Hi Paul

Have you seen the one in the latest mag? That's for 1m. long keels.

In fact it covers most of what you list!

Chris

Paul

This is a tricky one as you point out. Sometimes tools that can do everything are not the best for doing anything.
I have a Billings building slip which comes in kit form.

I built it and that was it. I have never used it and can't see myself doing so. The channel for the keel fits one size only and has to be packed out for thinner keels. Likewise the support for the stem. The sliding piece that is used to locate frames can only do one at a time and is not that accurate. Click here to see a picture.

I have a SLEC fuselage building jig which for those who haven't seen one, is supplied as a roll of printed vinyl to stick on a board of your choice. There are adjustable plastic supports and these are held by machine screws into captive nuts in the board. When I ordered mine I double the number of supports and added many more fixing points. I was glad I did.

Here is an aircraft fuselage in the jig and you can see that the supports can be used in any direction you like.

Here a nacelle is under construction which ended up quite boat-like.

And here the finished fuselage is back in the jig so I can line up the wings and tail plane exactly at right angles before fixing. So is it quite versatile.

The basic requirement has to be a good flat board and my biggest board is 1200mm x 370mm as this is the size of the SLEC jig. Of course the printed material could be cut down. I have lots of smaller boards for sub assemblies all faced with two layers of 4mm cork which seems to last forever.

My current project "Galileo" is on this board. I made a cradle to much a chosen frame station quite well forward where there is a pronounced V and the aft, flatter section of the hull rest on a set of blocks adjusted to the correct height. With the bow exactly over the line drawn on the paper and the centrelines matched up, the model can be registered easily and with good repeatability. The cork allows me to pin other supports in place.

Like here for instance where I had to take out a bit of twist.

I suppose for me the best solution would be a good board and a "kit" of parts that I could adapt to make the necessary supports. Once the shape of the boat is stable you can move it around as much as necessary.

I suppose most boats are at least started upside down.

Tim R

Hi Paul,

My multi use building board is the DIY version of Tim's SLEC fuselage jig, but consists of MDF 20mm thick window board comes primed, and the holes securing the bulkheads are easily filled after the first build and a coat of white emulsion and a centre line off we go again, usually comes with a rebate on one side and rounded on the other, put a G clamp on one side to to get 45 deg hull to make access for planking or sheeting easier.

I would think anything designed to have multiple uses will always be a compromise compared to a bespoke jig?

Regards Ray

Edited By Ray Wood 2 on 16/01/2019 15:13:00

Paul

What is your preferred size of model and how heavy are they likely to get during the time you want to manipulate them?

Tim R

You've certainly got a project to tax the brain cells there Paul!

I thought about getting a building jig for my first build but couldn't find anything really suitable. I adopted the temporary spine at deck level suggested to me on Mayhem and adapted the method by adding fingers to the spine and keel so that the hull could be worked on right way up or upside down and it worked really well with the fingers either screwed to a substantial batten on the baseboard or held in my Workmate. For a future build I'm going to use the extended frames/bulkhead method.

Obviously your design is complicated by the need to securely hold the hull once skinned or even completed and can't be done as per Ray's example as there isn't a chassis to fix to and is of a shape that is difficult to clamp. I think Tim's example has mileage if the side supports could slide from side to side and also be adjustable for angle and so clamp to the hull sides which would suit different hull shapes. For building the hull structure you would need to have the side supports move fore and aft and have some sort of tie between opposing pairs to position and square up the frames etc. Both of these requirements could be difficult to satisfy and be of a reasonable cost.

Add in being able to rotate the model and you have a real challenge. How do you attach to front and rear in a secure way and how to do it so that it doesn't get in the way of the work required?

Chris

Paul – When I first saw your posting, two things immediately came to mind. Firstly your "customer" needs to define a specification within which you need to comply. The `requirement' cannot be open ended. Secondly my idea would be to design something along the lines shown by Tim Rowe. My models are scratch builds and each build jig is bespoke to the model. My jig is a piece melamine chip board raised and braced to give a convenient height and a rigid base. The attachments which I use are blocks of soft wood, pieces of extruded aluminium angle of suitable size, cast iron angle plates etc. The choice of attachment being dependent upon the model. A Swiss Army Knife is fine, as is an adjustable spanner, but far better to have the correct tool for the job i.e. if you wish to tighten/loosen a bolt with a 17mm head, then use a 17mm spanner and not an adjustable spanner.

Hi Paul

22kg! That's nearly a statutory bag of cement. With the sizes and weights you mention, safety is going to be a major factor as well.

At 4' long you are going to need something that will go past each end of the boat so you are looking at something that has the capability of stretching to maybe 1500mm.

Manipulation something safely at that size and weight will need some serious engineering so here's something of an idea. Think along the lines of a hog roasting spit.

Description:
Two frames or tripods that can be spaced apart at any interval up to 1500mm with a adjustable and lockable bars between them. Thinking welded steel angle for the frames and a hollow squares sliding inside larger hollow squares for the spacers.

An horizontal axle at each end to create the "spit" like device. One end could have an indexing plate so the axle could be locked at various angles.

The axles fitted with brackets that a building board can be bolted to. Long boards would almost certainly require some bracing. When the board has served its purpose as a building board you could then cut out the centre in the shape of the waterline and the boat will then sit "in" the board and clamped or strapped for rotating wherever you want. Ok, you cant get to the waterline in one go but you could pack the rim of the cut-out with hard foam or similar and the boat would sit slightly higher to vary the access.

Alternatively you could keep the frames or tripods at a fixed distance to take the largest model and make a rectangular frame that could take boards of fixed width but vary the length. Crikey, you could even build two smaller boats at once.

Footnote:
A variation of Chris's idea of foam etc is to use a collection of bean bags or bags filled with the sort of rounded grit used in aquariums. I got this tip from a fellow aero-modeller and the great thing is they have some weight for stability and can be shaped go fit around almost anything.

So to end. I think you are going to end up with a basic machine and a "kit" of various universal and bespoke parts.

Tim R

Hi All,

Looking at the more humorous side of this quest, I was involved with installing Boeing flight simulators at Gatwick, maybe the hull should be mounted in a fully gimbaled platform mounted on hydraulic rams? Or maybe a zero gravity environment where you could float around the model boat for access 😆

Sorry could' not help myself

Ray

Edited By Ray Wood 2 on 17/01/2019 18:39:39

Hi Paul

Tongue in cheek I know but you did say all ideas welcome. If your Y axis is the problem so if you stick to paddle steamers ……………

Tim R

My building rate is too slow to justify it Paul and there would be a space probem in using and storing it in my small workshop.

Colin