5958Re: [O14] Re: O14 wheelsets
- Jul 31, 2014When I established my O14 kit range, the tyres and axles only were bought in and I injection moulded my own centres. The tyres were from MayGib and the axles shared in batches of 20,000 in concert with Alan Gibson.From 11mm dia bar, a tool was turned which received the tyres, flange uppermost, without any play. The centre was bored and reamed 1.5mm. Also made was a tool to insert the moulded centres (just less than the internal dia from the back), and a similar tool, with a coned end, centre drilled to accept the pinpont of an axleIn use, the tyre holding tool was put in a machine vice on the mill/drill table, and the centre insert tool placed accurately in the quill chuck. After locking all but the downward movement, a trimed moulding was placed in the tyre mouth and the quill brought dwn to neatly push it in place.One a pile of tyres with inserts had been accumulated, the insert tool was replaced with the pinpoint tool and an axle introduced betwwen the two and checked for absolute verticality. With this done, one wheel was placed in the lower tool, an axle held over the centre hole and engaged with the pinpoint tool which, as it pushed down, pressed the axle firmly and precisely in place. The part assemby was taken out, another wheel put in the holding tool and the part assembled wheel/axle pressed on.The quill stop was micro adjusted over the first few operations, the back to back being adjusted until 14.40 min - 14.50 max was consistently acheived. The resulting wheelsets were rolled along the metal bench top to check for visual wobble or any eccentricity. Once a rythym was established, very few wheelsets required any futher attention beyond packing into the kits.All this is a lot harder to describe that it was to actually do, but I always felt it helped modellers to have them ready assembled.Roy
Sent from my iPadHi GuysIn his e-mail of 21st July ‘mjm’ asked, “Does anyone have a methodology for mount these [KB Scale] wheels so they are correctly gauged and true?” I had been hoping that one of the more engineering minded members of this group might rise to the challenge. So this is a case of fools rush in ...I use a vertical drilling machine, but the method work as well with a lathe, milling machine or half decent drill press – mine only cost £25 (quite a few years ago). All operations are with the power OFF.I mount the axle in the chuck for about 1/3 to ½ its length, a quick rotation of the chuck (by hand) will assure you it has been mounted true.With the machine vice closed and placed so its vertical grove is directly under the axle end, place a wheel, face up on the top of the vice. Position it carefully so the pin of the pin-point enters the axle hole in the wheel and press through gently. As soon as it bites release the downward pressure and rotate the work. Again you should see everything is true.Press down again, pushing the wheel as far on to the axle as the chuck will allow.Repeat for the second wheel, this time placed face down on the machine vice.With my eyesight problems there is no way I can see clearly the centre of the second-wheel, so remembering the old dodge I looked for something giving ,e a 90 degree angle that I could press against both wheels. My vee-block was too tall and would not clear the chuck. By luck I found some 10mm staples from my Staple Gun (10mm staples for 15” wheel, 12mm for 18” wheels). With the wheel already mounted on the axle lowered so it sits inside the “U” of the staples the loose wheel is pushed firmly against the staples and the axle can be lowered. (Of course, those of you with properly working eyes can skip this Heath-Robinson stuff!)Only push the axle home until it bites. I have recently been mounting a batch of 15” wheels on to 1.5mm x 18mm axles and got to know how far to press by about the third axle. Do not push it so far home that the wheels touch. The reason for not doing this is that if you apply any pressure to the wheel rims they will slide off – so always try and move the wheel on the axle by applying pressure to the plastic boss rather than the rim. (If I understand correctly, forcing a metal shaft through a tight hole in plastic sets up pressures which take some time to recover; so that the initial grip between hub and axle is fairly weak but it builds up in strength over time.)Again give the work a quick turn to check everything is true.Remove the piece from the chuck and tweak the metal rims and plastic hubs to make sure everything is ‘home’. With the 18mm axles I use a piece of card and using pliers pressed flat against the boss to push the wheel down on to the card. Repeat for the other end. Then place the wheelset in a back to back gauge and adjust as necessary, (try finding thicker or thinner card and no adjustment is needed). For the longer axles I use my Wheel Press and that centres the wheel automatically.I am not claiming this method is foolproof – although it works for me! I cannot remember the last time I had to reject a wheelset due to wobble.I like to apply a smidgen of thin superglue to the boss-axle joint to future-proof the gauging- over the years some wheelsets seem to wander a little. The other problem I have had over time is that rims separate from the wheel-bosses and although generally these can be replaced without too much trouble a George England tender with pick-ups does cause some head scratching (and it has happened to both Prince and Princess!)I hope this helps. It works for me and it might even get someone who knows what they are talking about to tell us how to do it properly!CheersDavid
From: "mjm@... [O14]" <O14@yahoogroups.com>
Sent: Monday, 21 July 2014, 8:53
Subject: [O14] Re: O14 wheelsets
John,Are you considering RP25-100 or RP25-88 wheels? One issue I see is that the flanges on RP25 wheels are much thicker than the flanges on KB Scale wheels. If the back to back is set to the recommentded 12.4mm then I have found that the the wheels are very tight to 14mm gauge.In my own case I bought some RP25-88 wheelsets from Steam Era Models in Victoria, Australia. I ended up setting the back to back gauge to about 12.2mm so that they would ride properly on the track. This does not leave much room for wheel wobble when going through a set of points.The KB Scale wheels have a much finer flange and narrower tread. The flange works well with a back to back of 12.4mm and 1mm flangeways (You would expect this as these wheels and flangeways were developed together.) However, there is not much tread to cope with wide gauge. At this stage I have not managed to mount KB Scale wheels squarely on to axles. I get far too much wobble. Does anyone have a methodology fro mount these wheels so they are correctly gauged and true?It would be very nice to have more than one manufacturer able to supply wheels for 14mm gauge.Regards,Michael Milway.
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