The MA thread - AKA Everyday Fan Vault Construction for Beginners.

[Jacob]

I remember pulling up floor boards in a house built in the 1600 to put some pipes in and the boards were only flattened where they sat on the joists.

I saw a table top like that - several wide boards where the top and the underneath as far as on top of the apron were flat and finished but the inside underneath surface rough and riven. Saves a lot of bother!

 

[Adam W.]

While we're waiting for something to happen, here's some piccies from backstage St. Pauls.

A Solomonic column and a nice bit of woodwork.

A look down the chior. (I think that's what it's called)

Storage, note the beading on the oak frame, very posh.

More storage

Extrados of one of the domes in the choir, complete with wooden bungs.

The fabulous Great Model. Well worth a look for those interested in such stuff.

 

[Sgian Dubh]

@Sgian Dubh I wonder how he figured that out ?

I don't recall. I don't own the book so I can't reread the relevant referenced section to indicate to you how the author came to that conclusion. I borrowed the book from a university library as background research for a manuscript I wrote. Slainte.

 

[Adam W.]

Off we go then.

Seeings it's a good day to start the ball rolling, I've made a move on starting the carving of the first part of the vault, which is the tas de charge or springer.

This piece is where the spring of the vault starts curving up towards the flat spandrel. It has a single curvature that rotates around the central axis to make the conoid shape for the fan.

I have turned the basic form from a single piece of oak. The ribs will be made seperately and then tennoned into the shaft with a straight joint at their connection point with the top of the springer.

It's about 17" long and 6" diameter at its widest point. Here it is roughed out and I'll carve the lot of them, 6 in all, before I finish the details. I can't put the moulding on the ribs until I've decided on its profile, which will be when I make the ribs, so there's a bit of backwards and forwards, but I know its width and depth.

At the bottom of the springer there will be a carved and gilded foliate boss, which will be attached by a socket and spigot or threaded joint. That's where the vault will stop at its lowest point as it's going to hang from the ceiling.

The ribs go from nine to three with a fancy overlapping gothic arch form, containing a cusped cove detail. You'll have to bear with me on that, as I'm still working out how I want it and I'm now designing and making on the hoof, as I'm drawn out and don't feel like doing lots of projections.

I set the ribs out on the lathe, as this had a handy reference point ( the bed) and I could rotate the springer around its central axis and step off the 16 ribs, 7 of which will be cut off, as they won't be used.

I'll cover the setting out another time, as I need to take the photos first, but it was fairly straightforward to do.

The shaft at the top of the springer gets a lap dovetail cut into it, which will fit into the oak frame from which the vault will hang.

It might not look much at the moment, but it has taken a few weeks to figure it all out and it needs to work first time as the whole vault will sit on top of it and it determines the form of the vault.

I found some 8" x 6" air dried oak that had been drying for 15 years in the shed and it carves like silk, beautiful wood and a joy to work with.

 

[Adam W.]

I use the lathe and a center height gauge to set these things out.

Starting by striking a few lines, I step off 16 ribs along each line with dividers. The adjustment is so tiny to get it right that it inevitably takes a few goes, as I don't bother to measure it. I do use a fresh line each time, otherwise the tip of the dividers falls into the old hole and causes an error at the end.

Once I've got it right, I strike parallel lines using a template off the bed which is set to the centre height of the lathe.

Strike them all round and its done. This line denotes the centre of the rib and I can chop along it knowing I've got it right.

These shapes are tricky to hold, so I stick it in a jig so that it can rotate as I carve it without messing about with clamps.

A paper template for the gothic shaped cut out.

and I can start removing the waste with a parting gouge and forming the top of the rib with a back bent gouge.

It needs to go through the dogs dinner stage before it looks like anything, but it's quick work and I can rough one out in 3 hours.

The central springers are now roughed out and I'll start on the corner ones next.

Once it is roughed out, it goes back on the lathe for a fresh set of lines.

I'll make them match each other and straighten things up so they look even once they are all roughed out. The finishing cuts will happen once the ribs are moulded.

 

[Adam W.]

Four......

I'm enjoying using the lathe very much. This is exactly what I bought it for and if it was any smaller, I think I'd start to struggle with capacity very quickly.

 

[paulrbarnard]

Four......

View attachment 125749


I'm enjoying using the lathe very much. This is exactly what I bought it for and if it was any smaller, I think I'd start to struggle with capacity very quickly.

Your quick!

 

[Adam W.]

There's still a lot of finishing and minor adjustments on them and I'm thinking about carving the backs and the bosses at the bottom.

So I need to make quick progress with the stuff I'm ready for, as I know that things are going to get a bit complicated in about a month.

I was thinking about doing something like this on the backside, and I really like the detail at the bottom, so that might be what the bosses look like in a way.

 

[Ollie78]

This all looks like proper fun. In a sort of bloody difficult but satisfying way.

Ollie

 

[Adam W.]

Now there are six.

The radius of the single curvature on the springer gets gauged with a small boxwood compass plane, which I made for the job last summer. This leaves a flat on the top of the rib where I'll strike the line again. Then I'll check the ribs for straightness and adjust the gothic arch detail so that they all look similar, but not exactly the same.

The small flat at the end of the rib gets chopped off once I've made the next part, which is the main part of the rib with the double curvature, and it's there at the moment to protect the arris from damage.

 

[Adam W.]

So, I go to London on a timber run with the intention of going through the red channel to ask if I need to declare said timber.

So through the red channel I go, only to get diverted via a convoluted chicane back into the green channel.

On the way through I see a sign which read "If no one is here, use the red phone to contact HMRC". So I trek back to the red phone, only to see a sign "RED PHONE NOT IN USE".

My god!

 

[--Tom--]

Really interesting project and keen to see the progress. If you need a hand with irons for planes let me know as I’m set up well for heat treating and happy to knock some up to dimensioned drawings

 

[Adam W.]

@--Tom-- Thanks, I'll bear that in mind when I start on the rib moulding.

 

[Adam W.]

Blimey!

Rib making begins with air dried riven stuff which looks like this.....

With a handy triangular section.

This gets hewn and planed into a pile of ribs which will be fitted to the cylindrical shaft coming out of the top of the springers.

Then I'll cut a chamfer on the moulded section to receive the moulding and cut a rebate to make a large tennon which gets fitted to the oak frame above.

This should keep me busy for the week, whilst I think about making the planes to cut the moulding.

 

[Sgian Dubh]

Adam, I haven't said anything in this thread before, but by posting now I'm just letting you know that I'm watching it and enjoying seeing progress and the photographs plus discussion of your research and learning.

On a side note, did that book we were talking about ever turn up at the college library? Slainte.

 

[Adam W.]

Richard,
Unfortunately we have been subject to a few thousand pounds worth of book theft from the library this term, so I think the budget won't stretch to new purchases, which is a shame.

 

[Sgian Dubh]

... we have been subject to a few thousand pounds worth of book theft from the library this term, so I think the budget won't stretch to new purchases, which is a shame.

That's a bit of a bummer, the thieving, I mean. Just curious, but was the theft one large one, or a case of various people nicking a few books at a time over a longer period? Slainte.

 

[Adam W.]

Quite a few books in a short space of time..

 

[Cooper]

Did you plane all those ribs by hand or have you got a planer thicknesser out of shot. I felt exhausted just looking at the pile! You are becoming quite a turner already.
Cheers
Martin

 

[Adam W.]

All done by hand. It goes quite quickly after a while when they all get lined up. I'll start rebating them for the moulding today after I figure out the quickest and most efficient way to do it with accuracy.

I've got a couple more ribs to make, as I've changed my mind on the main transverse ribs and I'll show you how I go about it later.