Need some workbench advise.

[Matt Meiser]

A couple years ago I built the bench pictured below from an article by Chris Schwarz in Popular Woodworking. Its made from SYP with a top made from 4 layers of Baltic birch which is about 5' long by 27" deep. The base is about 25-1/2" x 45-1/2". In all, its a decent bench, pretty heavy and very stable. But the front vise didn't work well for things like cutting dovetails which I'm trying to learn so I've decided to do some work on it.

First, I sold one of the Record vises. The other will continue to be my end vise as that works pretty well for me. Next, I bought two Lee Valley bench screws which I'm going to use to build a twin-screw face vise. The plan was to keep the top, though I really wanted it to be about a foot longer.

Today on Craigslist, I found a 30"x96"x1-3/4 maple top in great shape other than some separation at the glue lines at the very ends. And, it was only about 5 miles from my house so I bought it for $140. Probably not a steal, but much less than any other option. Inspection with a metal detector shows that it doesn't have any hidden metal rods too, which is a bonus.

To this top, I want to add a front apron made from 8/4 maple to accommodate the twin screw vise and stiffen the top since it is a little on the thin side. I want to reuse as much of my existing base as possible to save time. "Someday" I can always build a new base. The stretchers that connect the two leg assemblies are attached to the leg assemblies with just bench bolts, so I can disassemble and make new stretchers.

I'm thinking I'll cut the top down to 72" long (thats about the longest that I can put where I want my bench to be.) If I were to just set it on the existing base, that would leave about 13-/14" overhang on each end. That seems like too much, but I'm not sure. If I make new stretchers, what would a good length be? The record vise needs at least 8-1/4" overhang on the end.

Will this design result in a stiff enough top for an occasional neander and for general work? Or should I consider adding a beam at the back legs in addition to the front apron to stiffen the top? Anything else I should consider?

[Doug Shepard]

I'm wondering if you couldn't just take the 2 ft piece you're going to cut off, rip it into strips and glue 2 rows of strips into a 6 ft piece, staggering the joints along the way. Then glue that under the back edge (for a 3-1/2" back edge)? I wouldn't think there'd be movement problems since it's all from the same stuff and should already be stable. From what I can see in the pics, it looks like there might be enough rear overhang to do it?

[Greg Hines, MD]

It depends on how big of a twin screw vise you envision. If you create a 16" vise with the two screws, you would need at least 18-20" on that end of the bench. In that scenario, your base should work fine, just be offset towards the end with the twin screws.

That said, if I were to add a twin screw vise to my bench (which I built just like yours, by the way) I would put it on the end of the bench. Then you can use it with dogs down the length of it, or as a large face vise off the end.

One thing that everyone says about a laminated top like that. Resist the urge to put dog holes to use with your face vise, whether it is the Record or your twin screw. You can delaminate the top by trying to clamp a piece between dogs and the vise, with just the glue line between the laminates to resist the force.

Doc

[Matt Meiser]

It depends on how big of a twin screw vise you envision. If you create a 16" vise with the two screws, you would need at least 18-20" on that end of the bench. In that scenario, your base should work fine, just be offset towards the end with the twin screws.

I'm curious about this comment--I had kind of planned to straddle the leg with one screw outside the leg and one inside. Is there a reason that won't work well? Now would be a good time to find out. :eek::)

[Greg Hines, MD]

I'm curious about this comment--I had kind of planned to straddle the leg with one screw outside the leg and one inside. Is there a reason that won't work well? Now would be a good time to find out. :eek::)


I suppose that would work fine. That would allow you to use the leg for jacks and such as well. If I did that, I would definitely drill dog holes down that leg every few inches to support the end of a panel you are working on, or a piece that you are working.

I still think that you should do ok, but don't break it apart with bench dogs.

Doc

[Chris Friesen]

I'm thinking I'll cut the top down to 72" long (thats about the longest that I can put where I want my bench to be.) If I were to just set it on the existing base, that would leave about 13-/14" overhang on each end. That seems like too much, but I'm not sure. If I make new stretchers, what would a good length be?

Make the length as long as you can. A 14" overhang isn't crazy...I'm making an 84" bench with 18" overhangs. With a 48" base it ends up being just about the perfect amount of overhang to cause equal amounts of sag at the ends and in the middle.

[John Thompson]

I suggest you put the top on two saw-horses and let it over-hang 14" on the ends. Clamp it down.. hold one end down while you ask your 300 lb. friend :D to stand on the over-hang on the other end. And when you discover that the 1 3/4 maple won't bend or break.. proceed with your plans.

It will only affect the asthetics.. making it look slightly out of proportion. But frankly... who cares as it is a work-bench and not a formal dining room table. That doesn't change it's purpose. You can add longer strechers latter if you desire.

And if the twin screws work out so you have to go through the legs as mine do... that's what they make hole-saw attachments for the drill for. I looked at your legs and they should be plenty wide enough if they go through center. Otherwise.. offset or other arrangements will have to be made. I design bases the width to accomodate a twin screw as I have used one for awhile an find it very valuable.

Good luck...

Sarge..

[michael osadchuk]

I agree with John Thompson... I think there is sufficient "stiffnes" in the contemplated overhang of the 1 an 3/4" laminated top....

..... but I'm wondering why not put the 1 and 3/4" laminated top over the existing four layers of Baltic ply, instead of to "the base" (the 25-1/2" x 45-1/2"). This would give you a benchtop thickness of 1 an 3/4" plus whatever the the thickness is of the 4 layers of Baltic ply: lots of weight and "pounding" resisting. The overhang of the 1 and 3/4" laminated top would only be 6" on either end from the the 'existing' top.
...... although you certainly don't need to "stiffen" a 6 inch overhang of 1 and 3/4" laminated top, you could glue 6" wide strips sawn from the excess piece of laminated top to the underside of the overhang to "bulk" up that area for attaching a vise.


I don't understand Greg Hines' comment about not drilling dog holes in a "laminated top like that"..... I know that Lee Valley's own laminated benchtop - which are 2" thick - come with drilled dog holes........ the strength of the glue joint between 1 and 3/4" solid wood lamination is not going to be overcome by the clamping force used to secure a workpiece being planed, etc., between bench dog holes.....

...I think that one of the best feature of a laminated bench top is the ability to bring it into -and maintain - flatness; get a straightedge, fashion some winding sticks out of 90 degree iron rails with sharp edges and go to it with some fine planing......

.... I think $140 was good buy; one of the Lee Valley stores in Toronto has a few of their 10-3/4 x 2" x 72" bench top selling for $160 (Cdn.) each

good luck

michael

[John Thompson]

Matt, it probably wouldn't be a bad idea to build up under the over-hang to give that end vise some support and a better anchor. If you ever add a twin screw.. you would almost have to as the jaw faces are required to be thick and pretty deep. Mine is 2" thick and about 7" deep made of maple laminated with face glueing.

Between it and the front jaw which is 2 1/4" thick.. you have some pretty hefty weight. I'm not sure that 1 3/4" in that case would support it under very heavy clamping. You need a very solid anchor as I have 5 5/16" diameter lag bolts run through the back jaw to the table-top end.

Just a thought while you are still tinkering with it. Easier to do it now just in case than latter after the fact..

Sarge..

[Al Navas]

Call or send an e-mail message to Chris Schwarz. He will respond.


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[Wiley Horne]

Hi Matt,

Benchtop thickness. Where you really want the benchtop to be heavy is the first few inches back from the front edge. In other words, when you pound on something--like the end of a chisel--you want the bench to be 'dead' under the pounding, and to have zero spring. In my opinion, if you lag 8/4 maple onto the 1-3/4" laminated top, that will be sufficient, particularly since you can do your pounding over a legpost. That way, all the force will be carried instantly to ground, and it'll be dead to impact.

You could add a second 8/4 stretcher at the top of the front legs, immediately behind and up against your apron, and that would create a really deep front edge. However, that top stretcher behind the apron could well mess up your dog hole strategy, and might also result in the main nut for your front vise screws being placed far back from the edge, creating a long cantilever which would not be good. Just a couple of considerations, if the thought occurs to you to add a stretcher of that kind. All in all, I think you will be fine with the stiffness provided by the apron.

Overhang. Your existing base should work fine. That overhang you mentioned will be no problem, particularly with the 8/4 maple apron lagged onto the front edge. By the way, I suggest you make the legs flush with the edge of the laminated top, and that will support the apron, and keep it plumb. Plumb is very good in an apron, because it will mean that your boards being edge jointed will be situated plumb as well, and that helps you develop your own sense of plumb and square, and will help with your edge jointing.

Dog Holes. I have not heard of that issue that Dr. Hines stated, about dog holes in a laminated top (of course, there are lots of very significant things I haven't heard of!!). I think I understand the issue. However, it appears to me that a glu-lam top like that is effectively monolithic, and I would like to hear of someone's personal experience of glue failure or separation resulting from pressure from clamping against dogs. Maybe it's so, but I'm kinda from Missouri on that one.

Wiley

[Johnny Kleso]

First looks like your shop is plenty big enogh to not shorten the bench.....

Bigger is better, all you need to do is un-bolt the old strechers and make new ones...

If you cut the width you can use then strips for under the dog holes...

I would say dont plan your new bench around the old stuff.. Build the bench you want!!

The over hang at the tail end on my bench (mostly for hand planning) is not used as much as the front vise.. Most of the pounding, chiseling and chopping is donr near the front vise so I would worry about a long over hang...