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[O-14] RE: The Truth about Romfords (14 mm gauge that is)
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Frank Sharp
I have the answer, I think, to why some of us are in gauge and some out
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of gauge. There appear to be two Romford wheel profiles knocking about, I would suggest that one is the old 00 standard and is the other the RP25 standard. I've hit the problem with the old standard. That is why my flanges catch the chairs on C & L track. Not only are the flanges deeper, 1mm, they are thicker. 0.65 mm. If you measure what I think are RP25 wheels, the flanges are 0.8mm deep, and only 0.5mm thick. Hence to get the old profile to come to the same gauge you need to lose 0.15 mm of the boss on the back of each wheel. Now on 00 the axle length over the round part of the axle is 14mm, 2.5 mm less than gauge, but on 14mm axles it is 12.1 mm, 1.9 mm less than gauge. There is 0.6 mm more 'slop' between the flanges and the rail in 00, so the old style wheels can never be tight to gauge in 00, but 14mm track is laid to the smaller 'slop' of EM gauge, and it can get too tight. Now this theoretically means that the back to back has to different, and a set of what I am calling RP25 wheels on an axle are a loose fit on my back to back gauge, and measure at 12.54 , whereas my old wheels with the bosses turned down a fraction are a tight fit, and measure at 12.47. If you put the wheel sets on 14mm track the RP25's have a touch more side play despite the bigger back to back. Deciding the correct point when measuring the flange root to flange root is difficult, but it appears to be larger on the RP25's. Now my problem is that these old wheels have been prepared for use in Festiniog Fairlies, with Wrightlines inserts in place on faces counter sunk with a milling machine to get the right dished look. I have to decide what to do next. If I turn the flanges down in HEIGHT it should solve the catching the chairs problem, but if I turn the THICKNESS of the flange down will they become too sloppy on the track. It is now 1.30 in the morning, I'll post this so those in other time zones can think about it and sort out whether in my tired state I have got the maths somewhere near. Frank -----Original Message-----
From: mattjcoleman@... [mailto:mattjcoleman@...] Sent: 08 December 2004 17:57 To: O-14@... Subject: [O-14] RE: The Truth about Romfords (14 mm gauge that is) Mark, I just checked with the wizards at the 3mm Society and according to them, the Romford 14mm axles were made specifically for 7mm modelders who wanted an accurate 2ft gauge driver. They are not known to be anything other than 14mm. Matt From: Mark Kendrick To: O-14@... Sent: Sunday, December 05, 2004 12:50 PM Subject: [O-14] The Truth about Romfords G'day All, I have heard it said that Romford 14mm gauge axles are actually 14.2mm gauge for Sn3. According to John Clutterbug's recently posted standards info (in the files), there is an extra 0.1-0.2mm back to back on Romfords. Does it make all that much difference? I haven't laid any points yet, but the track I have is laid to 14mm exactly (even around 6" radius curves) and the Romfords track fine around it (I come from N using proprietry track so am unaware of the intricacies of handlaid finescale track). From what I can tell (left my calipers at work), its only the flange thickness that is different from the RCL wheelsets. If it does make a difference, would it be a good idea for us all to send our axles back to Romford saying they aren't to the right gauge and asking for suitable replacements? Regards, Mark K Sydney Oz Who spent an enjoyable weekend playing with 1:1 2' gauge trains Yahoo! Groups Sponsor ADVERTISEMENT __________________________________________________________________ Switch to Netscape Internet Service. As low as $9.95 a month -- Sign up today at Netscape. Just the Net You Need. New! Netscape Toolbar for Internet Explorer Search from anywhere on the Web and block those annoying pop-ups. Download now at O-14 Photos area: O-14 Files area: Yahoo! Groups Sponsor < D=groups/S=1706043018:HM/EXP=1102615049/A=2343726/R=0/SIG=12i9deidt/*htt p:/clk.atdmt.com/VON/go/yhxxxvon01900091von/direct/01/&time=110252864921 0501> < D=groups/S=1706043018:HM/EXP=1102615049/A=2343726/R=1/SIG=12i9deidt/*htt p:/clk.atdmt.com/VON/go/yhxxxvon01900091von/direct/01/&time=110252864921 0501> Get unlimited calls to < D=groups/S=1706043018:HM/EXP=1102615049/A=2343726/R=1/SIG=12i9deidt/*htt p:/clk.atdmt.com/VON/go/yhxxxvon01900091von/direct/01/&time=110252864921 0501> U.S./Canada < D=groups/S=1706043018:HM/EXP=1102615049/A=2343726/R=1/SIG=12i9deidt/*htt p:/clk.atdmt.com/VON/go/yhxxxvon01900091von/direct/01/&time=110252864921 0501> < 528649210501> < s/S=:HM/A=2343726/rand=675907763> _____ Yahoo! Groups Links * To visit your group on the web, go to: * To unsubscribe from this group, send an email to: O-14-unsubscribe@... <mailto:O-14-unsubscribe@...?subject=Unsubscribe> * Your use of Yahoo! Groups is subject to the Yahoo! Terms of <> Service. |
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