Saturday, September 4, 2010

Installing the vise garter

Okay, bear with the photography.  I'm going to get a good camera for Christmas.

I was dreading completing the last task of making the vise for the bench, that of installing the internal wedge garter that locks into a groove on the top of the screw, so that when you back off on the screw, the vise chop automatically moves out with it.  I believe most ready made wooden vise screws now come made so that you purchase a nice brass garter, or two halves of a brass ring, that will screw right to the face of the vise chop.  But I bought my screw (I actually bought a pair) more than ten years ago, from an old gentleman who was, as far as I could tell, the only person in the country still making them.

His screw was made with a groove for a wedge - an internal, not an external garter.  This wouldn't be any big deal, except this requires you to drill and chisel and file out a mortise deep into the oak chop of the vise.  The mortise has to be precise - it has to wind up in exactly the right place, and with its inserted garter/wedge, must be a precision affair, locking with a smooth but play-free fit to give the vise a secure action.  There are lots of ways to weasel out of the job.  You could just drill in and put a dowel in there, for instance.  I saw a photo once of a garter that was a brass bolt that screws in from the side, and on its end is a nylon roller bearing that fits the groove...blah blah blah.  Which just proves that there are some people who will fine a machine shop solution to any and every conceivable problem.

Laying out the location of the mortise.

No doubt about it, I needed a proper hardwood wedge in a proper mortise.  I chose ebony, as I always have several pieces laying around, and once you start working with ebony, you will find excuses to use it.  It's wonderful stuff.

Using a marking gauge to lay off the thickness I need:

I just had to drill two 3/8" holes about 8" - 10" deep through the side of my vise chop, and have them intersect with the screw groove at exactly the right depth, and in the right place fore and aft so that the wedge would ride smoothly without binding.  You can see why I put this job off.

But, while waiting for some shellac to dry, I just tore into it.  First I measured the groove and started orienting in my mind how it would all go together.  I much preferred an internal mortise and wedge to a face garter - it's simpler and more traditional, and I can make it and repair it myself without having to buy expensive hardware.

At some point I couldn't put it off any longer, and I had to drill.  I don't know why but I chose to drill the top of the two holes (that would later be worked into a rectangular mortise) and it felt really right.  No way to know, though - it is too high up in the chop to enter into the 2" diameter screw hole.

Once that was done I did The Nasty - the actual hole that would cut into the screw hole and form the most important part of the work - the floor on which the wedge would rest as it intersected with the vise screw.

And it worked.  I can't carry a tune in a bucket, but I can drill a hole.  It wound up right where I wanted it.  My heart soared like the hawk.  All that remained was about an hour of chisel and rasp work.  Luckily I had a 3/8" square rasp (a tool I almost never use) and it did the trick.

And after some fussing and fitting, it all came together.  Good smooth action, full engagement into the groove, and solid glossy ebony that will probably not wear out in my lifetime.  I took my stub of a candle and greased everything up and the action in and out was super.  Some decorative file work on the wedge capped it off.

So the vise is finished.  Next job is the Roubo planing hook.

No comments:

Post a Comment