Square benchdog sizing

[Carl Beckett]

Hi all,

Sorry if this has been covered (it seems basic, and should be covered, but I didnt see it when doing a search).

What is the standard dimensions for square benchdog openings? I have seen metal benchdogs that are around 5/8" thick, and a fixture for cutting benchdog openings that was closer to 13/16 deep x 3/4 thk.

I am making a workbench and in the process of deciding sizing for the benchdogs (if I make my own dogs, I suppose it doesnt matter the exact size but it just seems like a good idea to go with something standard.

Advice?

[Kent A Bathurst]

My metal dogs are 3/4" x 5/8". The brass foot adds 1/4" to the 3/4" dimension. The side has a leaf spring that takes the 5/8" out to 7/8" when the dog is out of the hole

The holes I put in the bench I made are 11/16" x 13/16" with (I think) a 5* or 7* cant to them - don't remember for sure - been too long. ALso - of course - a setback to receive the brass foot when pushed all the way down.

I think there are two things going on that you need to consider: (1) the spring - if the hole is too wide, she won't hold; (2) there is a relationship between the 3/4" dog dimension and the corresponding hole dimension - locking down a board takes the dog to vertical (or near ??), and too wide a hole would cause it to travel past 90*. I don't know the exact math - I just followed instructions when I was building it. Has worked fine for 12 yrs or so.

[Sean Hughto]

I don't think there really are "standard" dogs. Because of that, if you are going to buy dogs, buy them, and then fabricate your holes to fit them precisely. If you are going to make dogs, the issue is really moot, as you can fabricate the dogs to fit whatever size hole you choose.

[Frank Drew]

An inch and a little by an inch and a little, something like that; I prefer shop-made wood dogs.

And don't forget to slightly cant the dog holes in the bench towards the tail vise, and the tail vise dog holes in the other direction

[Carl Beckett]

Thanks everyone for the comments/advice.

I was feeling like the metal dog sizing was a little small if I make wooden ones (just didnt feel beefy enough), but couldnt really get a read on typical sizing.

I found this fixture I am going to use:



Should come out about an inch deep and cut ~ 3/4 in wide. Only about a 1 degree tilt if I calculate it correctly, but am thinking this is a function of how tight the dog fits (if the dog is really loose, it will tilt more under pressure). And if it tilts too much then will be more point contact at the edges whereas a relatively lower tilt will allow the pressure to be spread out more at the contact points (assuming the wood compresses some). I can always angle the face of the dog a little to be sure it squares up under pressure.

There is a very real possibility that I am trying to make everything too accurate and too close a fit (this is a recurring theme for me...... ). Sometimes loose just works better.

Of course, if I get it built and dont like it I can always tear it all apart and remake it (unlikely), or just build another complete bench from scratch (and of course a better one, fixing all my mistakes from the first one and tweaking the design and all my dreams will come true... at least until the time for the next bench)

Stay tuned, much more to go.

[Sean Hughto]

FWIW, I made my own jigs like this:

http://home.comcast.net/~samson141/dog_hole_jigs.bmp