Thread: Building Wegner's "The Chair" .

Here is the next instalment - the start of the morticing. This shows one side of the chair, that is, two mortices completed. There is just so much to do in this regard that I thought it best to break it down into smaller chunks.

Your thoughts?

Link: http://www.inthewoodshop.com/Furnitu...rMortices.html

Regards from Perth

Derek

Ian, that is one very nice table.

Thanks for the tips on coping. I agree with all you wrote.

I hope to get to this stage in the next couple of days.

Regards from Perth

Derek

That's looking pretty good Derek.

When you cope the ends of the stretchers they will sit into the mortice a bit deeper than they do now by a few mm - whatever amount you remove with the coping. Have you allowed that little extra depth in your mortices so they pull up tight to the round leg or will you shorten the tenons slightly to account for that?

Looking very neat.

Hi TT

Interesting choice.

I'm inclined to remove a snitch from the tenon so as not to weaken the leg.

What would you do?

Regards from Perth

Derek

I'd skim the tenons on the stretchers past the tungsten saw blade... fast and easy. Test fit by hand & once satisfied with the dry fit - glue and cramp her up.

But,

As i said if it were me - I'd be using stop pinned tenons, and I'd use a jarrah dowel from the inside face of the turned leg - thru the tenon (but not out the other face) and I'd put it in once glued up.

I'd also pellet it with matching long grain jarrah from the offcut top or bottom piece of the leg so the grain and color matches the leg and the pellet is as close to invisible as possible.

In essence you'd have enough mechanical strength with a stop pinned mortice - to assemble the joints dry and not need glue.

In the old days when the used rendered down horses hoofs and tallow & hides etc to make animal glues - the acidic sap in the jarrah would break the glue down in the joints over time so all that held the joint together was the inherent mechanical strength of the joint.

Thus the use of stop pinned mortice and tenon joints - was as mechanically strong as you could reasonably get in timber.



You don't have to bring the dowel thru to the appearance face (outside of the leg - or seen face) as its depicted above.
By stopping blind - the dowell still engages the leg material on the far side to lock the tenon in place - but doesn't mar the finish appearance - because it stops blind, it isn't seen.

If the dowel is left just below the surface on the inside face - it can be pelleted to cover / disguise the hole to match the surrounding material which is an unseen face anyway.



Its use was more common in joinery - especially when the old glues were known to break down with time.

The pelleting just disguises the dowel hole a bit better.

Carbitech put out a barrel & plug cutter tool set - Drill & Barrel Plug Cutter Sets : CARBA-TEC



You can use them to disguise the tenon dowel holes... as described.

I have used them in the past even to decorative effect tho - by using contrasting timber for the plug.



It's a little different to the usual "inlays" some times.



They are only daunting if you havent used them before... once you do you find all manner of potential uses.

While most cabbies buy in their solid timber cabinet doors and they are all finger jointed I used to make my own with blind stop pinned mortice and tenon joints pelleted on the inside face so you couldn't see the dowel with the doors closed and could barely notice it when the doors opened.

The mass produced finger jointed ones can be expected to last about 6 or 7 years before the finger joints begin to fail when the electrically cured glue breaks down with the sap in the Jarrah.

With mine - using epoxy resin to glue up and blind stop pinned, haunch morticed & pelleted - reckon they were good for 200 maybe 300 years depending how they get looked after.

All i know is I won't be around by the time the do fail if ever.

Don't know how your fair using the plug and barrel cutter by hand tho - I used the drill press for the barrels and a battery drill for the plugs (pellets).

Its all about how much work you want to do - what tools you have access to - and how much trouble you want to go too.

With those spindly legs tho - I don't know if you have enough material left in the legs after 2 M & T joints to drill and pin them... you might increase the strength fo the joint at the expense of the overall strength of the leg itself... to sideways movement of the leg at the joint?

The chair has no kick rails near the bottom section of the leg to give that joint any engineered support, so that section of the leg takes all sideways (back n forth) stresses.

How many people who have never built a chair in their life -like to sit back and rock back n forth on only the 2 rear legs & destroy every joint in the chair?.

You watch people and they do it.

With this design (Wegners) the ONLY engineered brace for those M & T joints at the stretchers - is the arms and back...up top.

How much strain will those haunched M& T joints take, with say PVA glue after a few years - when the first person rocks back on the two rear legs?.

I'm not personally a "fan" of the design (I consider it deficient from an engineering standpoint in this respect) but I am a fan of wood work and making things, so enjoying your process - making this chair.

The curly grain in your jarrah material should look spectacular when finnished and probably outshine the chair you bought.

Being in jarrah it will also likely be inherently stronger than the chair you bought.

People who rock back on the 2 rear legs of chairs are one of my bug bears... its disrespectful to the owner, and the maker of the chair... my own kids always got a clip behind the ear if they tried it at the dinner table.. (and they did).

All the $ profit is in making dining tables and all th etime effort and expense and non of the profit is in making the chairs.

Others mileage will vary no doubt.

Great WIP as usual Derek!!!

I no longer have the inclination or the patience to do some thing
like this. I do, however, have a great interest in how things are made
and i find this fascinating.

Derek I have been following since the outset of your undertaking of this build. It appears to me that as you progress you are finding the best solutions to each task. I try at each stage to see if I can come up with a better way. So far I think you are spot on. There would be many powered options but not so many hand tool solutions. The skill that it takes to train ones eyes and sense of touch to accomplish such tasks is fascinating. I believe it gives us a great respect for those who did these things in the past by eye and feel with no powered options. I can tell by the way you write that you must get the same sense of accomplishment in what you do. Keep it up, I'll follow along and try to learn something.
JP

Hi TT

Thanks for the info on pinning the legs. I wish I could do this here. The original chair I have needs to be re-glued. The "furniture restorer" from who I bought it did a lousy job. Unfortunately, the legs are too thin for pegs and it is not part of the design.

I am, however, a believer in draw boring.





JP, yes - it is a case of planning as much as I can, but then discovering the need to think on my feet because there is something I did not take into account. This happened today. I had completed connecting the legs and the side stretchers. I did these because it seemed easier and I thought it was a good way to get my toes wet with the stepped mortices. However I really should have done the front and rear stretchers first. That would have made joining the straight side stretchers easy. Now I have to join curved stretchers. Not easy at all. I have a cunning plan More later.

Regards from Perth

Derek

I reached some of the coping earlier than I expected. Here is how it went ..

http://www.inthewoodshop.com/Furnitu...airCoping.html

Regards from Perth

Derek

Originally Posted by derekcohen

..I reached some of the coping earlier than I expected. Here is how it went ..

Looks like you coped with it pretty well...

I'm not sure how I would have gone with that gnarly tough stuff you're working on, Derek, but in general, I've found coping is not as difficult as it first looks. Takes a bit of care, but as long as you get the top & sides accurate, they usually fit nicely. On my little pedestal tables, I went back to cutting flats for the sliding dovetails, because I found the edges of the trench in the stem were a bit more fragile than those cut in a flat area. That doesn't apply so much with mortises, of course, though you do get more edge breakage when digging mortises out of a round vs. a flat surface.

I was struck again by the rather small glueing area on those rail tenons. Wegner's design is very elegant, no doubt, but these chairs are a bit deficient in the engineering department, I'm afraid. Back in the mid to late sixties, there was a rash of chairs made in this style around here, mostly from Black Bean (Castanospermum australe), which is a local look-alike for teak. The seat rail joints failed on most of the chairs within the first 20 years if they were well cared-for, & much sooner when they were used in public places & subjected to a bit of heavy use. I used to think they must've used the wrong glue, but reflecting on it now, I suspect that the force per unit area on these joints exceeds the strength of either glue or wood.

Over the years I have read quite a few discussions on the philosophy of reproductions. There seems to be two main schools of thought, each with a valid argument for their view. One school tries to copy everything, from tools used to methods of construction, even when it is clear the original method isn't sound, or better alternatives are available. These are the 'true' reproductionists, I suppose. The other school says that it isd the overall design we admire, so if better construction methods, or better materials are available, why not avail ourselves of them?

In the spirit of the latter school, I think if I had been doing this chair, I would have apologised to Hans, and brought half of each tenon for the fore/aft rails through the legs, flared the mortise a little & wedged them. Done well, it would be consistent with some of the Scandinavian design I've seen, and possibly a bit more durable, but of course not an exact copy of the original. And once you make one modification, the temptation to make others increases, so maybe it's better not to deviate even slightly, when you're after a 'real' copy...

Cheers,

Very thoughtful post Ian, and much better expressed than I would have done.

I remember repairing a couple of this style of chair because of loose tenons. I took the easy
route and re-glued, drilled small holes and used a small nail with the head cut off as a pin. I
didn't think there was enough timber to use a dowel.

Derek your hand tool skills are exceptional. There is no way I could have done
that job with such finess, especially considering the gum vein is in the most inconvenient place.

Originally Posted by artme

.....I remember repairing a couple of this style of chair because of loose tenons. I took the easy
route and re-glued, drilled small holes and used a small nail with the head cut off as a pin. I
didn't think there was enough timber to use a dowel....

Artme, not sure how I'd try to rehabilitate one of these chairs, myself. I guess the nail 'dowel' would help for a while, but it could also be counter-productive by concentrating the force in a small area if the glue fails, & it could create a catastrophic failure. One solution I've seen a few times is to twitch the legs together with a loop of twisted wire. It helps, but isn't quite in sympathy with the original design concept ...

There were several of these chairs in a place I worked at a few years back, and all were loose. I looked at them one day, & decided they were too difficult for me - the tenons had either been machined a little undersize, or the wood had been less dry than it ought to have been, so they were a loose fit even before any residual glue was cleaned up. Merely glueing them back together would have been a very temporary fix, I reckoned. The skirt of the matching table had also given up - it consisted of very narrow boards, about 60mm wide, and about 16mm thick, into legs that were not much more than 50mm diameter, so the tenons were tiny. The table's integrity depended on 8 little M&T joints and some metal corner braces. Eventually, it fell apart & was chucked out. The top was veneered particle board, so I let that through to the keeper, and souvenired the rails - can't remember what happened to the legs. Black Bean is a wood I work with very sparingly, in any case. As I'm sure you are aware, it's renowned for its toxicity...

Cheers,

Edit: I was trying to remember the name of the bloke who I think is the arch exponent of 'improving' when reproducing a piece - it was Harold Ionson

Lovely execution skills Derek.

TT, I'd like to hear more about hide glue and Jarrah as a combination. Your comments earlier were the first I had heard of hide glue breaking down in the presence of Jarrah. Of course, I would like to hear the comments of others as well.

My intension was to use hide glue. I must admit that I am a fairly recent convert to this, with only a few years under my belt. Until now I had relied on either yellow or epoxy.

I have been thinking increasingly about using epoxy as it is better with flex. However the need to repair a joint at some stage (witness the loose joints of my original) is a warning to allow for this - hence the prefeence for hide glue.

Thoughts?

Regards from Perth

Derek