Jeff Smith Posted January 23, 2018 Share Posted January 23, 2018 I am quartering an 0-6-0 chassis with two-piece coupling rods. The rear and centre wheels rotate satisfactorily with the rear coupling rods in place. Likewise centre and front. However when all six are coupled it binds.....any clues? Link to post Share on other sites More sharing options...
brossard Posted January 23, 2018 Share Posted January 23, 2018 (edited) Is the chassis square Jeff? Probably obviousness but I don't know what your experience level is. A similar thing happened to me once. Edit: If you have a longish 1/8" rod, inserting that into the bearings and having a squint can tell you if there's a problem. John Edited January 23, 2018 by brossard Link to post Share on other sites More sharing options...
Bluemonkey presents.... Posted January 23, 2018 Share Posted January 23, 2018 Hi Jeff, Sorry I can not help but I have a similar issue with my 0-6-0 chassis. It was perfectly fine under testing but once fitted binds slightly. I look on with interest. Hopefully someone will be able to 'kill two birds with one stone' here. Matt Link to post Share on other sites More sharing options...
Jeff Smith Posted January 23, 2018 Author Share Posted January 23, 2018 Just to give a bit more information about the chassis. It has Gibson sprung horn blocks so that the Gibson wheels could be squarely pressed onto the axles before fitting to the chassis. The chassis is square having been assembled using 1/8" assembly axle jigs and the coupling rods. The rear driver is effectively solid and has the drive gear. The centre and front drivers have some up and down movement but lightly sprung downwards. The front of the chassis is supported on the front bogie. Although the pick-ups have not yet been wired up I can drive the chassis with wires to the motor. The last chassis I built (0-4-0) did not run well when pushed but ran well under power! Link to post Share on other sites More sharing options...
Gordon A Posted January 23, 2018 Share Posted January 23, 2018 Have you tried checking the quartering. Disengage the gear box by grub screw or remove motor. Place chassis on a piece of track. Lean a straight edge say a 6" ruler against all three wheels on one side - secure in place with blue-tack.. Push chassis gentily forward until all three crank pins are touching the straight edge. Check alignment of crank pins on other side. Are they in a straight line? Are they parallel to the track? If no then tweak. Gordon A Link to post Share on other sites More sharing options...
Jeff Smith Posted January 23, 2018 Author Share Posted January 23, 2018 Have you tried checking the quartering. Disengage the gear box by grub screw or remove motor. Place chassis on a piece of track. Lean a straight edge say a 6" ruler against all three wheels on one side - secure in place with blue-tack.. Push chassis gentily forward until all three crank pins are touching the straight edge. Check alignment of crank pins on other side. Are they in a straight line? Are they parallel to the track? If no then tweak. Gordon A Gordon - that sounds like a good trick, I'll give it a go, thanks. Link to post Share on other sites More sharing options...
AndyID Posted January 23, 2018 Share Posted January 23, 2018 Hi Jeff, If all else fails try making temporary one piece coupling rods. The accumulated "slop" with two-piece rods can be a problem, particularly if the drive is not on the center axle. If it works with solid rods with the center wheels removed you can open up the clearances on the center wheels and put as little weight in the center axle as possible. Effectively it becomes a 0-4-0 with the center wheels "going along for the ride". It won't make any difference to the hauling power either. Regards, Andy Link to post Share on other sites More sharing options...
DCB Posted January 30, 2018 Share Posted January 30, 2018 I am quartering an 0-6-0 chassis with two-piece coupling rods. The rear and centre wheels rotate satisfactorily with the rear coupling rods in place. Likewise centre and front. However when all six are coupled it binds.....any clues? Sounds like there may be issues with the rod length and play in the axle bearings. I find it quite normal for chassis to run freely without a motor and bind under power and it is usually the rods are fractionally too long or short. Opening up the holes in the rods improves things without motor but as soon as you put any power through it it all binds up again. You should be able to set the quartering by looking through the spokes as well as the straight edge method. RTR chassis are often out of alignment, Split chassis can be tweaked straight as can ancient screw together Triang or Ks but Hornby are pretty bad especially the keeper plate variety and the old Airfix had so much slop it was amazing that they ran at all, and unsurprising that they packed up so quickly in most cases! Link to post Share on other sites More sharing options...
RMweb Premium Izzy Posted February 27, 2018 RMweb Premium Share Posted February 27, 2018 As has been said two piece coupling rods not jointed as one can cause running problems when there is too much slop in the centre joints. Ideally you should join the two rods using a pivot point as per the prototype so the overall coupling rod distances stay constant. This is often a problem with RTR coupling rods that are made as two pieces joined together because the pivot is loose/sloppy and the distances constantly vary. So long as the coupling rod centres match the wheelbase, opening up the rods so they are an easy fit on the crankpins isn't an issue, to allow up/down axle movement, but it does become one when pivoting rods which rotate individually around the centre crankpin are involved. Izzy Link to post Share on other sites More sharing options...
JaymzHatstand Posted April 5, 2018 Share Posted April 5, 2018 Exactly the same issue I'm trying to solve with a J21 0-6-0 chassis, and probably why it runs better in reverse as that is where the motor is! Looks like I might try making the rods solid and see how it behaves after that. The centre drivers do seem to have a bit of a wobble, but when checked appear to be on straight so this may be a result of the rods flopping about (hopefully) If it turns out that one of the wheels is a little out of true, is there a way to adjust them (Gibsons) or would it be easier to get a new pair? Cheers J Link to post Share on other sites More sharing options...
Jeff Smith Posted April 5, 2018 Author Share Posted April 5, 2018 Just to update the situation. The front coupling rods were slightly short so I made some new ones. The joint is on the centre driver crankpin. I then got the centre and rear wheels running OK, installed one of the front rods and adjusted the front axle quartering until the other front rod dropped on. Initially it would not run but then I discovered that in adjusting the quartering I had significantly reduced the back-to-back.......now it runs both ways under power. Regarding Gibson wheels they are hard to get on square. You really need a press but you can take some precautions. Put a short taper on each end of the axles, about a mm and a radius on the taper to end-face. This is to try to prevent the axle shaving the bore because once that happens you will never get it square. Also the last wheels I received had rims that came off easily, I had to superglue them all on, making sure each rim was fully home on the centre. Link to post Share on other sites More sharing options...
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