Using dogs with an MDF bench top?

[Jay Maiers]

Am I allowed to use the letters MDF in this forum? [insert duck and cover smiley face :D]

Hello all,
I'm in need of a bench and general work table in my basement. Most of my work is done with power tools, but I'd like to start exploring the Neander world. Will an MDF top (3 or so inches thick) work with bench dogs and hold downs, or is it too soft?

Please forgive me for topping it with MDF :) It's cheap, easy, and flat, and I think it will give me time to figure out some of my work preferences (and dictating some design principles for my future bench).

If it helps, I'm probably going to build in some sort of a wagon vise on the right end, and add a face vice on the front left corner. It's going to be supported with plywood legs and frame members.


Thanks,
Jay

[bradley strong]

I'm planning a similar bench soon. I've had a maple topped bench before, and they have to be flattened fairly often. The MDF may be too soft to stand up to years of use on the dog holes. My plan it to edge the bench with 10/4 maple and place the dog holes in the inside edge of the maple band. If you look at maple benches, they are usually built this way anyway. The edging is significantly thicker then the bench top, so it gives max strength for the dogs and it lines up with tail vises nicely. If you are going to use round dogs, you can always reinforce them with solid wood. Buy or make some 1 1/2" dowel, drill holes in the top with a forstner bit, glue in the dowel, and then drill out the dog holes. I am actually thinking about using OSB instead because it is very dense and durable. I will probably top it with hard board that can be replaced when it gets beat up. 3/4" OSB is about $11/sheet at the home center near me. 3 sheets will make a 4.5" thick top. 2 sheets will make 3" thick.

For me, it's not so much about saving money as it is making a bench that doesn't have to be flattened every year.

[David Weaver]

I would do the dowel method, as mentioned. Either that, or mortise squares and put an insert in the bench top and drill a hole in it.

Even if MDF would hold them most of the time, there is going to be the time you get peed off at something not holding and really hammer the holdfast down. At least if you do MDF only, you're thinking about thick, which you'll need. A hold fast would break out a thinner MDF top quickly.

If the bench properly dried wood, you really shouldn't have to do much or any flattening to it. My bench hasn't really moved in 5 years, and I haven't planed it - I just ROS the surface when I get something on it that needs to come off (like after doing the metalwork on a plane, some always ends up on the woodworking bench), and then rewax it.

you can hand plane MDF, it actually planes quite well, you'll just have to sharpen a couple of times for something the size of a bench, but that's not really that big of a deal.

When I made my router table, I made it out of MDF, and I wanted it laser light grid flat. When I bolted it to its base, it got a little out of flat and I planed it with a plane with an A2 iron. It worked fine, just dulled the plane fast, but it doesn't damage or chip the iron or anything, just wears it. just glue size it after you plane the skin off of it.

[Casey Gooding]

I like the idea of adding hardwood inserts. That's probably your best bet. You could use holes in the MDF and then use CA glue to stiffen up the exposed areas of the holes. But I think I would stick with inserts.

[Prashun Patel]

My mdf top has dog holes and they do get sloppy enough to bother me on occasion.

I've thought about overdrilling the holes, epoxying in oversized dowels, then redrilling the holes

[Ken Cohen]

I have 3 x 3/4 MDF top with hw edge banding and lots of dog holes. After 1.5 years of use, holes work fine for both bench dogs and hold downs.

Guess I have dowel technique available if holes fail before the top.

[Jay Maiers]

Thanks all.
I love the idea of dowels or inserts. Inserts are probably the way I will go, but I'm going to think on this before I start cutting.

[Robert Culver]

somthing i have considered is 2 pieces of 3/4 in ply with 1x4 maple laminated on top and bottom with a good solid edge band im not sure if I like the idea yet but I would think it would hold up a bit better than mdf I will be starting to laminate my top in a few weeks so I need to descide soon but Im honestly probable going to go with 6/4 solid something or other just thought I would toss that idea in your basket.

[Tim Janssen]

I built this bench in 2001, the top is 3 layers of 3/4" MDF with a 1/4" sacrificial layer of hardboard(masonite) as the very top layer, which I just recently replaced. The top is skirted with oak. I drilled 3/4" dog holes with a forstner bit and I use 3/4" dowels as bench dogs. I happened to have some vinyl hose of the right diameter and put a short piece of that around the top of the dowel so they don't fall through. I store the dogs in the side of the front legs of the bench. I also have holes in the moving jaw of the twinscrew vice at the right end of the bench which gives me the ability to clamp panels etc on top of the bench.

Tim

http://i129.photobucket.com/albums/p209/timwillift/Pic902.jpg

[Larry Frank]

My bench is also several layers of MDF with hardwood around the outside. On many of the holes, I put a 3/4" wooden nut fastened on the bottom side. This allows me to use a 3/4" threaded dowel and nuts on the top to hold things down along with just 3/4" dowels for dogs.

[Jay Maiers]

I built this bench in 2001, the top is 3 layers of 3/4" MDF with a 1/4" sacrificial layer of hardboard(masonite) as the very top layer, which I just recently replaced. The top is skirted with oak. I drilled 3/4" dog holes with a forstner bit and I use 3/4" dowels as bench dogs. I happened to have some vinyl hose of the right diameter and put a short piece of that around the top of the dowel so they don't fall through. I store the dogs in the side of the front legs of the bench. I also have holes in the moving jaw of the twinscrew vice at the right end of the bench which gives me the ability to clamp panels etc on top of the bench.

Tim

That sounds like a pretty good plan. I'm intending on using this as a bench for a while, and then keeping it around as an assembly table or just another all-purpose work surface. Adding the masonite or another 1/4" layer of MDF to the top seems like a good idea.

How do you have that top layer fastened to the core? I'm thinking carpet tape or small brass screws, but I'm plenty open to suggestion :)

[Jay Maiers]

My bench is also several layers of MDF with hardwood around the outside. On many of the holes, I put a 3/4" wooden nut fastened on the bottom side. This allows me to use a 3/4" threaded dowel and nuts on the top to hold things down along with just 3/4" dowels for dogs.

Larry,
Did you cut these nuts and threaded dowels yourself? I don't know that I'm going to go this route, but it is interesting. It seems like I could do this as a retrofit as well if I needed some sort of mechanical hold down in the center of the table.

[Nigel Tracy]

...I'm intending on using this as a bench for a while, and then keeping it around as an assembly table or just another all-purpose work surface...Hi Jay,
Have you considered baltic birch ply? I went through the same thought process as yours above recently and decided on bb ply, and couldn't be happier. At 3" thick it's super heavy, super flat, and has no problem whatsoever with bench dogs.

I based it on The Schwarz's "24-hour workbench" in his new book. It's a real pleasure to work on.

[Ken Cohen]

Carpet tape vs. brass screws.

I started with carpet tape. It is quicker, but produced a slightly uneven surface due to the thickness of the carpet tape (hard to believe, but true in my case).

So, I took the extra effort to drill/countersink small brass screws every 8" around the edge and approximately every 12" in the field. Dead flat. And, for change out, repeat the process.

Note that changeout of the tape is a nuisance since it left lots of residue on the MDF that I needed to scrape off.

[Jay Maiers]

Hi Jay,
Have you considered baltic birch ply? I went through the same thought process as yours above recently and decided on bb ply, and couldn't be happier. At 3" thick it's super heavy, super flat, and has no problem whatsoever with bench dogs.

I based it on The Schwarz's "24-hour workbench" in his new book. It's a real pleasure to work on.

Honestly, no. I've been thinking MDF because I have access to a fair amount of it at work. I thought about regular cabinet grade birch ply (again, available at my office for a very reasonable price), but I rejected it for a few reasons. The BB looks like a good option, and I'm sure it's much more durable. I'll have to add that to my list of possibilities.

Do you use some sort of cover sheet / top layer on your bench?

It's funny, I've been combing the web for quick workbench ideas. I've probably spent more time researching than I will building :rolleyes:. Somehow, through all of the looking I've done, I completely missed the Schwarz 24hr bench. It looks like a great bench, but it seems to violate one of the big features he likes: legs flush to the front apron / edge of the bench.

And, while I'm on the subject of Schwarz: New book???? ARRGGGGHHH! I just bought the other bench book. Ah well, it's not like I'm opposed to adding to our library :)

[Jay Maiers]

I absolutely believe the thickness issue with carpet tape.
I'm also more inclined to go with the brass screw method simply because of the adhesive removal issue.

Do you have any problems with the top surface growing or shrinking more than the substrate? I'd expect that's a no since they're the same material, but I thought I'd ask anyhow... I live in Georgia, and my shop is in an un-conditioned-ish space in the basement. It stays temperate throughout the year (except on the coldest days), but it can get a little humid. It's not nearly as bad as the garage or a completely un-conditioned space, but there is still a pretty big swing.

[Ken Cohen]

FWIW, I went through a similar process and spent way too much time exploring different bench designs. In the end, I wanted good performance, longevity and reasonable assembly time.

Don't know if you've come across it, but the ShopNotes bench met my needs. Very sturdy base with bolted tenons for ease of disassembly and tightening. I built the recommended hardwood wrapped MDF top (and added a hardboard layer). Built it with ash (~$2/bd ft) to save cost. Only hitch: room for improvement in vise mounting plan -- but glad to share solution if you are interested.

Good luck.

[Ken Cohen]

\

Do you have any problems with the top surface growing or shrinking more than the substrate?

Not that I notice. (I'm in NE). In my case, bigger issue was carefully planing the hardboard edge to remain coplanar with the MDF surface. Not especially challenging, but small errors are magnified when you start clamping on the edge and expect a piece to remain dead flat on the MDF.

[Nigel Tracy]

...
Do you use some sort of cover sheet / top layer on your bench?

It's funny, I've been combing the web for quick workbench ideas. I've probably spent more time researching than I will building :rolleyes:. Somehow, through all of the looking I've done, I completely missed the Schwarz 24hr bench. It looks like a great bench, but it seems to violate one of the big features he likes: legs flush to the front apron / edge of the bench
...No I didn't bother with a top sheet. If you're really going to be gunking it up with paints or glues of course it's a good idea and could be added easily. I just used a couple of quick coats of thinned oil/varnish for protection, but I have another surface I use for the really dirty jobs.

And you're right about the legs. I made mine flush. In fact in the book at the end of each bench chapter there's a "critique" and a "how to improve" on each design. Sure enough, he suggests making the legs flush on pretty much each one. I'm glad I did since I've already used it for a fair amount of edge work.

At some point ya just gotta pick one and go for it. My bench build was one of the most rewarding I've done so far since I use it every day I'm in the shop. Happy building!

PS. I included a standard face vise to my bench. Had a big ole record 53 waiting to be used so I included it in my bench for a face vise. Don't be afraid to stray from the plan to suit your needs :)

[Jay Maiers]

...Don't know if you've come across it, but the ShopNotes bench met my needs. Very sturdy base with bolted tenons for ease of disassembly and tightening. I built the recommended hardwood wrapped MDF top (and added a hardboard layer). Built it with ash (~$2/bd ft) to save cost. Only hitch: room for improvement in vise mounting plan -- but glad to share solution if you are interested.

Good luck.

The? Lol! How about one of the 15 choices...
I've got a couple of those articlas and am looking at a few more. I'd love to hear about or see pics of your vise install.

[David Castor]

This has been an informative thread for me - thanks for all the information. I have been thinking about putting together a Tom Caspar "torsion box" workbench, but this thread has given me some additional options to consider. I've got a big Jorgensen quick-release vise still in the box that I need to fit into my plans as well.

[Ken Cohen]

The? Lol! How about one of the 15 choices...
I've got a couple of those articlas and am looking at a few more. I'd love to hear about or see pics of your vise install.

Fair criticism. I used the January 2004 Woodsmith plan.

Here's a thread on the vise install with pictures:

http://www.sawmillcreek.org/showthread.php?115085-Lag-screws-or-bolts-for-vise-in-mdf-bench

You can see my initial solution. However, top mounted bolts failed to keep the vise from slightly sagging. (The bolts holes are on the back of the vise while all the weight is in the front).

In the end, I countersunk two holes through the hardwood edge that forms the bench side of the vice. I then added bolts into the pretapped holes in the side of the vise.
All is well now (unless I crack the casing, which I think/hope is highly unlikely).

Glad to provide add'l info on my bench build.

[Ken Cohen]

Apologies. I built my bench from a plan from ShopNotes magazine No. 65. It cost $10.

Here' the link: http://www.plansnow.com/wrkbenchsn.html

and pictures of the bench from the link: http://www.plansnow.com/wrkbenchsnclos.html

[glenn bradley]

Like Tim, I have used these dogs hard for years.

173898

I had the same concerns when I built my "next" bench (I assume I will build another later on) and was assured by those who came before. Now I'm one of them. I used 4 layers of 3/4" MDF and finished with BLO top and bottom.

I use bullet catches to add friction for adjustable height. Got a bag of 100 from Lee Valley on clearance years back.

173899

I use modified $2 HF clamps for holddowns. Easier to control than something you whack with a hammer.

173900

There's a lot of good ideas out there.

[Jay Maiers]

Fair criticism. I used the January 2004 Woodsmith plan.

Not really criticism Ken, just a bit of humor. I find it funny that there are a couple dozen different articles on "THE ULTIMATE BENCH FOR YOUR WORKSHOP!"

Anyhow, thanks for the picture and your explanation. It's crystal clear. I will have to do some thinking and see if I can avoid that same issue. If not, yours is bound to be the best solution.

Thanks again Ken and everyone. I've come away from this discussion with several easy yet valuable upgrades to my bench design.

[Larry Frank]

I cut 3/4 inch thick oak about 2" square and tapped the holes and then attached to the underside of the bench. It works very well for me and allows me to attach some jigs and fixtures to the bench.

[Tim Janssen]

That sounds like a pretty good plan. I'm intending on using this as a bench for a while, and then keeping it around as an assembly table or just another all-purpose work surface. Adding the masonite or another 1/4" layer of MDF to the top seems like a good idea.

How do you have that top layer fastened to the core? I'm thinking carpet tape or small brass screws, but I'm plenty open to suggestion :)

Hi Jay,

Sorry for the delay in replying I just now got back to the forum, if you check the link below you'll see more details on my bench including how I made it mobile, I posted that thread in 2006. I just used some sparingly applied squrls of regular glue when I replaced the top layer. I had used too much glue when I built the bench. So it took a fair bit of work to clean the surface, so this time I was quite stingy.
Good luck.

Tim

http://www.bt3central.com/showthread.php?t=24318