The 8th installment today - see blog archive to right of this page for previous posts.
I commenced work on the various hinge and pivot assemblies today. The spindles, or axles, for the swing out legs are to be solid Lignum Vitae. I will need to turn these spindles using a metal lathe, a machine I have spent a fair amount of time on when I was a younger man. I friend of mine has agreed to let me use his metal lathe this coming weekend for that task.
In the meantime, I machined a 0.75" square tenon on the end of the axle - this tenon, along with its opposite number, will engage in a yet-to-be cut mortise in the inside face of the short frame rails. I started by dragging my marking gauge over the end grain to define the tenon:
There's no wood material harder than Lignum Vitae end grain, as far as I know. It takes a few passes to get the mark in there so it is readily visible, and my gauge is sharp (er, perhaps better to say, was sharp).
A few machining steps later with my router, and the tenons were done:
The tenons are only going to finish at 1.0" long or thereabouts, but I cut them at about 1.375" length so that the live center on the lathe can dig into the end (the last portion of which will be trimmed off afterwards).
I kind of dropped the ball with the camera work today as I was in a bit of work groove and forgot to take pictures. I cut sections from the main support bolsters, and dressed the faces flat, again using an MDF jig and my router. These rebated sections form ledges for the main frame rails to rest upon when the bench is in the lowered position.
Then I set about mortising the inside face of the rebated area for some Lignum Vitae inserts. As per usual, first I drilled out most of the waste, then routed, then trimmed with a chisel. in that case I had to chop most of the way on the end grain surfaces as there wasn't enough room for my router (and I decided not to spend another half and hour making a separate jig):
Chopping Wenge end grain is a bit exciting, as the bits of wood can blast out of the mortise like bullets. I kept my head back from the line of fire - otherwise eye protection would have been a good idea.
A bit of chopping later, my chisels were definitely ailing but the mortises were done:
Then I machined up some Lignum Vitae for the inserts- these are to be drilled later for the main pivot pins for the bench, which will also be made from Lignum Vitae. Here's a trial fit of one of the 1.5" square inserts:
Then I glued 'em up and tapped them into place:
I'm not sure at all how well the glue will hold to either of these materials, however the fit is pretty tight and the insert piece is captive, so it won't go anywhere even if the glue is ineffective. The glue is simply extra insurance at best.
Here's the two bolsters with inserts fitted, waiting for the glue to set adequately:
Later on, I machined down the protruding inserts so they that were about 0.01" proud of the surrounding material. This will preclude the end grain side of the frame rail from rubbing on the side grain of the bolster from years of raising and lowering:
A little closer look:
The hole for the pivot pin will be 1" in diameter - here I've marked out the intersection of that spot on the insert:
Tomorrow I'll make inserts for the upper portion of the leg pieces in the swing-out assembly, and do the mortise/tenon for the stretcher that connects the two legs. I've also got a little mortise and tenon work to connect the Lignum Vitae spindles to the cross pieces. It's getting there - my plan is to put the oil on in a couple of days.
I must say that it has been tough working such extraordinarily hard materials. I'm starting to have dreams about things like Basswood! Of the two I'm playing with currently, Wenge and Lignum Vitae, I would say I prefer the Lignum Vitae, though perhaps not when it comes to running a hand plane over it. The Canarywood has been no picnic in the other project either.
That's all for today folks - thanks again for your time. Post 9 is next.