How to make a round window frame?

[roger wiegand]

One of the last projects I need to do to complete the interior trim on our house is to build a frame for and trim out a round (interior) window. The window came from an 1830 building at Harvard and was rescued from a dumpster by our architect 30 years ago. I've rebuilt and re-glazed the window itself, which will end up painted.

Now I need to make a frame for it. All of our interior woodwork is cherry. I've thought basically that I need to make a round piece that fits into the octagonal hole in the wall, coming out to the wall surface on each side then set the window inside of that with appropriate curved moldings. The frame on top of that can be simply applied to the wall. I've attached a picture of my current design concept, as well as a picture that puts the window more in context and shows what the other woodwork looks like.

I'm not sure of the best way to build the round frame. My first thought was bent lamination, and I've already cut and prepped thin cherry plies that will bend into that size circle. How to keep everything lined up and then pulled tight then? Again my first thought was a full size interior circular form made out of particle board or such where I could wrap the plies around and secure them with a band clamp. Past experience with this method is less than encouraging i terms of not having any gaps and getting perfect contact all the way around for 4-5 plies. Would a vacuum bag be easier? Should I try to do it all at once, or just add one play at a time, independent of holding method. The edges will be visible at the reveal so have to be both cherry and decent looking.

Is there an easier/better way to go about this that I've overlooked?

I thought about doing an enormous segmented turning, but I'm not sure all the joints would look good. It would be fun to try turning something 3 ft in diameter.

Bending ply might be easier to form into the right shape, but then it would need to be veneered on the inside of the circle and edges, which also seems challenging.

Thoughts or directions to a reference on how it's done by folks who know what they're doing would be appreciated.

TaviQHtYSUS01exsLWtlRA.jpg IMG_0790.jpg IMG_0791.jpg window.jpeg

First picture is the window, second the hole, third the hole from a distance, and fourth, the intended window design. The triangular areas will be birdseye maple like on the other windows, with the rest of elemts cherry, differentiated by using different thickness of wood to create reveal line.

[Darcy Warner]

I would do a segmented glue up with 8/4 cherry, bandsaw close on outside, maybe even cut through and do inside and then use my shaper with a template.

[Walter Plummer]

I think the segmented method would be the most reliable and probably the easiest. I don't think the joints would be a problem as long as the color is consistent.

[Jim Becker]

What Darcy said--segmented glue-up--and if no shaper, do an alternative milling method by using a trammel and multiple cutters in a beefy router to gradually form the profile. Or do the glue-up and have someone with a CNC cut it for you.

[roger wiegand]

I'm having trouble thinking about using a shaper-- we're talking about a hoop that's 5-1/2" tall and three feet in diameter. The tallest cutters I have are only about 2". Would you use a 6" tall cutter? That sounds scary. Making a 40" faceplate and turning it outboard on the lathe seems more feasible. Or am I completely misunderstanding the suggestion?

[Kevin Jenness]

Laminate two half circles with a bending ply core and cherry face, using epoxy, a male form, and a vacuum bag outside the form. Strap clamps to pull the layup into shape, bleeder fabric inside the bag, the form more than a half circle. Trim the edges, then the legs and join the halves together with biscuits and strap clamps. Band the edges with segmented cherry and trim flush. Depending on the radius you may be able to use the same form for laminating the stops, or make a form to the inside of the stops and pad it out for the jambs. Do a test to see if adjustment for springback is necessary.

You could segment and bandsaw the jamb halves, but it will take a lot of material and sanding the female curve. Shaping a bricklaid blank will take a heavy shaper and tall tooling with potential for tearout on the uphill parts. Laminating works well for jobs like this of any width. You can pre-sand the faces and get a cleaner look than bricklaying. I like to use 1/8" bending poplar for the core. It takes less force than all solid plies.

[Darcy Warner]

If you use a template and bottom bearing pattern head, you can take small bites. Do half, flip over with template on other side.

I would turn it on my lathe too, more than one way to make chips.

[Bob Coates]

Segmented perhaps 48 segments to a ring. Also if the window is frame is 5 1/2 inches deep(tall) how about making multiple rings like you would for a bowl or vase and build to the 5 1/2 inches. Make a plywood, or mdf to support the router and shape each ring as you build. OR
If you can turn 3' go for it.

[Paul Girouard]

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I’m prolly not understanding a few things , the frame is square or a retrangle so IF this assembly where to be made ONLY the premeter of the round window , which I assume fits into the round center hole needs to be the depth of the wall the entire assembly fits into. The triangular areas would be mounted on GWB and or framing IF this where a regular square window opening.

So you’d have two interior grade rectangular frames , connected by the center round section that the spoked window fits into.

Is that understandable ???

You can buy pre-formed plywood cylinders , I’d attempt to find one with a inside diameter that closely matches the OSD of the spoked window.

That could be veneered , or possibly even be ordered with the Cherry veneer you decide. The cylinder could then become the form you start your lay up on.

This is a really cool project! Your window wall appears very well done, did you do that trim out as well?

[Mel Fulks]

I've always used the segments . But I've never used the shaper to trim them. I use the bandsaw to make a block that is
just a bit smaller radius than frame. Then use double face tape to stick block onto pad of belt sander.

[Kevin Jenness]

Paul makes a good point about premade plywood cylinders. Here are two sources (I have no experience with them) https://www.kellerwoodproducts.com/h...d_consoles.php https://www.roberts-plywood.com/full-circles.html. If they have a stock size with interior cherry veneer that works for your project it would save you a lot of time.

[roger wiegand]

Cool-- Keller offers cylinders that are large enough in diameter, and they aren't very far away. I'll give them a call in the morning.

Yes, I did all the interior trim and floors in our house. The rest of the windows were just flat and square, so no real issues in trimming them.

[Paul Girouard]

680D15BA-F945-49AD-B013-CBE65DFB9122.jpgThe round trim I’d segment and rout a MDF ring that matched the inside and outside diameter on the what I’d call round casing , once the thru wall round section is made the ring could be routed to flush up with of just slightly overlay the face of the plywood ring.




I’d lay up the segmented casing over sized then rout it to the round shape using the above routed MDF form.

The segment you could use pipe clamps as it would be a octagon at the glue up time.

[Paul Girouard]

Cool-- Keller offers cylinders that are large enough in diameter, and they aren't very far away. I'll give them a call in the morning.

Yes, I did all the interior trim and floors in our house. The rest of the windows were just flat and square, so no real issues in trimming them.

Really nice work!
Break this window into pieces in your head. Once the round part is made up the square parts sort of just jigsaw puzzle in and around the round center.

There’s a few different suppliers on the round cylinders , I don’t recall who I got the last rounds from for the last round relight window I did. I still have a left over about 7 or 8” wide IIRC , I could check the diameter on the piece I have , if it fits I can ship it to you.

[Steve Jenkins]

I’ve used the Keller Products cylinders quite a bit and would go that route. The cylinder is ply not mdf. I’d then resaw a single piece of cherry to veneer the inside and segments to cover the front edge. I’m assuming the outside face doesn’t need to be cherry.