Problems with Heilan Lassie Drawings

[Robert HobbsParticipant @roberthobbs74912]

Hi there, if you have any information on other errors on LBSC drawings for Heilan Lassie I would be please to have your advice before I waste any further materials and time.

The length of the brake beam and tie bars are too short and spacers are required to line up the outer pull rod and the hangers. The dimensions for the spring system are poor. Regards Robert

[Robert HobbsParticipant @roberthobbs74912]

The dimentions for the brake system and the horns/springs on the tender are wrong .

[John FieldingParticipant @johnfielding34086]

Hi Robert,

I see you are another culprit of the late LBSC's designs.

You may not be aware but LBSC actually built very few of the locos he described. In fact in an old ME volume I was reading just y'day dated 1946 when he originally penned the "galloping sausage design" he admits openly that he had not built this loco and several others, but he didn't name those other ones.

I have had similar experience with his Netta in 3 1/2 inch gauge. It is riddled with dimensional errors. To be fair to Curly, he was forced into churning out lots of designs as his writing was so popular and I think he fell into the trap of not checking his work. When he was writing Heilan Lassie for ME he was also fully committed to another design in another publication and I guess he didn't have the time he would have liked to spend extra effort checking his "words and music". Right in the opening edition of HL he asked readers to let him know if they spotted any mistakes.

Today with 3D CAD it would be easy to spot errors and potential clashes of components, but it wasn't around in those days!

[J HancockParticipant @jhancock95746]

Build Olympiade to the drawings and you will not be able to turn the wheels if the axleboxes bottom out.

It is close to heresy to criticise anything LBSC but dimensional drawing errors abound !!!!!!

[John FieldingParticipant @johnfielding34086]

On the topic of Heilan Lassie and design errors, I wonder if these two points have been addressed. I have a bound copy of ME from 1946 where LBSC gives the original words and music for the galloping sausage. I have found two peculiar items which I think are an issue. The first relates to the inside big end lubrication.

Here we see the original drawing from ME May 9, 1946 on page 456. The two halves of the brasses are clamped onto the inside connecting rod with 1/8" silver steel studs with 5BA threads on each end. The oil cup fitted to the top has a 1/16" hole going into the back half of the brasses. The problem I see is a severe restriction to the oil flowing from the oil cup to the crank pin. The clearance hole given is a No 30, which officially makes a hole of 0.1285" diameter in which a 1/8" silver steel stud fits. This leaves a clearance around the stud of about 2-thou at best for the oil to flow around to get to the brasses. I have seen this method used but it always had an undercut in the stud to allow free flow of the oil. LBSC doesn't mention opening up the top hole to allow more clearance and I wonder how he thought heavy oil was going to find its way to the bearing surface? Also the little end seems to have no provision for lubrication? Was the intention to drown the parts in oil hoping some would find its way into the bearing? As the little end suffers exactly the same loading as the big end I would have thought this needs to be addressed.

With the re-adoption of BA threads by the British authorities we have a problem as the new standard only covers the even number of BA threads. So a 5BA is not included and although many modellers have a set of taps and dies it will be harder in years to come to find replacement taps and dies and probably also nuts and bolts of this size at a sensible price. I would strongly recommend changing to M3 coarse threads wherever 5BA is called for. 5BA is 3.2mm nominal and I don't think the slight reduction in diameter by using M3 is of any concern. My choice for the studs would be socket head (Allen) cap screws which have the treads all the way up to the head, so allowing many more paths for the oil to find its way to the bearing surfaces. Bolts have a plain portion under the head, screws do not. These cap screws are available in high tensile blackened steel and also in stainless steel, so corrosion isn't a problem, but with so much oil being flung about I don't think corrosion is our major concern!

The second point regards fitting the inside cylinder piston rod to the cross head assembly. LBSC tells us to drill a No 42 hole through the cross head and stainless steel piston rod and then to squeeze in a 3/32" silver steel pin to hold everything together. All well and good, but looking at the next picture had me really stumped!

Here we see a side elevation of the whole of the inside cylinder works as described so far and the cross head pin is clearly shown as being horizontal. How one is supposed to do this is not disclosed in the text. Bearing in mind that this whole gubbins sits between the two frame plates I would have thought a vertical hole drilled from above or from below through the cross head and piston rod was more doable. Having tried doing this on the outside cylinders of my 3 1/2" gauge Netta it is not an easy thing to do without some way of clamping the two parts tightly together so nothing shifts when the chassis is offered up to the drill press. To even attempt this with a handheld brace and drill bit is unthinkable. Drilling stainless steel at the best of times is always a task especially with small diameter drills. The way I tackled the job on Netta was to firstly mark and centre pop the two cross heads and then drill a smaller pilot hole though the cross head before offering up the piston rod. Then the rod was inserted and adjusted to the correct setting and then a drill was put into the cross head hole to make a witness mark on the rod. It was then removed through the cylinder front cover and clamped in the machine vice and drilled for the correct size hole for the pin. The cross head hole was also opened out to the same size and the the piston and rod was replaced and the pin forced in.

Incidentally I have recently been converted to using high tensile steel roll-pins for such purposes and I find them excellent and easy to fit. They are available in metric and imperial sizes from about 1.6mm in diameter upwards. The pin is springy and the hole only needs to be drilled and not reamed. They cost almost nothing in the smaller sizes and are more than adequate for most purposes, most car door hinges today use roll pins – known as "spring pins" to our North American cousins.

[Clive IndiaParticipant @cliveindia]

The technical question has been answered now, therefore a non-technical comment – I often wonder why nobody appears to want to spell Hielan Lassie as LBSC does in his ME articles. Perhaps it does not matter but …..

[John FieldingParticipant @johnfielding34086]

Hi Clive,

Well spotted! I fell into the trap of mispelling it myself. I had to go and look at the ME series to check the spelling. It is is indeed Hielan' Lassie!

What was it we were taught at schools? Oh yes I remember now – I before E except after C.

[Anthony KendallParticipant @anthonykendall53479]

It is of no consequence really – a bit like rivet counting, but if you search on the net you have to do it twice, once for each spelling. Still, it pales into insignificance compared to the effort in making one!

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Clive India on 22/02/2016 09:28:56:

The technical question has been answered now, therefore a non-technical comment – I often wonder why nobody appears to want to spell Hielan Lassie as LBSC does in his ME articles. Perhaps it does not matter but …..

.

Presumably an ambiguity prompted by pronunciation

Hielan is pronounced Heelan

MichaelG.

[Author]

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