How can I modify Sash window frames??

[john777]

Hi,
Need some advice on if it is possible to modify the 2 existing sash window timber frames in a double hung window setup.

I have picked up a 2nd hand double hung timber window with the old steel weights and cords setup in good condition.
The window is the correct width but approx. 400mm too high, so I am thinking to cut down and modify the 2 sash windows if possible. I have replaced sash cords and window glass before so am OK with this part of the work.......the top part of the window frame can be easily pulled off and reattached after the 2 vertical stiles have been cut down to the correct height.

The question is can anyone advice on how to cut down the height of the 2 sash timber frames without damaging mortice+tennon joins??.........I need to reduce height of both sashes by approx. 200mm each

I have demolished old timber sash frames before and these come apart easily by pulling the corner tenon out from the mortice after a few wacks with a hammer. I figured after cutting down the 2 vertical sides of the sash timber frame the only thing I need to do is recut new mortice holes an refix with glue.
Question ........will this work? .......what are basic tools required to cut mortice?

(the cost of new window which I need again with cords and weights is approx. $900-1000 so I think it may be worth modifying old frame)

cheers
:roll:

[SilentButDeadly]

You'll either need to make new sides for each sash or cut down the existing sides and redo the tenon on one end of each.

If you don't know how to do this well (and it seems you don't) then I don't want to discourage you but...

And having rebuilt such windows before...my time and effort plus the glass, putty and paint is worth the $900 for a new window.

Incidentally, a single light (or double light) double hung window from Sydney Woodworkers at Brookvale shouldn't cost you anything like that...more like $400 to $600 depending on size

[john777]

You'll either need to make new sides for each sash or cut down the existing sides and redo the tenon on one end of each.

If you don't know how to do this well (and it seems you don't) then I don't want to discourage you but...

And having rebuilt such windows before...my time and effort plus the glass, putty and paint is worth the $900 for a new window.

Incidentally, a single light (or double light) double hung window from Sydney Woodworkers at Brookvale shouldn't cost you anything like that...more like $400 to $600 depending on size

Yes I know the Sydney Woodworkers at Brookvale........the mainly do modern setups using Spirals .......not the weights and cords the last time I checked.
The house we are fixing is an 1800's Victorian terrace with all windows having cords and weights which work great. The new window I need to fit needs to go into an existing cutout in brickwork which will only work with the old style.

Can a Mortice hole be gut using basic tools such as drill with spade bit and sharp chisel?? .......The Tenons I hope to salvage from the existing timber frame
Also I have seen tenons with a couple of slices made to take wedges when fitting.......is this the easiest method to glue and fit?

[barney118]

Yes, it can be done with basic tools. I pulled one apart and did exactly that. I drilled a couple of holes slightly under then chiseled out and used a square file to tidy up. You might notice the tendon joint is held together with tiny wedges. I had to make a couple up. Time consuming but can be done.

[Black Cat]

It might be easier to modify the opening ... I plan to do that for a sash I picked up for a song the other day. My side window is smaller than the other three anyway, so it seems a good way to go (that, and the framing around the window is pretty dodgy and has to be replaced anyway ...)