RMweb Gold The Fatadder Posted October 14, 2022 RMweb Gold Share Posted October 14, 2022 I now have designed two 3d printed models of six wheel NPCCS stock which I need to source suitable chassis for, with an O5 siphon ready to go and a breakdown crane tool van almost ready to print. Having never built a 6 wheel underframe coach before I am looking for recommendations as to the optimal solution so that I can get some parts ordered and finish them off. For the 2 axle models I have just used Bill Bedford units (GWR Coach) as its what ive always used (even if now modelling in OO if it aint broke why change it), I see Eileens have a 6 wheel GWR coach version but I cant see whats different between it and the standard GWR coach units (or how it deals with the centre axle.) I have also seen that Brassmasters sell a 6 wheel chassis. Would be interested to hear opinions as to what works well to ensure good running. 1 Link to post Share on other sites More sharing options...
Miss Prism Posted October 14, 2022 Share Posted October 14, 2022 (edited) Bill's 6-wheel version is a 2mm o.d. tube (on which the wheels are mounted) sliding on a 1mm diameter centre axle. (At least it used to.) The Brassmasters version is a sort of Cleminson, but as such will require adequate space between solebars. I feel the deciding factor will be what kind of track radius you want to operate on. Edited October 14, 2022 by Miss Prism missing verb!!! 2 Link to post Share on other sites More sharing options...
RMweb Gold The Fatadder Posted October 14, 2022 Author RMweb Gold Share Posted October 14, 2022 Curves min radius is somewhere between 3ft6 and 4ft radius, I can’t recall the exact off the top of my head and the picture which would confirm it was lost in the RMWeb crash). Minimum radius of point used is an A6 Link to post Share on other sites More sharing options...
RMweb Gold ianLMS Posted October 14, 2022 RMweb Gold Share Posted October 14, 2022 There are posts on this forum referencing 6 wheel chassis kits for the Palethorpes van and the Stove R coaches. Macgeordie has designed and has etches made for a 6 wheel chassis which allow the centre axle to move and is linked to the other axles. Similar to the Brassmasters version but maybe easier to build and fit to the kit. Not sure of the vehicle u need to put it on but you may want to contact him to see if it will work for you or if he has a spare etch. Failing that, i devised one for a 6 wheel fish van using Comet w-irons. Works ok ish but not as reliable as his version. Ian 3 Link to post Share on other sites More sharing options...
RMweb Gold ianLMS Posted October 14, 2022 RMweb Gold Share Posted October 14, 2022 This is the link to the Palthorpes thread. I think the GWR also had similar vans. Again, i dont know the chassis length of the van you are building but it might be adaptable. Ian Link to post Share on other sites More sharing options...
Wheatley Posted October 14, 2022 Share Posted October 14, 2022 Bill's still uses a 1mm axle with the wheels mounted on 2mm OD tube, I've just built one (or most of one, I haven't sourced the axle and tube yet). The Brassmasters Cleminson is adjustable to various different lengths, it is unsprung but uses a standard axle in the middle. Link to post Share on other sites More sharing options...
RMweb Premium Siberian Snooper Posted October 14, 2022 RMweb Premium Share Posted October 14, 2022 I am shortly going to build a Brassmasters 6 wheel chassis, I will let you know how I get on. 1 1 Link to post Share on other sites More sharing options...
RMweb Gold The Fatadder Posted October 14, 2022 Author RMweb Gold Share Posted October 14, 2022 20 minutes ago, Siberian Snooper said: I am shortly going to build a Brassmasters 6 wheel chassis, I will let you know how I get on. Would also be interested to know what distance between the solbars is needed in order to get the appropriate clearance Link to post Share on other sites More sharing options...
brossard Posted October 14, 2022 Share Posted October 14, 2022 I have used both the Bedford and Clemison systems. I rather favour Bill's because it is easier to detail the underframe. I used the Slater's system on a heavily modified Hornby 6 wheel insul milk van: I managed to get all the detail in while making sure everything was free to move. I used Bill's system for my Comet Stove R: You can see the center axle has large clearance. The 1mm rod sits in the bearings. I think if you were to build in EM and P4 the clearances between wheels and solebar would be much reduced but then, in those gauges, curve radii are less too. John 8 Link to post Share on other sites More sharing options...
RMweb Premium Siberian Snooper Posted October 14, 2022 RMweb Premium Share Posted October 14, 2022 4 hours ago, The Fatadder said: Would also be interested to know what distance between the solbars is needed in order to get the appropriate clearance Hopefully there's going to be enough for EM gauge wheel set to negotiate 3ft radius curves, under IKB 6 wheel coaches designed for P4. Link to post Share on other sites More sharing options...
drduncan Posted October 14, 2022 Share Posted October 14, 2022 MJT do a 6 wheel chassis consisting (in order) of fixed, floating and rocking axles. It’s simple and doesn’t get in the way of under frame fittings like brake gear. Duncan 1 1 1 Link to post Share on other sites More sharing options...
Paul H Vigor Posted October 14, 2022 Share Posted October 14, 2022 #TangoOscarMike of this parish knows a thing or two about 6w chassis kits! Link to post Share on other sites More sharing options...
TangoOscarMike Posted October 14, 2022 Share Posted October 14, 2022 3 hours ago, Paul H Vigor said: #TangoOscarMike of this parish knows a thing or two about 6w chassis kits! Well, that's very gratifying! Perhaps I don't know all that much. I was pretty successful with the Brassmasters kit, in spite of my sketchy soldering skills. Perhaps this will give me the incentive to reinstate some of the pictures. 1 Link to post Share on other sites More sharing options...
Nick Lawson Posted October 15, 2022 Share Posted October 15, 2022 (edited) 21 hours ago, Miss Prism said: Bill's 6-wheel version is a 2mm o.d. tube (on which the wheels are mounted) sliding on a 1mm diameter centre axle. (At least it used to.) 20 hours ago, Wheatley said: Bill's still uses a 1mm axle with the wheels mounted on 2mm OD tube, I've just built one (or most of one, I haven't sourced the axle and tube yet). Bill's kit assumes the availability of exactoscale 1mm axles - which aren't any more. It is possible to buy a length of 1mm steel rod, cut it to length, and turn the ends in an electric drill with a file. (Assuming you don't have a lathe or a friend with one. It takes a bit of attention but isn't that hard to get an acceptable result. Edited October 15, 2022 by Nick Lawson Enter my text! 1 Link to post Share on other sites More sharing options...
MikeTrice Posted October 15, 2022 Share Posted October 15, 2022 The method I use is very simple. Eileen's GNR sprung w-irons for the outer axles, a MJT internal unit for the centre axle with a piece of lead as a weight and a length of N/S wire. The centre axle just goes along for the ride: 9 Link to post Share on other sites More sharing options...
RMweb Premium Chas Levin Posted October 15, 2022 RMweb Premium Share Posted October 15, 2022 Hello Rich, I've use the Brassmasters Cleminson a couple of times now and would thoroughly recommend it - here it is, underneath a Mike Trice 3D printed GNR Brake: I was initially surprised at how much there was to construct, until I'd got a bit further into the build and understood more fully how it works, at which point I changed my mind and decided it was very well designed, beautifully simple and surprisingly effective (usual discplaimed: no connection with the makers, just a happy customer). My layout has tight curves and somewhat poor trackwork in places and this vehicle runs as smoothly as anything else - kit-built or RTR - I have, with only minimal lead weighting too. I did have to take out some material from the insides of the solebars and the fact that they're quite a thick 3D print meant that was possible - I have several etched kits I plan to use this chassis on too and they'll require some careful pre-planning. You mentioned wanting to know measurements - please let me know if you want any points on this model measured, no problem, just let me knwo exactly where you'd like the measurements taken. The logic of the Cleminson design - that as the centre axle moves out sideways, both end axles pivot outwards too, so that the outer sets of wheels stay (relatively) parallel to the track, there's less resistance and less tendency to climb the rails - seems to me to make it a very good solution to the 6 wheel question. 🙂 3 2 Link to post Share on other sites More sharing options...
Brassey Posted October 16, 2022 Share Posted October 16, 2022 I have used the Brassmasters chassis on GWR stock and there were probably pictures on my coaches thread that have likely been lost by the RMWeb crash. They are adaptable to fit a variety of wheelbases. They don't leave much room for cylinders etc. underneath but with a bit of jiggling you can get these to fit. For LNWR I use the London Road Models 6 wheel underframes both 30' and 32'. I am currently converting a 32' to fit a postal/parcel van with a slightly different wheelbase. 1 Link to post Share on other sites More sharing options...
RMweb Gold The Fatadder Posted October 16, 2022 Author RMweb Gold Share Posted October 16, 2022 Thanks for all the photos, gives me a lot to think about both for the design of the van and the type of chassis to go for. 1 Link to post Share on other sites More sharing options...
brossard Posted October 16, 2022 Share Posted October 16, 2022 On 15/10/2022 at 04:17, Nick Lawson said: Bill's kit assumes the availability of exactoscale 1mm axles - which aren't any more. It is possible to buy a length of 1mm steel rod, cut it to length, and turn the ends in an electric drill with a file. (Assuming you don't have a lathe or a friend with one. It takes a bit of attention but isn't that hard to get an acceptable result. My build (see pics above) used 1mm steel rod bought in a hobby shop and cut to length. I filed the ends to be roughly pinpoint but the rod only has to rest in the bearing cavity so precision is unnecessary. John Link to post Share on other sites More sharing options...
Nick Lawson Posted October 16, 2022 Share Posted October 16, 2022 4 hours ago, brossard said: so precision is unnecessary @brossardWell my first attempt was such that the 1mm axle turned in the bearings but made a horrible squeaking noise when running, so I had it out for a second go. Perhaps I'd modify your statement and say either make the axle fixed, as you appear to have done, or if making it free turning then one needs to make a reasonable stab for precision to avoid such unpleasantness? I went for a free-turning inner axle as I'd seen someone say this was necessary (can't remember where/who); but presumably you get satisfactory running just from the outer axle turning on the fixed inner? Link to post Share on other sites More sharing options...
Nick Lawson Posted October 16, 2022 Share Posted October 16, 2022 @brossard PS I love the detailing on your Stove R! 1 1 Link to post Share on other sites More sharing options...
Wheatley Posted October 16, 2022 Share Posted October 16, 2022 (edited) This is the Bill Bedford system, the centre axle is a bit of 1mm brass rod turned to a point at each end on a mini drill, the wheels are mounted on a bit of 1mm ID 2mm OD tube (Albion Alloys BW10). The tube runs freely on the rod, I'm not sure the 'axle' is revolving at all but it all works. Brake rigging is also included, still to add. Edited October 16, 2022 by Wheatley 5 Link to post Share on other sites More sharing options...
brossard Posted October 17, 2022 Share Posted October 17, 2022 19 hours ago, Nick Lawson said: @brossardWell my first attempt was such that the 1mm axle turned in the bearings but made a horrible squeaking noise when running, so I had it out for a second go. Perhaps I'd modify your statement and say either make the axle fixed, as you appear to have done, or if making it free turning then one needs to make a reasonable stab for precision to avoid such unpleasantness? I went for a free-turning inner axle as I'd seen someone say this was necessary (can't remember where/who); but presumably you get satisfactory running just from the outer axle turning on the fixed inner? The steel rod axle may or may not rotate, it doesn't really matter. Wheatley has it right. The important thing, IMO, is that the 2mm tube turns freely on the axle. John Link to post Share on other sites More sharing options...
brossard Posted October 17, 2022 Share Posted October 17, 2022 19 hours ago, Nick Lawson said: @brossard PS I love the detailing on your Stove R! LMS used a standard underframe for their 6 wheeled vehicles with brakes on all wheels. Not all 6 wheelers had brakes all round though. My source was an article by Bob Essery in either Midland Record or LMS Journal where repro works drawings were included. I just love drawings. John 1 Link to post Share on other sites More sharing options...
RMweb Premium Siberian Snooper Posted October 17, 2022 RMweb Premium Share Posted October 17, 2022 Due to a lack of 10ba nuts and bolts, the Brassmasters chassis build is on hold until my Ebay order turns up. 1 Link to post Share on other sites More sharing options...
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