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page 5


buffalo

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Buffalo WorkBench

 

by buffalo

 

original page on Old RMweb

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This is the fifth and final page copied from the old RMweb.

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??? posted on Tue Aug 11, 2009 10:47 pm

 

LNWRmodeller wrote:

I've no doubt you'll get a variety of advice, including machining new ones from rare metals.
icon_smile.gif

 

You could start by asking Colin Seymour of AG to supply some more. Then, carefully ream out the axle holes slightly with a 1/8" parallel reamer, so that they are an easy push fit onto the axle. Fit them using a suitable retainer adhesive - I don't know if Loctite 243 is correct for plastics. According to their website, Ultrascale supply 603. I suggest you check the Loctite website.

No rare metal suggestions yet icon_smile.gif but I will ask Colin to send me some more. I'm hoping that you have the answer here and that they were just a bit too tight when I fitted them. Fortunately, there were a couple of spares in the kit, so I have now fitted one of these as you suggest by making it an easy rather than tight fit on the axle. I'll leave it another 24 hours to see whether it develops a crack. I'll also post a query on the Q&A forum to see if there's any more experience of success of failure out there with these particular cranks.

 

btw, 243 is the threadlock retainer. I used this only for the Gibson crankpin screw and that doesn't seem to have caused any problem. The cracks are spreading towards this hole, rather than from it. I've used this before to fit both Gibson and Ultrascale crankpins to their respective wheels without any noticeable problems. I used 603 to fit the cranks to the axles and, again, I've used it before to secure both makes of wheel to their axles. I did check the Loctite spec sheets as you suggested and for both of these compounds they say

"This product is not normally recommended for use on plastics (particularly thermoplastic materials where stress cracking of the plastic could result). Users are recommended to confirm compatibility of the product with such substrates."

I'll see if Colin has any comment on this as I'm sure he will know what type of plastic is being used.

 

Miss Prism wrote:

Not sure about machining new cranks from, err, 'rare metals', and I agree with Jol about trying again with another AG set - failing that, you could investigate Martin Finney's outside crank etch, which is a 3-layer-laminate, but I think that crank etch might be for turned down 2.5mm axle ends, so would require quite a bit of careful jigging, drilling and reaming etc to get them all the same. I think Martin's cranks will at least be a better overall size and shape.

I haven't seen Martin Finney's cranks, although a couple of his outside framed products are high on my wish list. Your mention of the reduced size of the axle ends made me wonder about the size of the prototype cranks, something I hadn't questioned before. It appears from the drawings in Russell that the axle end of the crank is about 12" diameter with a 6" axle end, much smaller than the Gibson cranks. Presumably the ends were turned down on the prototype axles as well, as I would have expected around 9" for the bearing journals. Unfortunately, I don't have any large scale drawings of suitable prototypes to hand to confirm this. If my estimates are anywhere near correct, I suspect the Finney cranks would certainly need some "careful jigging, drilling and reaming" and I wonder whether they could be made to fit a 1/8 axle.

 

Bertiedog wrote:

I have dropped you a PM about the cranks

Thanks, Stephen, see my reply.

 

So, the current plan is to see how the test with a single Gibson crank works out and, in the meantime, contact Colin about the problem. Hopefully, I'll manage to get the plastic cranks to work. After all, others must have done this... If all else fails maybe I'll have to think about making my own cranks.

 

Nick

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Comment posted by Craigw on Tue Aug 11, 2009 11:16 pm

 

Nick,

 

All the Martin Finney OF loco kits are supplied with multi layer laminated outside cranks. These are intended to be used with a special turned down axle that Ultrascale supply - I assume it is the same situation for the cranks he supplies as a spare part. I have not looked at the Gibson outside cranks, but the Finney ones certainly look close to scale to me.

 

You could order the Finney cranks and order the axles from ultrascale albiet that the wait for the latter may be significant.

 

Well done on the Buffalo, looks very nice indeed. I am severely tempted to get one to add to my wall of death.

 

regards,

 

Craig

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??? posted on Sat Aug 15, 2009 9:30 pm

 

After a discussion in the QQH&A forum, I've decided to get another set of the Gibson plastic cranks and fit these with Loctite 603 after carefully reaming them to size. My error appears to have been pressing them on when they were too tight, hence the splitting.

 

Leaving aside the chassis for the moment, I've been doing a bit of work on the cab and bunker. As supplied, the bunker front had a representation of a sliding coal hole door and two sandbox levers which were linked by a rod so that they could be operated together (see photo in this post. I've only found a couple of examples of prototype photos with this link arrangement, both after rebuilding as panniers, and plenty of evidence that the independent levers were the norm. All the indications are that the coal hole door was a simple flap and the vertically sliding door with prominent runners is, largely, a later feature. Similarly, the prominent rivets on the casting are not visible in any photographs. I am reasonably convinced that a raised floor, as intended in the kit, is probably mythical (see this post and another discussion in QQH&A), and that these engines had what seems to be the normal Dean tank arrangement of two sandboxes in front of the bunker and partially blocking the cab entrances.

 

The result of all this is that I have filed and sanded off all of the features on the front of the bunker, replacing them sith a simple flap and a pair of fabricated sanding levers. The cab sandboxes appear from photos to be placed with their long axis across the cab and to be a bit smaller than those at the front of the footplate. So, instead of ordering another pair of castings from Colin, I decided to make my own. Instead of the raised floor supplied in the kit, I have made up a wooden floor from 1mm thick basswood sheet to represent a simple planked floor directly on top of the footplate.

 

The current state of the cab can be seen in these photos:

 

blogentry-6746-12561500861303.jpg

 

blogentry-6746-12561500895845.jpg

 

blogentry-6746-12561500927552.jpg

 

The eagle-eyed will also notice that I've added the springs to the footplate. I was in two minds about these castings as they are not really of a modern standard. They are a little too short to match up with the spring shackles beneath the outer frames, there is no attempt to represent the leaves of the springs, and the match between the mould halves is quite poor.

 

blogentry-6746-12561500824068.jpg

The even more eagle eyed will notice that I missed one of the rivets... Actually, this photo shows the back of the casting but the only difference is that the front has a representation of the pins on the hangers.

 

I did consider searching for alternatives and even fabricating my own, but the thought of cutting and mounting 60 pieces of shim for the ten-leaf springs was a bit daunting. In the end, I decided I could always replace them later if I found a supply of better ones. Fitting them led to a small problem: it is not possible to feed them through the holes in the cab front, so I had to cut the rear springs in half and fit one part from the front and the other inside the cab. Ideally, then, they should be fitted before the cab. However, I would not be happy about adding white metal components so close to a point where I intended to use a high temperature solder, so the cab would probably need to be attached to the footplate with 100 or perhaps 145 degree solder.

 

Nick

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??? posted on Sat Aug 15, 2009 9:38 pm

 

Craigw wrote:

...You could order the Finney cranks and order the axles from ultrascale albiet that the wait for the latter may be significant.

I'm tempted to try these but, as I hope to get either a Stella or a Duke from Martin Finney in the near future, I think I'll leave it until I've seen how they are intended to be used (assuming I can get the Gibson ones to work). It would be easy enough to turn down the ends of Gibson axles, or make new from silver steel rod if I wanted to avoid the expense and wait for Ultrascales.

 

Well done on the Buffalo, looks very nice indeed. I am severely tempted to get one to add to my wall of death.

Thanks icon_biggrin.gif Your "wall of death" conjures up images of an entire loco fleet with their wheels glued to the wall, either that or very unprototypical speeds... icon_wink.gif

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Comment posted by Bertiedog on Sat Aug 15, 2009 10:52 pm

 

If you have access to a lathe, then springs are a doddle, no need for shims etc, just take a brass disc of the diameter to match approx the radius of the top of the spring, and mount on a face plate with super glue.

 

A series of very fine lines are machined on to the face of the disc, matching the spacing of the springs. The disc is made as thick as the scale springs need, remove with heat from faceplate, and the all you have too do is cut up each "spring" to length, and then notch file each step of the under side of the springs, really does not take long. The whole "spring" can than be annealed and bent to the compound curve the real things have, in over words the ends are at a tighter radius, and have the shackles, and main spring rod, soldered on etc.

 

No shims, no parts except shackles and they look 100% accurate.

 

Stephen

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??? posted on Sat Aug 15, 2009 11:20 pm

 

Excellent, thanks Stephen icon_thumbsup2.gif That's one of those 'blindingly obvious but only when you know how methods'. I just hadn't been thinking about it from that direction. Even so, I've cut balance weights out of a circle before now, so I should have thought of something like this...

 

Nick

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Comment posted by Miss Prism on Sat Aug 15, 2009 11:36 pm

 

Really like that cabwork, Nick, but what gives with the brass rod outrigger?

 

Concerning the springs, I don't think the lack of leaves is that noticeable after a coat of paint, and possibly the only real visual problem is the 'filled in' section between the shackles. They can be drilled/filed out, but...

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??? posted on Sat Aug 15, 2009 11:44 pm

 

Miss Prism wrote:

Really like that cabwork, Nick, but what gives with the brass rod outrigger?

Thanks, Miss P. For some reason, I really like doing cabs. My 14XX/48XX is full of quite invisible details when the roof is on, but I know it's there and comments like yours really help to make it worthwhile icon_smile.gif

 

The brass rod is the start of the outside mounted shut-off lever for the sight glass, a common GWR feature of the period as I'm sure you're aware. In the first photo you may be able to see the other end fitting into a hole in the top of the sight glass.

 

Concerning the springs, I don't think the lack of leaves is that noticeable after a coat of paint, and possibly the only real visual problem is the 'filled in' section between the shackles. They can be drilled/filed out, but...

You're right about the paint and and the filled-in bit. They are only stuck on with a tiny spot of epoxy so, if it bothers me, I'll give Stephen's idea a try.

 

Nick

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??? posted on Fri Aug 28, 2009 10:56 pm

 

A quick update on progress. The chimney is now attached to the tanks, but the dome and safety valve cover will not be fitted until after painting as I want them to be removable for polishing, if needed. The motor cutout in the underside of the boiler has been filled in and a front panel for the firebox added so that the motor and gearbox will be completely hidden. The various details were added to the underside of the tanks, including the injectors and balance pipe. Some short pieces of 0.5mm bore tubing were added in front of the balance pipe and matching holes drilled in the footplate. Together with some 0.45mm wire, these will form the fairly prominent pipes running down to rail level. I read somewhere that these were for washing the railhead, is this true, if so why?

 

The front sandboxes and toolboxes were added next before soldering the tank/boiler unit to the footplate. The pipe flanges at the bottom of the injectors had previously been drilled 0.75mm and matching holes drilled in the footplate. Once the boiler had been mounted, short pieces of 0.7mm wire wire inserted through through the footplate and into the injectors to represent the exhaust pipes (I assume that's what they are) which emerge from behind the outer frames. I've noticed that many of the saddle tanks had these pipes passing through the footplate like this though, after conversion to pannier tanks, the pipe is often routed over the top of the footplate.

 

blogentry-6746-12561501528156_thumb.jpg

 

So, not much remains to be done on the body. The whistles need to be added to the cab roof but, unfortunately, the castings supplied with the kit are the wrong type. They have a right angle bend immediately below the whistle parts so that the pipes can pass through the cab front. Whereas this pattern in common on later GWR designs, most, if not all, Dean era engines had the whistles passing vertically through the cab roof. I don't think there is a Gibson casting for vertical whistles, but I'll have to check with Colin to see if they have an alternative available or, failing that, fabricate my own as I did for the 48XX. Had I known, I could have used these for that model...

 

Other outstanding parts are the old style lamp sockets. I ordered some of the LNWR type which should be quite similar to the GWR pattern from London Road Models some time ago but, although everything else from the same order arrived quite quickly, these are still outstanding. I'll have to contact them again to see what's happening.

 

Nick

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??? posted on Mon Sep 07, 2009 10:39 pm

 

buffalo wrote:

...Other outstanding parts are the old style lamp sockets. I ordered some of the LNWR type which should be quite similar to the GWR pattern from London Road Models some time ago but, although everything else from the same order arrived quite quickly, these are still outstanding. I'll have to contact them again to see what's happening.

Just a quick update to record my thanks to Jol Wilkinson (LNWRmodeller) and John Redrup of London Road Models icon_thumbsup2.gif After my last post, I received an email from Jol about the missing lamp irons and within hours the problem was sorted. It turned out that John had sent the castings with a copy of his catalogue, but the package arrived looking like the postman had given it to his dog to play with and without the lamp irons. Once it was realised what had happened, John immediately posted a replacement and these have arrived safely today icon_biggrin.gif So one of my next tasks will be some minor adaptations to make them look more like the GWR pattern lamp sockets.

 

Nick

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