JonL
Elder Statesman
WWSME (Wiltshire)
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Post by JonL on Mar 25, 2019 12:16:08 GMT
On another forum a while ago I asked about building a Brit and if there are any issues I should be aware of. One that came up from Julian Atkins was:
Can any of the Britannia builders on here tell me please if they had any of these issues? I'm about to start on the expansion links within the next few steps and would rather go in forewarned but I can't find other references to it.
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Post by Deleted on Mar 25, 2019 12:21:52 GMT
I can't help directly Nobby but Julian is a member of this parish so I'm sure he may find more info. I can tell you that 'expansion' links, in general, have to be assembled 'on the job'. IE: you can't build them as a whole and then expect to fit them, they have to be fitted in pieces.
Cheers
Pete
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barlowworks
Statesman
Now finished my other projects, Britannia here I come
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Post by barlowworks on Mar 25, 2019 12:42:10 GMT
Send Jim a PM, he's finished a Brit, though in 5 inch gauge. He may have some advice.
Mike
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Post by simplyloco on Mar 25, 2019 16:01:09 GMT
My Brit was made entirely to the words and music and there were no problems whatsover with his drawings or the instructions.I have onlymucked about with details ! John
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JonL
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WWSME (Wiltshire)
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Post by JonL on Mar 25, 2019 16:35:35 GMT
Ok, maybe the issue is people not following the instructions fully. I'll proceed with caution, thanks all.
Hopefully Julian is able to clarify? I may have misunderstood.
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jma1009
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Post by jma1009 on Mar 25, 2019 19:33:11 GMT
It is just possible that the problems were with LBSC's 3.5"g 'Evening Star' and my recollection, which in any event was qualified, may be completely wrong.
I am a bit busy the rest of this week, plus am going down with a bad cold, but if I get a chance I will try and dig out where and when this problem was raised in ME, and the online search engine will help me locate the relevant copy/ies of ME in my collection.
The problems with the throatplate joint on the boiler are well known.
Cheers,
Julian
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JonL
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Post by JonL on Mar 25, 2019 20:50:43 GMT
Excellent, thank you Julian, much appreciated. The issues with the throatplate I am aware of and have my boiler inspector assisting me with, in line with the recommendations on this site.
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JonL
Elder Statesman
WWSME (Wiltshire)
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Post by JonL on Mar 26, 2019 7:36:00 GMT
Model Engineer Mag PDF
I found this reference which may be the one you are referring to: on page 1233 the builder refers to issues with the reversing link; he couldn't get the link with its trunnions brazed on to fit between the lugs holding the bearings despite the dimensions matching the drawings. He ended up bending the lugs outward to get the trunnions to fit, which doesn't sound ideal.
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Post by franstrein on Mar 26, 2019 22:02:33 GMT
Hi, I ran into that problem as well. I also remember reading somewhere (on the forum) about a restauration of an older Brit or Evening Star where some-one ran into that issue when dis-assembling the motion work. My issue might also have been caused by me using small ball-bearings for the trunnions. When adding the inside bearing caps, as the instructions tell you, there is no space to wiggle anymore. At the end, I milled small groves on the inside of the trunnions, from the bottom up to the axis. The trunnion pins just go through that space into their position. This way, these are not visible. On this picture, from the bottom, you see what I did: Frans
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don9f
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Les Warnett 9F, Martin Evans “Jinty”, a part built “Austin 7” and now a part built Springbok B1.
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Post by don9f on Mar 26, 2019 23:00:50 GMT
Hi Frans you are probably referring to me who had the problem with expansion links on my 1980’s built 9F. Like you I slotted the trunnion brackets once I found that the links wouldn’t fit when the whole arrangement was made as per the Les Warnett drawings. This was of course in 5 inch gauge and I assume it’s because the bits and pieces involved are not true to scale....they are more “chunky” than the full size. The Britannia and 9F expansion link arrangements are very similar, if not the same!
I have no experience with a 3.5 inch gauge Britannia but it sounds like there could possibly be similar problems for some builders and its definitely something to watch out for Nobby when you get to that stage.
Cheers Don
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JonL
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WWSME (Wiltshire)
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Post by JonL on Mar 27, 2019 7:02:05 GMT
This is exactly what I was after, thank you for your help. I was planning to use ball bearings but I don't know if I'm giving myself a hiding with no massive benefit. I'd still like to use them if possible, but not if it makes me want to throw the whole assembly out the window! At least I know now what to expect to an extent.
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JonL
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WWSME (Wiltshire)
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Post by JonL on Mar 27, 2019 8:12:45 GMT
I just noticed Model Engineers Laser do a motion bracket kit for silver soldering together. That looks like it might be a better option than trying to machine the castings I have on my vertical slide...
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don9f
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Les Warnett 9F, Martin Evans “Jinty”, a part built “Austin 7” and now a part built Springbok B1.
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Post by don9f on Mar 27, 2019 18:37:40 GMT
Finally found a bit of time today and looked up these photos that appeared in my 9F thread some time ago (sadly non-moving at the moment). They show the problem I mentioned yesterday and my solution, which once everything is assembled is completely unseen..... My expansion link brackets and trunnions bearings etc. are fabrications in gunmetal of 3 different castings, held together in a jig for silver soldering. I don’t have the drawings any more and can’t remember exactly what was specified, but the castings all came from Norman Spink back in the 80’s. I think the problem really lies with the expansion link assemblies themselves and it is quite possible that a bit of fettling or rounding off of parts of them may mean they could be made to fit without a problem? Cheers Don
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JonL
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Post by JonL on Mar 27, 2019 21:28:34 GMT
Ive received Malcolm's drawings, he scaled down the 5" versions for the 3.5 apparently.
"Yes the castings are a pig, my fabricated bracket is fine if you take your time over it"
I think I might get these and give them a go. It does look a little intimidating to a novice, but its a skill that needs to be acquired. He does mention using a slitting saw on the back of the metal work before bending.
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Post by Deleted on Mar 27, 2019 22:48:58 GMT
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JonL
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WWSME (Wiltshire)
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Post by JonL on Mar 28, 2019 7:19:39 GMT
I suspect our posts have crossed paths pete! Thats the Malcolm I am referring to in my post, I agree it sounds like a good answer. It seems very reasonable, although I worry about getting neat bends on the material.
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Post by workshoppete on Jul 6, 2019 9:44:59 GMT
Hi Al I am attaching my query to this link as its loosely associated. Several years ago I purchased a finished 3 1/2" LBSC Britannia chassis the craftsmanship is good but the painting and general state is poor requiring a full strip down, cleaning and painting. The one thing I have noticed is that the leading end of the lifting arm (The end with the short drop link attaching to the valve rod) fowls the top forward corner of the expansion links. My question, is this a known fault or is there something wrong with this build. Since I am going to totally strip the chassis down once i have built the boiler (which is now 50% finished) any modification should not be a problem. Thanks Peter
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JonL
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Post by JonL on Jul 9, 2019 16:14:44 GMT
In the bits of research I've done I've not heard of that one, but if there are any two Britannias the same out there I should be very surprised...
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Post by mr swarf on May 23, 2020 10:41:41 GMT
Ive received Malcolm's drawings, he scaled down the 5" versions for the 3.5 apparently. "Yes the castings are a pig, my fabricated bracket is fine if you take your time over it" I think I might get these and give them a go. It does look a little intimidating to a novice, but its a skill that needs to be acquired. He does mention using a slitting saw on the back of the metal work before bending. How did you get on with the laser kit. I might do a bit more on mine in the next few weeks and not sure which way to go, castings or laser kit. Paul
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JonL
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Post by JonL on May 23, 2020 19:47:55 GMT
It was ok, I've only done side so far. To be honest now I have a mill if I were doing it again I probably would use the castings.
Probably down to my inexperience I struggled to keep everything square during soldering.
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