P4 conversion work

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jim s-w
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Re: Starting out in P4

Postby jim s-w » Wed Nov 05, 2014 10:30 am

It's a pickle isn't it. The vi trains 47 suffers the same problem with a big gap and they reduced the height of the body to compensate. I rather like the approach hornby took with their 50, ie fit smaller wheels. It's a shame they cast the extra pad for the ride height on the chassis as its a bit of effort to fix.

Cheers

Jim

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Colin Parks
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Re: Starting out in P4

Postby Colin Parks » Wed Nov 05, 2014 10:50 am

JFS wrote:Hello Colin,

... and many thanks for the kind words. The design is a reflection of the way my mind works (and that is not a good thing - just ask Mrs JFS!). But I have to confess that the real thing got there first and the escapement crank idea is pinched from a combined point and FPL operating mechanism.

The tubing did indeed come from Eileens but you do have to be a bit careful as 1mm OD tube does not always fit in 1mm ID stuff, and sometimes tube sold as a metric size turns out to be an imperial equivalent (that is a general comment - not related to any bad experience with Eileens) so I did size the holes to fit specific tube sizes, then, when I knew all was well, I bought in bulk.

There is slightly more to the micro switch operation than might meet the eye. In fact the extra bit soldered to the rodding is a bit of nickel silver fret waste (I have quite a lot of that!) about 6mm wide. The white piece with 14E/W scrawled on it is .060" plasticard with a bit of (about) .150" x .080" welded on edge to it against which the rodding bears. The micro switches are glued (!) to this plastic base, then the whole lot is slid behind the wire and fixed with some small screws. The idea is that it can all be assembled on the bench then fixed as a unit. If any of the switches ever pack up then a replacement is on hand for the offending unit (assuming the geometries are all the same!) I have seen people mount micro switches so that they are "pushed" by the END of the rodding but to me this is bad form as the spring in the switch is then putting the rodding in compression, and only the last bit of movement is called upon to do the switching.

Very Best Wishes,


Hi Howard,

I have noted the materials used by you for point operation. As you know, I have been toying with the idea of using foam board for baseboard tops, but looking at that lot in the photo, it would be very hard to fix to securely. Hmm.

Studying the photo of your layout's rodding and switches, it appears that the 'top' switch (no. 14) has six connections. I can understand a three terminal switch's function, but forgive me for being ignorant, what does this six terminal switch control? I like the block instruments that you have in that picture.

Colin

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Colin Parks
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Re: Starting out in P4

Postby Colin Parks » Wed Nov 05, 2014 11:10 am

Simon Glidewell said:

That looks lovely Colin and the new wheels finish it off a treat! It always seems a pity to paint the wheel rims. The early BR livery really suits these locos. I remember just how well your 73 ran on Newhaven Harbour. The Dapol class 73 is rumoured to be appearing on the market around January or February 2015; I just wonder how much "better" it will be than the Hornby/Lima model? My fear is that the gap between the bogies and the body will be too great, as with the class 22 which was really spoilt by this blemish. This is almost impossible to cure, by lowering the body by modifying the gear towers, as this drops the buffer line too low. I saw an example of a class 22 that had had this modification, but lined up with a wagon it just looked all wrong. The venerable Hornby class 73 looks spot on in this respect and really captures the look of the prototype. I'm in two minds about my own Hornby conversion, as to whether to replace it with the Dapol model, and then there's the problem of fitting replacement P4 wheels to the newcomer. I have also considered the possibility of "purchasing" one of the phantom DJM class 71's if they ever appear, but again I fear with a "Dapol" heritage it could suffer from the same bogie and body gap problem.

All the best
Simon[/quote]

Hi Simon,

I would expect the Dapol class 73 to be an improvement on the Hornby/Lima version in the chassis dept.. Looking at the pre-production Dapol model, it looks pretty good, especially the bogie detail. However, the Lima tooling of the class 73's body is not bad at all - even though the grills are not see-through. On my 73 the horns were replaced and the cut-away on the cab roof was filled in. The moulded handrails were also removed and wire ones added, being filed flat to look more like the real thing.

The body was lowered on the chassis by altering the height of the bogie pivots, to produce a near-scale gap between the bogies and body side. This did make the ride height a bit too low, but bearing in mind that the Hornby model is fitted with Lima style wheels of too small a diameter (11.5mm), once the 13mm Ultrascale replacement wheels were fitted, the ride height came back up to normal again.

I can't comment on how easy it would be to convert a Dapol class 73 to P4 or how to rectify the problem gap on the class 22, but the idea of buying a class 71 is very tempting!

Colin

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Colin Parks
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Re: Starting out in P4

Postby Colin Parks » Wed Nov 05, 2014 11:28 am

jim s-w wrote:It's a pickle isn't it. The vi trains 47 suffers the same problem with a big gap and they reduced the height of the body to compensate. I rather like the approach hornby took with their 50, ie fit smaller wheels. It's a shame they cast the extra pad for the ride height on the chassis as its a bit of effort to fix.

Cheers

Jim


Hi Jim,

Re. the Vi Trains 47: Didn't someone suggest moving the bogie side frames up to reduce the gap? Perhaps the gap is too great to move the frames enough without the axle boxes being noticeably out of line with the axles. Hornby and Lima luckily did seem to reduce the wheels diameters to compensate for the wider gaps which they saw fit to design into earlier diesel/electric loco models.

As I mentioned in my recent reply to Simon, the class 73's body-to-bogie gap is easy to rectify as it the wheels are too small. Improving the chassis detail is another matter. It sometimes seems as though two different designers are responsible for some models. It is hard to believe that the 73's body was designed by the same person who designed the chassis!

It took me a while back in 2006 to persuade Mr. Ultrascale to supply me with 13mm dia. wheels for the Hornby 73 instead of the direct replacement size of 11.5mm. I reasoned with him that if someone was going to fit his wheels, they would also address the problem of the ride height too. He did agree, and has supplied that size ever since. Other models might be more difficult to alter. maybe I was just lucky in my choice of prototype!

Colin

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jim s-w
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Re: Starting out in P4

Postby jim s-w » Wed Nov 05, 2014 11:36 am

Hi Colin

It wont fix the body though. See the below comparison with Lima (left on a vi trains chassis) and pure (but lowered) vi trains on the right.

Image

Cheers

Jim

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Colin Parks
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Re: Starting out in P4

Postby Colin Parks » Wed Nov 05, 2014 11:57 am

jim s-w wrote:Hi Colin

It wont fix the body though. See the below comparison with Lima (left on a vi trains chassis) and pure (but lowered) vi trains on the right.

Image

Cheers

Jim


Crikey Jim, that looks like an insurmountable problem with the gaps and the bodies on those 47s! There is not much that can be done to extend a squat body. Hornby did the same thing on their infamous 4 VEP EMU model, where the body sides are about 1mm too low. I didn't buy one.

Colin

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Simon Glidewell
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Re: Starting out in P4

Postby Simon Glidewell » Wed Nov 05, 2014 1:13 pm

This is my unfinished P4 conversion of the Hornby class 73 into a 73/0 with the same Ultrascale wheels that Colin has used, plus the gap between the bogies and body was reduced. The brown etched grill still needs painting into BR blue; there is full relief detail behind it. The bogie steps are etched by Pete Harvey and my loco was the Guinea Pig for these before they went on sale. The bogies themselves and the underframe detail were completely rebuilt with many scratch built parts; the oily plastic that Hornby use make glueing details to the bogies very hard indeed!
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Class 73.jpg
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JFS
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Re: Starting out in P4

Postby JFS » Wed Nov 05, 2014 5:05 pm

Colin Parks wrote:
it appears that the 'top' switch (no. 14) has six connections. I can understand a three terminal switch's function, but forgive me for being ignorant, what does this six terminal switch control? I like the block instruments that you have in that picture.

Colin


Hello Colin,

It is because 14 is a crossover - two points, one lever, one rod - so there are two switches one for each point worked from the same bit of rodding. Because the "roads" on which the points are located have separate feeds the two "positive" connections are independent.

The block instruments are of course the best - Southern Railway Standard Three Wire Three Position - as hitherto featuring at Newhaven Harbour!

Very Best Wishes,

JFS
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Re: Starting out in P4

Postby JFS » Wed Nov 05, 2014 5:07 pm

Simon Glidewell wrote:This is my unfinished P4 conversion of the Hornby class 73 into a 73/0


Very nice Simon.

Of course, we are still awaiting your thread on your working third rail and pickups!!

(and how you avoid something like this getting "gapped"!

Best Wishes,

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Tim V
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Re: Starting out in P4

Postby Tim V » Thu Nov 06, 2014 5:58 pm

JFS wrote:Now having said all of that are you SURE that a miniature relay is that much more reliable than the contacts in a micro switch? I am siting beneath my "Signal box Simulator" the computer interface for which includes about twenty relays - and one of those (admittedly a sub miniature) failed within six months [draws current but fails to pick-up]. On the other hand, I wonder just how many people who use micro switches actually read the data sheet for them? There are specified limits to the extent of travel and one suspects they are there for a reason...

Signal Box.JPG


Best wishes,


Wow, a very nice shelf there Howard. Have you explained it elsewhere - I seem to have missed this?
Tim V
Scalefour News Editor

JFS
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Re: Starting out in P4

Postby JFS » Thu Nov 06, 2014 7:10 pm

Hello Tim,

Thank you for the kind words!

I've not really described it anywhere - it is based on Ford (Sussex) as it existed in the late fifties. The instruments were mostly obtained through a well known e-auction site, and I built the PC interface using off-the-shelf USB interface cards. It is all wired up to be driven by a programme I wrote for the PC.

If you (or anyone else) wants it have a play with the programme, it (and a few others) can be download from here:-

http://www.blockpostsoftware.co.uk/downloads.php

..creating that lot is my excuse for slow progress on Minories :D I think they are quite good fun but beware - they are a bit addictive!

Best Wishes,

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Colin Parks
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Re: Starting out in P4

Postby Colin Parks » Sat Nov 15, 2014 8:16 pm

Today, my attention was turned to making something for the easy assembly of Exactoscale wheels to their axles. I had tried to use the society's B2B gauge, but it only has a compass of 270 degrees and is of a smaller diameter than would be suitable for wagon or coach wheels.

A piece of 5/8" brass bar was turned to match the society B2B width (exactly) and drilled through to just clear the Exactoscale axle diameter. A slight counter-sink was needed to allow clearance for the wheel boss (and even a bit more than shown in the photo!) A slot was milled down to the axle centreline with an improvised 6.5mm end milling cutter was ground down from a suitable drill. The milling process took a while - (must buy a few sizes of proper end mills before long). The slot is wide enough to ensure that an equal gap between wheel and axle at each end can be seen and maintained, without loosing too much of the bar's circumference. A pair of discs were turned and drilled with a clearance holes for the protruding pin-point axles, plus counter-sinks for the wheel bosses. Just standing the whole lot upright on a flat surface while the Loctite 603 cures seems to be adequate, but lightly clamping the assembly could be possible.

IMG_7694_1.JPG


IMG_7693.JPG


It still means only one wheelset at a time can be produced, but by Christmas I should have quite a pile!

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Simon Glidewell
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Re: Starting out in P4

Postby Simon Glidewell » Sat Nov 15, 2014 9:57 pm

Very neat Colin! You'll be selling those in the society stores before long!

All the best
Simon

Brinkly
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Re: Starting out in P4

Postby Brinkly » Sat Nov 15, 2014 11:29 pm

Simon Glidewell wrote:Very neat Colin! You'll be selling those in the society stores before long!

All the best
Simon


Yes,

If you did go into production, I would certainly buy a set!

Kind regards,

Nick.

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Colin Parks
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Re: Starting out in P4

Postby Colin Parks » Sun Nov 16, 2014 10:23 am

Thanks Simon and Brinkly for your comments!

There is no chance of me going into production sadly, it just takes too long for me to make this jig. Having assembled the first set of wheels in this way, the jig has been proved to work. However centring the axle on the wheels is still a matter of judgement by eye, which seems a bit unsatisfactory.

I can't think of a better way of positioning the axle in the jig as yet. Perhaps some sort of screw adjustment bearing on the pin-points would be possible. It still means lining the axle up on the wheels by eye though.

Colin

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grovenor-2685
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Re: Starting out in P4

Postby grovenor-2685 » Sun Nov 16, 2014 12:37 pm

Could your end caps accept only the defined length of axle end so that fitting the end caps automatically centralises the axle?
I thought that was the idea otherwise I see little benefit over the normal right angle BB gauge.
Regards
Keith
Regards
Keith
Grovenor Sidings

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Colin Parks
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Re: Starting out in P4

Postby Colin Parks » Sun Nov 16, 2014 2:43 pm

grovenor-2685 wrote:Could your end caps accept only the defined length of axle end so that fitting the end caps automatically centralises the axle?
I thought that was the idea otherwise I see little benefit over the normal right angle BB gauge.
Regards
Keith


Hi Keith,

Yes, an end stop would be the solution. It could be in the form of an adjustable grub screw in a wider 'end cap' which would then be placed at the bottom when assembling the wheelsets. The main reason that I am making my own jig is that the Exactoscale B2B gauge is out of stock (and costs £25.00 + VAT when it is!)

Colin

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Colin Parks
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Re: Starting out in P4

Postby Colin Parks » Mon Jan 19, 2015 6:23 pm

Now to clear up one point raised by Will Litchfield in the last S4 News: No, my membership number was not inherited, I joined the society in 1979 at the age of 19 but never really did anything other than buy a few parts to experiment with. Hope that clears up the mystery Will. Perhaps my photo is in need of an update though, having been taken five years ago!

Before Christmas I was messing around with an SR brake van which had been converted to P4 using its existing 00 MJT compensation units with spacers to hold the wheels in position. (This wagon having been made a while a go with compensation to see how compensation would perform on 00 track.) The livery is based on a photo of a van which can be seen on Paul Bartett's website. The green patch-paintwork is rather quirky, but typical of the 'mend and make do' policy on the Southern Region in the seventies.
This will truly be a 'brake' van as it has a wire bearing on one axle to create some rolling resistance. When coupled to the end of a train, a brake van so fitted keeps the couplings taut throughout the train. (The problem of the bunching of loose-coupled wagons was just as bad with Bachmann couplings, which all my 00 stock had.)

IMG_7723.JPG


IMG_7724.JPG


The van has Lanarkshire Models buffers (heads a tad big for this prototype), couplings which comprise of Masokits hooks, home-made links and a pair of old PC Models Instanter coupling links in between. Now I have a problem: There seems to be only one supplier of etched Instanter links of the BR type, but nice as they are, they are about 20% too large as can be seen in the next photo (and the first):

IMG_7725.JPG


Does anyone know of an alternative supplier of these links - other than of the GWR bar type?

Colin

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grovenor-2685
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Re: Starting out in P4

Postby grovenor-2685 » Mon Jan 19, 2015 7:56 pm

Well, Exactoscale did the Instanters but it seems they have been withdrawn!
http://www.finescale.org.uk/index.php?route=product/category&path=541_542_543
Regards
Keith
Regards
Keith
Grovenor Sidings

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Colin Parks
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Re: Starting out in P4

Postby Colin Parks » Mon Jan 19, 2015 11:41 pm

Hi Keith,

Yes, there is no reason given for the withdrawal of the Exactoscale etch, leaving only the Ambis ones for the BR modeller. I had always wondered why so many models of BR stock were fitted with GW type instanters and not the BR pattern, well now I know! There are a few of the GW type links included on the Masokits very excellent etch for screw type couplings, but not enough in proportion for my wagon fleet's needs.

All the best,

Colin

Terry Bendall
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Re: Starting out in P4

Postby Terry Bendall » Tue Jan 20, 2015 7:38 am

I use Smiths 3 link and Instanter couplings, which may be what you have used Colin. Yes they are overscale but they do give a better chance of actually coupling up. In the absence of anything better, it would probably be possible to take a file to the centre link and thin it down a bit, and to make new end links using a simple bending jig. As with everything else, it depends on what you want to achieve and how far you are prepared to go to achieve it.

Terry Bendall

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Colin Parks
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Re: Starting out in P4

Postby Colin Parks » Tue Jan 20, 2015 8:37 am

Thanks Terry,
I shall have a look at the Smiths Instanters links. I had thought of filing the present In starter links, but it still leaves to slot in them too long which is what makes the links hang too low. The PC etched link looks about the right length for an Instanter link. I could make the upper and lower link of each coupling to exact scale, though that would just make the Ambis link look even bigger.

All the best,

Colin

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Colin Parks
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Re: Starting out in P4

Postby Colin Parks » Mon Sep 14, 2015 6:52 pm

I am shocked to see how long it has been since I last updated this topic. To tell the truth, there was not much to update. Below are pictures of work on wagon conversion, which has so far this week involved converting three vans and ballasting them up to weigh in at about 40g. The Digest says 25g per axle, but it would be a great squeeze to get that much lead under an open wagon with no load, so 40g it is -for now.

IMG_7816.JPG


The upturned banana van shows how much of a tight fit it was getting the lead between the moulded chassis members. Even that was not enough, so the roof was prised off to add some more weight inside. The vans all have the very nice Masokits screw couplings fitted.

IMG_7817.JPG


The plan is to have AJs on the outer ends of trains of wagons with authentic couplings within the train. Still no luck with a definitive Instanter coupling link.

Colin

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Lord Colnago
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Re: Starting out in P4

Postby Lord Colnago » Mon Sep 14, 2015 7:29 pm

Hi Colin,

I always leave the roof off my vans until I've weighted them up. Cut a piece of lead to fit just inside the van. The thickness I use comes out at more or less the required 50gm and its easy to trim a bit off to get the whole wagon weight just right. Just make sure that you centre the lead within the wagon when you glue it in place and don't move it until the glue goes off!

Opens, as you infer, are a different kettle of fish. I used to try to hide the lead in the underframe as you have done with the van in the photo but I find it extremely difficult with some of the more detailed underframes to get the lead in past the detail, not to mention the problems of getting sufficient in to make up the weight. I now tend to cut a piece of lead to as precise a fit as I can get inside the wagon and scribe the plank lines on it. You lose some of the depth inside but it looks OK. Just another of those little compromises we all have to make with our modelling from time to time.

An alternative is that used by Justin Newitt. I think he wrote it up on his workbench thread, but he cuts the plastic wagon floor away, leaving a little bit for fixing to the underframe. He then cuts the lead sheet to fit in the hole that he cut away. It looks quite neat and doesn't lose any depth. You pays your money, as they say.

Good luck with the modelling, I like the vans. Not sure the perfect instanter links exists though. Another case for compromise?

John.
The second best priest

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Lord Colnago
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Re: Starting out in P4

Postby Lord Colnago » Mon Sep 14, 2015 7:48 pm

Hi Colin,

I've just had a look to see where that fiendish Mr. Newitt had hidden that bit on wagon floors that I mentioned in my reply. Have a look on his workbench thread under the "A 16T rarity" heading. Its a good read in any case, with lots of useful hints.

John.
The second best priest


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