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PostPosted: Sat Oct 05, 2019 10:51 pm 
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Wefalck

The images do not show for some reason.

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PostPosted: Sun Oct 06, 2019 3:19 am 
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Sorry, they were linked as https, as some other fora require. Corrected.

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PostPosted: Sun Oct 06, 2019 4:18 am 
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Very nice work :thumbs_up_1:


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PostPosted: Sun Oct 06, 2019 11:41 pm 
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Wow! Your model of the EOT is very small! Nice work.

I seem to recall reading somewhere (on this Forum?) that the Engine Order Telegraphs on the first US monitoes (USS Monitor) had a horizontal display.

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PostPosted: Sun Nov 03, 2019 11:45 am 
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Thanks, gentlemen !

*********************

Binnacles
SMS WESPE was originally equipped with three binnacles, one on the bridge, the mother-compass on a sort of pole in front of the engine-room skylight, and the third one in front of the emergency steering-wheel at the stern. In the 1890s a fourth binnacle was installed on a platform atop the engine-room skylight, but is left off here. As SMS WESPE was built in 1876 the original binnacles lack the conspicuous compensation spheres, that were only invented in the 1880s by Lord Kelvin. Also other type of compensation gear is not visible on the lithographs and the earliest photograph. A photography of the early 1890s shows a much more substantial binnacle in front of the emergency steering-wheel, which preumably now houses the compensation gear and also sports the compensation spheres. Originally, the compasses must have been illumanted by petroleum lamps, but from the lithographs it is not clear, where these lamps would have been attached. At least there are exhaust funnels on top of the binnacles, which have disappeared in later photographs. This seems to indicated that electrical illumination might have been introduced, when a dynamo was installed on board in the early 1890s for a search-light.

Image
The binnacles as they appear on the early 1880s lithograph

For the model the individual binnacles were redrawn from the lithograph in order to serve as a basis for working sketch to guide the lathe- and mill-work. One needs to keep in mind that the total height is somewhere between 10 and 15 mm.

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Redrawn binnacles, broken down into individual components to facilitate machining and painting

The columns presumably were made from mahagony and were turned from brass rod before being transferred to dividing head on mill to cut the octogonal shape.

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Milling the octogonal section of the binnacle columns

The actual compass was made, as usual, from brass and so on the model. Body and funnel did not provide a particular challenge, not considering the small size. To the contrary, the glass hood with its narrow frames of perhaps 15 mm width on the original. The body was roughly turned from Plexiglas and then transferred to the mill. Here the octogonal pyramid was milled. Using a 0.3 mm ball-head burr narrow grooves were cut into the edges and these grooves filled in with brass paint.

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Set-up on the micro-mill to shape the octogonal pyramid of the glass hood

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Milling the faces of the octogonal pyramid

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Cleaning up the faces after painting the edges

Once the paint had thoroughly dried, the faces were very lightly milled over, which resulted in sharp narrow brass strips at the edges. This is a technique that I copied from making engraved scales.

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Each binnacle is made up from four parts

Originally I had the crazy idea of placing a miniature compass-card underneath the Plexiglas hoods, but even without it, assembling the binnacles was fiddly enough.

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The binnacles provisionally assembled, pending the painting of the stands (apologies for the poor quality picture and the missing match for scale)

To be continued soon(?) ...

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PostPosted: Mon Nov 04, 2019 3:08 am 
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The brass paint is indistinguishable from the brass parts; did you mill the excess paint ?


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PostPosted: Mon Nov 04, 2019 3:41 am 
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Yes, I brushed the paint all over the Plexiglas part and then lightly touched the faces again with the milling-cutter, so that the paint would remain only in the groove milled into the edges.

I am using the excellent metal paste made by the Czech company AGAMA: http://www.agama-color.cz/en/products/. I read a very positive review a few years ago and then happened to be in Prague shortly thereafter, where I bought their whole suite of pastes at a very favourable exchange rate. They are really good.

Unfortunately, the German product 'Standard-Gold' has been discontinued years ago. When you stirred it and then let it settle again, the tiniest particles floated on the surface and when applied to a polished plastic surface, they looked like 'metallised' plastic parts (e.g. bathroom fittings). It's a pity that sometimes really good products are discontinued ...

Talking about gilding: as a natural scientist I have been aware of and actually used gold-sputtering of specimens for examination under a scanning electron miicroscope. Last year I ran into a British gentleman at the great shipmodelling meeting in Rochefort (France), who used this technique to gild 3D-modelled and -printed sculptures for a Georgian navy model. He is lucky to have a son, who works at Imperial College in London and who has access to a sputtering facility. Not cheap, the technique though. I wrote an article about this gentleman and his model in the LOGBUCH (the quarterly of our German Association for Shipbuilding History).

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PostPosted: Sun Dec 01, 2019 5:31 pm 
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There are some really delicate parts lined up now, such as the frames for the freeing port along the bulwarks. My original thought was to have them photoetched from 0.1 mm brass. However, given the difficulties I had in creating good, dense etching masks, I thought of trying a different route and something that is less messy. Laser-cutting seemed to be an interesting proposition.
So I got myself a new little toy at 100€ incl. shipping. Toy is perhaps an adequate description for these small compact machines that are now on the market. Their design-purpose probably is to mark merchandise with a burnt-in logo etc. For this reason they are mobile, so items of any size can be marked by just putting the little (15 cm x 15 cm x 15 cm) box on them. Their power is limited, 3W. A mechanical resolution of 0.05 mm is claimed, with a diameter of the laser-spot of 0.1 mm. The engraving area is 53 mm by 53 mm. The software driver works by converting the images into bit-maps and then it runs them down line by line. I should try to find another driver that uses vector graphics, which would speed up the cutting process presumably.

Image
KKMoon-Lasercutter with a 3W laserdiode

The software allows to adjust various parameters, including the contrast of the image, the power output of the LED, and something called ‘cutting depth’, though it is not clear what the latter really does. The focus of the LED can be adjusted manually to allow for materials of different thickness, but it is difficult to judge, whether really the minimum of the spot-size has been achieved.
Given the power of only 3W, there are limitation to what materials can be worked with. The cutting resp. engraving effect depends on how much energy is needed to burn or vaporise the material. Paper works well, but a 0.4 mm cardboard seems to be the limit. I did not have much success with white styrene, only some light surface marks resulted even at the highest settings. Hard paper (phenolic resin impregnated paper) would have been my favourite material, but apart from the strong smell (the fumes are also not terribly healthy) a 0.2 mm thick sheet was only cut half-way through. Semi-transparent tracing paper does not take up enough of the energy and remains untouched. A sufficient optical density is required in order to absorb the energy and burn/evaporate the material. Strangely enough, the laser left quite visible marks on the piece of roof-slate that I used as fire-proof protection under machine.
Converting a drawing into a cut-out piece is not quite straightforward. I first had to work out a way to scale the bit-map and JPEG images that I created from my CAD-drawings. The solution was to draw a box around the graphics to be exported, measure this box and then to scale the exported drawing in Adobe Photoshop to a number of pixels the resulted in the box of being of the desired size when laser-cut. The resulting scaling factor was 1 mm = 20 pixel, which was indeed the claimed resolution of 0.05 mm.
On an image everything that is black will be burned away and everything white will remain. However, simply converting the CAD-drawings into images resulted in too narrow/small parts due to the fact, that the each burnt point has a diameter of at least 0.1 mm. Therefore, it was necessary to adjust the sizes of the areas to be burned away so that the remaining parts have the desired dimensions. The effect depends on the burning parameters and on the material. So, unfortunately, each new material and new part will require a certain amount of trial and error.
I tried my luck on another set of very delicate parts, namely the steering-wheels. They have an OD of just under 12 mm. Turning the complex shape of spokes of 6 mm length appeared to be daunting task, even if one could have perhaps made the handles and the spokes themselves in two parts. The laser-cut ones look quite good after a few trial runs, but I have to see, whether I can build up enough thickness from several layers. Cutting them from 0.4 mm thick cardboard was not fully successful.

Image
Laser-cut steering wheels of 12 mm outer diameter

I just wanted to share the first experiences with this new workshop toy and trials will continue.


To be continued soon(?) ...

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PostPosted: Wed Jan 15, 2020 5:25 pm 
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Steering wheels

The WESPE-Class boats had two sets of steerings wheels, the main one on the bridge and the emergency one in the stern. Both had double wheels that worked in the traditional way on drums and ropes. There is a rather good photograph of the emergency steering position, which allows to deduct the details of the wheels.

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Emergency steering position in the stern

After some tests with the laser-cutter, I finally chose 120 g/m2 Canson-paper, which is 0.15 mm thick and has a smooth surface. It cuts well with the laser-cutter, as it is not ballasted with inorganic material, such as barytes.

Some trials were needed to determine the right cutting parameter combination of contrast, laser-power and cutting depth. One should assume that for a simple B/W-picture the contrast should be 100%, but somehow changing the contrast setting changes the width of the cuts. For this reason the final dimensions of the parts depend on the contrast setting.

Laser-cutting is contactless and the cut-out parts are not moved during the cutting process. Therefore, it is possible to cut them out completely and in contrast to the photoetch-process they do not need to be attached to some frame.

When designing the image with which the laser-cutter works, one needs to consider all these factors that sometimes can only be determined by trial and error.

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The laser-cut parts of all four steering-wheels

The wheels are built up from several layers in order to simulate the joinery work and to arrive at the necessary 3D-rendering. Two core parts are thickened by two more layers the outline of which was drawn a bit smaller to simulate the profiling of wheels and handles. A further layer on each side simulate the rim and hub. The individual layers were cemented together with zapon-lacquer, which impregnates and stiffens the cardboard. Unlike many other glues this lacquer only forms a very thin layer, not adding to the thickness of the wheel, and the parts can be adjusted, as long as the lacquer has not dried.

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Assembled wheels before finishing (the grid on the cutting mat has 5 mm spacing)

Handles and spokes where ‘rounded’ with some thinned PVA glue applied in several layers.

The prototype steering-wheels were re-enforced by brass-rings screwed on each face. My intention was to make these rings from real brass shim (remember: only real metal looks like real metal ...). However, I did not manage to cut so narrow rings from 0.05 mm brass-shim. In the end, I cut the rings from cardboard. They will be covered, after the wheels have been painted, in in gold-leaf.

The idea was to produce the rings on the lathe. To this end a dozen small squares of brass-shim were glued together and stiffend by squares of 0.5 mm bakelite. A central mounting hole of 2 mm diameter was drilled through the package and mounted onto the lathe on arbor. The package then was turned to the required outside diameter. The 1.5 mm thick package then was transfered to a ‘wheel-chuck’ on the watchmakers lathe. However the attempt to bore out the inside diameter did not work.

The next step will be the construction of the steering-wheel stand

To be continued ... hopefully soon ...

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PostPosted: Tue Jan 28, 2020 5:31 pm 
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Steering-wheels, third edition

A colleague challenged me to turn the brass reenforcement rings. I took up the challenge and bored out a piece of round brass stock to 6.8 mm and turned down the outside to 7.2 mm. From this tube with 0.3 mm wall thickness slices of 0.1 mm thickness were parted off. After a few trials to get the settings right this worked fast and repeteable. The rings were deburred on 600 grit wet-and-dry paper, ground finely on an Arkansa-stone and polished on a piece of paper with some polishing compound.

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The new steering-wheels, above the brass rings

As it would have been very difficult to remove the old rings from paper from the wheels, I used the opportunity to produce a third edition of the wheels in which I left out one of the middle layers. The second edition was actually slightly too thick. Using the tried-out cutting parameters and now with some practice in assembling them, the new wheels were ready soon. The brass rings were glued on with lacquer.

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The freshly cut wheels (I use a roof slate as cutting support)

The axle including drum for the steering rope were turned from brass.

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A pair of steering-wheels provisionally assembled and the component parts

The wheels will be spray-painted painted all over and then the paint rubbed off from the brass rings. This will nicely simulate the rings let into the wood as per prototype.

To be continued ... hopefully soon ...

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PostPosted: Wed Jan 29, 2020 9:05 am 
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splendid and fine work...


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PostPosted: Tue Feb 04, 2020 3:58 pm 
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Thank you :thumbs_up_1:

***************************

Steering-stands

The steering-stands consists of two pillars supporting a pair of wheels. These pillars were somehow bolted to the deck, but drawings and photographs do not show how it was done. On the model this detail will be barely visible, as the lower part of the columns will be hidden by the gratings platform.

The grating actually were photo-etched a long time ago. However, I did not like the rounded-out corners, which are due to my somewhat primitive etching process. Therefore, I cut the gratings also with the laser from Canson-paper. By playing around with the settings of the laser-cutter, I managed to produce reasonably square field and sharp corners. The fields resp. the ‘laths’ are only 0.3 mm wide and the grating is 0.3 mm thick (0.3 mm in 1:160 scale is equivalent to just under 50 mm for the prototype). I would have found it impossible to produce a grating in these dimensions prototype fashion.

Image
Steering-stand gratings: Image as input for the laser-cutter

The gratings are made up from two layers of paper 0.15 mm thick each. Imitating the prototype to some degree the lower layer only had transversal laths. Both layers were glued together with lacquer. The transversal reenforcing bars are built up from three layers of paper and glued to the gratings again with lacquer.

The platforms are raised above the deck by four short columns that were turned from brass rod. They were slotted for the reenforcing bars on the micro-mill.

The steering-wheel pillars were designed on the basis of the photographie showen earlier and what can be deducted from the lithographs. There is a pole protruding from the front pillar of the stand on the bridge, the function of which is unclear to me. It may have supported an indicator for the rudder or just the lanyard for the steam-pipe. The only known photograph that shows a boat before the armoured command tower was installed is too grainy from the printing grid (it is only known from a publication) to allow to discern such details.

Image
Steering-wheel pillars: JPG-Image as input for the laser-cutter

The pillars where built up from three layers of Canson-paer, which allowed to represent the cannelures. The pillar appears to be rather thin, but this is how it is drawn on the lithograph.

The axle of the steering-wheel rests in bearings that are clad in brass or bronze. A piece of 2 mm brass rod was bored out for the round heads of the pillars and then a thin disc was parted off. For further machining the discs were held in special insert collets with a low recess turned into the front (so-calle jewelling collets, used by watchmakers to machine watch jewels or bushings)

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Machining the bearing caps in a 'jewelling' collet

The profile on the front was turned with a small boring tool and the dome-shaped cap over the axle was formed with a cup burr, as used by jewellery-makers to round off wires.

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Shaping the covering cap of the wheel-axle using a cup burr

The caps are actually only segments of a disc and were milled of on the micro-mill accordingly.

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Milling of the segment-shaped caps

All parts were glued together using lacquer

Image
The individual parts of the steering-stands

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Steering-stand on the bridge loosely assembled (a 1 €-cent coin for reference)

To be continued ...

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PostPosted: Thu Feb 06, 2020 6:15 am 
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oh boy, oh boy, oh boy... a real gem, a very small one...


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PostPosted: Sun Feb 09, 2020 2:35 pm 
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Thank you ! Yes challengly small ...

************************************

Freeing Ports

Originally I had planned to surface-etch the lids and the frames on the inside of the bulwark. The drawings for the masks were ready, but I never got around to actually etch or have the parts etched. Since I now have the laser-cutter, these parts were cut from printer-paper (80 g/m2 = 0.1 mm thick). With a width of the frames of only 0.5 mm, the surface-etched rivets may not have come out anyway. The same for the rivets on the hinges of the lids. At least not with my somewhat primitve home-etching arrangement. If I had etched the parts from 0.1 mm nickel-brass, the overall thickness would have been reduced to a more correct 0.05 mm (= 8 mm for the prototype).

The lids have no latches to lock them and the ports no bars across them to prevent items or people being washed over board. This makes their construction simpler.

Papers, even the smoothest ones, alway have a certain surface-roughness, at least compared to the bakelite of the bulwark. Therefore, the chosen paper was soaked in wood filler and spread to dry on a thick glass-plate that was covered in cling-film. The latter allowed to remove the paper without it rolling up. The surface was then smoothed with very fine steel-wool. The lids were cut from the thus prepared paper, but it needed several trials to find the right cutting parameters in order to arrive at parts of the correct dimensions. This is a disadvantage of such simple laser-cutters and their software. As the material is practically free, this is only a nuisance, but no other loss. Also the etching may not work out right in the first go, which may mean a considerable loss of money and time, if the process had been outsourced.

Image
Laser-cut lids for the freeing-ports

Unfortunately, it does not work for very small parts with the paper prepared as above. It turned out to better for the very small parts, including the frames, to cut them from unprepared paper. Perhaps I should switch to dark paper. Due to its lower albedo (reflectivity) it absorbs more energy from the laser. Unfortunately, all the coloured papers I have come by so far are quite rough on the surface.

I cheated somewhat for the freeing-ports. As I was afraid that I would not been able to cut them out cleanly and evenly, I abstained from it. Also, the bakelite-paper used for the bulwark for reasons of stability would have had a scale-thickness of 64 mm, when looked on from the side. Therefore, frames and lids were glued flat onto the inside and outside of the bulwark respectively. I hope one will not notice this too much, once the stanchions are in as well.

Frames and lids were glued on with zapon-lacquer. Little laser-cut rectangles of 0.3 mm x 0.5 mm were stuck onto lids to simulate the hinges.

Image
Installation of frames and lids

To be continued ...

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PostPosted: Thu Feb 20, 2020 3:29 pm 
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Doors in the foredeck and the deck-house

Foredeck and deck-house were accessible through various doors. These were cut from 0.1 mm bakelite paper with the laser-cutter. The hinges were laser-cut from thin paper. In both cases various tries were needed with different cutting parameters and slightly altered drawings in order to arrive at the correct size. Die parts were assembled using zapon-lacquer. Zapon-lacquer was also used to glue the door into place.

Image
Laser-cut doors from bakelite paper before clean-up

On historical photographs I noticed that each door had a narrow step. These were represented by shaped and laser-cut tiny strips of paper.

Image
View of decks-house and back of the fore-deck with the doors installed

Once the door were in place the hole for the bullseyes were drilled out. The laser-cut hole served as a guide. Once the boat is painted, the glazing will be installed in form of short lengths of 1 mm Plexiglas rods. The front of the rods will be faced and polished carefully on the lathe.
At a later moment also the door-knobs will be turned from brass and installed.

P.S. Apologies for the somewhat poor quality of the photographs, but I have been too lazy to take out the SLR camera and took them with the telephone.

To be continued ...

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PostPosted: Fri Feb 21, 2020 1:32 am 
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wefalck,

You certainly are making good use of your laser cutter!

I do have a question about using the laser with Bakelite. As you certainly know, Bakelite was once used extensively for insulators in electronic equipment (especially in the high voltage vacuum tube days). But it was phased out of use because it gave off toxic vapors when it burned. Apparently it contains formaldehyde, and some of the older stuff contained asbestos. It definitely had a distinctive odor when it burned (guess how I know?).

Do you have any concerns about burning it with the laser or when machining it?

Phil

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PostPosted: Fri Feb 21, 2020 2:36 am 
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Yes, I am aware of the issues with the fumes. However, until my twenties we were using a formaldehyde containing medicine against sore throat - probably got a good exposure to that.

In my application so little mass is burned that one barely smells it - even my odour-sensitive wife did not complain. If I was doing this more frequently, of course, I would think about an exhaust system or take the cutter outside.

I think this bakelite paper is a very useful material, as it is much harder than styrene and sands and polishes well.

There are various bakelite-based composites. The common forms are layers of paper impregnated with the liquid resin and then cured between heated steel-plates. It is produced in thicknesses from 0.1
mm to about 10 mm. In the other common variant layers of cotton cloth are embedded. This is used for making ‚silent‘ gears and other mechanical parts.

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PostPosted: Mon Mar 02, 2020 6:03 pm 
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fascinating stuff!
:thumbs_up_1: :thumbs_up_1:

and you think I am fiddling about with small delicate detail.... ha!

==> Onwards

JIM BAUMANN :wave_1:

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PostPosted: Sun Mar 08, 2020 4:26 pm 
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The lower carriage of the 30.5 cm gun

The lower carriage of the gun was a rather complex construction from rolled L-profiles and thick steel sheet. Unfortunately only the drawings in GALSTER (1885) and the coloured synoptic drawing from the Admiralty have come to us. Many construction details are superimposed onto each other with dashed lines, so that the interpretation of the drawings is rather difficult in places. As aids to interpretation with have one close-up photograph, the large demonstration model in the navy museum in Copenhagen, and the preserved guns of Suomenlinna Fortress off Helsinki. The carriage for the Danish iron-clad HELGOLAND, however, differs from that of SMS WESPE in some details, being actually a turret-carriage. The carriages in Suomenlinna are Russian copies of Krupp fortress carriages, but they allow to verify certain construction details that are not clear from the drawings.

Image
Synoptic drawing of the 30.5 cm gun (from http://www.dreadnoughtproject.org/)

Originally I had planned to construct the lower carriage, like the upper carriage, from surface-etched brass parts. To this end I produced some time ago already the needed detail drawings. Surface etching is a very good process to simulate rivetting. In the meantime, however, I had purchased the laser-cutter, so that laser-cut parts would be an alternative. I had hoped to cut the parts from bakelite paper. Various trials with different cutting parameters unfortunately were not very successfull for the intricate parts. The 5 mW laser ist too weak to burn the material fast enough. Burrs of molten and partially carbonised resin form. Therefore, I fell back onto Canson-paper, which is a bit over scale with its thickness of 0.15 mm.

Image
Base-plate and races laser-cut from Canson-paper

The drawings for the etching masks had to be reworked for laser cutting. It turned out during assembly that I had made several mistakes or misinterpretations. If I had send them off for etching this would have been costly, as both masks and etching would have to be redone. When cutting paper with a laser such corrections can be made quickly and easily – and the material costs practically nothing.

Image
The basic frame of the lower carriage from the rear

The laser-cut parts were soaked in nitrocellulose wood-filler and once dry rubbed with very fine steel wool. To double up parts and for assembly zapon lacquer was used. This dries so fast that no special arrangements for fixing the parts are needed.

Image
The basic frame of the lower carriage from the front

I did not take pictures of the different steps of assembly, as this would have rather impeded the process. First all parts to be doubled up were cemented together using zapon lacquer and weighed down to keep them flat during drying. The longitudinal parts of the carriage had slots cut into them, so that the transveral parts could be positioned exactly. The frame assembly then was cemented to the base plate (which in reality was not a plate, but rather the frame was put together from L-profiles and steel sheets). The racers, again in one piece, where glued on top of this assembly. Underneath the base plate the housing for the training gears (which will be very much simplified as they will be barely visible upon completion of the model).

Image
The basic frame of the lower carriage from underneath with the housing for the training gears

One can see on the laser-cut parts marks for the rivets. These will be added as tiny spots of white glue. More details will be added in the next steps, but have not all been drawn yet.

Image

Image
The basic frame of the lower carriage with the upper carriage and the gun put temporarily in place

To be continued ...

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Eberhard

Former chairman Arbeitskreis historischer Schiffbau e.V. (German Association for Shipbuilding History)

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PostPosted: Sun Mar 15, 2020 8:49 am 
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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.

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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.

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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.

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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 ...

_________________
Eberhard

Former chairman Arbeitskreis historischer Schiffbau e.V. (German Association for Shipbuilding History)

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