Using steel bench in hole bore in MDF may work for occasional use.
Now that your bench is all build you have to use it. I would first try
wooden dogs and do a dry run with steel also.
Normally hole bored in thick hardwood is preferred. However, if after
several use of the steel dogs you notice some damage you will have to stop
and find an alternate way. On the other hand with the amount of work you
are doing it may work fairly good.
If not you may have to rebore the holes to accommodate some metal
sleeves/bushings. A snug fit with epoxy should hole the bushings in place.
When you make your bushings make sure that the inside diameter is bore with
a close tolerance . This will held to minimized the play between the dogs
and the inside of the bushing. If you have too much play between the
outside diameter of the dog and inside of the bushing it will eventually
cause enlargement of the holes in the MDF.

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Dukester wrote:
I'm thinking of building this beast as a workbench:

http://www.shopnotes.com/images/issu...nch-medium.jpg

If you're too shy to go to the page, it's a workbench with 2 full 3/4"
MDF
layers and 2 "semi" MDF layers for the top (MDF on the ends and edges),
and
a hardwood banding around the edges of the MDF. Looks to be very stable
and
heavy.

My question is: will the MDF do alright for using benchdogs, or will the
MDF
wear out quickly? I'm thinking of the round Veritas dogs for easy
installation.

I never saw that picture but when I built my bench, my budget limited
me to what was on hand. That was, a load of white oak two by fours
rough cut, some hard maple I got from a freebie pile, and a whole lot
of mdf from when I pulled out some shelves. I knew mdf sagged, but it
was either that or no bench. And I had two NICE vintage vises a friend
had given me.

I layered three of the 3/4 mdf and banded it with the oak, and used the
oak for the legs and braces too. Came out pretty flat. When I put a
straightedge across the length, at the very middle, you could get a
corner of a dollar bill under the middle but not the whole bill. It's
been two years and I think you can get more of the corner under the
straightedge but not the whole dollar bill. And it's massive but it
rolls on its casters just fine and when I raise the casters it's solid
on the floor.

I've got a row of dog holes in it and use Veritas dogs. I don't think I
use them enough to say it's getting normal use, but I do use 'em.When I
finished it with Waterlox, I also put some in the dog holes. The dogs
are still hard to slide around. I *think* the holes are beginning to
wear. If they do, I plan to drill out the holes to a larger size, plug
'em with a hardwood, and drill that out. Or something like that.

I'll figure something out. I like that bench. I figured it would be one
of those things where as soon as I build it and use it, I'll figure out
what I really want in a bench and I'll build another one. I just
haven't had cause to feel that way yet. This sucker is solid and
dependable and it rolls around when I want it to and stays put when I
tell it to. I even like the way it looks.

I don't know if that's a recommendation or not. I guess I should say
that I don't think two layers of MDF is enough, and the bands on the
sides don't look thick enough in that picture but I'm probably not
objective any more.

Oh, and mine is smaller in length and width. That probably has an
effect.