wefalck

Thanks for the praise
 
At a matter of fact, it is all in my head. These days I don't even make working drawings   Sometimes I make dimensioned sketches for machining, literally on the back of envelopes, in order make sure that what I imagined actually works out. Most of the times things seem to come out as I imagined them. Not alway though   Just struggeling with the motor mount now, as my original idea would create a too long lever, when clearing various parts of the mill, with the risk of amplifying vibrations ... have to re-think it.

Was kind of working holiday: had to work on finishing off the decoration and furnishing of our part-time home in Spain - putting in/up wardrobes, building a mock fire-place (unfotunately, we can't have real one there), etc.; jumping up and down the ladder at around 30°C made me loose some 4 kg in weight - feeling a lot fitter than before the holidays - but have been to the beach only once ... grilling on the beach in the August heat is for German and British tourists only anyway
 
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The milling spindle will be secured in its place between the two brackets by a lever-actuated excentric bolt that pushes it down. I found a rough excentric bolt in my scrap-box of odd lathe parts, but it would have been as easy to start from scratch. The excentric was worked over holding the bolt in the 3-jaw-chuck with a brass-shim to give the off-set.
 

Rough and ready method for excentric turning
 
The head was turned with the help of the shop-made radius-turning tool (which I originally made to be able to turn miniature door-knobs and the likes). The tool-bit diameter was chosen to match the neck and shoulder of the bolt. The turning operation was followed by smoothing with wet-and-dry paper and steel-wool of various grades. Finally, it was polished with polishing paste. The pictures below show the various steps of this machining process:
 

 

 

 

 

 
To be continued ...

Was kind of working holiday: had to work on finishing off the decoration and furnishing of our part-time home in Spain - putting in/up wardrobes, building a mock fire-place (unfotunately, we can't have real one there), etc.; jumping up and down the ladder at around 30°C made me loose some 4 kg in weight - feeling a lot fitter than before the holidays - but have been to the beach only once ... grilling on the beach in the August heat is for German and British tourists only anyway
 
************************************
 
The milling spindle will be secured in its place between the two brackets by a lever-actuated excentric bolt that pushes it down. I found a rough excentric bolt in my scrap-box of odd lathe parts, but it would have been as easy to start from scratch. The excentric was worked over holding the bolt in the 3-jaw-chuck with a brass-shim to give the off-set.
 

Rough and ready method for excentric turning
 
The head was turned with the help of the shop-made radius-turning tool (which I originally made to be able to turn miniature door-knobs and the likes). The tool-bit diameter was chosen to match the neck and shoulder of the bolt. The turning operation was followed by smoothing with wet-and-dry paper and steel-wool of various grades. Finally, it was polished with polishing paste. The pictures below show the various steps of this machining process:
 

 

 

 

 

 
To be continued ...

Now, with the summer holidays behind me, I am back in the fora and in the workshop   However, first a little postscript on things that were completed before the vacations:
 
A couple of pictures that show the different components of the y-axis spindle. Also visible on the first picture are the parts of the friction brake for the dial, short piece of acrylic rod that is pressed down on the spindle with a set-screw. Tightening or loosing the screw allows to adjust the friction.
 

The parts of the y-axis spindle
 

Spindle assembled
 

Spindle in its working place
 
To be continued ...

Was kind of working holiday: had to work on finishing off the decoration and furnishing of our part-time home in Spain - putting in/up wardrobes, building a mock fire-place (unfotunately, we can't have real one there), etc.; jumping up and down the ladder at around 30°C made me loose some 4 kg in weight - feeling a lot fitter than before the holidays - but have been to the beach only once ... grilling on the beach in the August heat is for German and British tourists only anyway
 
************************************
 
The milling spindle will be secured in its place between the two brackets by a lever-actuated excentric bolt that pushes it down. I found a rough excentric bolt in my scrap-box of odd lathe parts, but it would have been as easy to start from scratch. The excentric was worked over holding the bolt in the 3-jaw-chuck with a brass-shim to give the off-set.
 

Rough and ready method for excentric turning
 
The head was turned with the help of the shop-made radius-turning tool (which I originally made to be able to turn miniature door-knobs and the likes). The tool-bit diameter was chosen to match the neck and shoulder of the bolt. The turning operation was followed by smoothing with wet-and-dry paper and steel-wool of various grades. Finally, it was polished with polishing paste. The pictures below show the various steps of this machining process:
 

 

 

 

 

 
To be continued ...

Was kind of working holiday: had to work on finishing off the decoration and furnishing of our part-time home in Spain - putting in/up wardrobes, building a mock fire-place (unfotunately, we can't have real one there), etc.; jumping up and down the ladder at around 30°C made me loose some 4 kg in weight - feeling a lot fitter than before the holidays - but have been to the beach only once ... grilling on the beach in the August heat is for German and British tourists only anyway
 
************************************
 
The milling spindle will be secured in its place between the two brackets by a lever-actuated excentric bolt that pushes it down. I found a rough excentric bolt in my scrap-box of odd lathe parts, but it would have been as easy to start from scratch. The excentric was worked over holding the bolt in the 3-jaw-chuck with a brass-shim to give the off-set.
 

Rough and ready method for excentric turning
 
The head was turned with the help of the shop-made radius-turning tool (which I originally made to be able to turn miniature door-knobs and the likes). The tool-bit diameter was chosen to match the neck and shoulder of the bolt. The turning operation was followed by smoothing with wet-and-dry paper and steel-wool of various grades. Finally, it was polished with polishing paste. The pictures below show the various steps of this machining process:
 

 

 

 

 

 
To be continued ...

Now, with the summer holidays behind me, I am back in the fora and in the workshop   However, first a little postscript on things that were completed before the vacations:
 
A couple of pictures that show the different components of the y-axis spindle. Also visible on the first picture are the parts of the friction brake for the dial, short piece of acrylic rod that is pressed down on the spindle with a set-screw. Tightening or loosing the screw allows to adjust the friction.
 

The parts of the y-axis spindle
 

Spindle assembled
 

Spindle in its working place
 
To be continued ...

The blank on its arbor was then transfered to the dividing apparatus on the milling machine for engraving the dial. For this a 15° engraving bit was used. in the same set-up the hole for the friction brake of the dial was pre-drilled.
 

Set-up for engraving the dial
 

Engraving the dial
 
The numbers were stamped in a make-shift set-up in a vice. In order to ensure that the number-stamps were applied exactly radially a purpuse-made guide-block was used.

Set-up for stamping the dial
 
Finally, the dial was mounted back on the arbor and the burrs from engraving and stamping cleaned up with a couple of light cuts in the lathe.
 

Cleaning up the engraved and stamped dial
 
The two parts were separated on the lathe with a jewelers saw substituting for a parting tool. The dial then was degreased and the engravings laid out in black enamel paint. After the generously applied paint had dried, the dial was cleaned up with very fine wet-and-dry sanding paper.
 

Painting the dial
 
To be continued ...

Thanks, Pat. I was actually surprised myself, that it turned out so well

Per, as it never was, the mill doesn't have a price-tag   ... unless you were indeed prepared to pay me at my commercial rates, which means that you would have to trade-in a decent car, may not quite an Aston Martin (but I would gladly exchange it for the mill, BTW)
 
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For the dial on the y-slide I had a piece of 21 mm diameter brass to hand. This was faced in the 3-jaw-chuck, drilled and reamed for the 5 mm spindle, and then bored out to fit over the spindle bearing-plate.
 

Preparing the blank for the dial
 
The blank was the mounted on an arbor with a 5 mm stem so that I could turn the outside shape. At one end there is the notorious convex knurled ring. For this, a ring of 1.2 mm width and 1 mm height was left standing with edges slightly chamfered.
 

Turning the blank for the dial
 
For the next machining step the knurling tool with the concave knurl was mounted to the cross-slide. The knurling tool was fed slowly into the slowly rotating blank. It catches quite quickly at the edges and the pattern evolves fast. As expected, the processes is both, a cutting as well as a shaping one – the relatively soft being squeezed into the indentations of the knurling wheel. While generously lubricating with WD40 the knurl was fed into the faster rotating blank until the pattern had developed fully.
 

Knurling the dial
 
To be continued ...

Thanks Pat and I hope you have enough Kleenex around
 
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After some disruptions due to travelling (spent inter alia a couple of days in Pisa for work ) I tackled a job I had never done before:
 
Digression: making a concave knurling wheel
 
Today, concave knurls to produce the convex knurling seen on many older high-end precision machines are obtainable only at prohibitive costs. Therefore, I embarked on making my own knurl, encouraged by a few examples on the Internet. Knurling wheels normally have to have a certain diameter in order to prevent their bore from being distorted under the stress of the knurling process. I choose a blank of only 10 mm diameter for a bore of 6 mm in order to reduce the mass to be heated, when attempting to harden the knurl with my rather limited heating capabilities. I also had a cut-off from a Schaublin collet-blank available, which I assumed would harden nicely.
 

Hobbing the knurl on the milling machine
 
The proposed process of creating the knurling wheel employs an ordinary threading tap as an improvised hob. This, stricly speaking, would result in a 'rope' knurl, but the helical angle of a, say, 0.4 mm pitch tap is barely perceptible. The easiest way to hold the blank for cutting seemed to hold it in the knurling-holder for the watchmakers lathe that I made a few years ago. This means, however, that the process could not be done on the lathe, because it would have been not so easy to mount the holder on its side. Cutting the knurl on the lathe would have been better, as the end of the tap could have been supported in the tailstock in order to eliminate flexing. Unfortunaly, the DIXI horizontal mill does not have an overarm, which then would make it the ideal machine for the job. So the job was done on the vertical mill.
 

Hobbing process in detail
 
The blank was drilled and reamed for the arbor of the knurling tool holder. Some polishing ensured that it spun freely. A M2 tap was chucked in a collet as short as possible and offered to the blank with its uppermost end in order to keep flexing to a minimum. Initially, the mill was run at slow speed and with a small feed. After each incremental feed, the blank was allowed to make several revolutions until no chips were produced anymore. Once the pattern was created, the mill was run at a somewhat higher speed and the amount of incremental feed increased from around 0.03 mm to 0.05 mm. Every time blank and tap were flooded with WD40 in order to wash out the chips that then were wiped off. A first failed trial showed, how important it is to wash-out chips. The second attempt was successful.
 

The finished concave knurl
 
After the machining, the knurl was hardened by heating it to a cherry-red colour and quenching it in ice-cold water. As I don't have a very strong torch, the knurl was pre-heated to 450°C using the hot-air soldering gun and then brought to temperature with the gas-torch. The knurl was also rubbed in soap to prevent scaling. After some cleaning, the hardened knurl was tempered to a straw-yellow colour using the the hot-air gun. A test with a file showed that the hardening was successful.
The knurl in the tool-holder for the watchmakers’ lathe
 
... well, it actually worked as you will see in the next contribution
 
To be continued ...

The original bronze spindle-nut seems to have had a left-hand thread of 4 mm x 1 mm, so it was drilled out 3.7 mm for the 4.5 mm x 1 mm thread and the thread re-cut with the appropriate tap. The odd digs and dents were removed by a light cut on both ends in the lathe.
 

Parts of the spindle and its bearings
 
A test assembly showed that everything worked as planned. The ball-handle crank has been bought-in and is fixed by set-screws, rather than being pinned as was the Lorch-practice.
 

Spindle in place, but micro-meter sleeve still to be made
 
To be continued ...

The long hole for the spindle in the cross-slide was opened up to 5 mm using the Dixi horizontal miller as a boring mill.
 

Drilling out the the spindle hole in the old top-slide
 
However, the travel of the slide was too small, so an extension was made to give the slide a travel of around 50 mm, allowing the milling spindle to reach across a face-plate mounted in the dividing attachment on the mill. The extension is a fairly complex piece, fashioned out of a block of aluminium. This is jointed to the existing top-slide with two location pins and two countersunk screws (the holes used were already made by a previous owner).
 

Top-slide extension (under side)
 

Top-slide extension (upper side)
 
To it screws the housing for the y-spindle bearing. Watchmakers lathes usually have simple sliding bearings there, the end-play of which is controlled by a nut with a very fine thread. The elements of this arrangement would have been ground to give a smooth sliding. I decided instead to use miniature thrust-bearings with I.D. of 5 mm and an O.D. of just 10 mm. Two are needed, with the thrust-collar on the spindle in between. This gives an arrangement of 12 mm in length.
Centering the future y-slide spindle bearing-plate in large 4-jaw-chuck
 

Turning stub for spindle bearing-plate
 
The bearing-housing was made from a piece of 15 mm x 15 mm aluminium bar. The section was centred in the large 4-jaw-chuck on the lathe and the stub turned on. The piece then was reversed and taken into a 3-jaw-chuck so that the face that screws down onto the slide extension could be turned flat and perpendicular to the axis. The through-hole was drilled and reamed for the spindle. In the next step the seat for the bearings was bored out to exactly 10 mm diameter and a tad unter 12 mm depth.
Reaming bearing for y- spindle
 

Boring-out seats for thrust ball-bearings
 
Finally some cosmetic milling operations gave the bearing housing a more elegant shape.

Shape milling of the spindle bearing-plate
 
To be continued ...

While sorting out the replacement motor for the mill, I turned my attention to making the spindle for the y-axis. Most WW-lathes seem to have the odd thread of 4.5 mm x 1 mm pitch. The spindles from the old cross-slide I am using were missing, but must have been thinner, probably 4 mm. As I have both, a die and a tap for the usual left-hand thread, I decided to adapt the cross-slide for this.
 

 

Set-up for cutting the thread on the y-axis spindle
 
 
First the spindle was made. Unlike the original desing on watchmakers’ lathes, it will have two ball-races as thrust bearings, but otherwise the design will be similar. The ball-handle crank is a commercial product. I started out with a 5 mm rod and turned it down to 4.5 mm and then set-up the lathe for cutting the left-hand thread.
 

The first pass
 

Almost finished spindle
 
This means cutting proceeds towards the tailstock. As the torque on the WW-lathe transmission system is too low, the thread was cut by hand-cranking. For this purpose I had made an adapter for a ball-handle crank already a long time ago. The thread was cut with full cuts until it was about 90% complete.
 

Calibrating the thread using a 4.5 mm x 1 mm die in the tailstock
 
The final cut then was made with a die in the tailstock die-holder to calibrate the diameter, which might have been a bit bigger in the middle due to the flexing of the long spindle. In order to eliminate the effect of flexing, the cutting bit was run along the thread several times without adavancing it into the work, until no material was taken off anymore.
 

The finished spindle thread
 
To be continued ...

Thanks for the 'likes' !
 
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... these day I really became angry – some time ago the nice Sherline-motor (https://www.sherlinedirect.com/index.cfm?fuseaction=product.display&Product_ID=405]) for my Wolf, Jahn & Co. milling machine (http://www.maritima-et-mechanika.org/tools/horologicalmillers.html) that I had imported from the USA some 15 years ago began to make strange noises.
 

Sherline-motor, as used on my lathe and milling machine
 
Upon investigating, I disovered the the brushes were completely run down, in fact the motor was running on the copper contact-plates. I contacted the Sherline and they quoted my 25$ plus shipping for a new pair of carbon brushes – the German/Austrian distributor near Vienna just shrugged the shoulders. I trailed the well-known bight up and down and finally found some of about the right size in China. Three weeks of milling-break.
Once arrived, I ground the carbon the the right size and inserted them. The motor was running again, but somewhat noisily. I suspected problems with the ball-bearings. A week later, suddenly during the work loud noises and bang – rien ne va plus. I opened the holder for the brushes and found that they had already worked down by half and the contact-wire ripped off. I dismantled the motor-holder and idle-shaft in order to be able to take the motor out for further investigations. With a doctor’s eye-mirror I tried to look down at the commutator, but couldn’t see much. The only solution was to dismantle the motor. Of course all the nuts and bolts are imperial and had no suitable spanner. Had to go into town and get for some good money a 3/8” spanner for the nut, the screw-head had a 5/16” head, which is almost equal to 8 mm – learned some interesting this way: in the USA screw-heads and matching nuts don’t have the same size, as is the case in the metric system.
The motor turned out to be completely filled with carbon-dust, which then spread around my workshop. After having cleaned the rotor a bit (whereby a good deal of the carbon settled on me) the problem became apparent: several lamellae of the commutator had been ripped out and the end of it was that some of the connectors to the coils had been cut – a total write-off ...
 

Ripped commutator of the Sherline-motor
 
In my ‘scrap’-collection I found an old capacitor-motor that originally came with one of my milling machine. I did not use it, because controlling the speed is difficult and one looses torque (unless one buys an expensive inverter). However, as I had acquired a good idle-shaft since, controlling speed on the motor-side is not so important anymore, as the belts can be shifted to various-sized pulleys. I now had to adapt the motor-mount to the new motor and I was back in business. The good thing about this kind of motor is that it is much quieter than a mechanically commutated motor.
 

Motor running-capacitator (bottom)
 
So, milling began again – but not for very long. After two hours rien ne va plus encore. The motor only hummed with the 50 Hz, but didn’t want to turn. Touched the motor and and shrieked back, it was really hot. Perhaps not enough ventilation in the motor housing of wood to protect the open motor from flying swarf. The heat killed the capacitor that must have been several decades old already. Measured the motor through, but the coils were ok. Back to the bight and trying to find a new 7µF-capacitator. Found one, this time in Ireland, which meant only a few days, rather than weeks break ... got it yesterday and I am back in business again ...

Some travel got into the way of progressing this project and on reporting on it ….
 
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In order to mount the y-axis to the column, an adapter is needed. This adapter is fashioned from a small aluminium-block that was bored for the 20 mm column. The top-side was milled to a close fit on the lower slide from the WW-lathe, which is clamped down with a bolt. In this way the lower slide can be moved by about 15 mm, giving a greater depth of throat, if needed. It was planned to use a rectangular key to lock the adapter to the column. However, it appears that the two set-screws lock it sufficiently secure to the column. Practical experience will show whether this is true.
 

Drilling the adapter for the y-axis
 
The 20 mm-hole was drilled and bored on a face-plate in the lathe to ensure that it is exactly vertical to the top and bottom of the adapter block. The aluminium-block was srewed down onto the face-plate using a 6 mm hexagonal bolt. Luckily, a suitable hole was needed anyway for the locking bolt of the slide. Other hexagonal bolts prevent the block from moving during the machining operations and act as counter-weights.
 

Boring the adapter for the y-axis
 
After the functional machining was complete, the adapter was 'beautified' by giving the edges a half-round camfer. For occasional jobs on aluminium like this, I use cheap woodworking router bits ... don't tell any real mechanic.
 

Camfering the adapter for the y-axis
 

Finished adapter block
The Lorch, Schmidt & Co. milling attachment will be held between two angle-irons screwed-down onto the slide. The locking will be effected by an excentric bolt acting as a cam. I had hoped to use the threaded holes that a previous owner of the slide had made, but they did not fit the angle-iron I had in my stock, so new holes had to be drilled and tapped. The pair of angle-irons was squared and trued on the mill using a fly-cutter.
 

Squaring and trueing angle-irons in pairs
 

Angle-irons to hold milling-head
 

Angle-irons to hold milling-head
 
The above picture shows also the drive unit made for the toolpost-grinder of the WW-lathe, which in fact looks very similar to what the future motorised milling head will look like.
 

Provisional set-up of motorised milling head
 
 
To be continued ...

The maker of the miniature Bridgeport is the British model engineer Barry Jordan: http://www.craftsmanshipmuseum.com/jordan.htm
 
@hof00: Proxxon (and all the other makers of small milling machines) don't make a machine of the Aciera/Sixis/SIP type as I discussed above. They all are conventional 3-axis-machines, to which perhaps a fourth axis can be added by deploying a rotary table or a dividing head. Even the smallest Proxxon, the MF70, still is somewhat bigger than what I am building here.
 
Updates will follow over the weekend, didn't have time to take and process the pictures yet.

Was kind of working holiday: had to work on finishing off the decoration and furnishing of our part-time home in Spain - putting in/up wardrobes, building a mock fire-place (unfotunately, we can't have real one there), etc.; jumping up and down the ladder at around 30°C made me loose some 4 kg in weight - feeling a lot fitter than before the holidays - but have been to the beach only once ... grilling on the beach in the August heat is for German and British tourists only anyway
 
************************************
 
The milling spindle will be secured in its place between the two brackets by a lever-actuated excentric bolt that pushes it down. I found a rough excentric bolt in my scrap-box of odd lathe parts, but it would have been as easy to start from scratch. The excentric was worked over holding the bolt in the 3-jaw-chuck with a brass-shim to give the off-set.
 

Rough and ready method for excentric turning
 
The head was turned with the help of the shop-made radius-turning tool (which I originally made to be able to turn miniature door-knobs and the likes). The tool-bit diameter was chosen to match the neck and shoulder of the bolt. The turning operation was followed by smoothing with wet-and-dry paper and steel-wool of various grades. Finally, it was polished with polishing paste. The pictures below show the various steps of this machining process:
 

 

 

 

 

 
To be continued ...

Was kind of working holiday: had to work on finishing off the decoration and furnishing of our part-time home in Spain - putting in/up wardrobes, building a mock fire-place (unfotunately, we can't have real one there), etc.; jumping up and down the ladder at around 30°C made me loose some 4 kg in weight - feeling a lot fitter than before the holidays - but have been to the beach only once ... grilling on the beach in the August heat is for German and British tourists only anyway
 
************************************
 
The milling spindle will be secured in its place between the two brackets by a lever-actuated excentric bolt that pushes it down. I found a rough excentric bolt in my scrap-box of odd lathe parts, but it would have been as easy to start from scratch. The excentric was worked over holding the bolt in the 3-jaw-chuck with a brass-shim to give the off-set.
 

Rough and ready method for excentric turning
 
The head was turned with the help of the shop-made radius-turning tool (which I originally made to be able to turn miniature door-knobs and the likes). The tool-bit diameter was chosen to match the neck and shoulder of the bolt. The turning operation was followed by smoothing with wet-and-dry paper and steel-wool of various grades. Finally, it was polished with polishing paste. The pictures below show the various steps of this machining process:
 

 

 

 

 

 
To be continued ...

Was kind of working holiday: had to work on finishing off the decoration and furnishing of our part-time home in Spain - putting in/up wardrobes, building a mock fire-place (unfotunately, we can't have real one there), etc.; jumping up and down the ladder at around 30°C made me loose some 4 kg in weight - feeling a lot fitter than before the holidays - but have been to the beach only once ... grilling on the beach in the August heat is for German and British tourists only anyway
 
************************************
 
The milling spindle will be secured in its place between the two brackets by a lever-actuated excentric bolt that pushes it down. I found a rough excentric bolt in my scrap-box of odd lathe parts, but it would have been as easy to start from scratch. The excentric was worked over holding the bolt in the 3-jaw-chuck with a brass-shim to give the off-set.
 

Rough and ready method for excentric turning
 
The head was turned with the help of the shop-made radius-turning tool (which I originally made to be able to turn miniature door-knobs and the likes). The tool-bit diameter was chosen to match the neck and shoulder of the bolt. The turning operation was followed by smoothing with wet-and-dry paper and steel-wool of various grades. Finally, it was polished with polishing paste. The pictures below show the various steps of this machining process:
 

 

 

 

 

 
To be continued ...

S.M.S. WESPE (HENK, 1895)
 
History and context
The WESPE-Class armoured gun-boats of the then young Imperial German Navy were born out of a tactical concept that dated well back into the Napoleonic era. The idea was to mount a heavy long-range gun onto a highly mobile small craft that would be able to retire into shallow coastal waters, beyond the range of even the heavy artillery of an attacking fleet. The addition of a steam engine and the increase in calibre followed the development of the time, of course. Adding heavy armour to the front (mainly) was meant to give the gun-boats a certain attacking capability. It also owes something to the floating batteries used in the defence of Copenhagen during the Napoleonic wars and to the armoured floating batteries used by the allied French/British forces during the Crimean War (1854-55). In fact, adding armour plating to a (rowing) gunboat was already proposed as early as the late 18th century in Spain, as documented by a model in the Museo Naval in Madrid, but apparently never put to work in full scale.
 

S.M.S. WESPE, brand-new and still without the 30.5 cm gun (1875)
 
At the time of the conception of the WESPE-class in the early 1870s a former cavalry(!) general was the naval chief-of-staff in Germany. The tactical dogma was ‘proactive defence’: an attacking enemy was to be awaited near home waters and fenced off. The main threat was seen in amphibian operations attacking the German coast. Thus, the landing of troops at strategic points had to be prevented. Long-range strategic and oceanic operations were out of the scope of the German naval planners of the time. There was a certain logic in this, as Germany, unlike Britain, is/was a more or less land-locked country and largely self-sufficient in many respects at that time. Overseas trade then did not have such an importance as in Britain or as in later globalising economies. Therefore, attempts to severe overseas supply chains was not so relevant. There was, indeed, active resistance from trade interest groups, particularly the merchants in the cities of Hamburg and Bremen, to a navy that would engage itself overseas. These merchants relied on their network of friendly contacts and on sailing under a neutral flag.
Hence, the WESPE-Class was designed to be mainly a heavily armoured gun-platform, giving long-range protection to the tidal North Sea harbours that are surrounded by mud-flats and to give mobile protection to the deep fjords of Schleswig-Holstein's Baltic coast. They would be backed-up by heavy artillery (and later fixed torpedo batteries) in coastal forts.
The guns in such boats usually could only be trained by turning the whole boat. This seems more difficult then it probably was, because even in the old days of the rowing gunboats they would attack by rowing in a wide circle and when the intended target passed through the line of aim, one would fire. As the WESPE-Class was designed to let themselves fall dry on mud-flats, a possibility to train the gun itself was needed.
This distinguished the WESPE-class from earlier boats of similar design in Britain, namely the ANT-, GADFLY-, and BOUNCER-class of the 1860s. Man other navies took up the same concept and there were examples in the Danish, Dutch, French, Norwegian, Spanish, and even the Argentinian navy. Some of the were armoured, while other were still constructed from wood or composite.
 

S.M.S. WESPE under construction (HENK, 1895)
 
Technical Description
The WESPE-class comprised ten boats delivered in two batches between 1876 and 1880: WESPE (1876), VIPER, BIENE, MÜCKE, SCORPION, BASILISK, CAMAELEON, CROCODILL, SALAMANDER and NATTER. They were all built by A.G. Weser in Bremen. With a length of 46.4 m and a beam of 10.65 m they had a dead weight of 1157 t, drawing 3.37 m. The dimensions vary somewhat according to source, but this may be due to different reference points, such as length overall compared to length between the perpendicles etc.
Two inclined double-expansion engines on two propellers gave a maximum speed of 11 knots. Their original complement was 3 officers and 73 crew. Steering was from a stand on the hut and an emergency double steering wheel abaft. Very early on they were also retrofitted with an electrical generator.
The WESPE-class were the first German warships (and indeed among the first of any warship) that did completely without auxiliary sails. As the consequence they only had a light mast for signalling. In spite of sporting quite some leading edge technology, they were only of limited seaworthiness and their handling was far from perfect. This resulted in them being given a collection of rather unfavourable nicknames. They were also not very popular with their crews and officers due to the cramped conditions below decks, but then they were not meant for long voyages in the open sea.
 

Admiralty illustrative drawing (before 1883)
 
Armament
The main armament was a single 30.5 cm rifled breech-loading gun designed and manufactured by Alfred Krupp AG in Essen. At the time the WESPE-class boats were designed, fast torpedo-boats did not exist yet – the automotive fish-torpedo was just being developed. When in the mid-1880s small torpedo-boats became a tactical reality, some form of self-defence against them was necessary and two bronce(!) 8.7 cm/l24 breech-loading guns in ‘disappearing’ carriage and two 37 mm Hotchkiss revolving guns came on board. In fact, very early on (1883) also two 35 cm underwater torpedo launching tubes were installed to increase the attacking capabilities.
 

Instruction model for the Rk 30.5/l22 on the Danish HELGOLAND in the Orlogsmuseet Copenhagen on a carriage similar to that of the WESPE-Class
 
Scale
The scale chosen for the model is 1/160, which admittedly is somewhat unusual for a ship model. However, the reasoning behind this choice was that a large selection of N-scale railway figures is available that eventually will crew the ship. There are also space and portability consideration, which are important for someone, who has to move from time to time for professional reasons.
The model will be a waterline model. This will allow a scenic presentation of the finished model. Besides, the hull below the waterline is not quite so graceful. Above the waterline the hull is also more or less prismatic, with vertical bulwarks and virtually no sheer. These parameters together call for a bread-and-butter construction.
 

Artist’s impression of a WESPE-Class gunboat (1891)
 
Sources
Owing to the loss of most of the archival material from the former Admiralty Drawing Office during and after the end of WW2, detailed source material is rather scant. Some lithographed drawings that must have been made before the major refit in 1883 have survived and serve as a basis for the reconstruction. The Bundesarchiv/Militärarchiv in Freiburg i.B. has some drawings, but unfortunatelly they only pertain to a much later refit of S.M.S. NATTER. However, the WESPE-Class was a bit of a novelty at its time and some Detaildrawings of bothm the ship and the armament, have found their way into textbooks of the time. Relatively recently a very detailed original drawing of the gun became available on the Internet from a private collection (www.dreadnoughtproject.org). Historic photographs from the early days of the ships are quite rare and mostly of not so good quality, but some reasonably good ones from the end of their active life have survived.
Based on the information that was available in the 1980s Wolfgang Bohlayer drew and published a plan of S.M.S. WESPE as she might have looked like after the major refit in 1883 (available from VTH, http://shop.vth.de/wespe-1876.html). Based on the information available today, this plan would need to be revised in some details.
The available information is summarised on the page on the WESPE-class on my Web-site: http://www.wefalck.eu/mm/maritime/models/wespe/wespeclass.html
 
To be continued ...

I gather the best source of information on 1:72/1:75 scale (25 mm) figurines (in plastic) is this review site: http://www.plasticsoldierreview.com/.
 
You will have to scan the site for suitable manufacturers and ranges.
 
Information on (white) metal figurines is more disperse and difficult to come by.

… don't have a gun license 
 
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The upper gun carriage
 
Based on the profile drawings from (http://www.dreadnoughtproject.org)
 

Part view of the drawings for the photo-etched upper carriage cheeks
 

Surface etched cheeks for the upper carriage
 

Filler and covering pieces laid out for soldering
 

Assembled cheeks and ties laid out
 
A core for the cheeks was sawn from 0.8 mm brass sheet and the etched covers soldered on. Then 'rivetted angle-irons', from etched parts were soldered on. These are connected by tie-plates. The frame of the upper carriage is also strengthend by horizontal ties. These are composites from several etched parts in order to show the rivetting. The horizontal ties were soldered to the side pieces, while the bulkhead-like ties were glued in because it would have been to difficult and risky to bring the heat for soldering at the right places. The covers for the trunnion-bearings were bent from an etched part and soldered together.
 

Assembled upper gun carriage from the rear
 

Assembled upper gun carriage from the front
 
The upper carriage was further kitted-out with wheels. The front and rear rollers were turned from steel to give them a real 'steel' appearance. On the prototype the rear rollers sit in excentric bearings that allows them to be brought into to contact with the rails on the lower carriage: when being fired the upper carriage slides back on these rails, the rollers allow it to roll back into the firing position.
 

Carriage with the barrel in place. Note the trunnion bearings cover (not yet trimmed to length)
 

 

Added the rollers plus the sockets aft for the lever that is used to turn the excentric bearings of the rear rollers
 
(Sorry, replaced the toothpick with a match - normal size not the large fire-place one   )
 
To be continued ...

Lock for the 30,5 cm gun
 
The next thing to be tackled was the lock piece or ‘wedge’. This 'wedge' has a rather complex shape with a flat front, but a round back and various recesses and cut-outs. I decided it would be best to undertake most of the machining operations while it is still attached to some (round) material that can be easily held in a collet. The round back was milled in an upright collet holder on my mill's rotary table after the various coaxial holes had been drilled and the flat sides milled, all in the same set-up. For machining the other recesses the piece had to transferred to the diving head on the mill.
 

Round-milling  the lock piece in an upright collet-holder on the rotary table
 

Cutting off the finished lock piece
 
The most time consuming part turned out to be the cover piece for the lock, which in the prototype was fastened by five hexagonal head bolts. It holds the moving and locking screws in their place. It took me four tries before I produced a half-way satisfactory piece. Soldering the microscopic bolts (0.4 mm head diameter) in place got me quite a few grey hairs. Finally a fake locking screw was turned up and the moving screw, which moves the lock in and out, was faked from a couple of drilled-together 0.1 mm copper wires, covered in a thin layer of solder to make them look like steel.
 

Milling square and hexagonal bolts
 

Facing the locking screw in special protective brass collet
 
The large re-enforcement ring for the barrel was also turned up and two holes drilled into it for seating the rack quadrant that forms part of the elevating gear. In fact, I had cheated a bit, when drilling/milling the lock seat: the front of the hole should have been flat, which is difficult to machine; so I continued the elongated hole under the re-enforcement ring, which was made as a separate part and slipped over the barrel.
The various parts of the lock were assembled using lacquer and cyanoacrylate glue.
 

 

 

The (almost) finished gun barrel with its lock (toothpick for scale)
 
To be continued ...

@bear, I must say, you rather embarrass me with your praise   I gather, a professional mechanic would throw up his hands into the air seeing me doing things, being just a self-taught amateur. Actually, collecting old machine tools and their restoration developed into a hobby of its own: http://www.maritima-et-mechanika.org/tools/toolsmain.html
 
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Back to the subject ….
 
Rack-and-pinion drive for training the gun
 
The gun was trained by pinion acting on a circular rack. The pinion was driven from under deck by a sets of gears and a couple of cranks manned by a number of sailors. The chief gunner was able to connect and disconnect the drive with levers from his aiming-stand behind the gun.
I set up my hand-shaper (http://www.wefalck.eu/mm/tools/shaper/shapers.html) for cutting the rack teeth, but had to throw away the first two attempts because of the poor material and because - again against better knowledge - I did not lock the traverse slide when cutting. The table was removed from the shaper and the home-made dividing head bolted on instead. For lack of a proper tool grinder (another project now in hand) I hand-ground a cutter for the rack teeth (0.1 mm at the bottom) from a rod of high-speed steel. For holding this tool-bit in the shaper, an old lantern-style tool holder from the watch lathe came very handy. The unwanted parts of the ring were cut away on the shaper using ordinary left and right hand lathe tools. Finally the necessary sections were trimmed off with a fine saw blade on the lathe's sawing table.
 

Hand-shaper set-up for cutting the toothed rack
 

Cutting the toothed rack with a specially ground tool
 

Cutting away the unwanted part of the ring with an ordinary tool
 

Rails and rack provisionally in their place inside the barbette
 
 
To be continued ...