Rocking Chair update

[Chris Knight]

I have finally finished the laminating work for the rockers and back braces and have commenced on some things that are more interesting than watching glue dry. This page follows the one where I left things, last time. http://chrisknight.info/woodwork/rockin ... hair_5.htm

The jointing is getting interesting, I am having to cut what seems like nearly everything at an angle other than 90 degrees - mostly 84 degrees. I guess it shows that my 3D sense is no good but it is giving me quite a headache as I try to envisage how the joint I am cutting is going to mate with an existing piece. I sometimes get a bit panicky in the middle of a cut and ask myself if the cut I am making is the right one, or should I have measured the angle as a mirror image?

I have been stretching the use of my TS 2000 to the limits to emulate Hal Taylor's 10 inch unisaw. In the process I have discovered that I can do nearly everything I need to on my smaller saw but I am nonetheless going to look for a bigger one! One thing that really caught me by surprise was to find that there are circumstances where a sliding table is not as useful as the Murricans' ubiquitous crosscut sled. I had to build a crosscut sled to accomplish one particular joint!

I will have made so many jigs by the time I finish this chair, I shall definitely have to make a few more chairs to justify all the jigs.

 

[Anonymous]

Chris,

You're making cracking progress - and putting both my workrate and standard of work to shame completely I can't imagine getting the seat holes drilled so accurately and at the correct angle - that must have taken quite a bit of patience I imagine.

You've obviously got quite a collection of clamps, but I was wondering if you might have found a male and female former easier to work with when making the back braces and rockers? It's something I've seen used elsewhere, although I know you have to take the gap between the pieces into consideration when making the matching parts. The other thought that occurs is you've really missed a great "I need a new tool darling" opportunity. Surely it crossed your mind that a vacuum press was an easy sell for all that laminating :wink: Having said that, you got all those Besseys so not a bad haul I guess...

Cheers!

AG

 

[Steve]

What a fantastic piece of work. I await the next instalment - and my compliments on the photography!

Steve

 

[Alf]

Yikes, Chris! :shock: I had a feeling it was the case before, but now I know for sure: rather you than me. Oh, and what an excellent gloat, btw. All the clamps? No. I mean your SWMBO helping out of course.

Cheers, Alf

 

[Chris Knight]

Thanks guys - it continues to challenge but thankfully the fun element is still present!

AG, you make a couple of good points. I had wondered why Hal did not go for a mating form - I need to ask him though because I still don't know the answer. My guess is that it comes down to the potential inaccuracies that could arise in first computing and then making a curve with different radii from the "primary" one. The back braces have a couple of reflex curves in them and I reckon this could be problematic, especially if people don't cut the lamination strips exactly to the prescribed thickness.

Any inaccuracy in the mating form will result in a variation in clamping pressure - maybe to no clamping pressure at points and that would be fatal.

I do have a vacuum press actually (an airpress model which I use for veneering) and had thought I might be able to use it - until I researched the glue properties. The data sheet for Titebond specifies 250 psi clamping pressure for the sort of thing I am doing and unless one lives on Jupiter, the best our atmosphere can manage is a measly 14.7psi. I must say, I have never really thought about clamping pressures before - except to worry about applying too much and then suffering a dry joint. I reckon that is baloney now that I have looked into things a bit more.

I am starting to wonder why my veneer sticks so well too.. It's hell when you start to doubt your sanity - at my age one worries about senile decay!

Alf, you are so right, that is my best gloat. SWMBO is my secret weapon - a mean wielder of the glue brush, a great adviser on important design details, a hawk eye for colours (great for matching stains) and a pretty strong pair of arms when it comes time to haul something I have made upstairs - mind you I do insist she accompanies me to the gym 3 times a week!

 

[Anonymous]

Chris,

Your thoughts about the mating form approach confirms what I'd wondered - the risk of getting it wrong probably outweighs the cost of a few more Besseys. The clamping pressure you found in the Titebond spec is frightening. Which of their glues is it - I'm not sure I'd be keen to use it if that's what it takes to laminate.

I wonder if Extramite or some other glue would be a viable alternative in terms of strength without needed such high clamping pressures. I'm wondering whether it would even be viable to achieve 250 PSI with individual clamps - the issue being the gaps between clamps, as that's a hell of a lot of pressure, and with thin strips of wood I can't see them keeping that kind of pressure between clamps, even with the number of clamps at your disposal :wink:

I wonder if it's just one of those "old wives tales" things that Titebond have jumped onto, which would explain why your veneers (and the veneers & laminations of so many other Airpress owners) are staying stuck? In my (very) limited experience, as long as the mating surfaces are good and the clamping has been sensible, any failures occur in the wood and not the glue line. Nice drive-by on the Airpress, btw 8)

Keep the pictures & story coming,

AG