MDF workbench top & dogs

I'm thinking of building this beast as a workbench:
http://www.shopnotes.com/images/issues/089/heavy-duty-workbench-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.
Cheers! Dukester
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Dukester wrote:

I wouldn't trust the MDF to stay flat around the holes personally.
Could you rout out a 1.5" channel along your bench, and mount a nice 3/4" thick strip of oak or maple or something in there for your bench dogs?
-Nathan
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I like that idea - even a 1/4" thick strip of something hard would last a lot longer than plain MDF. I may have to implement something like that in my own bench (holdfast has been purchased but not yet installed; bench is 2 layers of melamine-coated particleboard over 1.5" pine). Wouldn't be too difficult with a router and clamped straightedge guide. Thanks, Andy
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MDF could dull your router bit fairly quickly.
The best way to do this sort of thing is to incorporate the hardwood during construction. Just cut the peices to total the top work surface area. Then join everything together with glue and whatever fasteners you were going to use.
No need to use a router when a saw will do. You can even use a saw guide and cut multiple times if the top is already assembled. It would be like a long dado cut. Clean the groove out with a chisel or router. Just make sure that there is no metal in the way of any blade or bit.
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Just route the groove. Why all the screwing around?

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I did precisely that because the dogs blew out the holes in very short order. I also added a strip on the underside (though not inlaid) for where the dog end comes through the bottom of the table. No problems since.
J.
N Hurst wrote:

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Dukester wrote:

Don't waste your time, it'll sag. Two layers of good 3/4" ply with thin MDF over the surface is useful though,
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I built a workbench using lumber and MDF. I used two MDF slabs (30x80) for the table top. The finishing touch was hardboard on top of the MDF and it functions just fine. Use a table saw to cut MDF. You might need some help cutting the MDF, depending on the size of your table top. Also, I used a nice trim to finish the edges.
Happy woodworking!
Mike

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Do you use benchdogs on it?

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Dukester wrote:

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.
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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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I used plastic pipe for the inserts on my MDF workbench, and it's gone over seven years without any problems. The grey threaded stuff cuts easy and is not so hard that I have to worry about hitting it if I get careless. There are two things I encountered however:
1. The outside diameter is non-standard. for drilling the holes, I ground down a spade bit.
2. While very close, I discovered that some of the piping is slightly off size. I did not notice this for years until I got some dogs that were too snug. Five minutes with a drill fixed that.
snipped-for-privacy@nb.sympatico.ca says...

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It's good enough for me. Actually the bench has 2 full slabs of MDF on top of 2 12" slabs around the perimeter (I think the article was trying to get by using 3 whole sheets). In any case, where to dog holes will be it would actually be 4 layers thick. I may try the wooden dogs first or even some plastic ones Rockler sent me a while back for free.
Thanks for the info!
Cheers! Dukester
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I took a course at a Woodcraft store and they had benches made from MDF and the dog holes were OK. Overall, it was a beefy, low cost bench.
I opted for plywood, two sheets of 3/4". I just like the looks of it better and the cost was minimal over the MDF.
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wrote:

Just another option for low-cost benches- mine is 100% jummywood. I got about $50 in framing 2x4s, and ripped a 1/4" off either edge to make lumber with square corners. Using the 3" x 1.5" lumber, I routed 3" wide by 3/4" deep dadoes at the top and about 5" up from the bottom of each leg piece, and then glued the halves together to make easy through mortises that one of my modified 2x4s would slide into.
The long stretchers are slid into those through mortises, and glued in place, and feet on either end take the place of the short stretchers.
With that done, I made the top by laminating the remaining 2x4s face-to-face to make a top that is 3" thick. I took the extra step of boring a couple of holes through the edge and running some threaded rod through to make extra sure that the top would not delaminate, but I doubt that is necessary.
While it may not sound like much, being made from framing lumber, it's really sturdy, and looks quite a lot like one you might see in a woodworking catalog. It's held up well for quite a while, and a bit of plywood laid over the bottom stretchers makes for a handy shelf.
Biggest problem in the whole project was hand-planing the top after glue-up. If I'd have had a handheld belt sander, that would have been much easier. What I've got described above might vary a little from what I did, as I've got it mixed up a little with the router table stand in my head right now, but am too lazy to go check- I figure that's good enough to give the general idea, anyhow.
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On Tue, 16 Jan 2007 10:36:54 -0600, "Dukester"

I don't know if it would work or not with dogs, but my personal inclination would be to route a dado along the top and lay in some solid wood where the dog holes are being drilled. Doesn't necessarily have to be a hardwood, if you're trying to do it on the cheap- some 1x pine boards would go a long way towards preserving a decent hole for the dogs.
The thing I'm thinking of here, and your results may vary, is that with my square dog holes and homemade dogs, there is just a little play in there, so that they tilt a couple of degrees when the clamping pressure is applied. From what I've done with mdf in the past, that seems like a recipe for crushed and crumbling edges.
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