How do I tackle a curved exterior door?

[lorna llan]

I want to make a hardwood (well, oak, chestnut or maybe larch) outer door for a round tower, curved to match the masonry doorframe. It would be about 2' wide, a section of a circle about5'6" (using imperial measurements because this is a retro garden folly). I want to make a simple door with about 5 narrow upright boards, braced across the back. I imagine I could very slightly angle the sides of each board with a table saw, so that when they were butt joined they would fit in the curve of the frame. Could a table saw make that very precise angle? I have a table saw but no experience of using it, yet.

Next question, once the angle is right, what is the opinion about joining the boards with glue? I plan to fasten the boards to shaped horizontal pieces on the back of the door. In an exposed position outdoors, would glue be a help or a waste of time? The door doesn't have to be as weathertight as a house door.

Grateful for any advice, including pointing out the snags I haven't even thought of yet.
Lorna

 

[SketchUp Guru]

Hi Lorna,

Yes, a tablesaw could be used to cut the bevels on the edges. I would use epoxy to edge glue the boards. It would be waterproof and very strong.

I think you would find it useful to layout the arc for the door full size and use that to figure the bevels and so on. Use a scrap of wood the same thickness and width as your staves to help with marking out. If you can do it, leave the inside of the door flat as it will make it easier to fit the horizontal pieces. In fact you can screw the staves to them as you assemble the door. That will help you with your sanity as you are working.

Cover the edges of the horizontal pieces with clear packing tape so the epoxy won't stick to them. After the door is glued up, you can remove the horizontals temporarily to clean up any squeeze out. Then reinstall the horizontals with screws only. Set the screws in counterbores so that you can plug the holes with bungs cut from scraps of the door lumber.

If you plan to have a smooth curve on the outside as opposed to facets, make sure the wood starts out thick enough. You could make a template for the outside curve from the full sized layout and use that to check the curve as you work off the corners. I can also see a jig for a router that wouldn't be difficult to make but it would make quick work of the rounding.

I suppose I could do some sketches for you if you'd like.

Edited to add: Consider starting the layout of the door from the center line and working outward. Then if you have to trim the door to width, the trimming can be done on both edges and keep the door looking symmetrical.

 

[lorna llan]

Hi Dave,
So, I might do it like this: make 2 or 3 horizontals for the back first, with five facets to mount the staves on. Screw on stave 1 from the back of the horizontal. Protecting the horizontal piece from glue, glue stave1 to stave 2, and mount stave 2 on the horizontal, and so on.

I would like to have a smooth curve on the outside the of the door, if I can get thick enough wood, but I can't imagine how it could be made with a router. What would the jig be like?

Thanks!
Lorna

 

[SketchUp Guru]

Yes, that's pretty much the way to do it. Depending upon the lumber you can get, you might need to work with narrower staves.

As far as a jig goes, you'd make a sort of bridge a bit longer than the door. The router would slide back and forth on the bridge and the bridge would move on a couple of arc-shaped pieces at the ends. I'll make a sketch for you. It'll make more sense.

 

[SketchUp Guru]

Would you clarify dimensions for me?

Is the circle 5'6" diameter or radius? Is the 2' wide, the chord length or the arc length? How tall is the door?

 

[lorna llan]

The circle is actually 60 1/2 inches diameter, radius 30 1/4 inches (768 mm).
The arc is 21 1/8 " and the chord is 20 1'2". (535mm and 521mm)
The height of the door is 66 1/2 " (1690 mm).

I would appreciate a sketch of that bridge.
Lorna

 

[SketchUp Guru]

Thank you for the information. I'll make a sketch for you when I get home from work in an hour or so.

 

[Steve Maskery]

What an exciting project! I'd love to have a folly which could take such a door!

As far as the smooth outside curve goes, I think you best best would be to do it by hand. You'd have to ensure that all the boards were assembled with the grain going in the same direction, but that would be easy enough. After the door is assembled (stainless steel screws BTW, counterbored and plugged), you could just plane away happily for an hour or two, until the surface is smooth. Make a template against which to test it at regular intervals.

For final sanding a ROS with a countour pad (foam sanding pand which sits between the ROS and the sanding disk ) would be perfect.

We demand pictures!

S

 

[SketchUp Guru]

I don't know what a folly is but if Steve thinks this is an exciting project, maybe I should have one. I'd probably be the only kid in town with a folly. :lol:

Steve's point about planing by hand is good and you might want to do that. If you want to use the router idea, here's a quickie sketch. Front left is the layout for the door and the horizontal members.

Center and right is the bridge for the router. The bridge needs to be wide enough for the base of the router to fit in and the sides need to be high enough to prevent it from sagging. The pivot is set at 30 1/4" below the desired face. You'd likely need to make several passes with the router until you get to the final depth. Make light passes to prevent chipout.

Looks like if you start with wood around an inch thick, you can make a door that is 3/4" thick or a wee bit more. I don't know how thick you want it but you can work that out with a full size layout. You might want to consider some thicker pieces on the edges for hinge mounting and so on.

Hope this is helpful.

 

[Shultzy]

Dave, in architecture, a folly is a building constructed strictly as a decoration, having none of the usual purposes of housing or sheltering associated with a conventional structure. They originated as decorative accents in parks and estates. "Folly" is used in the sense of fun or light-heartedness, not in the sense of something ill-advised.

http://en.wikipedia.org/wiki/Folly

This one and the Edgbaston Waterworks tower are said to be the basis of J. R. R. Tolkien's Twin Towers

http://en.wikipedia.org/wiki/Perrott%27s_Folly

 

[SketchUp Guru]

Thanks for that information. I'd best not mention that to SWMBO. I'm tall and often don't seem to have much purpose. She might call me a folly. :lol:

 

[compo]

Hey Lorna

Make sure you post some photos. Sounds like a great job :wink:

 

[dennis]

Lorna

As it is always better if possible to fix the thinner material to the thicker one option would be to drill and counter bore the boards and fix with screws then plug the holes with squared off pegs from the same wood as the boards left standing proud as a feature.

Dennis