RMweb Gold Roy Langridge Posted May 24, 2019 RMweb Gold Share Posted May 24, 2019 On 23/05/2019 at 17:43, adb968008 said: Wouldnt it be easier just to get a chassis and have a casting made from it ? someone did that a while back for a Grange, the costs I recall were very low and the casting good for hundreds. If doing it commercially it maybe wise to ask Hornby first, but if it was a private venture between a limited few subscibers I wouldnt have thought it an issue. Peters spares have produced some parts off their initiative, the gearbox casing of the T9 was one, which was mazak prone, they made a replica in brass. To be honest, I don't see how that would work. When you make a pattern for casting to you have to allow for shrinkage as the cast metal cools. If you create a mould from a finished piece as the pattern, anything that you cast from that will be small. Looking at the figures, brass shrinkage is about 1.5%, cast iron 1% and cast steel 2%. The resultant casting may well need to be machined as well, and there would be no "spare" for machining. A CNC milled chassis, if it can be simplified from the Hornby chassis, would be much more reliable and easily produced to order. Roy 1 Link to post Share on other sites More sharing options...
Fat Controller Posted May 24, 2019 Share Posted May 24, 2019 21 minutes ago, Roy Langridge said: To be honest, I don't see how that would work. When you make a pattern for casting to you have to allow for shrinkage as the cast metal cools. If you create a mould from a finished piece as the pattern, anything that you cast from that will be small. Looking at the figures, brass shrinkage is about 1.5%, cast iron 1% and cast steel 2%. The resultant casting may well need to be machined as well, and there would be no "spare" for machining. A CNC milled chassis, if it can be simplified from the Hornby chassis, would be much more reliable and easily produced to order. Roy How feasible would it be to use a CNC-milled chassis as a pattern, having made it the requisite amount oversize? Link to post Share on other sites More sharing options...
RMweb Gold Roy Langridge Posted May 24, 2019 RMweb Gold Share Posted May 24, 2019 1 hour ago, Fat Controller said: How feasible would it be to use a CNC-milled chassis as a pattern, having made it the requisite amount oversize? That is feasible, but I don’t see the advantage of casting something you have a design to mill. If it is set up for CNC, just create more... Roy 1 1 Link to post Share on other sites More sharing options...
bigherb Posted May 25, 2019 Share Posted May 25, 2019 18 hours ago, Roy Langridge said: To be honest, I don't see how that would work. When you make a pattern for casting to you have to allow for shrinkage as the cast metal cools. If you create a mould from a finished piece as the pattern, anything that you cast from that will be small. Looking at the figures, brass shrinkage is about 1.5%, cast iron 1% and cast steel 2%. The resultant casting may well need to be machined as well, and there would be no "spare" for machining. A CNC milled chassis, if it can be simplified from the Hornby chassis, would be much more reliable and easily produced to order. Roy I have had replica car parts cast from originals. The casters apply a wax to the original to increase the thickness of the original to allow for shrinkage. 1 Link to post Share on other sites More sharing options...
Pandora Posted June 28, 2019 Share Posted June 28, 2019 With the 31 back into production, do we know of a part number for the chassis block as a spare part? Link to post Share on other sites More sharing options...
RMweb Gold Roy Langridge Posted June 28, 2019 RMweb Gold Share Posted June 28, 2019 4 hours ago, Pandora said: With the 31 back into production, do we know of a part number for the chassis block as a spare part? I am pretty sure the block was not identified as a spare part on the service sheets. Roy 1 Link to post Share on other sites More sharing options...
rob D2 Posted June 29, 2019 Share Posted June 29, 2019 On 28/06/2019 at 16:46, Pandora said: With the 31 back into production, do we know of a part number for the chassis block as a spare part? If you read further up, you’ll find reports that say it’s a different design and I don’t think Hornby ever produced the blocks as spare anyway. 1 2 Link to post Share on other sites More sharing options...
RMweb Gold Roy Langridge Posted January 12, 2021 RMweb Gold Share Posted January 12, 2021 Just come across a worrying possibility. On ebay somebody is selling a Hornby 31452 in DCR livery with a hairline crack "on the cab end". Sounds so familiar but is from a 31 much newer than had previously been reported as having problems. It claims that the loco had only just been removed from the box for the first time since new. I hope that this is just an odd occurrence... Roy 2 Link to post Share on other sites More sharing options...
RMweb Premium boxbrownie Posted January 31, 2022 RMweb Premium Share Posted January 31, 2022 I wouldn’t worry about the chassis rot, Rails of Sheffield must value them very highly https://www.ebay.co.uk/itm/133958067528?epid=1356728713&hash=item1f3085e548:g:C~QAAOSweAxhsMeK Link to post Share on other sites More sharing options...
GordonC Posted January 31, 2022 Share Posted January 31, 2022 22 minutes ago, boxbrownie said: I wouldn’t worry about the chassis rot, Rails of Sheffield must value them very highly https://www.ebay.co.uk/itm/133958067528?epid=1356728713&hash=item1f3085e548:g:C~QAAOSweAxhsMeK I'm surprised thats still on there (as in surprised that they're still flogging a dead horse rather than surprised it hasn't sold), it was pointed out to Rails before Christmas about the ridiculous price 1 1 Link to post Share on other sites More sharing options...
RMweb Premium Izzy Posted January 31, 2022 RMweb Premium Share Posted January 31, 2022 But it is a sound fitted model. Take the cost of that away, £100 give or take so long as it isn’t TTS, and the rest is what many cracked chassis examples go for now. Quite easily repairable in many cases. It’s how I put a better chassis under a railroad (exLima) TTS 31. Bob Link to post Share on other sites More sharing options...
GordonC Posted January 31, 2022 Share Posted January 31, 2022 47 minutes ago, Izzy said: But it is a sound fitted model. Take the cost of that away, £100 give or take so long as it isn’t TTS, and the rest is what many cracked chassis examples go for now. Quite easily repairable in many cases. It’s how I put a better chassis under a railroad (exLima) TTS 31. Bob For a new chip possibly, but this is a second-hand DCC sound chip so even for a Loksound V5 that would be top end. Still £70-£100 for a near 20 year old rotted chassis model. Better off with a railroad or Lima one 2 Link to post Share on other sites More sharing options...
RMweb Premium boxbrownie Posted January 31, 2022 RMweb Premium Share Posted January 31, 2022 3 hours ago, Izzy said: But it is a sound fitted model. Take the cost of that away, £100 give or take so long as it isn’t TTS, and the rest is what many cracked chassis examples go for now. Quite easily repairable in many cases. It’s how I put a better chassis under a railroad (exLima) TTS 31. Bob Go for it…. Link to post Share on other sites More sharing options...
david12345 Posted September 13, 2022 Share Posted September 13, 2022 Just getting back into my loft layout in time for the Autumn after a few months off, and find that my 31110 in Dutch livery has joined this club. Cracking appearing on the cab end, but nothing obvious on the chassis apart from being awkward to separate from the body. Ill see if I can get some pics in the daylight. 3 Link to post Share on other sites More sharing options...
RMweb Premium richierich Posted December 13, 2022 RMweb Premium Share Posted December 13, 2022 On 28/06/2019 at 21:25, Roy Langridge said: I am pretty sure the block was not identified as a spare part on the service sheets. Roy Hornby part number is X5329. However, they’ve never been widely available. AC Models once had some. https://www.acmodelsspares.co.uk/product/x5329-Hornby-spare-class-31-underframe/ Link to post Share on other sites More sharing options...
RMweb Premium richierich Posted December 13, 2022 RMweb Premium Share Posted December 13, 2022 (edited) On 24/05/2019 at 18:31, Roy Langridge said: To be honest, I don't see how that would work. When you make a pattern for casting to you have to allow for shrinkage as the cast metal cools. If you create a mould from a finished piece as the pattern, anything that you cast from that will be small. Looking at the figures, brass shrinkage is about 1.5%, cast iron 1% and cast steel 2%. The resultant casting may well need to be machined as well, and there would be no "spare" for machining. A CNC milled chassis, if it can be simplified from the Hornby chassis, would be much more reliable and easily produced to order. Roy My latest thought is to cut from some 3mm or maybe 4mm mild steel plate (ideally with a laser or water jet cutter for accuracy) the outline of the chassis with holes for the bogies gear towers and bogie pivot holes. The steel would give some weight. I’ve produced a prototype in plastic card. Then produce a motor cradle and mounts for the circuit board, decoder and maybe speaker. This could be scratch built or ideally 3D printed, which then screw to the chassis plate. A 3D print of the buffer beams which could again screw or glue to the chassis plate and re-use the buffers. Finally the battery box can then be reused as well. Just need a water jet cutter, 3D printer and some steel plate to have ago… There is a guy on Facebook who has built a replacement chassis from sheet brass. The easiest answer is Hornby make the X5329 chassis block available as a spare again in a reasonable quantity. Edited December 13, 2022 by richierich 1 Link to post Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now