I have a cheapie woodworker's bench that has an end vise and two rows of dog holes along the bench and dog holes in the end vise. You're supposed to be able to hold a workpiece in place horizontally on the surface of the workbench by pinching the workpiece between the bench dogs.
I have to use a couple of pieces of scrap wood, one on each side of the workpiece, for proper spacing and to protect the workpiece from being gouged by the metal bench dogs.
The problem is that when I turn the vise to squeeze the workpiece, the scrap pieces and my workpiece all get pushed up in the air and nothing is held in place.
The bench dogs are in round holes. The heads are square and only about 1/2 inch high. When the vise applies force, the dogs lean over a little in their holes and thus become off-vertical and the heads press against the lowest part of the scrap spacers and this is what pushes them up in the air.
It seems that if the dogs could be made to stay vertical (e.g. by deeper holes and a closer fit) and had heads that extend up say an inch high, then my boards would not be pushed up.
Am I doing something wrong or is this what you get with such a cheap bench? Anyone had this problem? Any workarounds?
Actually, the round dogholes can be square to the bench top but the face of the dog should have a 2-4 degree slope
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Get things snug and then tap the dogs down a little.
Does your vise jaw have a "lean into it" taper that'll go to almost vertical when tightened against something? If the jaw starts out vertical and theres any flex it'll end up leaning back.
Is the top of the vise jaw at the same height as the bench top?
Maybe you might want to look into the Wonder Dog. Fits 3/4" round doghole and has a jaw on a threaded rod that gives you about a 3 inch reach.
If you've got an MDF top with a temper board top surface your dogholes are probably oval along the axis where the force is being applied. You can drill out the holes, glue in a larger hardwood dowel then redrill the dogholes.
My bench top is hardwood and the holes do not appear oval but the shaft of the dog has a fair amount of play in the hole. The vise top is flush with the bench top and the vise has no taper or slant.
From what you and Father Haskell are saying it looks like the bench dog should provide a slope _toward_ the workpiece, and not away from it. Mine slopes away from it, contacts the bottom of the board, and thus pushes it up.
How do the dogs on good workbenches work? Are the square tops of the dogs actually beveled so they slope toward the workpiece? Or is there such a close fit between the dogs and the dog holes that the dogs don't slope off vertical?
Let's be kind and call it "classic workbench design". I think some modern designs are good too.
No the whole dog hole is tilted at something like 2 degrees
Closer... but the bottom line is the final orientation of the baring surface, however to achieve that.
If I were you, I would try making your oen wooden dogs. Try a just under 3/4 dowel (most 3/4" dowels are probably undersized enough) with a square cap. Slant the face of the cap a couple degrees.
This is al least a cheap "proof of concept" to see if a combination of more snug dogs and a canted baring surface solves the problem.... go from there.
To clarify - "square" and "round" usually refers to the shank shape and the shape of the hole, not the dog head. On "square" dogs, the "hole" does slope/tilt - on the bench side it's towards the vise, on the vise side it's towards the bench. The face of the "square" dog may also slope - towards the piece being held. On "round" dogs, the hole should be 90 degrees to the bench top.
On "round" dogs, it makes more sense to drill the round holes 90 degrees to the bench top and angle the head of the "round" dog. This allows for - using the round dogholes to hold other fixtures on the bench via round dowels in the bottom of the fixture to fit in the round dogholes. Example: a simple bench hook for hand sawing doesn't work well with a japanese saw since they cut on the pull stroke. But if the bench hook has dowels to fit in the dog holes ... - turning the head of the round dog do in any direction in order to clamp non-straight edged parts - like a round table top or chair seat. The traditional "square" dog and dogholes don't permit such flexibility. - reversing the dogs and using them to pull things apart. - using a traditional hold down - the updise down "J" kind. Hit it on top to tighten, tap on the back to loosen
Remember, the bench is also a giant clamp. The more ways it can be used to hold things or pull them apart the better.
Another thing worth noting. Square dogs, once snugged up against the piece can be tapped down to tighten them up nicely. Since, unlike round dogs, they're long and extend below the bottom of their holes, you can hit them up from the bottom to loosen them quickly, without having to turn back the vise jaw. Once the piece is clamped in you can release it quickly, turn it around, tap one of the square dogs down to tighten and you're good to go. Round dogs don't usually go through the bench top so they don't have this option.
A traditional work bench has all kinds of less than than obvious little refinements which developed over a long period of time - for a reason. Watch Frank Klausz's video - "making a dovetailed drawer" and you'll see his bench get a work out. If you go with a traditional bench you may build in some capabilities you may discover the more you use it.
Anyway, here's a link that shows a "square" doghole and dog
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And here's a link for "accoutrements" you may be making in the near future.
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Gives you more things to worry/think about?
It's ironic that having a traditional workbench when one first gets into woodworking would make things so much easier. But at that point one seldom has the skills to make one.
"Zaster Sap" wrote in news:_lPzc.5172$ snipped-for-privacy@bignews5.bellsouth.net:
----Big Snip here--- Ah just make yourself some dogs from a dowel, snug fit and add a piece of rubber gardenhose to the top of dowel as a stop ...should make things a little easier.(G)
I like the idea suggested by Stephen M and GJP: make my own dogs out of dowels and wood blocks so that I can make the face with exactly the right slope.
I want to thank all of you who have responded to my post. You have given me some good info to think about.
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