I just watch a video on Folklife Chronicle of Mr. Liebich using these bench dogs. He is a fascinated man and I hadn’t heard of him before your post. Thanks for sharing this!
Do you think this could work with round dog holes, or would they rotate as soon as you tried to get pressure on the workpiece? I'm interested in making something like this, but lacking a tail vise I would also have to make one of the points adjustable - I'm thinking akin to the point that screws in and out in the poppet of a pole lathe.
well, I'd only be guessing so I can't say with any authority. I wouldn't think they'd rotate, the pressure is all in line - but it is a lot of torque on the dogs. One way to find out...
I think if the point sat behind the hole, it would be fine. By this I mean that when the material pushes against the point, the material passes over the hole before it contacts the point. Any force that would otherwise pivot the bench dog would pivot it into proper orientation.
So the basic geometry should be one where each bench dog comes up from the bench at an angle away from the other bench dog. The angle should be drawn from the center of the hole to the metal point in the dog.
It reminds me of something called ‘wheel trail’ in bicycle design: the contact point of the front tire on the ground, is located behind the the bicycle fork’s axis of rotation in the head tube. In this way, as the bike moves, the front wheel is dragged into alignment by the wheel.
First application that's made me consider putting a tail vice on the new workbench I'm building.
And some nice square dog holes to go with it.
Till now, when making octagonal legs, I've messed around with sash clamps in my leg vice, but it's a pain.
I just watch a video on Folklife Chronicle of Mr. Liebich using these bench dogs. He is a fascinated man and I hadn’t heard of him before your post. Thanks for sharing this!
Do you think this could work with round dog holes, or would they rotate as soon as you tried to get pressure on the workpiece? I'm interested in making something like this, but lacking a tail vise I would also have to make one of the points adjustable - I'm thinking akin to the point that screws in and out in the poppet of a pole lathe.
well, I'd only be guessing so I can't say with any authority. I wouldn't think they'd rotate, the pressure is all in line - but it is a lot of torque on the dogs. One way to find out...
Pardon my presumption here...
I was just entertaining the same question.
I think if the point sat behind the hole, it would be fine. By this I mean that when the material pushes against the point, the material passes over the hole before it contacts the point. Any force that would otherwise pivot the bench dog would pivot it into proper orientation.
So the basic geometry should be one where each bench dog comes up from the bench at an angle away from the other bench dog. The angle should be drawn from the center of the hole to the metal point in the dog.
It reminds me of something called ‘wheel trail’ in bicycle design: the contact point of the front tire on the ground, is located behind the the bicycle fork’s axis of rotation in the head tube. In this way, as the bike moves, the front wheel is dragged into alignment by the wheel.
Thanks for this, Peter. I just finished a pair for my round-holed bench, they work just fine.
Looking forward to that book.
I think a solution is to make poppets, at least one, that are insertable into two dogholes