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posted: 5 Dec 2010 08:22 from: roythebus
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A bit of advice needed here, having nearly finished my track plan, I've started building a double slip using C&L components in OO gauge. Is it recommended to use PCB sleepers in certain places such as under the K crossings as this would seem a weak spot, and it is difficult keeping things in alignment just using the C&L plastic chairs glued to plastic sleepers. Also, does anyone make a V crossing jig as I have to make about 50 for my layout and to use the ready made C&L units would be rather beyond my pocket! |
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posted: 5 Dec 2010 13:06 from: JFS
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You can't solder rail directly to PCB sleepers as they will support the rails at a lower height than the chairs. I always use small brass or N/S strips to secure the different bits of rail which comprise the crossings. These can then be secured to the (plywood) sleepers using Exopy. It has the advantage that the rails are electrically bonded in the process and makes very strong trackwork. I get the strip from fret waste chosen to support the rail at the same height as the chairs. (I did read an article - in MRJ? - where someone used PCB strip for this exact purpose - but why - no insulation is needed). You can see from the pic that I use chairs slipped on the ends of the rails to hold the rail "vertical" - this makes the job doable with only two hands! I would recommend the Exactoscale special chairs for diamonds and slips - they look excellent. Just be aware that the timbering for these seems to be slightly different from that produced by the default Templot settings (don't know why - Martin?) A massive advantage of using Templot is that you can print off a second version of the template on which to assemble the crossings without the sleepers in the way - I stick these to a piece of flooring laminate. You can very acurately mark the rails for length then cut them using a piercing saw although I only cut entirely through the rails where electrical gaps are needed using the Exactoscale insulating fishplates as you can see in the pic. Using this approach I have never needed jigs for crossings - most of mine have been to odd angles or been curved in anycase - but do make a simple wooden clamp to hold the rails for filing. (as per the very original Protofour method - available via the Scalefour Soc website) Best regards, Howard. 1129_050750_130000000.jpg 1129_100905_120000000.jpg |
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posted: 5 Dec 2010 13:28 from: roythebus
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Thanks, that's more or less what I thought. I didn't think about using scrap brass fret, I've lost track of how much of that I've chucked out recently! | ||
posted: 5 Dec 2010 14:10 from: JFS
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... couple more pics of the same job. 1129_050831_500000000.jpg By the way, this pic was taken BEFORE the crossing was positioned and fixed down - you will of course be more careful to get the base strips more acurately positioned!! Next time, I will leave the strips over length, blu-tac them to the template then cut then off flush to the railside after the job is finished. And the finished slip... 1129_050833_500000000.jpg This formation - in P4 - is all at 1:6 and curved to produce a 36" minimum radius (with 0.2mm gauge widening and continuous check rails). If my 28xx and 9F will go through this, they will go anywhere... One other tip to help you get nicely flowing curves - I always "pre-curve" a longer length of rail to the radius of the completed formation, then cut pieces, file the angles then assemble the crossings with the rails still over-length. Only then, when everything issoldered up, do I use the piercing saw to cut the rails accurately to length. You can use bits of blu-tac to hold the rails and chairs to the template while you solder everything up. You will see from the pics that I soldered up a complete assembly of the K crossing and the two adjacent switch / stock rails and then split the crossings from the switch blades in so that they could be reassembled with the insulated fishplates. I hope that is all clear, I am about to start something a bit more complex, so I anyone is interested, I could take a few pics to show how I do it. (not that my way is the only / best way - just it works well for me). This kind of fiddling about does not suit everyone - but I like building nice looking track for the same reason that I like building Martin Finney loco kits!!! This was a "test Track", and I experimented with the templates stuck directly to the baseboards (no underlay) and the sleepers glued directly and permanently to the Templates (after they had been shellacked to keep them from cocking under the glue). It builds amazingly accurate track but the noise levels are of course a bit higher than track fixed to underlay. Yes, the point rodding is fully functional, (you can see two working compensators in the pic) but then this was just a "test track" - not sure it would be practical for a more complex layout or a real operational environment - every time you trail through a wrongly set point, you knock the rodding out of adjustment! I used the rather beautiful Ambiss stretchers. Best Wishes, Howard. |
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posted: 5 Dec 2010 17:39 from: Jim Guthrie
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roythebus wrote: Thanks, that's more or less what I thought. I didn't think about using scrap brass fret, I've lost track of how much of that I've chucked out recently!C&L actually supply PCB strip for the job which is 0.6mm thick which matches the distance between sleeper and rail bottom which their chairs set. It is Part No. 4ZC101A at the bottom of the 4mm track web page http://www.finescale.org.uk/index.php?option=com_virtuemart&Itemid=51#fishplates Jim. |
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posted: 5 Dec 2010 19:25 from: JFS
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Indeed Jim, but given that it will only be glued to wood, and electrical continuity horizontally is a positive need, why use PCB? For me, where tiny pieces are subjected to my heavy handed wielding of the soldering iron I don't trust that there is any strength left in the bonding! So for me, 24 thou fret waste is better for the job as well as being free :-) Having said that, perhaps there are those who build track but not etched kits? Perhaps Brian should offer brass or NS strip as an alternative:-) Best Wishes, Howard |
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posted: 5 Dec 2010 20:31 from: Jim Guthrie
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JFS wrote: Indeed Jim, but given that it will only be glued to wood, and electrical continuity horizontally is a positive need, why use PCB?Howard, It could be that Brian at C&L could get PCB which was the correct thickness and which could easily be cropped into strip form - probably by the person who crops PCB sleepering. Getting narrow metal strip in thicker gauges is not all that easy. I model in S scale and I was looking for 0.7mm metal strip to do the same job and I was not successful in finding strip at the prices I was prepared to pay. The easiest way to guarantee flat strip would probably have been to etch it from sheet, but the setup costs for doing that were very high. I finished up using brass boiler band strip sold by model engineering firms for larger scale steam locomotives. It is nominally 22swg, which is the correct 0.7mm/28thou thickness, but it is concave across its width due to the shearing operation and is more like a nominal 30thou. I have to draw file the strip to get it to actual 28thou. So C&L PCB strip might be the cheapest way of achieving a marketable product. Jim. |
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posted: 5 Dec 2010 20:45 from: mike47j click the date to link to this post click member name to view archived images |
I've used a mixture of plastic and C&L laser cut strips for timbers. I've glued bits of thin brass strip (the same height as a chair lifts the rail) to the timbers in places that can't take chairs but need the rails to be fixed. Then trimmed the end of the brass off where half a chair can be fixed, but then I'm working in 7mm which is probably a lot easier to work with. Mike Johnson |
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posted: 5 Dec 2010 22:41 from: JFS
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Jim Guthrie wrote: Getting narrow metal strip in thicker gauges is not all that easy. You surprise me a bit Jim, but then, we can take nothing for granted these days! I will have a trawl round a few places and see what I can find, then report back. Best Regards, Howard. |
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posted: 6 Dec 2010 21:29 from: JFS
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JFS wrote: Jim Guthrie wrote:Getting narrow metal strip in thicker gauges is not all that easy. I had a quick look at K & S, and their .026" by 1/4" brass is £1.05 for a foot. Albion alloys is £4 for 4 foot for 0.25", I agree that's a bit steep - but then we don't need huge amounts and at least it is easy to get hold of. Just looking at Brian's site, the PCB is about 1/4 the price but I would still use the brass even if I had to buy it! One thought - it might be worth contacting a few of the etched kit suppliers (or even builders) to see if they have fret waste to "give" away - especially those who do 7mm coach kits - I am fairly sure the stuff I am using came from a 7mm Comet Models kit I built about 25 years ago! Best Wishes, H |
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posted: 6 Dec 2010 22:18 from: Richard Spratt
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JFS wrote:One thought - it might be worth contacting a few of the etched kit suppliers (or even builders) to see if they have fret waste to "give" away - especially those who do 7mm coach kits - I am fairly sure the stuff I am using came from a 7mm Comet Models kit I built about 25 years ago!Roxey Mouldings always has a box of brass offcuts on their stand which might have what you are looking for. |
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posted: 7 Dec 2010 13:58 from: Jim Guthrie
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JFS wrote:Howard,Getting narrow metal strip in thicker gauges is not all that easy.You surprise me a bit Jim, but then, we can take nothing for granted these days! I will have a trawl round a few places and see what I can find, then report back. Maybe I should have set out all the parameters for the strip. I was looking for a product which could be sourced for the Parts Department of the S Scale Society, so it had to be accurate thickness - 0.028"/22swg/0.7mm - it should be the same width as the base of the society's new plastic chairs, and it should be flat. I did approach commercial suppliers and a solution which would give all three requirements was etching from sheet. However our projected requirement for the product was quite low and that meant that the setup costs for etching made the product too expensive. Someone with a larger requirement for the product might find the etching process viable. Another method I could have used myself was to set up a flat sheet in my horizontal mill and use a slitting saw to cut as many strips as I required, and that might be a way to go if a small amount is required. At the moment I just draw file the soft brass boiler band strip which gives me what I want, and takes a lot less time than setting up a milling machine. Jim. |
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posted: 7 Dec 2010 15:18 from: Stephen Freeman
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Hi, Slightly thicker than you want but could have one side etched off is this 0.79mm PCB Stephen |
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Last edited on 7 Dec 2010 15:19 by Stephen Freeman |
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posted: 7 Dec 2010 15:34 from: Jim Guthrie
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Borg-Rail wrote: Slightly thicker than you want but could have one side etched off is thisI actually did find 0.7mm PCB on the web but the suppliers seemed to be based in China and I reckon that they probably preferred to sell acres of the product rather than a few square inches. Jim. |
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posted: 7 Dec 2010 16:26 from: JFS
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Jim, Jim Guthrie wrote: I was looking for a product which could be sourced for the Parts Department of the S Scale SocietyAh, that does make a difference! What width are you looking for? Is it not possible to find an outfit with a precision guilotine who could chop up a sheet or two of half hard brass? It sounds like the boiler band strip has been through a coil slitter which, not being a precision process and coupled with the softness of the material will induce the curl. But etching - let alone milling - sounds like technical overkill and hand filing sounds like hard work - do you not have a planishing hammer Just out of (even more off topic) interest - was the set up cost for the etching for the use of direct electronic tooling? When I checked (with Chempix) a few years ago direct printed resist was much cheaper than photo tooling if you only wanted a single sheet or two. H. |
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posted: 7 Dec 2010 16:43 from: Stephen Freeman
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Hi, This guy is actually based in Canada and will happily sell you a single sheet, though not sure how much postage would be. Stephen Jim Guthrie wrote: Borg-Rail wrote:Slightly thicker than you want but could have one side etched off is thisI actually did find 0.7mm PCB on the web but the suppliers seemed to be based in China and I reckon that they probably preferred to sell acres of the product rather than a few square inches. |
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posted: 7 Dec 2010 22:33 from: Jim Guthrie
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JFS wrote: Just out of (even more off topic) interest - was the set up cost for the etching for the use of direct electronic tooling? When I checked (with Chempix) a few years ago direct printed resist was much cheaper than photo tooling if you only wanted a single sheet or two.Howard, I'm afraid I'm not sure what method would have been used but I think I remember discussion about the cost of a photo tool. I'm assuming that direct electronic tooling might be exposing an image onto a photo sensitive etch resist - a process I recognise from one off electronic PCB manufacture. However, I must thank you and Stephen for your interest in the matter. At the moment, nearly all of my pointwork has been constructed using the boiler band and the S Scale Society's Parts Officer hasn't flagged up a demand for the product as yet so I don't have an incentive to proceed further as yet. So I am taking note of what has been suggested just in case I get a call sometime soon. Jim. |
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