Disassembling wedged M&T joints

[Setch]

I am in the process of cleaning up an old school woodwork bench, of the type I@m sure most users are familiar with:

I acquired this a good few years ago from my old uni' workshop, and I'm finally getting round to cleaning it up. I've knocked the base apart, and all the fixings are marinading in WD40, whilst I plane/scrape the worst filth off the faces of the frame. The frame is comprised of two roughly square assemblies at either end, which are bolted to a stretcher at floor height, and to the bench top, via coach bolts under wooden plugs. Racking is prevented by an apron under the top, which screws to the end assemblies and sits flush with the bench edge.

I've got everything apart, and with a light plane/scrape cleaned it up well, but the end assemblies have some slack in the joints, and I'm tempted to separate them, take the opportunity to plane the inaccessible faces and corners clean, and then re-wedge the joints to remove the play.

Any thoughts on whether this is a good idea, or how to separate the joints? They appear to be wedged above and below the tenon, rather than into cuts in the tenon itself, but despite the slight gappy-ness and movement in the joint, seem reluctant to come apart...

My final plan for the bench is to flip the top over and refit it, which reveals a nice level-ish, clean top. The current top surface is very scarred and rough, and despite hours of work when I first got the bench is still studded with more screws and pins than your local B&Q, testimony to thousands of boring lessons spent knocking in nails to pass the time. Flipping should also allow me to reverse the vice location, making the bench left handed, like me.

 

[AndyT]

Two thoughts on the M+Ts:

Chisel out the exposed tenon, dismantle, re-build with loose tenons. OR

Leave it as it is but fix the wobbles by glueing in some extra wedges.

 

[Racers]

Hi,

You can pull the wedges out with a long screw and a slide hammer, if they are loose and you take it easy.
You will have to make new steeper wedges.

Pete

 

[Phil Pascoe]

If you can't get them apart, cramp them up tight, drill holes at the bottom of the mortise and inject plenty of glue. You could drill holes to match any dowels have and dowel them for extra strength.

 

[Mr T]

Hi

It depends when it was made, but if animal glue was used for gluing up applying some hot water to soften the glue before trying to pull out the wedges might help.

Chris

 

[Matt@]

drill them out using a very thin drill bit first (that goes to the start of the wedge) then increase drill sizes as wedge gets fatter, then remove waste with small chisel . A messy way of doing it, some guesswork involved but if all else fails, its better than nothing!

 

[Setch]

Thanks for the responses.

The bench was made in March 1950, 'cos this is stamped on the underside of the benchtop (DT / LCC / 3/ 1950). The glue line looks very much like aliphatic resin or PVA. I think I'll try Pete's solution first, sounds like my kind of plan.