wefalck

As we are getting older, good lighting is important. The eye looses gradually its elasticity and therefore the ability to focus on close items. This can be to some extent compensated for by a greater depth of field, which is effect of narrowing pupilles due to stronger light. By and by I have replaced all the incandescant bulbs in my lamps with LED-bulbs of 150 W equivalent. Due to the waste heat such strong light would have not been possible with tradtional bulbs - it also happened to me that I burnt myself on halogen bulbs. I also bought a sort of indoor LED flood-light that I installed above the worktable. It was actually cheaper than a strong LED-bulb. Some people advocate daylight LED-bulbs (5600 K), but I prefer 'warm' ones (3600 K - 4000 K), as they give a more pleasant atmosphere. The models would be typically viewed under such light conditions, so the light colour would be appropriate for that reason too and colour changes become unimportant.

Thanks, I am sure Valeriy won't mind the short digression. Once you are far enough in the planning, many of us wouldn't mind another building log, I think !

For our German association we will in all likelyhood also have to cancel the AGM in late September this year. Even when most of our members are also above 60 years of age and should have received their second shot by the end of summer, a vaccination only means that you are most likely not to develop severe sysmptoms, but you can still catch the virus. So we should all avoid gatherings until 2022. A hobby is not worth the risk.

Funny that you should mention this. One has too many tools and then forgets about them - particularly, when one is set on a particular process. When writing the text above, it occured to me that I just didn't think of the very fine watchmaking cutting and smoothing broaches I have. I have to try this on some leftover laser-cut blocks. However, it does not resolve the problem with the sanding. Perhaps one should soak the paper in CA, rather than lacquer - but I hate CA ...

Block-Making 1 The 1/160 scale from certain perspectives is rather inconvenient actually: too big to fake things and too small to do them properly due to practical limitations of tool sizes and materials dimensions. Blocks at this scale would probably come in the range between 0.8 mm and 2 mm length. The latter would be a hefty 32 cm (or 13”) in real size, at least for smaller ships. When I started dabbling with photo-etching in around 2007, I had the idea to fashion blocks from surface etched parts folded up and soldered together. As the need for blocks only arose now, I had never tried out the idea. Since then I got the laser-cutter and thought I might give the same principle a try, laminating the blocks from laser-cut pieces of paper. I am aware that larger blocks, build up from laser-cut wood pieces, are commercially available now. My preoccupation was to produce blocks of the correct outside shape and through which the rope passes prototype fashion, i.e. to avoid the brick-like thingies from which the ropes sticks out vertically and then goes down with a sharp kink, as seen all too often on models. ********************* Warning, the following text describes some dead ends without success - As aligning the tiny parts correctly would be the main challenge, I drew the pieces at their correct relative location into small frets of several blocks that would be laminated onto each other. Once the lacquer was dry, the blocks could be separated. As I needed various double-blocks for the boat-davits and the anchor-cranes, I started out immediately with that challenge, thinking that, once mastered, single blocks would be comparatively easy to make. In fact, due to the thicknes of the Canson-paper, I needed seven layers, one for the outer shell on each side, one in the middle separating the sheaves, and the sheaves made up from two layers each. While the lamination as such worked well, aligning the seven frets precisely enough did not work too well. It also proved impossible to sand the tiny paper blocks to shape and smooth enough. The main problem, however, was that somehow the hole for passing through the rope always got clogged up. Opening it up with a drill then invariably let to the distruction of the block. After a dozen of tries with different variants of the laser-cut parts to facilitate alignment etc. I finally gave up that idea. Next came several experiments with the classical methods of carving blocks from billets, but using styrene or acrylic glass, rather than wood. While both materials are easy to drill, they proved too soft for shaping the grooves etc. cleanly, particularly the styrene. Attempts to cut slots for the sheaves, then to glue on a bottom piece to close the slots, and to later insert turned sheaves failed also. It was impossible to keep the 0.2 mm wide and 0.8 mm high slots clean enough from glue and cleaning them out afterwards at this dimension is hardly possible. Using brass and soldering equally failed to produce the desired result. ************************** Now comes the success story - In the end I resorted to my trusted bakelite. This material is hard and does not smear, but is much more brittle than the other materials. Drilling 0.2 mm holes is still quite easy and doesn’t strain the drills too much. Drilling 0.2 mm holes into bakelite strips I cut strips of the required width from a 1 mm sheet of bakelite to start with. The micro-mill then was used as a jig-borer and a row of holes drilled for a batch of blocks. Using a broken 0.2 mm drill, ground flat at the end, was then used as an end-mill to cut the grooves that simulate the slots for the sheaves. Milling 0.2 mm slots into bakelite strips A stereo-microscope helps to safely perform the machinining with 0.2 mm tooling The profile of the blocks was roughly milled to shape using various cone-shaped burrs. The final shaping was done by first hand-filing with a diamond nail-file and then using a fine abrasive wheel in the hand-held drill. Row of double-blocks ready to be separated To separate the blocks, the strip was taken into a collet of the dividing head and the blocks were sliced off with a circular saw. To prevent them from disappearing into any black holes of the workshop, the strip was backed with some adhesive tape. The sides of the block-shells were smoothed and shaped with the blocks clamped in a kind of special hand-held vice. This vice has brass insert jaws that are curved and stepped so as to clamp the block securely while working on it with an abrasive wheel. A collection of blocks and the special pin-vice to hold them A collection of blocks and 1 Euro-Cent coin for comparison Two sizes of blocks of 2 mm and 1.6 mm length respectively The blocks now have to be finished off with their external metal straps and hooks – another fiddly challenge ahead. To be continued ....

Which Brazilian gunboat will that be ?

Thank you very much for the kind words ! Regularity in the spacing of the steps was indeed one motivation for re-doing the stairs with the laser-cutter. Although milling the slots into the bakelite-paper can be done quite accurately, somewhow the assembly did not turn out as regular as I wished.

The term 'life-time warranty' always gets me - whose life and how long ?

One should not overemphasise this. Wood dust in general, when inhaled is not so good for your lungs and some people can develop allergic sensitivities, when exposed more frequently to the dust of certain wood species. So you won't fall over dead, when working with ebony. Good ventilation and a mask when working with it should solve most of the problems. Personally, I never worked with ebony, but heard from colleagues - and can quite imagine this due to its hardness, that ebony is very difficult to bend and prone to splitting. In fact, it seems to be mainly used for carving, inlay work and the likes. I would not use it for structural parts. In fact, there seems to various tree species originating in different parts of Africa and Southern Asia the wood of which goes by the name of 'ebony'. So there may be a certain variability in its workability.

I would agree with Ron and wonder, why there was no top-silde in the first place. I have seen such combination machines by different makers/vendors and they normally have one. You would need it for short taper turning and finer work. Having said that, I would consider saving up for a small lathe, such as the smallest PROXXON for instance, for really small work, rather than buying a top-slide, which is probably a third or a quarter of the cost of the PROXXON. It may be worthwhile to scan the secondhand market too.

On navy boat the thwarts were kept clean, neither tarred nor painted. I think I have seen that in other boats too. Depends a bit on how the boats were stored, i.e. how exposed they are to weathering. I could imagine that the thwarts were taken out and stored in a shed.

Does your not have a top-slide ? Turning the whole carriage with the crank at the bed on the right seems to be rather cumbersome and it seems difficult to crank, keep an eye on dial readings and watch what happens. How do you turn the taper without top-slide ? Most of my turning of such things is done with a knife-tool that I grind from a HSS-bit. For such dimensions the width at the front should equal or be less then the shortest between two rings. The most used tool has a width of only 0.4 mm at the front and clearance on three sides. In this way I can turn to the left and the right without changing the tool. I normally make myself a dimensioned sketch and then decide on zero points for movements in both, x- and y-direction. I then note down in the sketch how much I need to move the carriage between the rings, taking into consideration also the width of the tool at the front. In order to avoid backlash issues, all the turning is done in one direction only. In this way I avoid measuring on the workpiece (at least for duplicates). With such a procedure you can turn out identical pieces within the accuracy limits of your machine. If the rings on the cannon need to be rounded, there are two options: you can use either a file to do that or using a forming tool in a secondary operation. As you don't seem to have a QCTP, chaning tools might not be such a good option though.

Some people also mill or plane the rough shape from a square billet and then slice it up to get the individual knees. The main stress occurs, when you are handling the pieces. Once in the model, stresses are of no concern.

If it doesn't have to be natural wood, there are various other materials, such as brass, acrylic glass or bakelite paper. If you find a dark brown version of the latter, it can look almost like wood, when polished. I am using it for blocks.

I don't know how it was done on your specific, but in in general metal brackets were fixed along the coaming and the cover fixed with battens that were wedged against the coaming with pairs of wooden wedged driven in from opposing sides. On the picture below you can see the arrangement on a somewhat later ship around the coamings of the skylight. http://www.maritima-et-mechanika.org/maritime/models/wespe/Laverrenz-20.jpg On the sailing ships of old, that would be at sea for months, the battens may have been nailed down in addition.

I gather it also depends on the absolute size you are talking about. Some people use the 'planking-first' strategy on small boats, where it might be difficult to cut a clean rabbet. Having said that, if you don't care about mimicking the real building techniques and are only interested in the appearance, a sort of hybrid strategy can be considered: rather than cutting a rabbet proper, you can put the keel and stem together from two pieces each, being the inbord and the outbord part respectively.

What wood are you using, that you are worried about splitting ?

Good progress. I somehow figured, that you would probably tighten the laminate onto the template with wire or string. Be cautious when working with ebony. It seems that ebony dust is not very healthy ...

There are different CAD systems, of course. If you work on a 2D CAD, the dimensions in one plane are not normally correlated with another plane. What I mean is that the body-plan is drawn separately from the plan of the waterlines. They are two independent drawings. This in turn means that you can make all the same mistakes as in hand-draughting. Only, when you use a 3D CAD system and print out different sections of the the same 3D body, everything should tally.

We are veering off a bit from the original subject of thread ... nevertheless the article quoted above seems to show an ordinary 2D pantograph engraving machine, though I didn't carefully look at all the details. As matter of fact, such engraving machines for door-bell signs, fountain pens, sports trophies (with special mounts) are an application of pantographs that persists until this day. The letters etc. to be engraved come in sets of templates. The machines and the special grinding machines for the engraving bits are still being sold. Otherwise, pantograph work has largely been replaced by CAD and CNC-milling or laser-cutting.

I have a pair of safety-glasses that have +2 lenses in them. There may be also stronger ones. They are very comfortable, like normal glasses and protect you, when working with machinery etc. I used to have safety-glasses with neutral lenses (being myopic), but found that with increasing age (or may increasingly small parts) I have to resort to the +2 ones.

Stairs and ladders 2 While struggling with something else I will be reporting on shortly, as a diversion at looked at the stairs and ladders again. I had fashioned the stairs from bakelite paper some three years ago (time is flying), but somehow I was not 100% happy with the result. The bakelite paper has a smooth surface and edge can be filed smooth too, but the glueing with CA was not quite so neat as I had wished. In principle it can be cleaned up well with a sharp chisel and fine steel-wool, but the inside edges of the steps are difficult to get to. Below is the result from that time: Selection of stairs (not yet trimmed to length) Having now the laser-cutter at my disposal, I decided to try my luck with it. The photo-etching templates I had drawn quite a while ago where modified for use on the laser-cutter. The idea was to build up the stringers from three layers of 0.15 mm thick Canson-paper. The innermost layer has slots for the steps. The steps themselves are build up from two layers of paper. Laser-cut pieces for stairs waiting to be assembled First the stringers were laminated together using lacquer and the edges sanded smooth, dito the steps. One stringer was then leaned against a little steel block with exactly square side on a glass plate. In this ‘jig’ the topmost and the bottom step were glued to the stringer with lacquer. Next the second stringer was glued on, while held exactly vertical with another little steel block. It was also checked that the step were at a right angle to the stringers. This assembly was let dry thoroughly. Still between the two steel blocks as ‘jib’ the remaining steps were slotted in and fixed with a drop of lacquer. Using the laser-cutting process ensured that the upper ends of the ladder had a uniformly rounded shape and the bottom was cut off at the correct angle to the deck. Collection of stairs and ladders (the stairs are 4 to 5 mm wide) The stairs were held in place (I assume) by shoes made from bronze. I cut out these shoes with the laser-cutter and attached them to the bottom end of the stringers. Eventually, they will be painted in bronze colour and glued to the deck. The colour of the Canson-paper soaked in lacquer comes close to that of teak, from which they were made presumably on the prototype. However, the actual colour depends on the number of layers of shellac I happend to apply and varied at places. So I will have to spray-paint them eventually to also get an uniform sheen on the surface. Assembly of ladders for the barbette The barbette is provided with two ladders, that allow the crew to scramble in and out of it, while for more leisurely access there is a narrow stair leading down from the bridge area. The stringers of the ladders, presumably steel on the prototype, were also cut from Canson-paper with holes for the rungs marked by the laser, which were opened up with a cutting reamer to exactly the right size for the wire to be used as rungs. Trimming flush the rungs of the ladders using a pair of cutting-tweezers After the trimming a second layer without perforations was laminated on. The ladders eventually will be painted white as the inside of the barbette will be. To be continued ....

This kind of sophisticated pantographs was used by cartographers in the old days, for instance, when they had to transfer the hand-drawn ordonance survey map originals onto the plates for printing. In fact, any time you needed a (technical) drawing for printing in a different size/scale you would have to re-draw it using a pantograph. Important point by Bob about transferring points, rather than lines. The same technique was/is used by sculptors, when they want to transfer their clay 'bozzetti' (the design model of the sculpture) onto a block of e.g. marble - but using a 3D-rig.

That's a very clever way of making the rivet heads in situ ! Did they just form by themselves by the heat, or did you use some sort of punch in addtion ? This rivet-making started my thinking, that one could make a head-former (die) as in real rivetting by shaping the hollow with a round burr in some brass rod. Using a piece of brass with appropriate holes as heat sink, one could mass-produce little styrene rivets in that way. Smaller rivets could be also made from stretched sprue or stretched styrene rods. Have to keep this idea in mind ...

My knowledge of the coconut trade is limited, but my understanding is that it is waste product from copra production. I didn't check, but I am rather surprised that the fibres should absorb so much water, given the fact that mooring and towing ropes are made from coconut fibres because such ropes float. Staining of cargo probably is not issue, as goods for sea-shipment would normally be sufficiently wrapped.