Thread: Biscuit joining options

Sir S.,

Oops. Just realized your stock is probably too big for it to be feasible to attach it to a tenoning jig. But you could still cut a 1/8" groove with a router and edge guide or using a mortising jig.

Rocker

Originally posted by Rocker
Bob,

I would guess that, unless you have a lot of metal-working expertise, bending half-inch steel rod to exactly 90 degrees would be pretty tricky.
Rocker

Nah, it is really very easy to bend the steel to 90 degrees. Just put one end in the vice and bash the other end with a lump of heavy metal until it is half way over. If it isn't enough then hit it again. If it is too much then just hit the elbow part a few times to straighten it out a bit. Check with a square and I'm your uncle.

Having said all that, I prefer the idea of using the brass and getting the extra decoration out of it.

I'd like to cast a dissenting vote here - in a lot of years of repairing basket-case furniture, I have never yet seen anyone's attempt at repairing a bum joint with metal work any better (or even as well, for that matter) as a well-made, all-wood, joint in the first place. Granted, these were practically all 'after the fact' attempts at shoring up what was an inadequate bit of joinery to begin with. The fixings of the metal bits were often of questionable engineering soundness, too.
When I first tried biscuits, I made a couple of joints like Stinky is suggesting, and then deliberately broke them. The joints were all amazingly (to me, anyway) strong and broke with virtually 100% failure of the substrate wood. (Soon after that, there was an article in FWW which did similar things, with similar results, and they measured the forces required to bust the joints). Conclusion: As long as the glue holds up, the joint will be pretty strong. But as someone has already pointed out above, we don't know how long THAT particular piece of string is!
If the glueing area is the same, and a few other minor conditions are controlled, I really can't see any difference in strength between haunched tenons, floating tenons or biscuits - all rely on glue for the integrity of the joint.
For me, the right-angled rod solution would be the most technically challenging to get right, and I reckon would be the first to fail. I've had very spotty success glueing metal to wood, despite trying all sorts of suggestions I've seen in FWW and elsewhere. Epoxy and brass are particularly fickle lovers. Methacrylate type glues seem to be more reliable for me, but are a fair bitch to use on any but the simplest glue-ups.
(BTW, Would another woodie really like to see one of his grandchildren putting a 1/2" steel bar through his favourite old carbide cut-off blade???):eek:
Cheers,

And before anyone else jumps on me - the metal 'buttons' used for attaching table tops to the skirts DO work, very well..........

Youre in good company S
I have seen an identical coffee table made on a woodworking TV program in UK
The guy used method 'B' for the biscuits.
I've also seen it done with 2 end legs & 2 side legs the same that are joined with more bisuits to look like a normal table with mitred corners.
These days, many commercial things are made with biscuits. They are strong once the glue cures.

I have read about and used biscuits for many small table legs and the answer is method A. again it comes down to long grain. On both the legs and the apron the slot for biscuits will be going with the grain. However in method B both slots will be across the grain: that is you will be gluing the long grain on the biscuit to the end grain on the leg/apron. Try cutting a slot with your biscuiter and see what you get.

The Taunton book on tables goes through the differing orientations of the slot and states that you will have a weak join if the slot is across the grain.
Suresh

Hi Ian

Quote: For me, the right-angled rod solution would be the most technically challenging to get right, and I reckon would be the first to fail.

I wasn't suggesting that that the legs be joined using only the steel rod but also using another kind of jointing method as well.


And I don't think my grandchildren will be putting a carbide blade through any steel rods as molecular disruptors don't have any moving parts and also leave an edge that is absolutely plane no matter what the material being cut.

My two cents....

Stinky you said that the table you are making is going to be used as a dining table. I suspect that unless you are going to have wild parties with friends and you do some table dancing, biscuits applied in manner "A" should be plenty strong. I agree with IanW that the substrate would give way before the glue or biscuits do.

I made a little table for my kids to do their creative things on in a very similar manner, and while they don't do table dancing, it cops a fair amount of abuse. Yes it is smaller than a dining table, but there is a degree of relativity present.

And in regards to the glass, I'm not sure of the cost, but if you intend using as a table top, I would advise against it. I have seen ladies stilettos when table dancing go straight through, especially when there is more than two glasses of wine involved. You could use tempered glass, but that costs more.

I hope this helps

This board is of constant amazement. I posted a question thinking that I knew the answer but there are so many other ways at looking at the problem.

I have spent some unproductive work time on a model of the table so all can see what I had planned. As I said previously the design is a rip off of a major commercial stores design but as I am sure you can appreciate as a woodie I was not willing to fork out the big dollars on such an easy design. We also wanted the table to be slightly larger than the standard 900x1800 so there really was no choice except custom made.

Diagram A and B are just some views to give you an idea of the overall form. There are basically two end legs (70x70) that are mitre joined. There is a small foot on the bottom of each leg which is chrome. This may be difficult to see on the model. The two end legs are joined by two metal bars that are recessed into the cross bar. It may look like there isn't much support to stop movement but I have seen it in three stores and as long as it is put together correctly it is stable.

Diagram C shows the complex joining method. There will be 4x biscuits as in the first diagram running perpendicular to the mitre. When glued I will then drill down through the top rail with 4x 12mm timber dowels approximately 100-120mm. I will then drill out a further 10mm or so of these timber dowels and insert 12mm solid aluminium dowels. The aluminium dowels will be sanded flat with the timber cross bar. Diagram D will show the view down through the glass top to the four aluminium dowels.

I hope this makes sense. As for the longevity of the joints I really don’t see this table being handed down to my childerns children. It’s a nice thought but I know for sure when we more to our next home I will be told to build another table which will be much longer. I will then cut down the legs and make pepper grinders and possibly some pens

Originally posted by Dewy
Youre in good company S
I have seen an identical coffee table made on a woodworking TV program in UK
The guy used method 'B' for the biscuits.
I've also seen it done with 2 end legs & 2 side legs the same that are joined with more bisuits to look like a normal table with mitred corners.
These days, many commercial things are made with biscuits. They are strong once the glue cures.

My mistake. I meant Method [size=large]'A'[/size]

"molecular disruptors don't have any moving parts and also leave an edge that is absolutely plane no matter what the material being cut."

Will these molecular disruptors be able to recognise fingers so we can get rid of those damned in-your-way guards, Bob?
No more *#@* sandpaper?
I want one now!
I like this forum - I guess it's a cultural thing, but most of the posters seem to share a good sense of self-deprecatory humour. They sometimes get a bit pompous over on the FWW BB.....
avagooday

Can I just suggest that before you go too much further with it, you check the cost of the toughened safety glass?

It's been a long time but when I was in the glass business, safety glass panels for sliding doors were a couple of hundred bucks each and they were made in bulk. If we had to make special orders, they were quite a bit more.

silentC,

I am not rushing into it .... I just like to plan. The advantage of planning over actually working is that it is much cheaper and the accuracy you can get on the computer is amazing.

The garden needs to be finished (Est end April) before I can start on the table. As for the price of the glass I know that it is going to be the most expensive part and we were thinking of around $400. The price for the table in the shop is $799 from memory, but as I mentioned earlier we would like something wider than the standard 900mm. I feel that I will be able to produce a better product of using real wood for the same sort of money. Even if it comes out at $850 I would still be happy as the difference in quality between the commercial unit and my own will be worth much more than the extra $50.00.

Without ringing around and finding prices I have estimated the following.
Glass $300-$400
Timber $20-$30 plm ($200)
Aluminium $60
Getting to play with the new SCMS - Priceless.

Total around $600-$700 with the savings helping to pay for a few of the chairs plus the bonus of having a wider table which is what we want.

Stinky.

Sir Stinkalot,
Slightly of topic perhaps but what software did you use for your drawings and how long does it take you to whip them up?