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Post by arch1947 on Sept 23, 2014 22:07:09 GMT
Hi Everyone, Some time ago someone showed a very good way of making the "U" parts of a screw link coupling but I can't find it. Can anyone help?
Thanks,
Arch
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Post by Deleted on Sept 23, 2014 22:31:31 GMT
hi Arch... check either Jim's or JB's (simplyloco) build threads... i thought I had detailed it in my own but on checking I seem to have covered everything except forming the 'U'...lol
Pete
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Post by Jim on Sept 23, 2014 23:48:31 GMT
Hi Arch, While I made my own screw link couplings for Boadicea I don't think I ever detailed making them on the thread. I shall go and have a look at my notes as I have to make a new screw link for the tender. Perrier's drawings have the length of the U too short to clear the end of the hook. I also included a gedge to allow the whole coupling to be removed. Jim edit: Looking at Pete's comments I know it can't have been my thread, I always come up with the most complicated way doing a task.  I'll still check though. |
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Post by Jim on Sept 24, 2014 0:41:00 GMT
Will wonders ever cease? I went through my files and found I had in fact kept sketches and notes for making the screw coupling. Just to clarify the ss in the second sketch refers to silver solder and the 'Alxxx' bar should read 'bar used to align the ends of the U.  Hope this all makes sense.  This is J Perrier's drawings for the screw coupling along with my notes. The 'Correct size for 5"g' is an enlargement I made to glue to a blank as a pattern to follow when cutting out.  The screw coupling completed and in place.  Jim |
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jma1009
Elder Statesman
Posts: 5,901
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Post by jma1009 on Sept 24, 2014 2:46:06 GMT
hi arch,
this thread is very relevant and so pleased you raised it!
on GWR locos the drawhooks have slots for the 'U' to slide into with their eyes on the ends - but on STEPNEY the hole in the drawhooks is just over the diameter of the 'U' without the eyes on the ends if this makes sense, so i will have to silver solder the eyes on the end after slipping through the hole in the drawhook. ive never had to do this before!
as per jim, ive made the eyes on each side of the 'U' a single piece relieved in the middle when silver soldering together, then cut out the relieved portion. a similar proceedure is used for the eyes on the ends of smokebox door hinges.
as ben has very kindly confirmed recently for me the SR type coupling on STEPNEY has a tommy bar in the middle with a R-H and L-H thread either side. this isnt something im looking forward to! nor am i looking forward to cleaning up and repolishing the drawhooks after silver soldering the eyes to the 'U' when fitted in same!
cheers,
julian
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Post by Jim on Sept 24, 2014 3:53:49 GMT
Having to add the eyes to the U after fitting through the hole in the hook really makes an already fiddly task even more difficult. I glad it's you and not me Julian.
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Post by ejparrott on Sept 24, 2014 9:06:58 GMT
Ahhh the joys of narrow gauge....one enormous centre buffer coupler and I'm done!
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Post by arch1947 on Sept 24, 2014 22:31:19 GMT
Thanks Everyone, Give me something to chew on.
Regards,
Arch
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jma1009
Elder Statesman
Posts: 5,901
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Post by jma1009 on Sept 24, 2014 22:48:37 GMT
hi arch,
proper scale screw link couplings are a real pain! they cant be used so just for appearances sake, yet are so prominent that worth reproducing properly but they take a lot of time to make. John (simplyloco) has added/repeated his description of how he made his lovely screw couplings today on his Brit thread.
i wish the SR type were as straightforward as the GWR/BR type! thanks jim for your condolances!
cheers,
julian
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steam4ian
Elder Statesman
One good turn deserves another
Posts: 2,069
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Post by steam4ian on Sept 24, 2014 23:57:35 GMT
G'day Arch.
I think I'd take the hint from the name you gave to this thread, screw link couplings, and go for automatic couplers instead.
Helpfully yours
Ian
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Post by arch1947 on Sept 25, 2014 2:37:20 GMT
G'Day Ian, I am inclined to agree.
Regards,
Arch
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Post by ejparrott on Sept 25, 2014 9:29:06 GMT
GL5 use 3-link and screw link couplings all the time, so it's not true that they 'can't' be used.
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Post by Jim on Sept 25, 2014 10:46:12 GMT
When it's said screw link couplings can't be used I think it's in reference to passenger hauling. Three links and screw couplings are certainly used in trains of scale rolling stock here.
Jim
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jma1009
Elder Statesman
Posts: 5,901
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Post by jma1009 on Sept 25, 2014 10:59:27 GMT
 here's a pic of one of the screw link couplings fitted to my 5"g GWR 57XX loco. jim's method of construction is what ive used - you cant 'spring' the 'U' with eyes attached over the block that fits between (or at least ive never been able to do this!) cheers, julian |
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Post by fostergp6nhp on Sept 25, 2014 15:34:00 GMT
Use heat so there is no spring, it's how the full size were done.
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Post by Jim on Sept 25, 2014 22:16:34 GMT
I like the jointed end to the 'tommy bar' on the coupling's screw adjuster Julian, that's a very nice attention to detail I must say. Sorry, I can't think of the correct technical terms..old age? Jim |
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I'll still check though.
