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Post by Deleted on Oct 7, 2008 20:44:43 GMT
I thought perhaps you'd like to see some real progress, made out of scrap in the best LBSC tradition! After seeing JJ's fantastic rolling road I had to have one, but this one is a little more modest. The base rails are made from old rusting shelving supports, the 'bearings' are 1" alloy discs running on 5/16" brass journals, held up on 3/16" alloy strip, and the base is a bit of old chipboard! As I have a lot to catch up on I knocked this out yesterday. The wheels have yet to be finish painted dull and pressed on. Good fun this! JB  The quartering jig was today's output. It is a copy of Tim Coles' design, and very neat thing that is too. I cheated, and made it out of 3/8" alloy plate instead of steel, and I have some two thou brass shim to stick in place as wearing strips, if only I can find some superglue, but it should do the one off job required of it. The book says that one should make a good job of it, as other people will want to borrow it! That concludes the slide show, this week we quarter the wheels and make coupling rods..... |
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simonwass
Part of the e-furniture
Cecil Pagets 2-6-2 of 1908. Engine number 2299. Would make a fascinating model....
Posts: 472
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Post by simonwass on Oct 7, 2008 22:43:25 GMT
Why would you need wearing strips?
The crankpins only rest on the frame so you'd need to lend to a lot of friends to see any wear ;D
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Post by Deleted on Oct 7, 2008 22:47:21 GMT
True, but I suppose I distrust ally as a wearing surface!
Given your response perhaps I won't bother!
jb
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tbsteam
E-xcellent poster
Posts: 231
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Post by tbsteam on Oct 8, 2008 12:14:59 GMT
Are your eccentrics done, because you can't quater the wheels (driving) until they are on.
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Post by Deleted on Oct 8, 2008 13:09:27 GMT
Yup, eccentrics are done, but thanks for reminding me to put them on first!
JB
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tbsteam
E-xcellent poster
Posts: 231
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Post by tbsteam on Oct 8, 2008 13:21:36 GMT
I just thought because i am in the proccess of doing mine at the moment ready for quatering and coupling rods being fitted.
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Post by ettingtonliam on Oct 8, 2008 13:55:30 GMT
umm
Does a Britannia have eccentrics? I thought they had outside valve gear?
Richard
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Post by Deleted on Oct 8, 2008 14:05:47 GMT
Richard: it does have outside gear, but LBSC wanted a water pump and a lubricator as well!
JB
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tbsteam
E-xcellent poster
Posts: 231
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Post by tbsteam on Oct 16, 2008 10:42:20 GMT
JB,
Would you be able to scan the details of the quartering jig for me please?
Cheers
tb
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Post by Deleted on Oct 16, 2008 12:04:36 GMT
A pleasure TB. I hope Tim Coles doesn't mind me publicising his book 'A Beginner's Guide to Model Steam Locomotives'. I can recommend it to others, skilled or not!  |
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tbsteam
E-xcellent poster
Posts: 231
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Post by tbsteam on Oct 16, 2008 12:20:16 GMT
thanks for that JB.  |
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Post by Deleted on Oct 17, 2008 19:13:10 GMT
Here is the jig in action for real! I am pleased with it, but, on reflection, I should have made the gap for the wheels about 6mm larger. This is because it is not easy to see where the centres are when you are loading the wheels, and, I can assure you, you don't have much time to fiddle about before the Loctite goes off! It also helps for the wheels to be a free fit, so that that you can be confident that you are not straining anything - what am I saying? whilst aligning the crankpins. Oh, and yes, I remembered the eccentric AND the axleboxes!  |
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dva
Seasoned Member
Posts: 110
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Post by dva on Oct 22, 2008 20:15:50 GMT
Very impressive.
One thing I notice is that the 'slots' in the axle boxes have parallel sides. Whilst reading through the notes by Don Young on the construction of my 4F I found that he says that you have to allow a slight curve on the inside edges of the slot to allow for the loco axles being occasionally out of horizontal alignment whist the loco is running. He said that failure to allow for this could cause derailment.
What's you view on this ?
Dave
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Post by Deleted on Oct 23, 2008 7:05:29 GMT
Hi Dave. I have no opinion as I have yet to run the loco at some time in the distant future..... However, I understand the theory and I may well file a bit of radial relief on the boxes to prevent such a disaster!
Regards
JB
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Post by pcplod on Oct 23, 2008 10:08:09 GMT
Hi JB
Playing devil's advocate....
The jig is excellent for quartering, but would it not be a minor improvement to incorporate a couple of springs to make shure the back of the wheels were pushed up hard against the step on the axles to make sure they run true?
With wheels that diameter and weight, plus the clearance for the loctite, there is a possibility that the wheels may wobble a few thou at the rims.
Just a thought
Plod
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Post by Deleted on Oct 23, 2008 10:41:47 GMT
I take your point plod, but speed is of the essence, and I'm not sure one would have had time to connect springs as you suggest. I might have got over the problem because the wheels weren't slack on the axles: one wheel was a genuine press fit, the other stub axle turned so that the wheel was a good push fit for the last 2mm. There was no discernable wobble, but I dare not say 'Nuff Said' anymore. I'm doing the piston valve sleeves right now, and as they say in China, 'I'm living in interesting times'!
Regards
JB
PS, I was plod myself once, 32 years ago at Wembley. I only lasted a year. The last memorable occasion was at the 1976 Notting Hill Carnival, facing rioters and clearing streets at 2.30 in the morning!
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Post by baggo on Oct 23, 2008 16:10:48 GMT
One thing I notice is that the 'slots' in the axle boxes have parallel sides. Rather surprisingly, that's how LBSC described making them. There is no mention of radiusing the flanges of the boxes to allow them to tilt. I think you'll (JB) need to allow some freedom of movement for when the wheels are going over the 'Umps and Ollers' otherwise the boxes will probably jam. I tend to use axle boxes with just a single flange on the outside and forget the inside one. The axle box can't move far outwards as the wheel stops it and it can move sideways slightly when it tilts. I've read somewhere that it is better to make the inside of the flange 'V' shaped rather than a curve as this makes it less liable to jam when it tilts. Haven't tried this yet though. John |
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Post by Deleted on Oct 23, 2008 20:09:44 GMT
Thanks John, I'll certainly bear your advice in mind the first time I fall off! Here are the piston valve sleeves complete with end caps: two quite solid days' work. When I started this loco I honestly didn't realise how 'chunky' some of the bits are. If the caps look a funny colour it's because they are made of Aluminium Bronze! I selected it from my 'large brass' box and I thought it was a bit tough, but I just carried on regardless: it wasn't until I spoke with a certain mechanical fastener on this forum that I was enlightened as to my mistake. If you look closely at the LH cylinder casting you can see where I put in the liner following the blowhole discovery. Oh well, I WILL do the coupling rods soon......  I did the slots in the vice and used a slightly undersize carbide 3-slot drill. To ensure the slot flats were just about parallel I scribed a line on the end of the sleeve and used a square on the bed to align it. I have just to file up the exhaust ports.  |
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Post by baggo on Oct 23, 2008 23:31:11 GMT
Looking really good JB, you're really cracking on!  Any thoughts on the valves? Plain or PTFE? John |
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Post by Deleted on Oct 23, 2008 23:32:59 GMT
PTFE! But what are your consultancy rates? I'm only a poor old pensioner....
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