Author: efoeth

42 ft Motor Launch

When describing the 45 ft  motor launch that  “42ft motor launch was similar but had only a single rubber, like the 42ft sailing launch from which it was derived. The rubber or rubbing strake is the line at the outside of the hull running the entire length, either a timber of rope. I use Robert’s information to classify all large launches as either 42 or 45 ft.

Shelterdeck, part II

Continuing from Shelterdeck, part I.

This is a bit of work from just before the great audio project that ran over eight months or so and not work done in the last weeks. Remember to not leave your model unattended or properly protected against Sigrid the Destroyer when your attention is diverted to other projects.

There’s a small awning rail on the side of the quarterdeck bulkhead that was made from some leftover GMM ultra-fine 1:700 railing set. I prefer fixing the rail by drilling in the model, so I added a small line and taped the rail in place. With a 0.2 drill the right location was first ‘marked’, later drilled in using the pin vice. Then follows the horrible part; inserting the rail in bulkhead. I use a bit of tape to keep the part in place. I forgot to photograph the gluing process, using a small 0.25mm strip wedged between the rail and the bulkhead as a spacer, gluing one or two locations at a time. Some minor aligning and re-gluing is typically required afterwards (plus after handling damage).

Various eyebrows and details were added next. There’s a small je-ne-sais-quoi on the bulkhead, and a similar pair against the bridge superstructure (top left). It might be a pulley to pull up the awning, but I’ve not been able to find an image where this part is actually used. A small cover over the vent opening was added as well. A number of small vents and the supports for the ladders will added at the last minute; too worried they may break off during handling.

A number of aerial trunks is present, given in full in the AOTS, section F (rig), with each group running to a separate W/T office. An auxiliary W/T aerial runs from the top starfish to a trunk near the conning tower; this trunk as a small ladder (top left images). The main aerial and main auxiliary trunks are situated near the main mast; I managed to find only a few images that shows them both (top right images). The main trunk is a fair bit larger and is a open cylindrical structure with an access hatch seen open (outer top right). A third trunk is present just aft of the searchlight platform; according to the AOTS this trunk was added in 1937 and runs to the second W/T office (bottom-left images). The bottom right image shows the original position of this aerial trunk at the aft end of the shelterdeck, but it was moved aft when the pompom bandstand was added.

I found images of various aerial trunks on other ships with a larger trunk aboard HMS Prince of Wales, and a few smaller trunks aboard a destroyer and HMS Rodney.  A fair estimate was made to create the parts using my lathe (which was really fun to do).

Proxxon MF70 Milling Machine

I just bought the Proxxon MF70 Milling Machine (27110), a tiny machine that can be upgraded (or bought) as a CNC machine and offers a much higher rpm than my drill press or lathe: it goes up to 20,000 rpm. I was never able to drill anything below 0.5mm without drills breaking and more or less gave up on that idea without a watchman’s lathe or equivalent, until Marijn van Gils showed his brand-new MF70 could drill almost to 0.1mm in brass (See his HMS Victory Vs Le Redoutable build). As the mill is quite affordable and I no longer have to pump all my savings in my recently completed audio project, I bought one as well.

So I did use the Drill Press with a compound table (27100), a precision machine vice (24260) and a nice dividing head (24264). But, the rate of revolutions is low and the entire setup is quite flexible and as such not precise. More important, it does not have a proper collet system but uses a large three-jaw chuck that is inherently terrible for fine work.

Imagine my surprise that the MF70 does not have a proper collet system either; it uses the Micromot collet system. That’s fine, but these cannot old larger objects such as Proxxon’s own edge finders. For my small lathe, Proxxon failed to deliver a proper collet system for the tail stock too, though that was solved by brutally cutting an MC11 ER11 collet chuck. For the mill this is not an option as the spindle doesn’t use an MC11 system, but after minor search efforts I found a replacement part at USOVO; a new tuning spindle with an ER-11 chuck and it even comes with a small installation manual. Rejoice!

I do wonder why Proxxon seem to be content with their tools not being able to use the entire range of tool mods and expansion sets among them, but at least now I could use the Edge Finder Set (24434) that doesn’t fit the original MF70 to align the vice properly and to help finding, well, edges. I did perform some tests with the Micromot collets and these did hold some of my drills perfectly centered, so I can image some people not needing the ER11 collets. I added an extra collet set in a nice box (24154, but you better buy a set with more collets for less elsewhere as this set contains only 7) plus an additional vice (the vice vice). With these options the mill became roughly twice as expensive and I forgot to buy cutters as these are not included—not even one—but small cutters can be bought as small as 0.2mm at other stores. The mill did come with a cross table (27100) and a set of step clamps (24256).

Installing the new spindle took about half an hour. I used my sturdy Gorilla-proof 1.5mm Hex wrench the remove the motor plate screws that have been tightened very well and T10 (I think) Torx driver to remove a screw holding the spindle in place. The Usovo spindle comes with two bearings but I kept the bearing of the existing spindle. The set does not come with a tool to (un) clamp the nut or hold the  ER11 spindle; I had one for the ER-11 tailstock of my lathe so don’t forget to order one if you purchase this new spindle. You may also want to order a 3.175mm ER-11 collet separately, the default size of many of my drills.

First some experiments starting with something large: a 0.2mm hole through a 0.3mm slice of a 0.7 Albion Alloys tube. Zeroing the drill position is something you’d rather do with the edge finder (that hadn’t arrived at the time of writing) and still on the very first attempt the MF70 left my drill press in the dust. The main causes for inaccuracy went into inconsistently clamping the work piece in the vice and parting the small ring using this method.

My intended targets were the davits for the 27″ whalers. This is a terribly delicate section of the model and it would be really useful if the entire assembly could be mounted by pins into the side of the superstructure when the model is more or less done. These davits are not only very thin (0.5mm rod at the center, filed down to 0.3mm at either end plus a series of 0.7mm rings) but are also angled in slightly inward by 12 degrees. Here drilling in and soldering mounting pins and etched parts to the davit would be very useful; soldering the gripping spar to the davits would be even better as then the whaler could be glued to this spar; rope work can be added last minute. So each 12mm davit needs to be drilled in four times, two pairs of holes at perpendicular angles so the work piece needs to be rotated at least once.

With the ER11 chuck still in the mail I started with several different techniques that are all bad. I bent the davit before drilling it, worried that when bending after drilling it may break at a hole as some parts did. The drill was centered by eye (A). Bending first makes it difficult to clamp the davit so I used a block of plastic  and a small 12-degree alignment plate (B). Soldering the rings before drilling is easiest, but when traversing in steps of 0.1mm you really need to solder all these rings perfectly  if you want to hit them dead center (C). This went well but not really something to recommend as the part will flex.  When the part needed to be rotated 90 degrees I tried two plastic blocks and re-centering the drill (D); this is awful as the part may slip (slide or rotate breaking the drill) and your reference is all over the place. Reversing the part—using a bit of rod to eyeball the angle—went better (E); not really good either with the part poorly supported. The prototype did work out nice though (the one that survived that is), after the rings from the first exercise and some etched parts where added (F). With the part flexing and overall experimentation I lost quite a few drills but it was a great introductory exercise.

LX521: introduction

When your cathometer indicates it is too warm for modeling there’s only one thing left to do: building your own speakers. HMS Hood had to wait for a few months.

I previously posted the progress on my Orion speakers and initially wanted to build a few more. I had collected the 20 amplifiers channels and five filters ready to hook up the remain three. One beautiful day in 2017 my Siamese cat Blair mistook my stack of amplifiers for a tree and decided claim it as its own by marking it. At first we heard a cackling sound from the speakers, followed by the amps bellowing large amounts of white smoke. Finally the mains shorted out. I tried cleaning them as best I could but only one out of three Rotel 1077s would come back to life.

I brought them to the repair shop and they concluded that one mainboard had certainly to be replaced and one separate channel as fried. After a brief (not really) period of financial mourning I abandoned the upgrade path.

Meanwhile the Orion were updated a few times and not all components were available anymore; the electronics I built could not be modified easily to get the last update. Also, a new design appeared for the same designer, replacing the Orion: the LX521. I decided to switch projects and continue.

LX521: introduction
LX521: deriving the digital filter
LX521: building the analog filter
LX521: building the power amp
LX521: building the speaker
LX521: results

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