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Hick Crank Overhead engine

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AVTUR:
My work on the Boulton & Watt Bell Crank engine is coming to an end with just a little painting and the base to finish. These will be done in the autumn and I will post pictures and comments on the forum before Christmas. To fill the gap between now and the return to the Maudslay Table engine design, when winter forces me out of the workshop, I am starting work on a model of a Hick Crank Overhead engine.

I bought the kit of castings six years and was not impressed with the quality of three of the castings. Also one small casting was also missing. I saw it as a difficult project with many fiddly bits so I wrapped it all up in anti-corrosion paper and bubble wrap, put it in a plastic box and found room for it on a shelf. Every so often I have taken a look at it, to see if anything had changed, and thought about having a go at it.

The original engine, a compact 10HP engine, was shown at the Great Exhibition of 1851 by Hick, Hargrave & Co of Bolton. In 1956 Geoffrey K King (A.M.I.C.E., A.M.I.Mech.E, A.M.I.E.I, Mem: Newcomen Society etc.) drew up a 1/12 scale drawing of the engine which is the basis of this model. I do not know if he ever made a model but some have featured on YouTube etc and one was displayed at the Bristol model engineering show a few years ago. As yet there are no instructions available for the engine build.

I find myself very critical of the quality of model engineering drawings. I have to admit that with the advent of CADs they have improved. Geoffrey King’s drawings are quite good but he has crammed an awful lot on small sheets of paper. I can forgive the use of fractions and first angle projection but I have never found the latter easy. I have got into the habit of redrawing all model parts to my satisfaction using decimal dimensions and third angle projection. This leads to a better, or at least quicker, understanding of parts and machining operations. So far, last year,  I have redrawn most of the castings.

It would be nice to show general arrangement drawings and pictures of a model of the engine but the only ones I have are copyrighted. I have found a picture of an engine, attached, on the internet which is in the public domain. It shows the top of the engine. The cylinder and steam valve are hidden by the plinth.

More will follow.

AVTUR

b.lindsey:
Should be a very interesting build to follow AVTUR.

Bill

AVTUR:
I have now inspected the castings:
1.   One bearing block cap casting is missing so I will have to machine one to shape from bar stock or an odd lump of gunmetal.
2.   One bearing block has been replaced by a lump of gunmetal. This is not a problem since the block can easily be machined from stock.
3.   The edge of the casting of one standard has run into the fancy Egyptian decoration, see attached photograph. I feel that this is important and needs correcting: Small models need something that catches the eye. An awful lot of models displayed at shows, however good, don’t have a “look at me” appeal. The only things that stand out on this model are the standards and the complexity of the small moving bits.
4.   Other than the above all the castings are above drawing/machining size.
5.   All the iron castings can be touched by a file.
6.   The bedplate is an aluminium casting and the fillets are messy, see attached photograph. This will require careful work with a file, Dremell or ball end cutter. I fear that the aluminium will be sticky and nasty to machine.

I am happy with the above and have painted the castings with marking out ink (sometimes I wonder why, I guess I wanted to). I have started filing the castings smooth, to get rid of mould lines, risers, etc. They will then be shot blasted to give a controlled rough finish.

The redrawing of parts, starting with the castings, is progressing. As stated earlier this leads to an understand of the parts. After the completion of each drawing the required tooling (drill, cutter, tap and die sizes), fixings and fixtures are recorded along with any obvious difficulties. Some problems have become apparent:
1.   Strange BA sizes, 9BA nuts and screws are required. Fortunately I have found a firm that stock these. 9BA taps and dies are also available from a few places.
2.   A 7/64” slot cutter is called for. I don’t think they exist but there is an obvious work round.
3.   There are a number of 3/64” wide slots. Although such slot cutters appear not to exist one can buy 1,0mm slot cutters for about £25 each (how many am I going to break). This is one reason for my interest in an EDM machine. Another option, as discussed elsewhere, is to use a piercing saw and a very small file.
4.   The layout of the cylinder to steam chest fixings is too large (the first drawing mistake).

On the plus side I have not found any fixings smaller than 10BA.

The original drawings were made before the advent of modern anaerobic adhesives. Quite a few fixings are captive and these can probably be replaced using Loctite. In addition keys have been used on shafts. I see no point in using them except for show.

More will follow

AVTUR

Jo:
I would use M2 rather than 9BA  ;)

Is this the same Hick Overcrank Engine that has recently become available from Hemmingway as a set of castings and drawings ? I have attached the Hemmingway GA so you can see if it is the same engine. In case anyone feels the need to build one of these engines the castings are available from Hemmingway here: http://www.hemingwaykits.com/acatalog/Hick___Son_Overhead_Crank_Engine___G_K_King.html

Jo

AVTUR:
Jo

It is the Hemingway kit. I do not know if they have had any castings made recently.

I did not post the picture for fear of copyright.

AVTUR

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