Polar Star Posted June 22, 2010 Author Share Posted June 22, 2010 Progress has been slow over the last couple of months, primarily because of working out how to include springing for the axleboxes and doing the details of the tender front plates. So here are some photos of an original frame plate, a replacement frame plate with wider hornspaces for sprung axleboxes and a replacement frame plate with Slater's horngiudes. The inner frames of the tender have been assembled and the resulting 8-wheel cart has been tested with the turnouts on the layout. I have reduced the side play on all axles to about 20thou, by using Slater's etched 3/16" washers, and the tender frame negotiates A6 turnouts (built to S7 standards). Photos of the assembled frame and wheeled frame to follow. Peter Link to post Share on other sites More sharing options...
Polar Star Posted July 24, 2010 Author Share Posted July 24, 2010 This post is a question to those A3 masters, Dikitriki, Harrier-Mate and Christian... Guys, what is the clearance between the coupling rod boss and the connecting rod boss on the centre crank pin? (of a Finney A3 / A4 in 7mm scale). My model of the A4 Merlin is to S7 standards and uses Alan Harris wheels / crank pins. When the centre axle is "centred" about the frames, with the coupling rods pressed against the boss of the wheel and with the connecting rod aligned parallel to the frame plate... then there is about 1.8mm of clearance between the two rods. As far as I can see from the Finney instructions there is no guidance about what thickness of packing washer is to be placed between the rods. A figure of 1.8mm represents almost 3" clearance on the prototype, that is not reasonable and so there is a need to reduce that clearance in some manner. I can make a spacing bush for the crankpin or I can add overlays to the rear of the connecting rod and to the front of the coupling rod. Suggestions? regards, Peter Link to post Share on other sites More sharing options...
Christian Posted July 24, 2010 Share Posted July 24, 2010 Hello Peter, Obviously with us lesser mortals using slaters wheels, I don't know what system is used for the crank pin bushes on the Alan Harris wheels but the distance of 1.8mm clearence does seem a bit much. I used two of the miniture top hat bearings, end to end, the connecting rod and the coupling rod are seperated with a 0.4mm thick brass washer. This resulted in some excess movement of the coupling/connecting rods so I filed down one of the top hat bearings slightly, this still gives me a fair bit of movement and probably more than you would require as you are using Scale 7 wheels and I guess that any lateral movement of the axles would be very minimal indeed. I would be interested to hear what Richard and Nigel have done. Link to post Share on other sites More sharing options...
Western Star Posted July 24, 2010 Share Posted July 24, 2010 I would be interested to hear what Richard and Nigel have done. Christian, Thank you for explaining what you did for the crank pin bearing of the driving axle... I suspect that part of the problem comes from using wheels which are "thinner" than the Slater's equivalent, however I remain to be convinced. Like you I am keen to hear from Richard and Nigel. BTW - the bearing housing of the prototype coupling rods is proud to the front and back of the rod... there are no overlays for those bosses in the kit, what did you do with that aspect of rod assembly? regards, Graham Link to post Share on other sites More sharing options...
dikitriki Posted July 24, 2010 Share Posted July 24, 2010 Christian, Like you I am keen to hear from Richard and Nigel. BTW - the bearing housing of the prototype coupling rods is proud to the front and back of the rod... there are no overlays for those bosses in the kit, what did you do with that aspect of rod assembly? regards, Graham Hi Graham, Christian I used Derek Mundy heavy duty crankpins. The centre crankpins carry both the coupling and connecting rods, and were filed back until the return crank, when tightened, gives just a little play for the 2 rods. There is no washer between the coupling and connecting rods, so there is no visible separation between them. The return crank was soldered to the Mundy crankpin retaining screw, and the thickness of the head of the screw gives the requisite clearance between the connecting rod and return crank. The bosses were ignored Yours Richard Link to post Share on other sites More sharing options...
Western Star Posted July 25, 2010 Share Posted July 25, 2010 Hi Richard and Christian, So S7 wheels and frames give more room for the motion work? Wall, behind, ducks... (S7 wall of course!) Thank you and regards, Graham Link to post Share on other sites More sharing options...
ozzyo Posted July 25, 2010 Share Posted July 25, 2010 This post is a question to those A3 masters, Dikitriki, Harrier-Mate and Christian... Guys, what is the clearance between the coupling rod boss and the connecting rod boss on the centre crank pin? (of a Finney A3 / A4 in 7mm scale). My model of the A4 Merlin is to S7 standards and uses Alan Harris wheels / crank pins. When the centre axle is "centred" about the frames, with the coupling rods pressed against the boss of the wheel and with the connecting rod aligned parallel to the frame plate... then there is about 1.8mm of clearance between the two rods. As far as I can see from the Finney instructions there is no guidance about what thickness of packing washer is to be placed between the rods. A figure of 1.8mm represents almost 3" clearance on the prototype, that is not reasonable and so there is a need to reduce that clearance in some manner. I can make a spacing bush for the crankpin or I can add overlays to the rear of the connecting rod and to the front of the coupling rod. Suggestions? regards, Peter Peter / Graham, while not for an A3 or 4, the sizes for a Duchess are as follows thickness of the coupling rods at the bearing. Front and rear 3 7/8" Center 4 1/2". Connecting rod big end 6". Gap between coupling rod and connecting rod 1 1/2". While I know that the Duchess a bigger and more powerful loco it will give you a starting point. Now putting on the tin hat and getting behind the parapet. OzzyO. Link to post Share on other sites More sharing options...
Western Star Posted July 25, 2010 Share Posted July 25, 2010 Peter / Graham, while not for an A3 or 4, the sizes for a Duchess are as follows thickness of the coupling rods at the bearing. Front and rear 3 7/8" Center 4 1/2". Connecting rod big end 6". Gap between coupling rod and connecting rod 1 1/2". OzzyO. Thank you for the details, OzzyO. What you have written is close to what I might have suggested based upon photographs of Bittern when "she" was at Ropley. You may have noticed that I started a separate topic to see if anyone could provide an answer - and someone did. Is there no limit to the knowledge of Mike Trice???? regards, Graham Link to post Share on other sites More sharing options...
Crewe North Posted July 26, 2010 Share Posted July 26, 2010 Since posting the pictures of the modified anvil and punches I have heard from the Mr. Penn-Sayer who made those items for me. He is happy to supply matched anvil and punch sets at a price of ??16.00 per set plus post and packing. I can provide contact details for serious enquiries. Have sent you a PM re: the above, Link to post Share on other sites More sharing options...
Horsetan Posted July 26, 2010 Share Posted July 26, 2010 .......Is there no limit to the knowledge of Mike Trice????.... Dunno. From where I'm sitting, "bertiedog" would surely run him very very very very very close Link to post Share on other sites More sharing options...
Polar Star Posted July 26, 2010 Author Share Posted July 26, 2010 Have sent you a PM re: rivet punches Nice models on your Old Originals web site. Your PM noted. regards, Western Star (Graham Beare) on behalf of Polar Star Link to post Share on other sites More sharing options...
Polar Star Posted July 26, 2010 Author Share Posted July 26, 2010 Have sent you a PM re: the above, I have spoken to Mr. Penn-Sayers this afternoon and he has made a couple of sets of punches and anvils this year for other RM members. You will receive a PM with contact details. The punches which Paul made are for a Metalsmith tool and are a direct replacement for the Metalsmith equivalents. Paul made the first punches in response to the problems of distortion that Peter encountered when doing some of the platework for the Finney tender. So that the punch did not distort the metal around the etched hole, and pressed only on the half-etch material at the bottom of the hole, the punch was made with a parallel portion to the tip and of a diameter appropriate to the etch hole of specific kit components. Paul made several punch / anvil sets to cover the various "rivet" diameters which were to be embossed. regards. Graham (for Peter) Link to post Share on other sites More sharing options...
Polar Star Posted July 28, 2010 Author Share Posted July 28, 2010 This post is a question to those A3 masters, Dikitriki, Harrier-Mate and Christian... Guys, what is the clearance between the coupling rod boss and the connecting rod boss on the centre crank pin? (of a Finney A3 / A4 in 7mm scale). regards, Peter Thanks to the assistance of a Scaleseven Group member - Jonpaul Venus of this parish - I have the requested information.... JP has been able to measure the rods etc. on Sir Nigel and sent the following details.... Measurements on driving crankpin:- Coupling rod thickness at bearing 4"Gap 1/2"Connecting rod Thickness at bearing 5 1/4"Gap 1/2"Return crank thickness at bearing 2 1/4" where "Gap" is measured between the steel part of the bearing housings, the gap between the brass shell of the bearings being a few thou of a inch. Coupling rod thickness 2 1/2" between bearings. Connecting rod thickness 3 1/2" between bearings. Thank you, Peter Link to post Share on other sites More sharing options...
Polar Star Posted August 19, 2010 Author Share Posted August 19, 2010 Another slow month of progress, I have been made a start on the motion which can be seen in the photos below. Next job is to add all the bolts and nuts that are on the slidebars. When constructing the motion I added a tube for the piston rod to run in, to support the piston rod through it's full travel, ie stop it moving where it shouldn't. Also included is a photo of a nearly complete tender I am currently going through photos of castings which i might want to included on the finished tender, so probably no progress until after Telford. Regards Peter Link to post Share on other sites More sharing options...
JeffP Posted October 22, 2011 Share Posted October 22, 2011 Another slow month of progress, I have been made a start on the motion which can be seen in the photos below. Next job is to add all the bolts and nuts that are on the slidebars. When constructing the motion I added a tube for the piston rod to run in, to support the piston rod through it's full travel, ie stop it moving where it shouldn't. Also included is a photo of a nearly complete tender I am currently going through photos of castings which i might want to included on the finished tender, so probably no progress until after Telford. Regards Peter Was there ever any more to this? Is it continued elsewhere? Link to post Share on other sites More sharing options...
ozzyo Posted October 22, 2011 Share Posted October 22, 2011 Another slow month of progress, I have been made a start on the motion which can be seen in the photos below. Next job is Regards Peter Hello Peter, is that a rather nasty ding down the side of the tender? If it is I would use solder to fill it in, it will take some time but if you do it right it should not show under the paint work. OzzyO. Link to post Share on other sites More sharing options...
3 link Posted October 22, 2011 Share Posted October 22, 2011 Hello Peter, is that a rather nasty ding down the side of the tender? If it is I would use solder to fill it in, it will take some time but if you do it right it should not show under the paint work. OzzyO. Is it a ding ? Looks like a stain on the etch to me, mind you Oz maybe it's another senior moment . ATB, Martyn Link to post Share on other sites More sharing options...
Polar Star Posted October 23, 2011 Author Share Posted October 23, 2011 Was there ever any more to this? Is it continued elsewhere? In response, from september 2010 through to July 2011, I returned to University to complete my final year of my degree, as a result progress near enough stopped on all railway projects not just my A4. It is only now that I have finished my degree that I resumed work on my A4, the tender body is nearly complete, with the underframe detail progressing axleboxes and springs have been added and I currently working on the brakes. I recently started work on the Cab but have not photographed this bit of the build yet. In response to the marks on the side of the tender body, after soldering I place the model in a tub with a solution to neutralise the flux, however I left the model in for two long and as a result the two tone effect on the brass appeared. Regards Peter Link to post Share on other sites More sharing options...
JeffP Posted October 23, 2011 Share Posted October 23, 2011 Thanks for the reply, I look forward to further updates then. Link to post Share on other sites More sharing options...
Polar Star Posted October 29, 2011 Author Share Posted October 29, 2011 I mentioned that progress had been made so I have attached some pictures below. The nearly complete tender, and close up of the axleboxes, springs and the first set of brakes and hangers The photo below shows the brake cross shaft which is a casting that I have added to the kit from Ragstone Models. The shaft is not fitted to the outside frames but to some extensions that I made which attach to the inside frames, this is to allow me to remove the inside frames with brakes. The final photo is the progress made on the cab, this is in the early stages at the moment and progress is currently being made on the resin casting. Regards Peter Link to post Share on other sites More sharing options...
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