Thread: To use or not to use biscuits in laminated table top

All that the biscuits will give you is a locating point for when you are aligning the timber while clamping it up.

The biscuits will not really give you any increase in the strength of the joins but will cause you problems if you hit one while rounding the top.

Personally I have never found biscuits to be tight enough in the slot to give accurate alignment.

Yes I have found they are not tight enough,I soak some for 15 minutes so they swell a bit

If you are starting with 45mm thick and aiming to finish at ~40mm, you don't need any alignment aids. Therefore any good that a biscuit can do is overwhelmed by the grief they can possibly cause. Biscuit sized depressions in the finished flat top a month or two after finishing because you planed/turned localised swollen timbers.

as kuffy says, biscuits are likely to cause you more grief and any possible benefit.

odd to be turning the tops -- apart from demonstrating your big lathe.

personally, I'd use a router and trammel to get the top round.

I believe in the strength of biscuits in table top construction.
They can help if they are installed right . Don't just slap some glue in the hole and tap in the biscuit . You have to apply the glue in the hole both sides and then run a stick through it to make sure there are no air pockets holding it back from coating the sides of the hole. Then I wipe the biscuit through the extra glue sitting either side of the hole and make sure its totally coated.

They are small tops though at 700 diameter and at that thickness with well jointed boards , machined then hand planed, you could easily get by without them .

It also depends on the pine your using a little. Radiata is well known for shifting around . Cutting it close to size then stacking it out of the way for a month before re jointing then gluing up would be ideal . Or just grabbing some out of old dry storage . You can spot this stuff because its done its shifting about.
Other pines like the Golden Macrocarpa Cypress are known for their stability.

edit .

Jointing by machining then hand planing the joint is important as well . Not just machining then gluing up . They don't last as well .

Thanks for the replies guys, I will abandon the idea of using biscuits then.

Originally Posted by ian

odd to be turning the tops -- apart from demonstrating your big lathe.

personally, I'd use a router and trammel to get the top round.

The router would be fine for the outer edge, but not for the tapered under side, plus the base and centre will be laminated out of a few layers of laminated timbers (in brick form laminations) that are then also turned to a specific shape. Here is a photo of her initial idea although it has since been refined.

round table.jpg

I saw Wongo made a round table top recently and used biscuits/dominoes.

He just HAPPENED to cut it right at the point of a biscuit on the circle and exposed it on the edge!

Disaster!

As woodPixel said, best if you do use any biscuits or domino's to clearly mark their location so you don't expose one when you cut the circle.

There are router jigs for tapering the underside of the table. Essentially like a router circle cutting jig but the router sits on an angled sled that you could put any angle you like on and taper the underside of the table top. I saw it on a youtube video i'll try to find the link.

How come pine though? I wouldn't use it for a table top personally. Unless you're getting some nice quality stuff (celery top, etc) rather than the hardware store junk.

Pine is a fantastic material for furniture.

I suspect that if it weren't so widely grown here and imported, peoples perception would be that it's exotic.

Well dried it's great, but straight from the store it isn't really ready for production. I've found leaving them 6 months to dry further yields impressive results.

You can probably tell I'm an enthusiast

Originally Posted by dai sensei

the base and centre will be laminated out of a few layers of laminated timbers (in brick form laminations) that are then also turned to a specific shape. Here is a photo of her initial idea although it has since been refined.

round table.jpg

interesting project -- 3 possibly 4 separate components

have you thought about what sort of joint you will use between the different components, especially between the base and the table top.

Originally Posted by ian

interesting project -- 3 possibly 4 separate components

have you thought about what sort of joint you will use between the different components, especially between the base and the table top.

3 components. The top from laminated 45mm, the base from 2 layers 45 and 30, and the centre from 70x70 vertical (brick layers). The centre portion will have short tenons ~150 dia x 20mm at each end that will be glued into recesses in the top and base. So the joints will consist of a glued tenon and glued face (~250mm dia but end grain).

Are we going to see a write up on this
Because I pull up a chair

Cheers Matt


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Well at least a WIP, but I can't even start until after Maleny (client advised), so give me a few weeks

Here is a photo of that router bevel jig I was talking about.

Cheers.
5Ob1OvV.jpg