Polar Star Posted December 4, 2009 Share Posted December 4, 2009 Finney A4 - S7, 7mm scale 33mm gauge - A rivetting problem by polar star original page on Old RMweb __________________________________________ Comment posted by alcazar on Sun Aug 09, 2009 8:06 pm I have to admit that I've never understood that part of the MRJ article, either. Also, there seems to be a circuit diagram, mentioned in the text for the reverser, missing from the article And yes, you need either a new camera, or a close-up/macro lens Mind, the cost of either would just about buy you a new model loco.............. __________________________________________ ??? posted on Wed Aug 19, 2009 8:08 pm Major disruption to the progress of Merlin - the Antex TC50 went AWOL. I ordered a replacement from Sq**res last week and expected to be back at work by the beginning of this week. After five days I received a call from the supplier to say that the iron was out of stock, "would I mind waiting for two weeks until fresh stock was received?". Not really, so I am expecting an alternative by the end of this week. In the meantime, I have received some brass castings from Ragstone Models for the brake gear and some white metal castings for the bogie. All I need now is a working hot spanner. regards, Peter. __________________________________________ ??? posted on Sun Aug 23, 2009 8:45 pm Good to their word, a complete Antex 660-TC solder station arrived two days after placing an order with Squires. The bits have been tinned and the hot spanner has been put into service. At the moment I am assembling the laminations for the slidebars and fettling the crossheads to fit those slidebars. Some time back I completed the bogie frame and fitted the full-width dust shield using the Finney diagram as a guide. The lower fold, where the shield is secured to the front bogie frame stay, was achieved successfully. However the diagram does not provide any information as to the location or radius of the top fold (which is actually a curve). Whereas the lower fold in the plate follows the edge of the bogie frame the top curve takes the plate away from the bogie frame and as such is rather distinctive. My first attempt at the curve was not too good and in re-making the curve I managed to introduce a ripple into the metal. Thanks to the assistance of a RM Web member I have received a replacement plate which I shall try to fit more successfully than my original part. For those of you who have completed either the Finney A3 or A4 in 7mm, how did you achieve the curve which extends over the top 2-3mm of the dust shield? Thank you, Peter __________________________________________ Comment posted by alcazar on Mon Aug 24, 2009 4:44 pm Can you anneal it first? __________________________________________ ??? posted on Thu Aug 27, 2009 8:53 pm Polar Star wrote: MRJ issue no.94, (vol. 13, 1997) has an article on building the Martin Finney A4 in 7mm, the slidebars are described on page 89 where the following comment can be found:- "At the same time, the shape of the bracket on top of the slidebar needs to be modified at the front because it ought to be triangular in plan view, rather than rectangular". There are "before" and "after" photos of the slidebar on page 88. I can see, in the "before" photo, the rectangular shape on the top of the slidebar, I cannot see any triangular shape in the "after" photo. Can anyone please explain the MRJ comment? Or offer a prototype photograph? To answer my own question... Bittern can be found, occassionally, about 15 miles away on the MId-Hants. At the moment the engine is stopped as a result of a failure of one cylinder - caused, so the fitting staff think, by lack of lubrication. The RHS valve gear has been dropped and the corresponding valve rod removed for replacement of a piston valve liner. The engine is in the yard at Ropley and in a location which is suitable for photography, so pictures have been taken and the results are below. The shape of the front fixing of the slidebar bracket is "triangular", the shape of the rear fixing is "rectangular", both can be seen in the respectives pictures. The third picture shows the front end of the LHS slidebar and the minimal space between the slidebar fixings and the casting which supports the valve crosshead. Since some of the RHS motion has been removed there is good access for a photograph of the fixings of the slidebar to the rear cylinder cover. There are about 100 other detail photos of the frames, spring gear, Cartazzi and firebox supports if anyone is interested. regards, Peter __________________________________________ Comment posted by alcazar on Fri Aug 28, 2009 9:13 am Great photos, I'll keep them in mind, and PM you for them for when I build one, if you don't mind? What's the grey stuff that looks like metal "turnings" all over the valvegear? __________________________________________ Comment posted by PhilH on Fri Aug 28, 2009 9:17 am What's the grey stuff that looks like metal "turnings" all over the valvegear? Cast iron from the valve chest liner. __________________________________________ Comment posted by Western Star on Fri Aug 28, 2009 9:30 am PhilH wrote: What's the grey stuff that looks like metal "turnings" all over the valvegear? Cast iron from the valve chest liner. Given that the fitters are replacing the liner next week then cast iron might be a reasonable view. On t'other hand, look at the debris on the rear / top of the LHS slidebar (picture above), seems to be the same type of detritus. Bear in mind that the pictures were taken with electronic flash and that causes coal / soot / smuts / etc.. to shine. Irrespective, Bittern is not well at the moment and ought to get TLC soon. regards, Graham __________________________________________ Comment posted by PhilH on Fri Aug 28, 2009 9:39 am Irrespective, Bittern is not well at the moment and ought to get TLC soon. This thing is well maintained on the MHR - it has to be as a mainline certified engine. The cause of this problem has been identified and suffice to say was not part of the MHR's restoration. I've posted this link in another thread, but this archive of 60019's restoration at the MHR might be of interest to some: http://www.watercressline.co.uk/tw/archive.htm#Bittern It's possible that there could be some useful reference material in the pictures in this archive. __________________________________________ ??? posted on Sun Aug 30, 2009 8:17 pm When I posted pictures of the frames the structure of the frame rear extension (part 3) had been folded and then soldered to the rear stretcher of the main frame (part 5). Today I have started on the Cartazzi truck by adding the outer rear frames (parts 75 LH and RH). The instructions say that the outer frames are formed to fit after the extension frame structure has been soldered to the rear frame stretcher. Well, I could not form the outer frames around part 3 when that part is soldered to the rear of the main frame - the outer brackets of the rear frame stretcher prevent the outer frame from being bent into the correct shape for the curve just in front of the Cartazzi. So out came the hot spanner and the extension frame was removed from the main frame - the inward bend of each outer frame was then formed around part 3. The extension frame was then re-joined to the main frame whereupon the front bend of each outer frame was shaped to fit.... at which point an interesting snag popped up. The main frame plates had been "rivetted" as per the instructions and one "rivet" on each side was preventing the outer frame plates from fitting snugly. So the lowest / most rearward rivet on each frame plate was removed and the outer frames soldered in place. To help with alignment of the outer frames I put some 0.8mm wire through the co-incident holes in the outer / main frame plates whilst tack soldering the rear of the outer frames (the holes are intended for brake hanger support pins). Sorry about the quality of these photos. Might Richard or Nigel comment on how they formed the outer frames? regards Peter __________________________________________ Comment posted by alcazar on Mon Aug 31, 2009 6:07 am Am I right in thinking that MF kits DON'T have the correct radial pattern trailing bogie? I have a Dave Andrews Peppercorn A1, and it DOES. __________________________________________ ??? posted on Mon Aug 31, 2009 7:05 am alcazar wrote: Am I right in thinking that MF kits DON'T have the correct radial pattern trailing bogie? I have a Dave Andrews Peppercorn A1, and it DOES. I have not hear or read anything that says that there is an issue with the Finney A4 kit in that respect. Why do you think that the MF Cartazzi is not correct when compared to the DA version? Please post some photos to show the correct form of the Cartazzi. thank you, Peter __________________________________________ Comment posted by alcazar on Mon Aug 31, 2009 1:23 pm Not saying it's wrong, Peter, just asking if it has the true radial bearings, ie: the axle box swings in a radial block? I know the DA kits do, but does the MF, or is it just a "truck" pivoted behind the rear wheels, like most 4mm RTR stuff? __________________________________________ Comment posted by OgaugeJB on Thu Sep 03, 2009 11:26 pm If you have a look at the construction photo's of the Finney V2 (top of my wishlist) it does use the Cartazzi principle rather than just a basic truck, so I would assume (assumption being the mother of all ###### ups) that the A4 was correct too.. http://website.lineone.net/~cbwesson/V2.htm JB. __________________________________________ Comment posted by alcazar on Fri Sep 04, 2009 10:24 am Right, I hadn't seen those construction details before, and yes, it IS a correct Cartazzi arrangement, thanks. I DID think it a bit odd if an MF kit didn't have the correct arrangement, (spoiling the ship for a ha'porth of tar), but couldn't SEE it on that last photo. Looking forward to more on this thread. I want one more than ever now __________________________________________ ??? posted on Tue Sep 08, 2009 8:17 am If you have been following the discussion about rivets or bolts for the outer frame plates... Dikitriki started the ball rolling with the substitution of Scale Hardware nuts for the embossed bolts on his A3... and I was going to go the same way until I looked at some photographs of Bittern. No. 19 has rivets rather than bolts and a study of books (The Book of the A4, A4 in Detail, Yeadons Register) indicates that rivets might be more appropriate. I met Dikitriki at Telford where he showed me the picture which lead to the change on his A3. I am going to go with pan-head rivets for Merlin as per viewtopic.php?f=7&t=50152. Peter __________________________________________ ??? posted on Wed Sep 23, 2009 1:27 pm Some time back Alcazar asked about the way in which the Cartazzi axle was carried within the frame, so here are two photos of the way in which the trailing carrying axle is mounted into a radial axlebox. There are two "stops" on the radial axlebox to limit sideways movement of the axlebox within the frame, I expect to add packing washers to restrict movement of the carrying axle within the radial axlebox. There are two "lugs" on the axlebox for a spring wire which centres the axlebox and applies downwards pressure on the axle. And here is a photo of the the radial axlebox in a radial slide within the rear frame extension. The ashpan and lower firebox have been added to the rear frames, together with the corner washout plugs and the blowdown cock. The lower firebox etch has four etched round holes for the plugs so those holes were "squared" with a miniature file to take short lengths of the 1mm sq. brass wire which is supplied in the kit. The blowdown cock is a brass casting and fits into another etched hole in the lower firebox etch. I have now fitted the bushes for the driving axles using a Master Jig from Holiday Hobbies - a truly worthwhile piece of kit. So here is a photo of the frame with all of the wheels and one of the bogie. Those with keen eyes will realise that I have yet to fit the side checks to the bogie... and might just spot that I have changed the front dust shield. The full width dust shield has a curve to the top edge and I did not get that correct on the first attempt. To get a smooth curve for the replacement part I soldered a piece of brass rod across the etch, approximately four mm from the top edge of the etch. I could then wrap the top of the etch around the tube, unsolder the tube and clean up to leave the etch part with a smooth curve. Thank you to Mr. Alycidon for providing the replacement (and unwanted) part from your Finney kit. As a break from doing the engine I have started on the tender - here are two photos of the outer frames. The side frames were rivetted first and then folded to a right angle with the top plate(s). The front and rear dragbeams were then folded to complete the structure. I have yet to fold the tank support brackets down and I shall do that as part of fixing the embossed rivet strip to the top edge of the outer frames. And yes, I need to clean up the wheels and blacken them. Fumes from Carr's Black Label have got to the steel. Peter (sorry about the track - GWR 44' 6" panels in the style circa 1900, built from C&L and Exactoscale components) __________________________________________ Comment posted by alcazar on Wed Sep 23, 2009 1:47 pm Thanks for those photos of the Cartazzi arrangement, Peter. It clarifies what I asked, since from an earlier photo, it appeared as if the rear truck was to be a "pony" like on most OO RTR models. I did think at the time, "On a Finney kit? ", but never thought to dig out my unbuilt Finney A3's instructions to have a look. Are those AGH wheels? Have you thought of buying some of this: http://www.7mmlocomotives.co.uk/index.p ... &Itemid=52 to avoid the flux fumes damaging parts already fitted? I've heard nowt but good reports of it. Regards, Jeff __________________________________________ Comment posted by Western Star on Wed Sep 23, 2009 2:50 pm alcazar wrote: Are those AGH wheels? Regards, Jeff Certainly does look like wheels which have been turned and pressed onto axles. Graham __________________________________________ Comment posted by 3 link on Wed Sep 23, 2009 4:41 pm Polar Star wrote: And yes, I need to clean up the wheels and blacken them. Fumes from Carr's Black Label have got to the steel. Peter [sorry about the track - GWR 44' 6" panels in the style circa 1900] Hi Peter, just a suggestion I have been using a Safety flux from Building O Gauge online for sometime now, and it works a treat both on brass and nickel. It will not attack the steel, and no nasty fumes either. Brilliant stuff. Regards, Martyn. __________________________________________ Comment posted by alcazar on Wed Sep 23, 2009 5:22 pm That's the stuff I posted a link to __________________________________________ ??? posted on Wed Sep 23, 2009 8:20 pm alcazar wrote: Are those AGH wheels? Regards, Jeff Yes, the wheels are AGH. All the wheels on one side are insulated at the hub using Tufnol. The "insulated" driving wheels have Tufnol insulation in the boss for the AGH crankpins. One crank pin leads t'other pin by 120 degrees on each axle (an A4 has three cylinders) rather than the normal 90 degrees (for the more numerous classes with two / four cylinders). The driving wheels are on telescopic axles with taper pins and the carrying wheels are on threaded axles. I guess that I ought to add that Merlin is being built to run on 33mm gauge track - so the wheels have been turned to the S7 profile using an appropriate form tool which can be obtained from either AGH or the Scaleseven society. Peter __________________________________________ Comment posted by alcazar on Wed Sep 23, 2009 10:06 pm Polar Star wrote: alcazar wrote: Are those AGH wheels? Regards, Jeff Yes, the wheels are AGH. All the wheels on one side are insulated at the hub using Tufnol. The "insulated" driving wheels have Tufnol insulation in the boss for the AGH crankpins. One crank pin leads t'other pin by 120 degrees on each axle (an A4 has three cylinders) rather than the normal 90 degrees (for the more numerous classes with two / four cylinders). The driving wheels are on telescopic axles with taper pins and the carrying wheels are on threaded axles. Peter Wow! How do you get the quartering spot on? Mind telling us how much a set for an A4 goes for? And what was the waiting time? Also, in your opinion, what benefits do they have over Slaters? __________________________________________ ??? posted on Thu Sep 24, 2009 7:39 am [quote name="alcazar} How do you get the quartering spot on? Mind telling us how much a set for an A4 goes for? And what was the waiting time? Also' date=' in your opinion, what benefits do they have over Slaters? [/quote] The wheel castings were bought from AGH earlier this year, before the last price increase, and the price for the bogie, driving and trailing wheels was around ?‚??180.00 including the crank pins and material for making the axles (not silver steel stock from over the counter). I think that the waiting time was around four weeks. I say "around" and "think" because my wheels were part of an order for several engines from different railway companies. The wheels were not "quartered" as that would not be correct for an A4, the crank pins are set at 120 degrees. The wheels were mounted on the axle by using a jig which held the crankpins at the correct radial angle. I shall see if I can post a photo of the jig from the person who turned the wheels, Mr. Paul Penn-Sayer (who accepts commissions for turning AGH wheels, I can provide contact details. I believe that Buckjumper of this parish may be following a similar course). Why AGH rather than Slater? Appearance - finesse of the spokes, no screw in the end of the axle, correct relationship of spoke to rim / tyre for the A4, a decent representation of the boss, superb crankpins (which I suspect can be purchased from AGH and used with Slater's wheels). As with Slater's wheels the production process leaves spokes with a flat rear surface so I have taken a file to each spoke and rounded the rear corners. regards, Peter __________________________________________ ??? posted on Thu Sep 24, 2009 4:12 pm My apologies for omitting to post the tender photos yesterday. I have editted the relevant post to include the two photographs in the correct place relative to the text. Peter. __________________________________________ Link to post Share on other sites More sharing options...
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