Monday, April 9, 2012

60, Joinery, part three, Window frames.

With  the sander up and running I was able to finish preparing the timber for the window frames and assemble the units.

The machining of the pulley stiles proved to be a tedious chore, (most things I start seem to end up this way), each one needing to have a groove for the parting bead down the length of the face and cut outs, with rebates formed at the top ends to accommodate the brass pulleys. Many years back, when browsing through a restoration supplies store, I spotted a fantastic price labelled on these pulleys, I purchased about 100 of them, more than enough for my needs and stashed them away in the shed, below my workbench for "when I get a round 'tuit'"!.
By the time that I had finally commenced construction of the windows, I had forgotten about their existence and was investigating the purchase of more. I received a pleasant surprise when, as I was clearing the shed to create some more workspace for this part of my project, the dusty box was unearthed and it's contents revealed.
One slight issue that became apparent with these pulleys was that the solid axle was held captive by having its ends being beaten and flared outside the main casting. This necessitated the forming of a small notch at the centre of the rebate to allow the unit to be inserted. A trial fitting showed that the resulting gap was quite discrete so I proceeded down this path rather than risk damaging the pulleys with their modification. All going well, time will tell if this flaw in their design was the reason for the cheap price I had paid, not some other structural shortcoming. They seem to be quite solid solid units, being cast from solid brass.

Hidden pockets also had to be cut into the stiles, these being needed to access the counter balance weights, should any maintenance be required. I used a very finely kerfed, hobby saw blade, adapted to fit into a reciprocating saw to make the angled face cuts, this ensured a very neat, discrete joint. To minimise the width of the saw cut that runs along the parting bead groove, I fashioned a jigsaw blade from a section of fine hacksaw blade.
Normally, only the saw cuts  were carried out on manufacture, with the pocket being split out when repairs are required. To avoid the risk of any unwanted damage occurring in the future, should this be necessary, when some form of mechanical leverage would need to be applied from the faces, I removed them now by tapping them from behind.

The pocket piece, when reinserted, is held in place by the stepped "V" joint on the top and 2 brass screws at the bottom.

After having the parting and staff beads fitted , the pockets are well hidden.
When designing the windows, I copied, in general, the construction methods used in the recycled windows that I had restored for my original house, however, a few minor alterations were made from information gleaned from various referencing material. I had considered rebating the stiles into the linings, as appears to have been a common practice, but as my originals, (which I had procured from different sources), were not made this way, I opted away from that. I had also seen old examples of windows constructed using this method, suffering from splitting issues due to the necessary removal and replacement of the staff beading's during maintenance. The benefit of an absence of nail holes was also considered, but this advantage would have been superfluous, as all the staff beads, reveals and architraves will be face nailed anyhow.

The assembled frames, almost ready for painting and the next stage of the fitting of the sashes. To summarise; The stiles, of celery top pine are rebated into and screwed to the heads. They are rebated, wedged and screwed into the Lebanese cedar cills. The external linings, also of celery top pine and the blackwood inside linings are glued and nailed on. The screws and external nails are galvanised and past experience had taught me not to put any fixings into any of the pulley rebates or weight pockets!. Once the cast weights are installed, plywood cover boards will be screwed on the outsides.
Whether or not to install a "parting slip" to keep the weights separated from each other, is one issue which the jury is still out on, I have personally found them to be unnecessary if the windows are plumb and they can be a hell of a nuisance when trying to access the front weight during repairs.
To facilitate the installation of the splayed reveals, when the windows are in situ, I am also considering running an angled groove down the inner linings, into which a tongue on the reveal will slot.
Another issue which has been haunting me is the method of how to actually fix the window into position in the stonework. My head has been tossing around all sorts of ideas for brackets etc., however, nothing real simple has, so far, come to mind.

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