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Leg mortises into Top?

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As i look over the plans i see the legs are mortised in to the top one inch on each leg.  Since the top is held down to the base with the spax fasteners, what is the purpose for the mortises? I do not see any draw pegs. Just curious.  Thanks

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The spax screws will pull the top down onto the base, but they do very little to fight any sideways movement. The mortise and tenons in the legs prevent the top from moving around on the base.  There could be some movement from seasonal wood shrinking and expansion, and these are such thick timbers that the screws would just bend.  In addition, the leg vise itself pushes against the edge of the top slab.  Without something to resist that force, the top slab could move backwards and not be aligned with the base.

 

If you are not wanting to do the full mortise and tenon, at least plan to put in a couple large dowels at the top of each leg.  These could be just 1" dowels to connect the top and legs.

 

Hope that helps!

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I have no problem in putting the mortises in the top.  I see Chris Schwarz has pegged his tenons to the top in his book "Workbenches".  Just thought it was missed on the plans here.

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In addition to the points Aaron made, the spax screws are also fastened with an elongated hole to allow for movement of the slabs...which means they're even less effective at preventing lateral movement.  The screws simply hold the slabs DOWN onto the stretchers, the tenons are needed to keep the slabs from moving around. 

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I see Chris Schwarz has pegged his tenons to the top in his book "Workbenches".  Just thought it was missed on the plans here.

 

As far as pegged tenons, this makes them "mostly" permanent.  You could always drill out the pegs, but it's not going to be easy to take apart the joint.  The bench Marc built was designed to be disassembled if needed.  By using the spax screws and avoiding pegs, you can take off the top.  Then the base will come apart because of the bolts used down there.  If I recall correctly, Schwarz used drawbore pegs everywhere in most of his benches - so they don't come apart.

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