A question about loose tenons

[Derek Cohen]

Kevin, you may not be aware, but I built seats with integral tenons, and then decided that they were a poor risk as the tenons showed grain run out. What may not be apparent in the photos is that the tenons angle at 14 degrees. I was not prepared to take the risk. With loose tenons, I can choose the stock and orient the grain for maximum strength.

Regards from Perth

Derek

[Jim Becker]

I think that's a good approach, Derek. Make the loose tenons so that they provide maximum benefit relative to the (extreme) forces that come into play on a chair. I'm sure you've done this, but take sample tenons with both grain orientations and stick them into the mortise. Then sit there are stare at them, visualizing how someone sitting their (impressive) butt in the chair will affect the forces on those tenons holding things together. The mind is a great tool to visualize this.

[Kevin Jenness]

Kevin, you may not be aware, but I built seats with integral tenons, and then decided that they were a poor risk as the tenons showed grain run out. What may not be apparent in the photos is that the tenons angle at 14 degrees. I was not prepared to take the risk. With loose tenons, I can choose the stock and orient the grain for maximum strength.

Regards from Perth

Derek

I did see a photo of the original tenons and thought the runout was questionable, but did not follow the thread further. I think the loose tenons are a better choice given the design but there is not a lot of material surrounding the seat mortises, thus my comment. It seems the armrests joining front and back legs contribute to the overall strength of the chair. It's a lovely design and it is always nice to see how you work out the details, even more so when you are willing to scrap the original tenoned seats to make the build better.

Is the photo I responded to the same chair? I am not seeing the grain runout from that perspective.

[Derek Cohen]

Hi Kevin

When I started out, it was just going to be a couple of carvers, and I took inspiration from the DC 09 chair. Time was spent calculating angles and sizes, but it was moving along.

Then (after the tenons on the first seats blew up, or threatened to do so), and I started again, the DC 09 became a challenge to copy.

This is from the first seat design. You can see the run out here ...





The design if the seat and positioning of the tenons is different from the second design ...



Regards from Perth

Derek