Tripod table

[stuartpaul]

I've had a commission from a very demanding client (MiL :shock: ) to make a tripod oval table. Dimensions to be about 20" wide by 20" high.

This type of thing

Trying to work out out to fix the legs in position. I remember watching a Norm show ages ago where he did a similar thing using sliding dovetails with a router & jig on his lathe. I think dovetails are going to be crucial for strength so I want to pursue this avenue.

I have got a lathe but with no idexing or locking facility so positioning the 120 degree slots might be interesting.

Anyone undertaken a similar project and have any hints or tips on the best methods of doing this?

I've though about 'hexagoning' the leg and then being able to use the router table (straight cutter to remove the bulk and then finish off with dovetail bit). I can then use the lathe to achieve the roundness without destroying the slots. That's my initial thinking but haven't got much further.

 

[woodbloke]

The way to fix the legs in position is indeed with sliding dovetails, which are best cut using the router and three sided box jig. The round pillar blank is marked off at on end at 120deg spacings and secured so that each pencil line on the end is in turn vertical in the jig. The router moves along the top of the box and is contained in it's travel by a couple of parallel guides. I made a dumb waiter like this years ago and that's really the only way to do them.
Once the dovetails sockets are cut which isn't too difficult...it just takes some careful jig making and a bit of thought, you'll need to tackle the the dovetails themselves which are more difficult as the shoulders ought to be scribed in to match the curvature of the pillar...tricky :wink:
I'd make a full size end elevation view to work out all the jointing details before I started on this one - Rob

 

[Alf]

It's not the only way - I did them for both a Shaker side table and the Music Stand of Myth of Legend using the Woodrat. But for the non-Ratter, the tedium of building a box for the router to run on over the lathe is probably the only option. And rather than scribe the legs, I'd be tempted to put flats on the central column instead, assuming the design of the column allows you to conceal it.

Cheers, Alf

 

[Steve Maskery]

You can rout the sliding DTs using a universal mortising jig forthe router. Mine just slots over my vice jaws. It has stops for both the workpiece and the travel of the router.

Like Alf, I rout flats. Also, rout out the waste with a straight cutter before finishing with a DT.

This technique is shown in detail on Volume 2 of a certain essential DVD series!

Cheers
Steve

 

[xy mosian]

Flats on the end of the pillar is the way to go, as part of the design. If you can't hide it, make it a feature. Produce a box to sit over the pillar while it is still on the lathe. Lock the rotation of the lathe and rout/mill a suitable flat. Rotate the pillar 120 degrees and lock again. You will need this rotation again for the dovetails so some sort of lever resting against the newly created flat which mates against the face defining a 120 degree rotation might be a good idea. Repeat for the last flat/face.

Limit the router to move such that the dovetail is formed along the centre of the three faces and proceed as described by others.

HTH xy

 

[stuartpaul]

You can rout the sliding DTs using a universal mortising jig forthe router. Mine just slots over my vice jaws. It has stops for both the workpiece and the travel of the router.

Like Alf, I rout flats. Also, rout out the waste with a straight cutter before finishing with a DT.

This technique is shown in detail on Volume 2 of a certain essential DVD series!

Cheers
Steve

Steve,

How would the mortising jig work on a round column? Does it need to run on it's own jig mounted over the column on a lathe? Or could I take that 'hexigoning' approach to provide a flat?

I'd already convinced myself that I wouldn't be scribing the legs to the column, - small flats are definitely the way to go (for me anyway!).

Struggling to see how I can 'lock' the lathe in the required positions.

 

[Digit]

You're a very brave man!

Roy.

 

[newt]

Norm used flats

 

[Steve Maskery]

I have an auxiliary cheek for my jig, a V-shaped cheek which allows me to hold the cylinder in the vice. I do all 3 with a roughing cut to remove the bulk of the waste, then go round again to do the flats and the DT. Having two routers is very helpful here, I admit.

As I say, it's all on Volume 2.....
S

 

[woodbloke]

Flats is doable and easier, but if you you're a tad inaccurate in planing the flats either undersize or over then you'll see a bit of the flat if it's over and a gap under the shoulder if it's too narrow...still tricky - Rob

 

[Steve Maskery]

Nah, your router has a fine adjuster, doesn't it?

I wish I had a photo to post, but he last time I did this in anger was pre-digital.

I tell you, it's a piece of cake!


S

 

[stuartpaul]

Nah, your router has a fine adjuster, doesn't it?

I wish I had a photo to post, but he last time I did this in anger was pre-digital.

I tell you, it's a piece of cake!


S

Thanks Steve,

On that basis looks like I may have found myself a Christmas present!!

 

[xy mosian]

Photo of pillar to leg joint with flats on pillar. Taken from one of a number of Music Stands, and matching Stools, I made some time ago.



xy

 

[Racers]

Hi,

Have a look at this Video featuring (Saint) Roy Underhill making a tripod table with handtools.
He has a neat way of marking them out.

http://flash.unctv.org/woodwrightss/2900/wws2910.html

Pete

 

[Steve Maskery]

That is an astonishing piece of work. It's virtually one continuous shot! Excellent camera work and he's so fluent. I just go to pot if I haven't rehearsed every word!

Whilst I wouldn't want to do all my woodwork that way, I'm dead jealous of the space he has.

Thanks for posting.
S

 

[jimi43]

I think the WOODRAT is the way to go...but I am still smarting at the cost!

If I were not doing it with that thing - by hand is the way to go...nice video!

Jim

 

[MikeG.]

............yeahbut, that is some of the clumsiest chiselling I've ever seen! He busted off the main structural bit of the dovetail, and chiselled outside his saw cuts...........then pared as if he was carving a potato in primary school. He may be a saint, but he also a sinner!

Mike

 

[woodbloke]

Photo of pillar to leg joint with flats on pillar. Taken from one of a number of Music Stands, and matching Stools, I made some time ago.



xy

This is something that I personally would not be happy with. That the flats can be seen doesn't sit easy with me...if there's to be an intersection 'twixt flat (legs) and round (pillar) it ought to be seamless - Rob

 

[xy mosian]

Fair comment Rob.

xy

 

[Harbo]

I made a kitchen table a few years ago to be reassembled insitu. I used sliding dovetails to fasten the legs to the rails cut very easily on my Woodrat.
But over time this joint has proved to be a problem - with hindsight I should have used the much stronger M&T!
I have since been wary of using it again where a "strong" joint is required?
The wood I used was Sycamore so perhaps too soft for this joint?

Rod