Model Engineers’ Workshop – August 2019

Laser Cut Tank

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September’s issue, number 284, returns with more great

content, including some handy tooling to make yourself:

Make Derrick Marsh’s fl exible scribing

blocks

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In our

Content may be subject to change

The Story of a Shed - Des Bromilow builds

his dream workshop

Stewart Hart’s One Handed Depth Gauge

Coming up in issue 284

On Sale 9th August 2019

inserted into a quick virtual mockup of the engine bay, fig. 7. The

concerns proved false as the engine was dwarfed by the space,

leaving lots of room for cooling provisions in due time. Note

that the engine shown in fig. 7 is a custom made 22 cc originally

intended for the Whippet model.

The transmission (inside the hull) will consist of a reduction box

giving high, low and reverse gears and a steering box (fi g. 7, shown

in magenta and blue.). These gear systems will be based on Sturmey

Archer 3 speed bicycle hub gears based on a cut down Wilson

design by fellow tank modellers Mike Tull in Fareham and Iliya Cerjak

in Amsterdam (both of internet fame). At present the two boxes are

still simple virtual models in Alibre.

As an example of forward planning, using Alibre, see fi g. 8. This

shows the general layout of the internal power train for a 1/5th scale

WW2 M3 Stuart Tank.

The Whippet crew compartment and superstructure have

purposely been left until last as it is largely a cosmetic cover for

the working parts. In the original it consists of fl at plates riveted

or bolted to a semi continuous angle iron backing frame. This lack

of a full frame will probably require yet another set of jigs to aid

assembly before riveting/bolting. The whole structure will have to

be modelled in Alibre if only to get the exact shape of the individual

plates. However, a more convenient and stronger solution might be

to treat it as a sheet metal part and simply fold in the appropriate

places. My version of Alibre has the sheet metal module that will

take the virtual model and produce a template that can be stuck

onto a single, fl at metal sheet and folded along the proverbial

dotted lines. This module might not be in Alibre Atom.

I am no artist and am severely challenged by engineering

drawing either with a pencil or 2D CAD soft ware. The Engineer

illustration and blueprint cards give shape and relative position

information but few if any dimensions. Alibre has enabled me to

cope with these limitations and produce an answer that is not

too shabby for an amateur. The usual disclaimer applies reference

Alibre other than as a customer of their UK partner Mintronics who

helped me at every request. ■

Fig.7

A Mock-up of the Engine Bay to check space availability.

Alibre Mock-Up of the Engine Compartment for a 1/5th scale WW2

M3 Stuart Tank.