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Post by jordanleeds on May 1, 2016 22:41:25 GMT
Now As with many of us on here Ive a couple of projects on the go and recently an opportunity to aquire a part built Edward Thomas to the towyn model engineering design came about via ebay. Given the locos simple construction and smaller size than my other projects it fits nicely with a loco to teach my son on when hes old enough.
Has anyone else built one and come up against any issues with the design?
Certainly am looking to replace the axles with some that have a stepped wheel seat on them given that the drawing suggests just over a thou for this.
also looking to flange the smokebox and saddle tank before riveting up
Have sent Cylinder drawings away for quotation for a pattern to be produced
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mbrown
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Post by mbrown on May 2, 2016 11:12:09 GMT
I haven't built an Edward Thomas in any scale but I do know that published designs for the Hackworth valve gear are often a bit "out" - I can't vouch for this particular design but it would be worth going into the valve gear design in some detail before cutting metal - Modified Hackworth is not as straightforward as it looks. There were some exchanges on the subject in Engineering in Miniature some years ago (I think concerning the Sweet Pea design) and the most authoritative article was by John LH Bate, former Chief Engineer of the Talyllyn Railway who, after all, had kept the prototype Edward Thomas in good order for many years. The position of the shaft carrying the slides relative to the axle is very critical both in the vertical and horizontal dimensions. The full size Edward Thomas is currently set to run very nicely in forward gear - you can use all the notches up to middle and she pulls very smoothly, although she has never had a perfectly even beat - it's more of a "galloping" sound when she's running at line speed. But in back gear it is clear from the beat that it isn't quite so good, although on the TR that doesn't matter so much as most of the work is done uphill. This does suggest some of the limitations of Hackworth valve gear - but if it is accurately designed you can get a pretty good result in one direction and an adequate setting in the other.
Edward Thomas has had numerous alterations over the years - most significantly, John Bate's rebuild in c.1976 which extended the rear frames, making the cab more useable, beefed up the old marine-section rods and added much stringer cross heads - this in turn pushed the return crank out an inch or so necessitating a set in the valve rods. The tank is now slightly bigger than the original and the arrangement of boiler fittings has been modified over the years.
My fellow TR driver, Martin Fuller, recently published a superb history of all the TR locos prior to the formation of the TRPS in 1951 and included much technical detail of No.4 in Corris days. He is currently working on Volume 2, covering the locos since 1951 and that should include a lot of detailed information about Edward Thomas if you are looking to model it at a specific period in its varied history.
Good luck.
Malcolm
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johnthepump
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Post by johnthepump on May 3, 2016 9:45:11 GMT
Hi Jordanleeds.
I shall be following you thread with interest, I hope you are able to put up some photos as you go along, good luck with the axle boxes and the roller bearing idea.
Regards John.
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Post by jordanleeds on May 8, 2016 23:02:29 GMT
I haven't built an Edward Thomas in any scale but I do know that published designs for the Hackworth valve gear are often a bit "out" - I can't vouch for this particular design but it would be worth going into the valve gear design in some detail before cutting metal - Modified Hackworth is not as straightforward as it looks. There were some exchanges on the subject in Engineering in Miniature some years ago (I think concerning the Sweet Pea design) and the most authoritative article was by John LH Bate, former Chief Engineer of the Talyllyn Railway who, after all, had kept the prototype Edward Thomas in good order for many years. The position of the shaft carrying the slides relative to the axle is very critical both in the vertical and horizontal dimensions. The full size Edward Thomas is currently set to run very nicely in forward gear - you can use all the notches up to middle and she pulls very smoothly, although she has never had a perfectly even beat - it's more of a "galloping" sound when she's running at line speed. But in back gear it is clear from the beat that it isn't quite so good, although on the TR that doesn't matter so much as most of the work is done uphill. This does suggest some of the limitations of Hackworth valve gear - but if it is accurately designed you can get a pretty good result in one direction and an adequate setting in the other. Edward Thomas has had numerous alterations over the years - most significantly, John Bate's rebuild in c.1976 which extended the rear frames, making the cab more useable, beefed up the old marine-section rods and added much stringer cross heads - this in turn pushed the return crank out an inch or so necessitating a set in the valve rods. The tank is now slightly bigger than the original and the arrangement of boiler fittings has been modified over the years. My fellow TR driver, Martin Fuller, recently published a superb history of all the TR locos prior to the formation of the TRPS in 1951 and included much technical detail of No.4 in Corris days. He is currently working on Volume 2, covering the locos since 1951 and that should include a lot of detailed information about Edward Thomas if you are looking to model it at a specific period in its varied history. Good luck. Malcolm Many thanks Malcolm I know Martin very well and have just put foxcote manor round again for him and the society. Would like to turn the loco out in corris guise |
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johnthepump
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Post by johnthepump on May 9, 2016 12:44:25 GMT
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Post by jordanleeds on May 10, 2016 0:25:47 GMT
Cheers John certainly a very different beast to the model.and providing some good food for thought.
I spoke to Reeves today regarding the boiler and lack of working pressure on their drawings and they where most unhelpful simply unable to advise what it should be and where or how to work it out I will speak with my responsible person and start the process of doing the calculations and working up towards ordering the blanks for the flanging plates from my very friendly laser cutter along with the material to start the tank ends .
Riveted up one of the buffer beams this evening as when bought everything had been bolted together,
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johnthepump
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Post by johnthepump on May 10, 2016 8:21:40 GMT
Cheers John certainly a very different beast to the model.and providing some good food for thought. I spoke to Reeves today regarding the boiler and lack of working pressure on their drawings and they where most unhelpful simply unable to advise what it should be and where or how to work it out I will speak with my responsible person and start the process of doing the calculations and working up towards ordering the blanks for the flanging plates from my very friendly laser cutter along with the material to start the tank ends . Riveted up one of the buffer beams this evening as when bought everything had been bolted together, Hi Jordan, Western Steam made 3 boilers for this loco in 2011 in one batch, they were all for members of our Society. With a working pressure of 100psi. There were some recommended changes to the drawings, material thickness and flanging of the front outer firebox to take the boiler barrel and super heater tubes. I will try and find a photo. John. |
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Post by johnthepump on May 10, 2016 8:35:33 GMT
Hi Jordan. Here are a couple of photos of my pony truck fabricated. As it was fabricated I decided to put the curved slot in the truck to try and stop ash getting in, as it would the way it is shown on the drawing. You asked about oiling, on these the oil point is behind the spring pocket and on one of the others he drilled up the axle and a cross hole to feed the bearing. John  09.05.2016 by John The Pump, on Flickr  09.05.2016 by John The Pump, on Flickr |
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smallbrother
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Post by smallbrother on May 11, 2016 7:46:26 GMT
Now As with many of us on here Ive a couple of projects on the go and recently an opportunity to aquire a part built Edward Thomas to the towyn model engineering design came about via ebay. Given the locos simple construction and smaller size than my other projects it fits nicely with a loco to teach my son on when hes old enough. Has anyone else built one and come up against any issues with the design? Certainly am looking to replace the axles with some that have a stepped wheel seat on them given that the drawing suggests just over a thou for this. also looking to flange the smokebox and saddle tank before riveting up Have sent Cylinder drawings away for quotation for a pattern to be produced Is this project from Stationroadsteam a reasonable buy in your view? www.stationroadsteam.co.uk/stock%20pages/6977/index.htmI am sure a boiler would cost a large chunk of the £4650 price. Pete. |
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Post by marshall5 on May 11, 2016 8:31:56 GMT
I would say it's a very good deal price-wise. I had a 4" scale Hunslet boiler from Helen 4 yrs ago and that was 4.3k if that's any guide.
Ray.
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johnthepump
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Post by johnthepump on May 11, 2016 8:44:22 GMT
Hi Pete,
Jordan said that he had got his from EBay, but the boiler on the SRS site is one of the three that I mentioned in this thread.
John.
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smallbrother
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Post by smallbrother on May 11, 2016 10:57:36 GMT
Hi Pete, Jordan said that he had got his from EBay, but the boiler on the SRS site is one of the three that I mentioned in this thread. John. Is the rest of the loco at SRS made by someone you know John? |
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uuu
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Post by uuu on May 11, 2016 16:42:17 GMT
The cylinders do show a feature that was promoted by a visitor to the Pump House (although they weren't made there): The covers fit into a step in the bore. This allows for a re-bore if required, and the covers still fit. Unlike the old B1 cylinders we bored out, where we had to make plates to get the covers to re-register.
John's own cylinders have yet to be machined. It remains to be seen if he incorporates this feature.
Wilf
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johnthepump
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Post by johnthepump on May 11, 2016 18:09:29 GMT
Hi Pete, Jordan said that he had got his from EBay, but the boiler on the SRS site is one of the three that I mentioned in this thread. John. Is the rest of the loco at SRS made by someone you know John?
Hi Pete,
There is a long story about these three locos, They had been advertised in the 7 1/4"G magazine, 3 set of parts chassis wheel sets, castings etc. Two of us drove to Billericay and bought the lot, with a third party interested. I had already made the chassis, so new was sold to a member, who chopped off the back and got me to weld it on the front, so he could make it into a battery electric. The same member then bought the third set of parts. we then commissioned the three Boilers. The original member after quite a lot of work on his decided at his age the project was going to much for him, so he thought the Society should buy it, to finish as a club loco. unfortunately no one wanted to be a team leader, the third member did some work on it along side work on his own. In the end the Committee decided to sell it.
The other to are still here. Mine has been on the back burner for a long time for several reasons, but I have now put on the get on with it list, may do a little to it when UUU turns up tonight in the Pumphouse.
The other one has now taken a back shelf, a boat rebuild is taking up his time at the moment.
John.
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smallbrother
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Post by smallbrother on May 11, 2016 18:37:23 GMT
Is the rest of the loco at SRS made by someone you know John?
Hi Pete,
There is a long story about these three locos, They had been advertised in the 7 1/4"G magazine, 3 set of parts chassis wheel sets, castings etc. Two of us drove to Billericay and bought the lot, with a third party interested. I had already made the chassis, so new was sold to a member, who chopped off the back and got me to weld it on the front, so he could make it into a battery electric. The same member then bought the third set of parts. we then commissioned the three Boilers. The original member after quite a lot of work on his decided at his age the project was going to much for him, so he thought the Society should buy it, to finish as a club loco. unfortunately no one wanted to be a team leader, the third member did some work on it along side work on his own. In the end the Committee decided to sell it.
The other to are still here. Mine has been on the back burner for a long time for several reasons, but I have now put on the get on with it list, may do a little to it when UUU turns up tonight in the Pumphouse.
The other one has now taken a back shelf, a boat rebuild is taking up his time at the moment.
John.
Thanks John, The reason I ask is that I am wondering about a blockbuster project before I get too old and/or pop my clogs. I would need an awful lot of professional input to complete it but I would be prepared for that expense to get something worthwhile. Apparently though someone is viewing the stuff at SRS tomorrow and may walk away with it. The lovely boiler makes it a bargain as far as I can see. Pete. |
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smallbrother
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Post by smallbrother on May 11, 2016 18:38:11 GMT
The cylinders do show a feature that was promoted by a visitor to the Pump House (although they weren't made there): The covers fit into a step in the bore. This allows for a re-bore if required, and the covers still fit. Unlike the old B1 cylinders we bored out, where we had to make plates to get the covers to re-register. John's own cylinders have yet to be machined. It remains to be seen if he incorporates this feature. Wilf Thanks for the info Wilf. Pete. |
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smallbrother
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Post by smallbrother on May 12, 2016 18:57:00 GMT
No surprise that the SRS chassis and boiler have gone today.
Pete.
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johnthepump
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Post by johnthepump on May 12, 2016 20:39:50 GMT
No surprise that the SRS chassis and boiler have gone today. Pete. Hi Pete, Something else will come up one day John |
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smallbrother
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Post by smallbrother on May 13, 2016 8:54:12 GMT
No surprise that the SRS chassis and boiler have gone today. Pete. Hi Pete, Something else will come up one day John Very true John. They have a 7 1/4" GWR 11XX as a project. Not an Edward Thomas by any means but it is the sort of thing I really like. Pete. |
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Post by jordanleeds on May 14, 2016 23:54:36 GMT
The cylinders as designed use a two piece casting with mounting flange separate I've got a friend who's good with 3d modelling currently redesigning these to be one piece as per the prototype with a view to having these then cast by a local foundry
In other news the rest of the frames have been stripped apart ready for a rather big riveting session once I've made up a backing plate to keep the rivet heads in shape
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