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Post by runner42 on Feb 16, 2015 22:14:18 GMT
I can't understand if you have sketched a part to make why you need to proceed to formalise it in a CAD programme, it adds nothing only the precision of straight lines and curves? By all means take the trouble to produce a CAD drawing if you need it to be approved by a third party or you want the convenience of a digitally stored record of what you have done.
Now back to Boxhill.
Brian |
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Post by Roger on Feb 16, 2015 23:37:26 GMT
I can't understand if you have sketched a part to make why you need to proceed to formalise it in a CAD programme, it adds nothing only the precision of straight lines and curves? By all means take the trouble to produce a CAD drawing if you need it to be approved by a third party or you want the convenience of a digitally stored record of what you have done.
Now back to Boxhill.
Brian Ok, my last post on this..... I promise.... It's all about visualisation, checking how it fits with other parts and keeping a record. 3D modelling is almost as good as having the assembly in your hands to turn and view from any angle, cut into sections and just generally have a good crawl over. It enables you to see if what you've modelled fits together and is in proportion. Once you're happy, the drawings and as many views as you like are created for you. All I have by my Lathe and Mill is a computer screen with all this on it. There are no paper copies of any drawings, I don't need them. The permanent record of what I've made is valuable to me though, I can pull up drawings of everything I've ever made for SPEEDY. It's just a different, paperless way of working, that's all. |
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Post by Rob on Feb 16, 2015 23:55:27 GMT
It enables you to see if what you've modelled fits together and is in proportion. That's the biggest advantage to me. When redesigning the buffer beams for my 15xx, being able to compare the 3D model to photographs was a great help in working out what should go where and what size everything should be in relation to everything else. If you have a photograph from a particular distance and angle, you can replicate that in 3D, and check if it looks right or not. |
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Post by runner42 on Feb 17, 2015 6:21:04 GMT
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jma1009
Elder Statesman
Posts: 5,923
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Post by jma1009 on Feb 19, 2015 15:34:37 GMT
a bit more progress, and another awkward outstanding job out of the way... here's the cab handrails. the lathe hadnt been touched since i made those new injector steam cones last month, so it was set up for this kind of job. as i was dreading making them i wanted to ensure that they were the correct diameters and shape. dan (steamingmess) very kindly measured up the cab handrails off one of the IOWSR terriers at Havenstreet for me. as expected, martin evans hadnt drawn or dimensioned them correctly. so a big thank you to dan for his help! the taper was turned on lengths of 1/8" dia nickel silver. the taper is something like 1/64" over a 3.5" length. each one was done in about 3 passes along the whole length, slowly advancing the crosslide dial a bit at a time and a bit more in the middle to deal with the spring in the rod. a bit of wet and dry removed any machining marks or errors on my part. then the bosses top and bottom were silver soldered on and turned, 10BA tapped hole in the bottom, and a spigot turned on the top to fit into a hole in the cab surround. cheers, julian   |
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Post by steamingmess on Feb 19, 2015 17:33:08 GMT
hi julian. your work looks fantastic as always. as ive said beore, if theres any more measurements you need then please let me know.
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Post by Roger on Feb 19, 2015 19:26:19 GMT
You may dread doing it, but it's most certainly worth the effort. It's these sort of details, like your firehole door, that catch the eye and really make it special. I wouldn't have thought of Silver Soldering the ends on, I think I would have make them from solid and taken much longer to get it done.
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Post by joanlluch on Feb 19, 2015 19:28:37 GMT
I can't understand if you have sketched a part to make why you need to proceed to formalise it in a CAD programme, it adds nothing only the precision of straight lines and curves? By all means take the trouble to produce a CAD drawing if you need it to be approved by a third party or you want the convenience of a digitally stored record of what you have done.
Now back to Boxhill.
Brian Have you seen the video I posted about my axle pump in the "lsfornells" thread? It is already assembled and moving before even having build a single physical part. That's the point. |
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mbrown
Elder Statesman
Posts: 1,796
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Post by mbrown on Feb 19, 2015 20:14:58 GMT
Did you set the cross-slide over a degree or two to do this? I have got good results on tapered handrails by doing them between centres using an offset centre in the tailstock (my old EW had a separate tailstock barrel with a centre point which could be adjusted laterally) - that way I could set the tailstock over by half the necessary reduction in diameter and get a uniform taper over quite a long length. Now I have got rid of the trusty EW and acquired an ML7, I was thinking of doing a similar job for the NBL Burma Mines loco by putting my boring head in the tailstock with a centre in it, offset by the right amount. I haven't tried this method yet and if you got good results with the cross-slide set at an angle, that may be easier than my method.
Malcolm
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jma1009
Elder Statesman
Posts: 5,923
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Post by jma1009 on Feb 19, 2015 21:08:22 GMT
thank you dan roger and malcolm.
malcolm, whilst i could have set the topslide over, it would have required a lot of faffing about plus nickel silver can do strange things sometimes. it would also have been extremely difficult to get the topslide close enough unless the tailstock was fully extended. plus i would most likely have had a bulge in the middle due to the spring in the rod. so i just did it by eye without using the topslide. i was listening to BBC radio 4 extra and i think the 4 lengths were done in just over the length of one of the 30 mins comedy shows, the first one as usual taking the longest time.
in fact the number of times i use the topslide is very rare!
cheers,
julian
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Post by Deleted on Feb 20, 2015 0:35:22 GMT
You may dread doing it, but it's most certainly worth the effort. It's these sort of details, like your firehole door, that catch the eye and really make it special. I wouldn't have thought of Silver Soldering the ends on, I think I would have make them from solid and taken much longer to get it done. ------------- Hi Roger, well that's the difference between a "Production" approach and the "Modeler's" one I would say... |
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mbrown
Elder Statesman
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Post by mbrown on Feb 20, 2015 22:24:34 GMT
Thanks for that explanation Julian. The tapers I have to turn are for the canopy supports for my BMR tender - as the canopy has to be taken off to drive the loco, I expect the supports to be a bit vulnerable so I am making them from stainless. They go from about 5/32" dia to 5/64" over a 3" length. If I try it your way, I won't be listening to humorous Radio 4 programmes in case I laugh and get a dig-in with the tool!
Malcolm
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jma1009
Elder Statesman
Posts: 5,923
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Post by jma1009 on Mar 2, 2015 23:21:41 GMT
as we are a bit short on construction stuff at the moment, and as ive done nothing in the workshop the last 2 weeks, and as Jim Scott has sent me some brilliant pics ive taken the liberty of adding them here! these are for Jim's own excellent 5"g terrier which is quite a bit more advanced than my own. awhile back i was pontificating to Jim how i much prefer proper leaf springs as the loco performs so much better on the track with them. i'd made my own split axleboxes to incorporate a central pin for leaf springs and made the connectors to the spring buckles. Jim had already made his as per Martin Evans, and then cut them up to make them split and replaced the coiled spring studs with a recess and pin for proper leaf springs. anyway here's the finished products, and i hope you will all agree Jim has made a very fine job of them! ive been putting off making them as it's quite a long job to get right - but well worth it in the end... so ive no excuses now not to follow Jim's excellent examples! incidentally we found the original detailed Stroudley drawings of same in 'The Engineering' magazine of 1873! cheers, julian    |
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Post by GWR 101 on Mar 3, 2015 7:33:56 GMT
Wonderful very neat and well engineered, sorry if this may seem a dumb question but what is the material used in the leaves. Regards Paul
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Post by ejparrott on Mar 3, 2015 9:43:37 GMT
Spring steel and Tufnol mix by the looks of it
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Post by miketaylor on Mar 3, 2015 9:48:13 GMT
Julian,
What is the approximate load carried by each spring and what are the dimensions of the steel leaves??
Also, do you know the designed deflection under working load?
Thanks
Mike
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Post by Jim Scott on Mar 3, 2015 10:03:04 GMT
Mike
Out all day today, (need to get away from these pesky springs!) I will add the info you have requested this evening.
Cheers
Jim
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Post by miketaylor on Mar 3, 2015 10:16:12 GMT
Many thanks Jim.
I need to get on with some work too!!!
Mike
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Post by ejparrott on Mar 3, 2015 11:27:53 GMT
...and me...!!
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Post by Jim Scott on Mar 3, 2015 23:32:37 GMT
Hi Julian
You are welcome to post the photos, but I had better make sure I send you better quality ones in future...
Many thanks for your kind words re Earlswood, both recent and in earlier posts. However I suspect it is no better constructed than Stepney and at my rate of progress certainly won't be finished first.
As I don't post much on your 'Boxhill' thread I'll take this opportunity to thank you for the extensive and valuable exchange of information, photos, materials and anecdotes over the past 3+ years.
Kind regards
Jim
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