Curved rails and the tenons that go into them

[Highland Pairos]

A friend of mine approached me with a rough drawing of a driveway gate design today. The simplest way to describe it would be a frame and panel design, except that instead of a panel it would use slats or pickets in the field. The design would use a curved top rail and straight stiles and bottom rail. We had envisioned using M&T's to attach the slats to the rails. While it has raised numerous questions in my neophyte mind, the biggest one for now is how I would cut the tenons and their shoulders to go into a curved frame. I imagine that I could establish a line where the shoulder should be and rough out the material in an expedient manner and then work to the line with chisels, rasps, files, etc. Is there a better, more consistent, more expedient way to do this? Did any of this make sense?

SteveP.

[Juergen Hannappel]

[...]

What if you make the mortises in the top rail big enough to take in the whole slats? That way there are no curved tenon shoulders.

[jim]

What about creating a flat area where the shoulders attach so they could also be straight? I've never tried to make curved shoulders on a tenon, but I think it would be a bear.

Jim

[musials]

The simplest solution would be to rout a groove over the entire length of the top rail. Put in your pickets and then fill in the space between them with blocks wood thus creating your mortises after the fact. I would also dowel the pickets in place from the sides rather than from the top.

[Larry Jaques]

On Sat, 21 May 2005 03:32:55 GMT, the inscrutable "Highland Pairos" spake:

Grooves can be routed the entire length, then filler pieces placed in between the slats. I've seen that done to save time in wannabe M&T furniture.

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[Highland Pairos]

I'm liking the idea of a groove the entire length of the top rail, not cutting tenons at all and then using filler blocks. Is there a downside to eliminating the tenons all together?

SteveP.

P.S. Just wait until I start working out the structural integrity issues of this thing.

[Larry Jaques]

On Sat, 21 May 2005 19:59:16 GMT, the inscrutable "Highland Pairos" spake:

It's neither strong nor pure as far as joinery goes. Add a tension cable from the top of the pivot end to the bottom of the swung end. A turnbuckle can be used to keep it semi-square.

WHAT structural integrity?

- The only reason I would take up exercising is ||

so that I could hear heavy breathing again. || Programmed Websites

[C & M]

If you're afraid that the spacers/ filler pieces would eventually fall out, you could cut them into the slat, lookingkindo of lime this if layed on its side: [[===]]

It would require cutting each side of the slat in order to provide the filler at the top and an opening between the adjacent slats. HTH, Chiz

[Highland Pairos]

One of the big issues is going to be the fact that each panel will be seven feet from the latch to the hinges. My friend (who is a carpenter) was thinking that the rails would be 2x6. He is using a gate that is at a house he is working on as a model of what he wants. I will be curious to see what details he discovers about it.

SteveP.

[Larry Jaques]

On Sun, 22 May 2005 03:28:37 GMT, the inscrutable "Highland Pairos" spake:

Damnit, man, MUST you top-post?

Will this be painted? For integrity, he might use a few short vertical cables pinned between the rails, spaced so they can be a feature or point of interest.

- The only reason I would take up exercising is ||

so that I could hear heavy breathing again. || Programmed Websites

[Highland Pairos]

I believe the plan is to keep it natural. That will make forming the top rail a challenge. I asked him to try to look for glue lines on the prototype, but I have already started working out how to piece it together out of reasonable sized pieces of wood. There will be much template making and testing long before the real wood gets cut. I will raise the idea of vertical cables to him and see what he thinks. Are you envisioning a turnbuckle type arrangement?

SteveP.

[Juergen Hannappel]

[...]

1) Find tree grown in a shape that is very near to the wanted curvature 2) Have a party 3) Split tree from step 1 into two halves, hew/plane split faces plane, thickness other side, bandsaw-joint upper and lower faces, tidy up.

[Charles Spitzer]

think of how you'd replace a broken slat.

[Charley]

If I had to do that I think I would probably try to build a fixture that I could position on the curve that would allow me to use a plunge router to make the mortices at the correct position/angle. For the tenons (and possibly the mortices), I would use my Leigh FMT jig (because I just got it), but you could quite easily build a fixture (like a T with a hole in the center of it) similar in shape to the FMT jig that would allow you to rout the end of the slats and make the tenons. The slat would be clamped to the verticle leg of the T and the router would ride along the top of the T cutting the tenon through a hole in the center of the top of the T (tough to describe).

Like the other responder, I'm wondering how you would repair this thing at a later date. Possibly you could make the curved rail removable so replacement slats could be installed. You might also consider making a sub frame that would hold the slats and then fasten into the larger frame. It could later be removed and repaired without dis-assembling the whole gate.

[GrayFox]