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7.25" Tich

glennhow56

Joined: 17-03-18

Topics: 2

Replies: 1

Posted: Sun 18th Mar 2018, 1:54pm
7.25" Tich

Has anyone actually built the Kennion version of this loco without finding major errors in the drawings??
I have read of one chap who found that the motion physically could not go round without fouling.
I have had to insert shims and pack out the Cylinders and Motion Bracket in order to get the Coupling Rods to pass safely.
Are there other nasty surprises waiting for me?????
 

Replies To This Post

Xz

Joined: 1-01-92

Topics: 24

Replies: 296

Posted: Sun 18th Mar 2018, 5:37pm

I'm afraid the answer to that one is 'very likely'. In over forty years of modelling these things I've yet to find a perfect set of drawings. Some are better than others, few if any, seem to be better than Ok. In this day of CAD/CAM one can only hope that things will only get better. Quite a few folks now re-draw everything, in 3D CAD, to see if it works first. I hope they save it and pass it on.
 

Mick

Joined: 1-01-89

Topics: 9

Replies: 163

Posted: Mon 19th Mar 2018, 11:04am

I don't know whether you have bought the drawings recently from one of the model engineering suppliers or got them from some other source. Whichever, I have commented on this topic on the web site before: why do suppliers continue to sell drawings which have been proven not to work and therefore they know are not fit for purpose?
 

Pete

Joined: 1-01-95

Topics: 0

Replies: 6

Posted: Mon 26th Mar 2018, 10:12pm

I started building my 7 1/4” gauge Tich over 20 years ago and found the same thing as you. Having only in the last few years have I had my boiler successfully hydraulicly tested and I am slowly sorting out the valve gear! Mind you a lot of the bits I made in the early days were with great enthusiasm and less skill!!
 

nickc

Joined: 22-06-18

Topics: 0

Replies: 1

Posted: Sun 24th Jun 2018, 9:36am

There are many errors on these drawings that are down to several reasons. Firstly LBSC was not exactly blameless in this area. Secondly it was not his design originally - it was a general arrangement that he added 'the works' to without  building a loco until later - and then it was a belpaire firebox, outside stephensons valve gear version! Thirdly the drawings have been doubled up rather than redrawn so errors can creep in there with the best will in the world. 


I looked for images on the internet and found that no two locos seemed to be the same, particularly as regards the valvegear.


Finally have a look at this solid boiler stay that screws backwards into the backhead and simultaneously forwards ibto the smokebox tubeplate. Not impossible to erect (fit to the tubeplate and wind on the backhead to the stay before sliding the whole assembly into the barrel) But I don't think they meant to do it that way!

Nick
There are many errors on these drawings that are down to several reasons. Firstly LBSC was not exactly blameless in this area. Secondly it was not his design originally - it was a general arrangement that he added 'the works' to without building a loco until later - and then it was a belpaire firebox, outside stephensons valve gear version! Thirdly the drawings have been doubled up rather than redrawn so errors can creep in there with the best will in the world.


I looked for images on the internet and found that no two locos seemed to be the same, particularly as regards the valvegear.


Finally have a look at this solid boiler stay that screws backwards into the backhead and simultaneously forwards ibto the smokebox tubeplate. Not impossible to erect (fit to the tubeplate and wind on the backhead to the stay before sliding the whole assembly into the barrel) But I don't think they meant to do it that way!

Nick
 
 
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