what would be the best way to make the curved corners on this stained glass window frame ?

I’m no expert, but what about a bridle joint with a dowel pin through on each end of the radius? Might make a nice accent with a dark wood.

-- Rick

I would laminate the strips right into the straights, and join as a tongue and groove.

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I would use my domino to join it. to get the grain to flow, I would cut the peice you are going to use and domino them together, then cut the curve.

Instead of dominos, you could use dowls or mortice and tennons

Callum

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I would orient the grain diagonally and use a spline joint or mortise and tenon with or without pins. The pins could be decorative or functional. Functional would be better. Round or square pins depending on design preferences.

-- Oldworld, Fair Oaks, Ca

Dan – Strength is paramount here, you also need stability.

I think that you need to use laminated wood throughout this project. Bending such a tight radius with oak will require thin laminates – you could pre-steam thicker laminates. Important thing (appearance) to cut, number and sequence the laminates.

I would make the structure in 4 sections, allowing minor X,Y adjustment for size.

Jointing the structure – I would think long bridal joints should be sufficient, but you you could make locking bridal joints if there is an extreme of pressure present. Do not forget the appearance of the joint, where it is going to be viewed from.

-- Tony - All things are possible, just some things are more difficult than others! - SKYPE: Heron2005 (http://www.poydatjatuolit.fi)

whats a bridal joint?

-- http://www.furnituremann.ca/

I dido Tony’s remarks. I think that would give you the best frame for looks and stability.

-- Jerry--A man can never have enough tools or clamps

Hi Dan, I’m with rickf16,
I would cut the radiused corner out of one pc. ( take a block approx 2 1/2 wide ) draw the corner on it so the grain would run the length of the block. I would also do the bridal joint, which is just like a tongue and groove. I think I would make the tongue on the radious pc and the groove on the straight pc. ( Reverse of the drawing),

Some more thoughts and considerations on the seemingly simple question (I hope you do not mind Dan).

I think there is a fundamental flaw with the idea proposed in the drawing by bentlylj. This piece would have 8 joints, thus doubling the chance of a joint failure, vs the proposal I made (not that my proposal is the only or the necessarily the correct solution).

in addition as you can see from the sketch below, the tenon does not fully fit with the curved part, therefore leaving an area, that must be plugged/filled.

you are also limiting the length of the joint, whereas in my proposal you could make each joint several inches long, without a problem, thus increasing the strength of the joint

You also have to consider the size and weight of the glass panel being supported (37” x 28” x ?” thick) it is going to be heavy and probably very expensive and irreplaceable. You also have to consider how the whole assembly (Glass and frame) is going to be supported when finished as this will effect the stress points and the way the frame reacts.

I hope this clears up my thoughts on the problem

-- Tony - All things are possible, just some things are more difficult than others! - SKYPE: Heron2005 (http://www.poydatjatuolit.fi)

You make the joint easily with the pieces then after fitting them, cut the radius with your router. This way it will all blend perfectly.

-- making sawdust....

Tony, You are correct about the tenon, that’s why I suggested making the tongues on the curved sections.
Note the reverse of the drawing.
Just for rebuttle purposes, (not meaning arguement in any way) I don’t think it makes much difference how many joints there are if they are strong.

I also looked at the reverse sollution you mentioned, but you then going to have a “Short Grain” problem on the tenons. However loose tennons would solve that problem (The timberkid).

Number of joints – you are correct the number of joints if made correctly should not matter, but sometimes things go unseen during manufacturing, therfore twice as many joints, twice the chance of failure of one of the joints.

-- Tony - All things are possible, just some things are more difficult than others! - SKYPE: Heron2005 (http://www.poydatjatuolit.fi)

I’m no expert with short grain situations, but I doubt that a short grain situation on a frame this size wouldl have an adverse affect. I could be wrong.

”things go unseen during manufacturing”
Gluing and clamping bridal joints???

I knew this was brain teaser …. I’ve been thinking about it for a couple days myself figure it would be a good question to ask in the forum section … I’m still not positive on how I’ll end up doing this thing.
appreciate everyone’s thoughts … Regards DAN

-- work from your heart and your spirit will live forever

Hi Dan;

You could always use edge banded plywood.

Just a thought.

Lee

-- by Lee A. Jesberger http://www.prowoodworkingtips.com http://www.ezee-feed.com

Hello Lee … plywood crossed my mind, but doesn’t really fit the requirement. Forgot to mention in my topic that the piece is to look really old or antique when done

I’m using ideas from both Bently and Tony. I adjusted my design a bit, making the cross section 1 1/4 on the face sides and 1 7/8 on the side cross section.

I’m thinking if the finished joint doesn’t look strong enough I’ll run a 1/8 dia x 6 inch brass rod down the center of the corners.

-- work from your heart and your spirit will live forever

I would have made the corners as a bentwood lamination, with the t&g turned 90 degrees to mate with the laminated sides.

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I have not had much experience with bent lamination. Only a couple projects. In the photo above, the corners as shown only has about 2 man hours of labor. The mortises are about 11/16 wide and 1 & 1/2 deep… that leaves about 1/2 inch stock for the shoulders. Looks pretty strong …

-- work from your heart and your spirit will live forever