Any ideas on drilling straight holes via some sort of jig i can clamp to the top of the work bench to keep the holes plumb. I had thought of a plunge router but the issue becomes a bit that will bore a 3/4″ hole thru 1 3/4″ hand maple without burning up.I have tried with a hand held drill and forstner bit but can’t stay lined up and the top will not fit under the drill press for all the holes. Should i be looking at some other sort of drill bit set-up to get a good clean straight/plumb hole? Your thoughts will be greatly appreciated.
Replies
If you're worried enough, you can get an attachment for your power hand drill, that makes it a bit like a mini drill press. It holds the drill and bit at a pre-set angle (vertical in this case), while you push the bit through the benchtop.
But I did my dog holes by hand holding the drill. I've never cared if they were perfectly vertical -- they have never been a problem.
This is available from Woodcraft and others
View Image
http://www.woodcraft.com/product.aspx?ProductID=146143&FamilyID=3121
Get a fresh 3/4 forstner and go to town.
One option is to drill a smaller hole (1/2) all the way through. Then using a guide bushing and a jig clean out to 3/4" with a router bit as deep as you can. Then flip the top and use a bit with a bearing on top (using the cleaned out part of the hole as a guide) to open up the rest. You could also do the router approach and the use the 1" deep hole (router cut) as a guide for a drill to go the rest of the way.
That said I've been ok with a brace and bit going by hand. As soon as the screw penetrates go from the other side. For this option a 12" throw (if that's the right word) on the brace is helpful.
Edited 5/11/2009 5:25 pm ET by Joel7
You don't want the holes perfectly plumb - they should be angled slightly towards the tail vise, about 2 or 3 degrees. Router should work if you slow it down and clear the chips regularly.
You are correct, the hole should be out of square (plumb) with the top 2 or 3 degrees towards the vice. I have always done this with a forstner or multi spur bit in a block of hardwood that is clamped to the bench. I imagine a router would work if you made a base that is not parallel across the diameter.Some what like a wedge type of base.
When the dog is perfectly straight up and down it has a tendency to pop the board up at the dog end with moderate vice pressure. The hole that is angled toward the vice ,does the opposite. It has a tendency to keep the board down flat on the bench.This is true with any shape of dog,round or flat.
mike
I used an auger bit and brace. Rest the brace against your chest as you crank. The setup is tall enough that you can eyeball it pretty accurately, but I set up a combination square beside it as a reference. Some of the holes may be off a couple degrees, but they're not far enough off to make a difference.
tall,
ain't it nice, that after an anxiety filled time of it, one can go to knots and have so much just laid to rest?
eef
TO,
View Image
From:
http://forums.taunton.com/fw-knots/messages?msg=33837.25
Lataxe
My thanks to all, good info.
Wingdoctor's idea is a good one for a brad-point bit. Here's a modification of that I use for Forstner bits. In the drill press, using the Forstner bit, I drill the hole in the 'guide block' only deep enough to 'house' the head of the bit. Then I change bits to the size of the Forstner shank. Insert the Forstner shank through the guide block so that the shank is above the block and the head recessed in the hole. Clamp the guide board in place on the top, letting the smaller hole guide the shank and the larger hole the head. After drilling the hole as far as possible through the guide, either remove the bit - or use a second bit - to finish the hole. This also works with angled holes, but since the dogs I use have a sloped face, I don't see a particular advantage to the angles.
A hole of the desired diameter drilled near the end of a piece of 2 X 2 X 12 maple on the drill press, straight up or at a small angle if desired, makes a great drill guide for the dog holes. Cut a small bit off of the front edge at an angle to make it easier to see where you are aiming the bit, held in a cordless drill, hold the block firmly to start the hole and away you go. Once the hole is an inch or so deep the guide can be removed and the hole finished without the guide. I used this method, that I stole from a magazine somewhere, to drill my dog holes and it worked well. Sometimes simple will work!
Bruce
Thanks, what type of drill Bit did you use.
I used a brad point bit. It drills much easier than a forestner bit in a cordless drill.
Bruce"A man's got to know his limitations." Dirty Harry Calahan
Bruce,
What you describe is an excellent way to do this job - make a homemade jig of scrap lumber and clamp it in place.
I've never been able to hold a Forstner bit to any level of accuracy though, even using a jig. I've had better luck with a brad point bit. The full-width sides of the bit are guided better in the jig, in my experience.
ZoltonIf you see a possum running around in here, kill it. It's not a pet. - Jackie Moon
I used a brad point bit also. Forestner bits are great, but best in a drill press.
Bruce"A man's got to know his limitations." Dirty Harry Calahan
"A hole of the desired diameter drilled near the end of a piece of 2 X 2 X 12 maple on the drill press, straight up or at a small angle if desired, makes a great drill guide for the dog holes. Cut a small bit off of the front edge at an angle to make it easier to see where you are aiming the bit, held in a cordless drill, hold the block firmly to start the hole and away you go. Once the hole is an inch or so deep the guide can be removed and the hole finished without the guide. I used this method, that I stole from a magazine somewhere, to drill my dog holes and it worked well. Sometimes simple will work!"
There is a modification to this jig that I used to drill the holes in my latest benchtop that worked very well - drill the hole through the maple block at the desired diameter, and drill a second hole at the desired dog hole spacing. Mount a dowel in this second hole. Along with a straightedge clamped to the workbench top for the sed of the maple block to ride against, this dowel allows you to step off the holes with even spacing across the entire top without measuring and having to eyeball the hole locations through the maple block jig (it also obviates the need to clamp the maple block to the benchtop to prevent it from "walking" as the hole's drilled).
One other recommendation - I use a 7/8" bit to drill the holes. Most metal dogs (such as the ones from Lee Valley) have a spring that will hold the dog in the slightly larger hole, and while theoretically a 3/4" bit should provide enough clearance, that doesn't always turn out to be the case in practice - you can wind up with 30 or more holes that are very, very tight fits for a metal dog. So much so that you will have to sand down the diameter of the dog or rasp out the inside of the holes (which is a major PITA).
That is a neat way of having even spacing without all the measuring and marking!! Great job. I will remember that trick the next time I have to drill dog holes. Thanks.
Bruce"A man's got to know his limitations." Dirty Harry Calahan
I think you guys hit the nail on the head. It sounds like a fool proof set-up with the dowel pin and straight edge to reference off of. You don't feel your dogs are too loose with the 7/8" hole?
Thanks
This works for me, although with pine not maple:
Drill a 15 mm hole with a spade bit. Then open it up to 19mm with a router bit. You will need to mark out your router position before you drill the first hole
It was in the last issue-- you don't want round holes, you want square holes!
My vote is for the auger bit and large -throw brace. The need for perfect verticality escapes me.
Tom
Tom,
I like the brace & bit; used it on my own bench.
But there is a need to keep the holes as near vertical as possible, as many round dogs have a flat-face area at the top which is inclined at 3 degrees from the vertical, to stop clamped workpieces popping up when the dog squeezes them. If the dog hole was out, say by 4 degrees, the dog would present a 7 degree-from-vertical down-face in one position and a 1 degree-from-vertical up-face in the opposite position.
However, I was surprised to discover that it is possible to keep the brace close-enough to vertical (i.e. within 3 degrees) whilst drilling, via use of two small-ish engineers squares stood at right angles to each other on the bench-top and adjacent to the bit.
Lataxe
This forum post is now archived. Commenting has been disabled