Solving a riveting problem

By Gerald Wingrove

The aim of my current project is to build in 1/8th to one foot scale, a centre section of the iron hull of the four masted ship ‘Falls of Clyde’, to show the iron plate, frame and rivet construction. 

Thanking one’s self through a project, with no previous knowledge of how to proceed and, in fact, not knowing if the project can actually be made at all, is a very interesting exercise for the brain, particularly for an 80 year old one. Luckily mine is still very active, and with a good 60 years of innovative model making behind me, and much use and experience of tools, tool making and material, I felt at last, that I now had the wherewithall to get my hands dirty with the project. 

The main difference between building a wooden ship and an iron one is in the nature of the materials. In the former a large block of wood is carved and shaped by removing material from it, to match its place in the ship, so infinite adjustment of the exact shape is always available for the craftsman's hand and a sharp tool whether full size or in a model.

When the material is of iron the sizes are predetermined - iron plate is of a set thickness as is the angle iron used for the frames and the bulb iron used for deck beams and stringers, here there is no latitude and adjustment of the size and shape of the materials by removing metal. The plate, angle iron, and bulb iron have to be manipulated by precision machines, and very big those machine had to be in the days of iron ship building.

The only common feature between a yard for building a wooden ship and the yard for building an iron ship, is the slipway for actually building and the launching of the hull. For the rest one needed the services of a large engineering and blacksmith’s machine shop attached to the shipyard for manipulating the basic wrought iron forms - plate, angle iron and bulb iron, to the size and shapes required.

At the time when the Falls of Clyde was built in 1878, much of the work involving the manipulation of the angle and bulb iron for the frames was still undertaken by hand tools, albeit when the iron was red hot in most cases. But the bending, cutting and roller shaping of the iron plates needed very large and heavy machinery and the drilling and matching of holes for riveting the plates, beams and stringers to frames had of necessity to be precision engineering - a wrongly fitted rivet could and did let water into the hull which could jeopardize the whole project.

So, in setting out to build a scale representation of an iron hull I first needed to establish the size, and the materials I had available to use. I wished the model to be as small as possible, space is always at a premium, yet still show the impression of rivets. Iron is not available in small sizes, however brass is, including sizes for the plating and the angles needed, so the choice was made - I see no point in using actual rivets for the fixing, as only the heads show in the finished work, so the fixing for the final assembly would be solder, hard or soft as required.

The scale chosen would be 1/8th inch to one foot, or .010” to 1 inch. Making a large centre section of the hull - my initial aim for the start, to be of 40 frames making it 10 inches (254 mm) long by about 5 inches (122 mm) wide and 4 inches (102 mm) high, and would include a lower mast, hatch, deckhouse etc. Fully plated on one side and partly plated on the other, also fully deck planked on one side and no planking on the other, so the full structure of the hull could be seen. The finish would be dull nickel plating, to represent the original wrought iron, before the rust set in.

The more I studied the project the more answers I found in the use of machines, jigs and fixtures. There is no case here of filing a little off here or there to make something fit, the size of the basic materials set the pace, so it was a case of studying how the original material was worked and from there design and build my own machines to equip a miniature ship building engineering workshop. For this one needs to imagine ones way through the building process and solve the imaginary problems as they crop up. Of course once all the tooling is created and the model building process started, other ideas may come into play, as a more simplified way to approach the problem, but until one has some of this made, one cannot even start the first stage in the building.

The following represents the initial machine set up, all ten machines were designed and built over a period of nine weeks, the construction being in a very high grade of aluminium, apparently used in place of steel in the making of dies and moulds, which I obtained from a local scrap yard about 20 years ago - one of those things one sees, and thinks, “that will come in useful sometime” so I took away several useful sizes.

All bearings have brass inserts, spindles and cutters are of silver steel or gauge plate, the cutters hardened and tempered, all moving parts are micro adjustable.

So what are the key elements in building a replica of an iron hull?

1 - A means of simulating rivet heads - thousands upon thousand, all exactly the same size and placed with precession in rows at set distances, together with a means of also producing and placing single rivet heads individually.

2 -  A means of cutting to specific dimensions repeatedly,  the sheet and angle brass.

3 -  A means of bending the sheet brass plates to specified and varied angles repeatedly.

4 - A means of forming and assembling the individual frames, with micro adjustment to accommodate the changing shape, as no two frames are exactly the same.

5 - A soldering table with fully adjustable arms to hold parts for resistance soldering, as the normal soldering iron would appear to be to cumbersome for such fine work.

6 - A miniature ship yard with fully adjustable arms to hold the individual frames so that the plates and stringers can be assembled to form the ships hull.

The number one problem tool to design and make was the rivet head maker - with that done the next problem in line was to be able to cut sheet and angle brass to precise lengths repeatedly. The larger guillotine is OK for the initial cutting of the basic material, but the smaller parts can be very small. Hundreds of angle iron brackets, 12 to 18 inches long with rivets placed every 4 to 6 inches - on one eighth inch to the foot scale, that comes out at .125” (3.17 mm) to .186” (4.72 mm) long with rivet centres at between .040” (1.0 mm) and .060” (1.54 mm ) apart, is just one example.

The subsequent machine was a joy design and to make, being just seven inches long (18 cm) X two and a half wide (6 cm) and three and a half tall (8.5 cm) with the handle locked down for storage.  It is very simple to set up and works perfectly for the jobs it was designed to accomplish.