Author Topic: Affixing a chair seat?  (Read 766 times)

0 Members and 1 Guest are viewing this topic.

Offline JonathanJung

  • Posts: 243
  • www.timberlightdesigns.com
    • Timberlight Designs
Affixing a chair seat?
« on: September 07, 2021, 06:22 PM »
Float-mount a seat on a chair, or glue it down permanently?

I've been attaching the seats to my chairs similar to a tabletop, see picture. However, it's not as clean looking and the screws can't grab very much wood, because of the deep seat scoop. The main thing though is that it doesn't suck the seat down tight to the frame, as tight as I'd like. There is only 3/8 - 1/2" screw penetration so it's risky to really crank it down. Using the Wood Web shrinkage calculator, rift/qtr sawn walnut at 14" wide (the width of contact between seat and frame) has minimal movement, around 1/8". I'd rather be able to set a couple dominos and glue the seat down.

Does anyone know if glueing the seat down would be safe enough against splitting?

I've known breadboard ends on tabletops to not be an issue before. I realise that my customer's home humidity control will have an effect, so I calculated for an 8-12% MC variance.
« Last Edit: September 07, 2021, 06:26 PM by JonathanJung »

Festool USA does not pre-approve the contents of this website nor endorse the application or use of any Festool product in any way other than in the manner described in the Festool Instruction Manual. To reduce the risk of serious injury and/or damage to your Festool product, always read, understand and follow all warnings and instructions in your Festool product's Instruction Manual. Although Festool strives for accuracy in the website material, the website may contain inaccuracies. Festool makes no representations about the accuracy, reliability, completeness or timeliness of the material on this website or about the results to be obtained from using the website. Festool and its affiliates cannot be responsible for improper postings or your reliance on the website's material. Your use of any material contained on this website is entirely at your own risk. The content contained on this site is provided for informational purposes only and does not constitute professional advice.


Offline ChuckS

  • Posts: 2885
Re: Affixing a chair seat?
« Reply #1 on: September 07, 2021, 07:22 PM »
1/8" variance is too much for my comfort zone, unless the piece stays in a humidity controlled environment for good. (Many wood movement problems appear after someone moves from one place to another.)

"I've known breadboard ends on tabletops to not be an issue before."

Not familiar with your exact construction method and size of the piece, I've seen my share of breadboard end splits. The attached image is one of the many from the internet. More examples are found by furniture restorers.
« Last Edit: September 07, 2021, 07:26 PM by ChuckS »

Offline Birdhunter

  • Posts: 3557
  • Woodworker, Sportsman, Retired
Re: Affixing a chair seat?
« Reply #2 on: September 07, 2021, 10:29 PM »
Have you considered using Z clamps?
Birdhunter

Offline JonathanJung

  • Posts: 243
  • www.timberlightdesigns.com
    • Timberlight Designs
Re: Affixing a chair seat?
« Reply #3 on: September 08, 2021, 06:22 PM »
Have you considered using Z clamps?

Same thing as tabletop clips? Yeah, does the same thing as a Domino.

I think I'll try screwing through the base. Will oversize the hole and counterbore to allow for movement. I don't want holes though, since I imagine customers like to grab the curves under the seat.

1/8" variance is too much for my comfort zone, unless the piece stays in a humidity controlled environment for good. (Many wood movement problems appear after someone moves from one place to another.)

"I've known breadboard ends on tabletops to not be an issue before."

Not familiar with your exact construction method and size of the piece, I've seen my share of breadboard end splits. The attached image is one of the many from the internet. More examples are found by furniture restorers.

That split looks like someone sat on the breadboard and snapped it.

Offline bcrawley

  • Posts: 5
Re: Affixing a chair seat?
« Reply #4 on: September 08, 2021, 06:43 PM »
When I grab under a seat it is typically at the sides. If that is true for you, you could keep the holes to the front and back; do your domino thing on the sides if it seems you need that too.

Offline ChuckS

  • Posts: 2885
Re: Affixing a chair seat?
« Reply #5 on: September 08, 2021, 07:42 PM »
Snip.

That split looks like someone sat on the breadboard and snapped it.

I suspect that the whole breadboard end was glued to the top, with no allowance for wood movement whatsoever.

Top splits are pretty common in older pieces, too. I fixed a table top for someone; the piece was made in 1957 in England as part of a high school shop class (called secondary school there), and brought to Canada when the family moved over. The top was screwed to the aprons with no elongated holes drilled. The oak table is about 22" wide, in line with the smaller houses built in those days.

For a 14 or 15-year-old kid to build such a table with bridle and M&T joinery, it said a lot about the old British education system. (The joints also came apart with the passage of time.)
« Last Edit: September 08, 2021, 07:50 PM by ChuckS »