Arch top window

[Dokkodo]

Hi all, in a few weeks I have a project to do for some friends, they have an archtop window that needs replacing, about 6 foot tall and 2 foot wide.

The arch bit is new to me. I havent made one before and I was wondering whether anyone else had any advice to offer... I dont think im ready for steam bending, I imagine its a bit of an art? and the thought of my window unbending their cottage in half doesnt appeal... So my thought was to divide the angle into six or 8 segments, join those and then cut the radius out of that. I have read somewhere about 'brick laying' the segments in two layers, so that the joins are offset on each layer.

Does this sound ok? It will be made of hardwood, not sure which yet, and I imagine they wont mind the segmented approach even if its a stain or oil finish on the inside, i think it might even look quite nice.

any wisdom appreciated!

 

[Doug71]

The segment method will be fine, you won't need that many though, might only need 3 and 4. Offset them like you said, you can make the front ones the same thickness as rebate and back ones the thickness of back of window, saves having to cut a rebate in the arch.

 

[meccarroll]

Do you have any sketches with sizes for the proposed window?

No you would not steam bend the wood for this. Segments overlapped and glued or solid sections butt and held with M+T joints (or other joint) would be the way to do it.

A spindle moulder and bandsaw are very handy for this type of work.



Mark

 

[RobinBHM]

Thats how we make arched window heads, machine them in 3 layers overlapped. The large glue area is hugely strong.

If you like, you can overlap at the bottom of each arch, so forming a tenon joining the jambs.

These are great cutters for machining the curves

https://www.wealdentool.com/acatalog/On ... m_270.html

If its a radius arch, then make the template using a circle template router jig, easily homemade.

1 useful tip for a circle template, use a lath of timber, say 70 x 12 section, drill a hole near one end for the cutter to poke through, drill 2 mire holes to bolt to basd. Measure the length of your radius (be careful to remember which side of cutter you want) drill a hole at the centre of the radius. Then use the same drill to drill into your template material, I use 9mm mdf, then take the drill bit youve used and push through both holes.

 

[Jacob]

I've done completely circular windows and ones with semi circular heads. 4 pieces for the complete circle, two for the half circle, joined with wedged hammer head loose tenons (if you are into fancy trad joinery) or just as good - straight through pairs of loose tenons or slips cut in from the outer perimeter, and pinned with dowels.

 

[Dokkodo]

Amazing, great advice all!

I've done completely circular windows and ones with semi circular heads. 4 pieces for the complete circle, two for the half circle, joined with wedged hammer head loose tenons (if you are into fancy trad joinery) or just as good - straight through pairs of loose tenons or slips cut in from the outer perimeter, and pinned with dowels.

I was thinking loose tennons, but maybe ill have a go at the hammerhead at the bottoms of the arch depending on how im doing for time!

I have a bandsaw but no SM, just a fairly hefty router, I guess Ill do what I can with that and tidy up the rest somehow else.

The segment method will be fine, you won't need that many though, might only need 3 and 4. Offset them like you said, you can make the front ones the same thickness as rebate and back ones the thickness of back of window, saves having to cut a rebate in the arch.

Great idea thanks :idea:

Ill put some sketches up before I start to make sure im not missing anything, just waiting for more exact dimensions as they too far away to go and measure myself :?

one other thing, does anyone have a specific glue to recommend for this sort of thing? Pva/PU, or something else?