the bubble level with hot-melt or such. Drill some test holes, insert the rod, check for square both ways. Persuade it to plumb by fine-tuning adjustment hammer. And repeat as necessary.

Use the drill's handle to apply pressure, instead of hammering its butt.

Cheers,
Joe

Could you attach or clamp a long bit (in the chuck) to a spirit level, line up the bubble level on the back of the drill, and glue in place? May have to rotate bit to check level in all directions.

Tex

Thanks Joe, makes more sense now. And I'll try not to use the drill butt as a hammer...

I used the plunge router method. But if you think about it, there isn't any requirement for the holes to be perfectly perpendicular unless you are intending to use two dogs against the same flat surface of the workpiece you are clamping. If using one dog only against any one surface of the workpiece, the dog can be approximately 90 degrees and work fine.

Here is a link to level heaven

It's pretty clear people have given this some thought!

I do plan to use more than one dog hole in unison to clamp table tops etc.. so i do need some accuracy i think.

I also need to attach an end vice to the bench. I'm going to use the "construction" type where you add your own wooden jaws front and back. To attach the rear jaw i'll be drilling into the end of my bench, and also drilling up from the bottom to intersect, and use bolts with those "sideways" nuts... i know thats not the right name for them but cant think of the correct term. When I do this I'm definitely going to need to be accurate.

And the one thing building my bench taught me is that i'm NOT great at eye-balling things. I had to chisel out the counter-sunk holes I drilled for the nuts to fit on the thread rods. As I had to drill the counter-sink and then drill through from the other side of the leg... they weren't coming through on centre... rather a annoying.

So with that lesson learnt, and the prospect of future accuracy required, I dont think eye-balling will be the go.... so i might just bit the bullet and buy the contraption.

I'm sure in years to come it will get used again and I'll be glad I have a simple solution. And I do have a designated "tool fund" that can cope with the purchase.

I think i'll also get some of those levels for my drill as well for free-hand work. They look like they'd be very handy.

Thank you all for advice and thank you to Peter and Richard for your offers of equipment.

Tom

Originally Posted by Tex B

Could you attach or clamp a long bit (in the chuck) to a spirit level, line up the bubble level on the back of the drill, and glue in place? May have to rotate bit to check level in all directions.

Tex

YES!!!! A lot better than trial and error (and error, and error, and ...).

Cheers,
Joe

Like that little magnetic level I bought "cos it'll be useful one day"....

For a similar purpose (dog holes for a timber rack), I got one of the jigs like Richard has in post #14. There are lots of different cheap variants around, mine was around the $30 dollar mark and it was money very well spent. They are exceedingly handy for drilling a uniform hole in something you can't get onto your drill press (if you have a press that is). If you don't have a drill press then they are required buying IMHO.

In your situation I'd use one of these style of jigs, and a decent spade bit as suggested by other posters.


Cheers,


Justin.

When I drilled my dog holes, I used an auger bit rather than a spade bit or Forstner. Auger bit works so much better than a spade bit and so much quicker.

I'm not so sure that you need to be overly worried about vertical accuracy. I initially used my drill press to drill a 19mm hole into a block of hardwood about 75mm thick so I could clamp the block to the bench top and use it as a guide where I wanted to drill the dog hole. That kept it nice & vertical but then after a few holes, I just eyeballed one hole and found that I was able to drill a perfectly acceptable vertical hole without any guide at all. My bench dogs work very well despite no guide.