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Neal Clayton
12-08-2008, 5:50 PM
someone on an old house related site asked for help with window construction and i promised to post pics next time i built one, so i figured i might as well post it here too. information on the 'net is pretty sparse as i remember it as it pertains to window construction, i had to learn by trial and error when i started this a few months ago, so here ya go, might save someone else some trouble...

these were built with some cypress i brought home from new orleans, they were originally 2x8, 16 feet long. these windows are 1 3/4 thick with 2 inch wide stiles and a 3 inch wide bottom rail, so discounting planer snipe and what was lost from the edges in the jointer, it took almost exactly one board to build one complete double hung, minus a couple of ~6 inch squares that were left over.

this is the top sash of a double hung, the bottom sash is a single pane so basically just the reverse of the top.

from left to right...



the inside of the sash
the outside of the sash, window rabbet is 1/2 x 1/2
the top of the muntins with the coped inside face
the bottom of the muntins
the muntin mortises

the cut for the sides of the muntin tenons winds up being about 1/8, or, all you can cut without hitting your cope profile with your table saw blade. you could cut more, of course, but that would require handsaw/chisel work.

the muntin mortises are flush with the glass rabbet on the outside, and about 1/8 deeper than the glass rabbet itself. the end of the glass rabbet on the muntins is therefore cut 1/8 from the end to compensate.

since this is a double hung the bottom of the top sash and the top of the bottom sash interlock to form a square middle for an interior turn lock, so the bottom of the muntin in this example is square across, only the top of the muntin is coped. also, to create the same 'reveal' on the inside of the window, the stiles and top rail are a half inch wider than the middle two rails, due to the stiles sliding in a 1/2 inch deep channel on the window frame (old style mechanisms, pulley/chain/counterweight/spring bronze weatherstrip).

the muntin mortises are flush with the glass rabbet on the outside, and about 1/8 deeper than the glass rabbet itself. the end of the glass rabbet on the muntins is therefore cut 1/8 from the end to compensate.

continued...

Neal Clayton
12-08-2008, 6:00 PM
here's the rail/stile corner joints. open ended bridle joint i suppose you'd call it? in addition to glue it seems prudent to drive two finishing nails through the joint at a 45 degree offset, to stop any tendency for them to pull apart or lean from side to side.

and the last pic is a pic of the single pane bottom sash, which is just the top sash without muntins, and a 3" bottom rail that has the proper angle to match the frame beveled toward the outside for water drainage. and again the 1 1/2" top rail that winds up directly in front of the bottom of the top sash.

critiques from pros welcome, i started doing these just a few months ago and from reading 'modern practical joinery' from 1902 (which is neither modern or with power tools practical ;)), and 'woodwork joints' from 1920, as well as examining older windows that i came across at junk shops, this seemed like the feasible and proper way.

for others who may be interested, 'woodwork joints' is free now, author long dead and publisher is gone, so you can download or peruse it free here..

http://chestofbooks.com/home-improvement/woodworking/Woodwork-Joints/index.html

these are the google sketchup plans i started with, they don't show the router/rabbet detail, just the square board dimensions...

top sash (http://xayd.nbfl.net/topsash.skp)
bottom sash (http://xayd.nbfl.net/bottomsash.skp)

i think i added another muntin to the top after starting as well, but otherwise the drawings are accurate for this particular window.

Derek Stevens
12-10-2008, 3:07 AM
here are some shots of some of our sashes in the shop, and a pic of a 3 gang installed. I'll dig up some dimensioned drawings from the last century and post them if people want to see them.103245

103246

Neal Clayton
12-10-2008, 7:25 AM
someone else asked me about the thickness, and the short answer is, i dunno. the originals these were built to replace are 1 3/4 thick, i'm guessing due to the large'ish size of the opening (~44x70).

these will be put in the existing frame so to match the original pulley placement the thickness had to be matched.

and yes old drawings would be awesome derek, i'm especially interested in intricate patterns as i mentioned in the PM to you. when i get the ones i need built done, i'm gonna try to tackle some diamond pattern sashes.