Two or four stretchers?

Re: Two or four stretchers?

Scott in Douglassville, PA

>I put in four, plus two going front-to-back in both sets. I guess, depending on how you attach the top, you might be ok with just two.

I'll be interested in what others say on this'n...

Scott, raining south of you

Re: Two or four stretchers?

Bob Rozaieski

>I don't think I need any front to back since I have the 3" square feet and top caps (I guess they would be called stretchers too?). They aren't even pinned yet and the M&Ts keep the assemblies stiff and square. Plus it's only about 13" between legs (25" total front to back) so I think I'll be ok here, I hope! Now you have me thinking!?

Re: ways to skin a cat

paul womack

>Without doing an engineering analysis, I can't say what you need.

I can give you 2 extra options though, over and above the 4 stretcher solution you propose.

* deeper stretchers at the point of attachment; the "Kirby trick", as shown in the workbench book.

* since the point is to counteract racking use diagonal bracing; either a simple brace, or a full panel.

I used both tricks

Bill Taggart has (I suspect) one of the most strong and rigid bench bases in the whole US of A.

BugBear

Re: Two or four stretchers?

fmutchler@adelphia.net

>Bob, if you will be doing heavy planing I would certainly suggest 4 stretchers. The bench may not rack with two stretchers initially but I am willing to bet you will have problems down the road. If you are going to put in cabinets that would be screwed to each other and also to the inside of the legs you would probably be all right without the upper stretchers. I don't think you need any additional bracing front to back on the legs.

Re: Two or four stretchers?

Scott in Douglassville, PA

>Your setup is a little different than mine - I had post legs, stretchers right-to-left between, and then the front-to-back stretchers as well. I had an old 2x4, um, bench (a hand-me-down from a well intentioned neighbor) that, when loaded up with storage, the right-to-left doubled up stretchers bowed out. I was worried about an eventual cabinet doing this to my real bench, so I added the additional stretchers. FWIW. Not sure that this applies to your configuration.

Re: Two or four stretchers?

David Linnabary

>A single pair of 5"-6" wide stretchers will be quite sufficient to resist a surprising amout of racking force. Positioning it mid way up the leg is what I prefer, mostly because it allows me to stand and sit nearer my bench. Nothing like pulling up a stool and working at your bench.

Oh and try to imagine sweeping around stretchers positioned near the floor.

David

Thanks! Nice Bench!

Bob Rozaieski

>

Re: Two or four stretchers?

Bob Rozaieski

>Never though about the sitting/sweeping factor. My original thought was to put the stretchers low enough to allow the incorporation of a sliding board jack and let the bench top support the racking resistance, sort of like Dunbar's bench. I of course won't be able to mortise my legs into the bench top with my design but I was thinking about droping the bench top over some thick dowels in the top supports or other similar fastening mechanism. Seeing as the top will be laminated, and essentially quartersawn across its width, movement should be minimal. And if I assemble the stretchers with bolts, I can always disassemble if I move. The bolts would also permit the addition of an additional stretcher later if racking proves to be a problem.

Re: Two or four stretchers?

Ted Shuck, Centennial, CO

>When I built my bench I used the same approach; two stretchers positioned about halfway up the legs, each about 6" wide.

The reason I took this approach is that I had read somewhere (?) that the resistance to racking is proportional to the square of the width of the stretcher. By this logic, one six inch stretcher is more effective at resisting racking than two four inch stretchers.

Ted

Re: Two or four stretchers?

Wiley Horne--Glendora CA

>Hi Bob,

I'm pretty sure that lower stretcher alone, especially at 3" in the critical dimension, is not gonna cut it. In The Workbench Book, Ian Kirby (p. 238-9) shows a doubling (at the point of connection) of a single 3" stretcher, as Paul Womack points out, in order to get a much wider tenon into the legs.

Another thought: If you think you might want to add drawers later, you might fit a 3/4" plywood shearwall into the back, and route dados to take vertical dividers--just a thought.

The Kirby design that Bugbear points out is really worth a look.

Wiley

Re: Two or four stretchers?

Bob Rozaieski

>Not sure I understand the 3" critical dimension you refer to. The stretcher would be 1.75" thick x 5" wide. Do you mean a 3" wide tenon? I was going for more like a 4.25"-4.50" wide tenon. I figured 0.25" shoulders would be enough.

Stretcher design

Louis Bois

>This is how I'm making mine...I haven't finished installing the tail vise yet, but have clamped a few boards to the top for planing. This baby does not move at all. The top is sitting on a couple of bullet dowels like Frank's bench.

I've also shown one method of getting around the sliding board jack issue...since my stretcher is a bit higher up the leg.

The rendered image also shows a very short form of the bench...it's actually a few feet longer than shown and the board jack slides all the way to the tail vise jaw.

Here's the pic...

Louis Bois

>somehow didn't make the previous post...

I made a mistake

Wiley Horne--Glendora CA

>Sorry Bob,

I read your post too quickly, and got it wrong. As Bugbear said, it would take an engineering analysis to answer.

As a comparison, the Kirby bench uses most of a 6" effective stretcher (say 5-1/2" actual tenon height); the tenon is all the way through a 3" leg, and wedged, simulating a dovetail connection; and its lower edge is 9" off the floor for a bench whose top is at 34".. For whatever it's worth....

I apologize for my error,

Wiley

Re: I made a mistake

Bob Rozaieski

>Not a problem, just wanted to be sure I understood.

Mine, too

Ted Owen, Pittsburgh

>

Re: Two or four stretchers?

Ernie Miller Topeka

>used 4 and decided to p;ace tool boxes on the bottom streacher. I'm happy with it and it dosen't rack or scoot across the floor.

Re: Two or four stretchers?

David Linnabary

>I don't know lever theory but I think there's a mechanical advantage to positoning the stetcher midway up the leg where is concerns racking. Anyone???

Two ways I deal with the jack board issue, one is to trap the jack board in the tail vice. The other, for shorter boards or panels, is to just trap one end of the work in the shoulder vise and "quick clamp" the other end to the front skirt of the bench. Obviously you turn the clamp out of the way to the underside of the bench. I made some funky traditional style blocks that hang from the dog holes to trap odd shaped panels but they're not nearly as convenient.

I've come to appreciate being able to knock down my bench with 6 bolts. After my divorce I was a somewhat nomadic woodworker for a while. :)

Good Luck

David

Re: Two or four stretchers?

Jim in Burlington Ontario

>I have 2 and for sure there will be 4 on the next bench. I'll also make the next one with no bench bolts. At worst if it ever needs to come apart I will cut.

I just built

CJ McLaughlin

>the bottom bench base with four stretchers. It's bomb proof. I used 1/2" dia. x 6" long bolts to hold it together.

cj