SMS WESPE 1876 by wefalck – 1/160 scale - Armored Gunboat of the Imperial German Navy - as first commissioned

[Gahm]

This gun looks spectacular! It is a piece of art in itself.

 

Thomas

[wefalck]

Thank you, Gahm !

 

Keith, I just re-read the technical description in the contemporary textbook on German naval artillery (GALSTER, 1885): he explicitly states that each crank was worked by six men. This description is indeed very helpful for the interpretation of the complex drawings.

[archjofo]

An admirable job.

Especially remarkable is the scale in which this level of detail has been executed.

[BANYAN]

Very nice results with the laser cut parts Eberhard; that gun looks great!  As you say, a lot cheaper than PE so may need to investigate the process myself as it produces a wonderfully detailed result especially working with smaller scaled items.

 

cheers

 

Pat

[wefalck]

Thanks for the kind words and the 'likes' !

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The hydraulic recoil-brake

 

The 30.5 cm gun in pivot-carriage C/76 was one of the first guns in the Imperial German Navy that was fitted with a hydraulic recoil-brake, at a time, when compressors and brooks were still the standard.

The recoil-brake consists of a long cylinder with screwed-on cylinder-covers at both ends. The covers are pierced for piston rods and are sealed with packed glands. The piston rods are fixed at the front and rear end of the carriage respectivly. The piston is designed as self-opening one-way valve. The cylinder is filled with glycerine through a valve on top. The front-end cylinder covers acts also as cross-head and the upper carriage is linked up through two short forked connecting rods. The cross-head runs on a kind of slide to support the weight of the brake. The two piston-rods are only connected by the short piston, which also acts as valve, and that would not be able to support the weight.

 

 

Working drawing for the parts of the hydraulic brake

 

 

 

When the gun is fired, the upper carriage slides back and the piston is pushed through the glycerine, converting the kinetic energy of the recoil into heat. The valve in the piston prevents the upper carriage from sliding back into firing position. In order to bring the gun forward, the rear end of the carriage is raised by turning the excentric bearings of the rear wheels and opening the valve in the piston. To facilitate this, the rear piston rod is hollow and a spring-loaded valve-rod extends beyond the piston-rod. The valve rod can be srcewed in and out by the aiming gunner using a long lever. In this way he can let the gun roll back into the firing position in a controlled way.

Unfortunately, not much of the hydraulic brake will be visible on the finished model, so that it was reproduced in a somewhat simplified way. It consists of five parts.

 

 

The individual parts of the hydraulic recoil-brake (the grid of the cutting mat is spaced 5 mm)

 

 

 

The piston rods were fashioned from clothes pins of 0.6 mm and 0.7 mm diameter respectively. Clothes pins are very suitable for piston rods, as they have a nicely polished surface. The eye of front piston rod was milled/filed from the head of the clothes pin.

The cylinder was turned in one piece together with the covers from a short length of 2.5 mm round steel. On the micro-mill a hole was cross-drilled for another short piece of steel that had the cross-head pins turned on. This piece was soft-soldered into the cylinder cover. The packed gland is compressed by a hexagonal nut, for which the hexagon was milled on in the dividing head in the same set-up.

The forked connecting links were laser-cut from paper and consist of three pieces each.

The bronze housing for the valve spring was turned from 1 mm brass rod.

The valve lever will be added at a later point.

 

 

 

 

 

Dry-fitting of the recoil-brake into the lower carriage.

 

 

 

It’s kind of a pity that the recoil-break witll be barely visible once the upper carriage is in place. Two grills for the guns crew and a protective tunnel over the rear end will hide most of it.

 

To be continued ...

 

 

Edited March 15, 2020 by wefalck

[KeithAug]

Very nice work Eberhard. I noted with interest your use of sewing needles, a good idea which I will copy.

[FriedClams]

Such excellent work Wefalck.  The laser cut paper produced a very nice result for the lower carriage.  These specialty papers and materials you are using on this model are very interesting and something I must try at some future point.  Thanks for providing the details of your process.  The model is looking great and your log is always an enjoyable and educational read.

 

Gary

[wefalck]

Thanks for the kind words !

 

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Buffer beams

 

In order to limit the recoil and the running out of the gun, buffer beams are installed at both ends of the frame of the lower carriage. Each beam carries four buffers against which the front cross-beam of the upper carriage runs. The buffers are designed as pistons with piston rods screwed to the back of the beam. It is not completely clear what the elastic elements were. The drawings seem to indicate rubber discs with metal separating discs. On some of the guns at Suomenlinna fortress there are remains of rubber discs, while the demonstration model of the Danish navy seems to have spiral springs.

 

Buffer beams on the lower carriage

 

The bodies of the buffers were turned from 1 mm soft steel wire. The spring element was simulated by winding around it several turns of 0.15 mm tinned copper wire. Whether this is meant to meant to represent rubber discs or springs I will decide, when it comes to the painting stage.

 

One buffer dry-mounted

 

The nuts that keep the buffers to the beam were also turned from 1 mm soft steel wire. First, the hexagon for a 0.6 mm spanner width was milled on in the dividing head of the micro-mill. On the lathe a 0.4 mm hole was drilled and 0.3 mm long nuts parted off. And no, I didn’t cut a 0.4 mm thread

 

Buffers and fastening nuts

 

The parts of the buffer beams were laser-cut from 0.15 mm thick Canson paper and soaked in wood-sealer. They were folded and assembled using zapon varnish. In order to make folding more precise, a row of tiny holes were ‘punched’ along the folding lines with the laser-cutter, which weakens the material there. The rivetting was simulated by tiny drops of acrylic gel that was applied with a syringe and a fine injection needle. The needle was ground flat at the end for this purpose.

 

Buffers and fastening nuts – the buffer have a diameter of 1 mm

 

More details were added to the lower carriage. A heavy forged claw at each end of the frame hooks under the rail on which the carriage trucks run to prevent the carriage from lifting off the pivot. The profile of the hooks was taken off the original drawings and cut in multiple copies from Canson paper. These were glued together as a stack and sanded smooth – not a 100% satisfying solution, but filing such tiny but wide claws from the solid I found too fiddly. The lugs that attach the claws to the frame were also cut from Canson paper.

 

Safety claw, pivot plate and drive shaft

 

The gun is trained with the aid of a curved rack, a crown-wheel segment in fact. In to this rack made from bronze, a steel pinion engages that is driven by a shaft from a sort differential, which is powered by man-power from the deck below the barbette. After some consideration I decided not to make the pinion, though I would have liked the challenge, because it will not be visible once the gun has been installed on board. The driving shaft, which also is barely visible was fashioned in a simplified was from a clothes pin, the head of which was turned to shape.

 

To be continued ...

 

Edited March 28, 2020 by wefalck

[amateur]

Fantastic work on this little large gun.

 

If you remove that little coin, nobody would ever guess the gun is this small.

 

just a question: is it my screen, or is e cent not round in the pictures. To me it looks as if the foto' have been resized in a wrong length-width  ratio.

 

Jan

[wefalck]

Thanks, Jan, for your kind words !

 

The photographs were taken with a close-up lense and at an oblique angle, which probably resulted in some distortion of the image. The Euro-cent should look like an ellipse.

[KeithAug]

Very fine detail Eberhard, but you need to provide binoculars to any guest wishing to view it. 

[BANYAN]

Beautifully detailed Eberhard, especially at that scale.

 

cheers

 

Pat

[wefalck]

Belated thanks, Gentlemen, again

 

Since the effective work surface on my workbench gradually had been reduced to around 20 cm x 20 cm, a decluttering action was urgently needed. On the now freed-up workbench I made two improvements to my workshop equipment that I had been planned for a long time:

Tilting model stand
Decades ago, together with some antique lathe parts, I had received a beautifully made cast-iron foot, the use of which had long been a mystery to me. At some point I found out that it was a table base for a small vice, that I unfortunately don't have. In my drawers there was lounging also one of these hand vices with a grid of holes to allow to clamp irregularly shaped parts with the help of short pins. I never had a proper use for it. But both parts together made a useful stand for models during construction. Unfortunately, this stand could not be tilted. In my treasure chest with 'scrap metal' was a clamp for tilting lamps in nicely cast brass. This piece offered itself to make the model stand tiltable. It was done with some modifications to the existing parts and a lathe-turned intermediate piece. Various M10 x 1 threads (standard lamp thread) were cut on the lathe for it. Fortunately, I also had such a tap.





Magnifier holder for the micro milling machine
It is handy to have a magnifying glass permanently installed on the milling machine. A suitable magnifying glass had come to me a long time ago as a promotional 'gift'. In the mentioned scrap treasure chest there was also the gooseneck of an old lamp and various lamp fittings. A connectiing piece to fit the magnifying glass with it M6 thread to gooseneck was turned on the lathe. The magnifying glass can now be rotated in the gooseneck.
Once we can reliably order again in China, I will get another 'angel eye', a ring equipped with LEDs, as they are sold for installation in car headlights. This makes for very nice ring light, as I had fabricated for the 'large' milling machine. Only that here the ring will be integrated into the magnifying glass, because there is not enough space around the milling spindle.





Work continued on the WESPE too, but of that later.

 

[Bob Cleek]

That micro-milling machine is sweet! It's a beautiful piece of "steam punk" engineering. I love it.

[mtaylor]

Excellent modifications and "re-purposing" of equipment.

[BANYAN]

Nice adaptions Eberhard, I get tool envy every time you post one of these beauties

 

cheers

 

Pat

[wefalck]

Thanks, gentlemen. I have been collecting special 'scrap' for 30+ years with the idea of turning it into something useful ...

[Gahm]

The level of detail you are adding to your model at this scale is mind bugling! Excellent work and craftsmanship!

 

Thomas 

[wefalck]

Loading crane

 

Somehow I seem to move two steps forward and then one step back again. For one part completed there are several that jump off the table to be never found again or that are destroyed during subsequent steps of manipulation ...

Mechanically, the loading crane is a relatively simple affair, a rope winding drum driven through a pinion and cog-wheel, powered by a hand-crank, and for turning a worm-wheel drive equally powerd by a hand-crank. The console on which the crane rests is a quite complex part that was bolted together from several cast parts.

The loading crane on the demonstration model in the former Naval Museum in Copenhagen

 

The winding mechanism of the charging crane

 

My first thought was to mill the console from the solid or rather to solder it together from several milled parts. I finally decided to put the laser-cutter to work and fabricate it from several cardboard pieces. On the bottom line, this was the easiest solution and compatible with the rest of the under-carriage

The crane on the demonstration model in Copenhagen mainly consists of bright pieces of steel or cast-iron. Whether this was the case too originally on the prototype cannot be verified anymore, as no detail photographs exist. It is perhaps doubtful due to the continuous maintenance required to keep rust at bay. Although, the navy was not concerned about camouflage at that time, they were aware of the risk of early detection by the enemy due to bright metal part reflecting the sun. However, I allowed myself the artisanal-aesthetic license of bright metal, as I think it will be a nice contrast to the dark green of the gun carriage later.

The actual crane was milled from a 2.5 mm steel rod. To this end the thickness profiles in both dimensions were taken off the original drawings and ‚stretched’ out straight in the CAD software. After milling, the part was softened in the flame, so that it could be bent according to the drawing. The hole and slot for the pulley were machined afterwards, as the part could break there during bending. The final shaping was done with silicone-bound grinding bits.

 

Milling of the crane in the dividing apparatus

 

 

Pulleys and forks form them are tiny parts machined on the lathe and the milling machine.

Fork for the lower guiding pulley

 

The mechanism of the crane consists of a good dozen of lathe-turned parts, that were, apart from their minute size, were not particularly challenging.

The cog-wheel, the pinion, and the worm-wheel were turned together with their axes in one piece. On the photographs I counted 60 teeth on the large wheel, which gives, together with a diameter of 3 mm a module of 0.05. Making a single tooth mill seem to be too much work, so that I took the short-cut of just gashing the wheels with a 0.1 mm thick circular saw. It is only about the look and I did not intend to make these gears functional. Hobbing a worm-wheel of just 1 mm diameter was too big of a challenge, big of a challenge, but at least I tilted the axis 20° when gashing it.

 

 

 

Milling of the pinion and the cog-wheel

 

Partly assembled loading crane

 

The final assembly can only be done, once the crane-console has been attached to the carriage and the whole thing is painted.

 

 

To be continued ...

Edited May 1, 2020 by wefalck

[Keith Black]

Absolutely amazing work! 

[druxey]

A watch with complications should be easy for you after this!

[KeithAug]

Very impressive Eberhard. I  can loose much bigger parts than that with great ease. 

[BANYAN]

Just when I thought I was kicking some goals you come along to spoil the party   Seriously though Eberhard, that is some very (VERY) impressive micro-maching and the result looks excellent.  So much for me cobbling bits together to 'simulate' when you can do this at half the size I am doing it at.  As you have said in other logs, a machined item looks much better.

 

cheers

 

Pat

[wefalck]

Thanks, gentlemen, much appreciated !

 

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Folding tool

 

As will be seen in the next post, quite a number of delicate laser-cut parts will need to be folded. Therefore, I thought a folding tool might come handy. A number of commercial gadgets are available, but considering that they essentially consist of a couple of milled-to shape pieces of aluminium and a thumb-screw, I find them rather overpriced at €20 to €70, depending on what you buy where. Also, if I have the right materials and tools, I prefer to make such things myself.

I did not have a suitable piece of flat aluminium in stock, so I decided to make it from some 4 mm thick Plexiglas off-cut. This has the added value that you can better see, where you place the folding edge. Plexiglas is more vulnerable than aluminium, but I can always make a replacement, should the need arise.

 

A set of fingers ranging from 1 mm to 6 mm width were separated by notches made with a 4 mm cutter. The front was bevelled for better access to small parts. The opposite side was left straight for longer parts. For the moment, the front edges where milled at 90° degrees, but I can imagine that a slight overbending would be better. I am considering to mill on a 5° or 10° relief angle, but will first test the piece in practice. A more acute angle will make the edges more vulnerable to chipping. The underside is somewhat recessed over most of the width, so that tool really clamps with the front edge, where it is needed, and does not wobble.

As I also did not have material for a base in stock, I decided to use the base of the sanding tool that I made a while ago. It has the added value that no extra gadget is floating around the workshop. The folding ruler was drilled and two corresponding holes in the base were drilled and tapped for M3 thumb-screws.

 

 

[KeithAug]

Eberhard - I agree, it always feels better to make stuff like this rather than buy and then find yourself improving what you have bought. I will be interested to see how well it works.

[Louie da fly]

Good grief! I'm gobsmacked at the level of detail and precision. You are a true artist, sir.

 

Steven

[Rudolf]

Hello Eberhard, Thank you very much for your inspirational postings.

Do you think that your Little laser will be able to cut deck Planks, say 1,2 mm wide 6 cm Long out of  Costello or maple veneer?

Thank you.

Greetings,

Rudolf

[wefalck]

Rudolf, to be honest, I don't know. I haven't had a need to try the laser on wood (yet). It will be a question of thickness and density of the material. Due to the rather low power, the laser point would have to stay longer on a spot to get through, which leads to more charred edges and a perceptible kerf. This is already noticeable on the 0.15 mm thick cardboard I am currently working with.

[wefalck]

Folding tool update

 

After the first use of the tool, I immediately made a couple of modifications, which however, I had expected to introduce anyway.

When working with cardboard or paper one needs to ‘overbend’ the folds somewhat, so that they stay at the desired angle. This is different to working with soft sheet-metal. Styrene sheet also will have this spring effect. Therefore, the folding edges were given a 10° clearance angle. An angle of 15° may have been even better, but it works with the 10°. The edges are not really weakened by this.

The second modification was to place a spring washer under the folding ruler. I had in mind to do this right away, but could not find them in the first place. The washers lift up the ruler a bit, so that it is easier to slip the material under it.

 

 

Gun operating platforms and gratings

 

The gun is mounted effectively on a turntable, so that platforms for crew are needed to give them access to the gun, while is being trained left or right. These platforms are made of wire gratings that are placed into angle-iron frames. The frames are suspended from the lower carriage by brackets. The pictorial evidence (photographs, drawings) is not detailed enough to fully understand what the brackets actually looked like and how and where exactly they were attached to the lower carriage frame. Some additional information is given by the Danish instruction model and the Russian clones in Suomenlinna fortress, but the carriages of these guns differ in detail from that on SMS WESPE. So the reconstruction of these platforms remains somewhat conjectural.

 

Crew standing on the gratings and operating the gun

 

 

Gratings of the Danish instruction model

 

 

Detail of gratings on a gun in Suomenlinna fortress

 

There are 13 gratings and steps in total, plus the platform for the gun-layer. The original plan was to photo-etch the frames from brass sheet, but with the arrival of the laser-cutter I changed this plan. The drawings were modified accordingly. The obvious solution to simulate the angle-iron frame was to design an open frame and then fold-up the vertical parts of the angle. However, it proved impossible to fold the narrow, 0.3 to 0.4 mm strips consistently and without distortions. Not sure this would have worked with the PE parts either. It was then decided to make the open frame and the vertical parts separately as narrow strips and glue them together with lacquer. After several iterations of drawings and laser-cutter settings to arrive a workable width of the strips etc. I arrived at an acceptable solution, albeit the ‘angle-irons’ are somewhat over-scale.

 

 

Example of a drawing for the gratings and their supporting brackets

 

Assembly was a slow and nerve-wracking process. I did not manage to do more than one grating per evening and it involved a lot of (mental) foul language. Eventually, I got them all together. Zapon-varnish was used throughout the assembly. The finished parts are surprisingly strong.

 

First Version with engraved surfaces of the platform for the gun-layer

 

Final Version of the platform for the gun-layer (5 mm grid on the cutting-mat)

 

The original plan was to simulate the wire-mesh of the gratings by real wire-mesh and I obtained from wires.co.uk some really fine mesh in brass and steel. The idea was to pull every second wire in one direction, as the original mesh was rectangular. It proved, however, very difficult to cut such small pieces (sometimes only 1.5 mm wide) from the wire-mesh. Then a present to wife in form of a box with various (fruit) teas came to my rescue: some of the teas came in bags made from extremely fine but lightly woven fabric. I do not know what material it is, but as it dissolves in acetone, it is probably cellulose acetate silk or Rayon. Such fabrics are also used in silk-screen printing and I had not chanced upon the tea-bags, I would have looked there. This silk-screen or fabric can be precisely and easily cut with a new scalpel blade. The small pieces of fabric were dropped into the frames and fixed at the edges with a light touch of varnish.

 

Tea-bag fabric

 

The platform for the gun-layer is a more complex structure. A 5 mm sheet-metal armour shield is meant to protect him from shrapnel and small-arms fire. The armour shield is reinforced at the edges with rivetted-on metal strips. The original plan was to produce this as a surface-etched part. I realised that the laser-cutter interprets half-tone images as instructions to modulate the laser power so that it does not cut all the way through. Laser-engraving in other words. It did produce the desired effect, albeit with the engraved surface being rather rough due to the digitising effect. However, this part then was so thin and flimsy, that it would not stay in shape, when attempting to shape the round corner. I reluctantly accepted that it would be somewhat over-scale in thickness and cut the armour shield and the reinforcing strips separately. They were glued on top of each other with varnish and then the round of the shield formed over a rod. Folding and gluing completed the process.

 

The collection of gratings and steps

 

I am not entirely happy with the result and tend to think, that etched parts may have looked finer. But then their assembly would have required a lot of very delicate soldering work – I don’t trust CA for metal/metal bonds too much. On the other hand, attaching the gratings to the lower carriage frame is likely to be easier for the cardboard parts than for brass parts. Before that can be done, I need to add the wheels, which requires a lot of handling ...

 

To be continued ...

[BANYAN]

I'm not so sure PE will have looked that much better Eberhard, the effect you achieved in the second collection of photos is pretty close to the real thing - only difference being the square rather than rectangular mesh grating.

 

Looks good to the eye (based on the photo)

 

cheers

 

Pat