Workbench top question

[jim hollenback]

Thinking about building a new workbench. The present thinking has the top overhanging on each end. One end for the installation of a wood vise. The other end will have a mechanics vise, kind of big, kind of heavy. If I make the top out of two layers of MDF will the overhang droop down over time? How about plywood, would it droop over time? Not sure if I'm up to building a plank top.
TIA

[Ben Hatcher]

248221
I built mine as a torsion box. Instead of having it overhang the base, I mounted it a few inches above the base so that I can get a clamp head between the base and the top. My vise is mounted to a board. When I need it, I just clamp it to the table.

[Bruce Page]

It depends on the size of your vise's but I think even with small vise's it would sag over time.

[Andy Fox]

My benchtop is something like 2 3/4" thick and composed of multiple layers of particleboard covered by 1/4" hardboard. I have a very heavy front vise on the front left side, and a Veritas twin screw vise on the other end. The front vise is offset about 1" from the left leg, and the end with the twin screw vise overhangs the leg by about 12". The only sag I've noticed is in my back from moving this beast! (I'll have to get it down the stairs to my basement workshop soon.) :eek:

[jim hollenback]

I built mine as a torsion box. Instead of having it overhang the base, I mounted it a few inches above the base so that I can get a clamp head between the base and the top. My vise is mounted to a board. When I need it, I just clamp it to the table.

Nice bench and good idea. I'll have to think about that but didn't want to give up that much height to the top.


It depends on the size of your vise's but I think even with small vise's it would sag over time.
I did consider this, hence the question.


My benchtop is something like 2 3/4" thick and composed of multiple layers of particleboard covered by 1/4" hardboard. I have a very heavy front vise on the front left side, and a Veritas twin screw vise on the other end. The front vise is offset about 1" from the left leg, and the end with the twin screw vise overhangs the leg by about 12". The only sag I've noticed is in my back from moving this beast! (I'll have to get it down the stairs to my basement workshop soon.) :eek:
Yeah, I understand about the sag in the back :) I was thinking more like 1 3/4", two 3/4 layers and then a 7/32' plywood covered with Formica. Maybe I need to entertain the idea of another layer.

Thanks for the comments, I appreciate them.

[Michael E. Smith]

I have a small shop, so my bench is only about 60" long. But I did build it out of hardwood. It is about four inches thick. I have a small over hang on one end and about a 20" inch over hang on the other. I have a tail vise mounted on one side and I am going to install a Face vise on the other. Don'rt forget to leave over hang on one side for clamping purposes. I would suggest leaving the top flush with the legs on the front, that givse you a lot of support if you are clamping something large. It is a lot of work to build up a top like this. Well worth it in the end if you want bench that will last for as long as you need it, and then some. I have been working on mine for about a year, off and on. But the plan is to pass it on to one of my boys. It will last as long as they need it as well. I have used the particle board bench tops in the past. Over time they do sag and eventually you will have to cover them with a hardboard cover. If I new how to post pictures on here I would do that, but I have not figured that out yet. Good luck with your workbench.

[Sam Stephens]

I would suggest leaving the top flush with the legs on the front, that gives you a lot of support if you are clamping something large.

ditto. not sure what benefit the overhang offers unless your design includes a stretcher at the top of the legs. then the overhang would be necessary for clamping to the benchtop.

[Joe Angrisani]

Use 2x4s, laminated "on end" to make a 3-1/2" thick slab. The only drawback is time. Time for the wood to dry before you start. Go pick out twenty quartersawn 2x4s at the Borg, bring them home, and sticker them in your shop. This summer, joint and plane them to about 1-1/4", then build a nice, simple, solid, heavy top for about $40.

You could build it "wet", but you'll probably have to do some flattening in a year or so when things reach equilibrium.

If you're stuck on MDF, do Ben's torsion box approach.

[Michael W. Clark]

Use 2x4s, laminated "on end" to make a 3-1/2" thick slab. The only drawback is time. Time for the wood to dry before you start. Go pick out twenty quartersawn 2x4s at the Borg, bring them home, and sticker them in your shop. This summer, joint and plane them to about 1-1/4", then build a nice, simple, solid, heavy top for about $40.

You could build it "wet", but you'll probably have to do some flattening in a year or so when things reach equilibrium.

If you're stuck on MDF, do Ben's torsion box approach.

This is exactly what I did and I can confirm that if you put them together "wet", it will need flattening after a few years, but still very much serves the purpose. If I was doind an assembly table, I would look at MDF and torsion box. If doing a woodworking bench, I prefer some type of hardwood. Two layers of MDF does make an excellent utility type or general purpose bench. I have it on my mitersaw bench and it is much more durable than I would have expected.

[Jim Neeley]

FWIW, I bought kiln-dried construction 2x12's and ripped them oversize so I could plane them down once everything had stabilized.

YMMV..

Jim

[Andrew Joiner]

I have my mechanics vise mounted above a 4x4 leg. I can hammer on it's anvil with no bouncing. Any overhang may sag, and it would be very bouncy.

[Alan Lightstone]

I've integrated angle iron into my assembly table bottom to reduce sag. Seems to be working, but torsion box would work better I would think (but be bigger.)

[david a graham]

I've built two benches using 2x4's - they are both going strong 15 and 20 years later. I smoothed the first one with a belt sander and the second with a jack plane and covered the tops with masonite for a work surface.

[Ray Newman]

Once built a bench top approx. 3” thick – 4 layers of ¾” plyw’d glued and screwed together. Solid and heavy.

For a vise, I mounted a medium sized now no longer made Record.Mounted about 1” from the outside of the front leg. This looks like it:
www.woodcraft.com/product/2082711/32921/eclipse-9-quick-release-vise.aspx

Within 6 months, the top started to sag.

As Alan Lightstone said, probably the only way to prevent sag would be to reinforce the top with angle iron, esp. with a plyw’d. or MDF top.

David Graham is on to something when he made his bench top out of 2x4’s, esp. if laminated together and laid on edge and covered with tempered Masonite.

[Jaromir Svoboda]

I used LVL for woodshop bench and 2x12 for garage bench.Both are nice and solid,but I like workbench in garage better.

[Quesne Ouaques]

As I read these posts about MDF, I am curious to get some feedback about my setup. I built my bench about 8 years ago using a 32" x 108" x 1 3/4" laminated maple tops (like one of these (http://www.woodcraft.com/product/2005134/6882/24-x-84-laminated-maple-bench-top-98-lbs.aspx) from Woodcraft).

I have a Taiwanese patternmaker's vise attached to one end (http://i143.photobucket.com/albums/r125/quesne/Woodshop%20Equipment%20and%20Tools/PatternmakersVise.jpg), and a LV Twin Screw to the other (http://i143.photobucket.com/albums/r125/quesne/Woodshop%20Equipment%20and%20Tools/VeritasVise.jpg).

The bolts mounting the patternmaker's vice are offset about 1/4" from the outboard edge of the 2x4 cross-member. There is also a line of 6 dog holes drilled the width of the top right along that "load bearing" line.

The Twin Screw mounting bolts are about 1" outboard of the supporting 2x4 on its end. The dog holes on that end are well inside the load-bearing line.

I have checked the flatness across those support thresholds with a decent straight edge, and so far all is well.

My questions are:

Considering my top is much thinner than most of the commercially available laminated workbench tops I've seen (4", 3", 2 1/4") -- and given how my vises are mounted -- am I likely to suffer sagging over time?

Does anyone have direct experience mounting and using vises on these (relatively) thin laminated tops?

Thanks!

[jim hollenback]

Once built a bench top approx. 3” thick – 4 layers of ¾” plyw’d glued and screwed together. Solid and heavy.

For a vise, I mounted a medium sized now no longer made Record.Mounted about 1” from the outside of the front leg. This looks like it:
www.woodcraft.com/product/2082711/32921/eclipse-9-quick-release-vise.aspx

Within 6 months, the top started to sag.

As Alan Lightstone said, probably the only way to prevent sag would be to reinforce the top with angle iron, esp. with a plyw’d. or MDF top.

David Graham is on to something when he made his bench top out of 2x4’s, esp. if laminated together and laid on edge and covered with tempered Masonite.

I was wandering around the borg the other day and saw some heavy duty shelf brackets. The are around an inch or inch and a quarter wide and about 1/8 thick with a nice rod welded across the square. The look pretty stout. I'm thinking of using those under the mechanics vise. I don't think the wood vise is heavy enough to cause problems. If it does I'll use the brackets.

[david a graham]

I did lay the 2x4's on edge the newer one is 8' x 36" and it is very heavy and flat every few years I wax the masonite and it continues to serve me well.