P4 conversion work

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grovenor-2685
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Re: Starting out in P4

Postby grovenor-2685 » Sun Oct 19, 2014 8:55 am

I used the Ambis "PALM" setup for my test point, not a double slip but should not matter, it has stood up to quite a few years of carting around and messing with. Good for use with Servos or just a mechanical rod connection to the PALM.


Keith
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Re: Starting out in P4

Postby JFS » Sun Oct 19, 2014 4:39 pm

Colin Parks wrote:"This one" Howard, This one?! I had hoped not to have to go through this process twice.
Colin

:D :D

I'm sure this one will work very well. BTW the pain is much less with subsequent ones - I do seem to recall saying that a double slip was a baptism of fire...

Planning ahead really is the key to success, and now that you have this one under your belt, you know what the issues are likely to be. I will PM you with some ideas for mechanical operation.

Many thanks for the kind words re MRJ.

Very Best Wishes,

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Re: Starting out in P4

Postby grovenor-2685 » Sun Oct 19, 2014 5:45 pm

I will PM you with some ideas for mechanical operation.

Why hide it in a PM? I'm sure the rest of us would appreciate it as well Howard.
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Re: Starting out in P4

Postby JFS » Sun Oct 19, 2014 8:41 pm

grovenor-2685 wrote:
I will PM you with some ideas for mechanical operation.

Why hide it in a PM? I'm sure the rest of us would appreciate it as well Howard.
Regards
Keith


Good question Keith: It is just that it involves some of my own "custom etches" which - if they are not available to "everyone" (and I don't really want to "go into business" in competition with The Stores who already sell an alternative solution) - might not be of general interest. And the last thing I want to do is to hijack Colin's thread - which I think is generating some excellent stuff - with a discussion about the merits and otherwise of my way of working points, certain aspects of which - as you know - might justifiably be described as "eccentric" :D

Have I just talked myself into starting another thread?

Cheers,

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Colin Parks
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Re: Starting out in P4

Postby Colin Parks » Tue Oct 21, 2014 5:48 pm

grovenor-2685 wrote:I used the Ambis "PALM" setup for my test point, not a double slip but should not matter, it has stood up to quite a few years of carting around and messing with. Good for use with Servos or just a mechanical rod connection to the PALM.


Keith


Thanks for the videos Keith.

That PALM unit looks to have quite a benign action. It looks as if it could be operated with a wire-in-tube and lever system. Howard has devised something along similar lines. Perhaps he would like to tell us how his method works...

All the best,

Colin

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Re: Starting out in P4

Postby grovenor-2685 » Tue Oct 21, 2014 6:49 pm

Wire in tube is OK. For my mechanically worked points I have used below board rodding made with Model Aircraft components below board.
They are rather more robust that the small bore "Mercontrol" style. Model aircraft shops also have wire in tube 'snakes' to go with the rodding.
Keith
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Re: Starting out in P4

Postby Colin Parks » Tue Oct 28, 2014 4:02 pm

grovenor-2685 wrote:Wire in tube is OK. For my mechanically worked points I have used below board rodding made with Model Aircraft components below board.
They are rather more robust that the small bore "Mercontrol" style. Model aircraft shops also have wire in tube 'snakes' to go with the rodding.
Keith


Hi Keith,

Thanks for the tip about using model aircraft components to operate point work. The missing link now is literally how to get from under the base board to the surface, with some sort of small cranks to connect to the stretcher bar linkage.

Colin

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Re: Starting out in P4

Postby JFS » Tue Oct 28, 2014 4:38 pm

Colin Parks wrote: The missing link now is literally how to get from under the base board to the surface, with some sort of small cranks to connect to the stretcher bar linkage.

Colin


Hello Colin,

Give me a few days and I will post something - just a bit busy this week.

I see Simon is asking for help in Diamond crossings - you might be the man to help!

Very Best Wishes,

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Re: Starting out in P4

Postby Colin Parks » Tue Oct 28, 2014 5:34 pm

Thanks Howard,

No hurry with whatever it is you are posting. I shall be grinding away at planning the rest of the track formation using Templot for a while.

(Not sure what I can do to help Simon with diamond crossings!)

Colin

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Re: Starting out in P4

Postby Terry Bendall » Wed Oct 29, 2014 7:35 am

Colin Parks wrote:The missing link now is literally how to get from under the base board to the surface, with some sort of small cranks to connect to the stretcher bar linkage.


I use Tortoise motors but for the missing link I use a piece of 3mm dia. brass rod which runs in a brass tube bearing in the top of the baseboard. The top end of the rod is turned down in the lathe and a crank soldered on. Usually the crank is one from the Masokits range and it is double thickness. A wire from the streatcher bar is then connected to the crank by bending it through 90 degress at the end, passing it through the crank and then bending the wire down. It works and it is reliable. Yes I know that the wire from the streatcher bar is bending a small amount and is therefore under stress but it works.

Terry Bendall

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Re: Starting out in P4

Postby Colin Parks » Mon Nov 03, 2014 3:36 pm

Thanks for the advice Terry re. point operation linkage. I like the idea of the brass tube being used as a bearing for the 3mm brass rod. That certainly would be very robust. I do have a lathe, so turning down the brass rod to accept a scale size crank would be feasible.

Colin
Last edited by Colin Parks on Mon Nov 03, 2014 4:08 pm, edited 1 time in total.

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Re: Starting out in P4

Postby Colin Parks » Mon Nov 03, 2014 4:04 pm

Oh, if only it were all this easy!

On the workbench today is my Hornby class 73 which has had Ultrascale P4 wheels installed in place of the same maker's 00 ones. The conversion probably took less time this time than with the 00 ones as there is no need to carve away any of the power bogie's plastic moulding. The wheels will remain shiny until the loco has been tested. There is the forthcoming Dapol class 73 of course, but having spent quite a bit of time on the chassis detail (though not to the standard of Simon Glidewell's '73), I shall stick with this old 73. It also has a spare body with the later BR livery and TOPS code which can be swapped for this body in a few minutes. The P4 wheels do make the loco look hefty and just right, rather than having the appearance of standing on tippytoes with the 00 wheels.

IMG_1684.JPG


It was interesting to note that the 00 wheels that came out of this loco were quite fine. I seem to recall Brian Rogers of U/scale saying they were to 'Pendon' profile, which his father had developed with Guy Williams (at least I think he said that - it was eight years ago).

Not that I want to open any old wounds, but the 00 flanges are just 0.6mm deep and the tyre width only 0.4mm wider than the P4 wheels. So, if this loco ran on 00 track that was thrown together with not much care on its rather fine profile wheels, it looks promising that it will now run well on P4 track (which hopefully will not be thrown together) on wheels that are not much finer (famous last words etc., etc.!). It does weigh quite a bit, which must help too.

Colin

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Re: Starting out in P4

Postby Steve Carter » Mon Nov 03, 2014 5:22 pm

Well Colin, that picture takes me back to my time working on the full size version at Stewarts Lane :)
Great memories, thanks.
Well done
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Re: Starting out in P4

Postby Terry Bendall » Tue Nov 04, 2014 7:46 am

Colin Parks wrote: it looks promising that it will now run well on P4 track (which hopefully will not be thrown together) on wheels that are not much finer (famous last words etc., etc.!)


All things being equal Colin there is no reason why the P4 wheels should not run as well as when the loco was on OO track. A useful idea that I picked up from Phil Eames a little while back is to test the loco on its OO wheels first and if it is a three axle bogie check that all three axles are level. That way you know that some of the potential problems are OK before you even fit the P4 wheels.

Terry Bendall

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Re: Starting out in P4

Postby Colin Parks » Tue Nov 04, 2014 10:33 am

Hi Terry,

I have the advantage with this loco that it has run for nearly eight years on its 00 wheels without incident. I was quite heartened to see how fine the flanges were on the 00 wheels when I took them off, so I can't wait to get going with a test track now to see how the class 73 performs now on its P4 wheels. I also have the 08 shunter to finish off and that also needs testing first.

Fortunately, I have no Co-Co locos to complicate matters, so all conversions to P4 should be relatively easy.

All the best,

Colin

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Re: Starting out in P4

Postby Colin Parks » Tue Nov 04, 2014 10:44 am

Steve Carter wrote:Well Colin, that picture takes me back to my time working on the full size version at Stewarts Lane :)
Great memories, thanks.
Well done


Well, thank you for your comments Steve.!

Colin

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Re: Starting out in P4

Postby JFS » Tue Nov 04, 2014 1:44 pm

Hello Colin / All,

I did promise to post a few pics of how I arranged the under-baseboard drive to my switches so here goes... but first I have to say that I made some custom etches to solve this issue as I could not find anything "commercially" to do the job I wanted. I know that is a frustration for people who don't have access to such things, but nonetheless, I hope that my thinking might help others to develop their own solution. Equally, the Ambis PALM as described by Kieth above, has similar functionality as a readily available alternative.

The basic concept is to translate the underbasboard linear motion (in my case from the lever frame, though it may be a stall-motor of the Cobalt / Tortoise etc type) into an above baseboard movement to drive the switch blades. The key idea is the use of an "escapement" crank. This is driven from the "rodding" (which has a total travel of 15mm) in such a way in such a way that the first and last 2mm of travel produce no rotation of the crank - all the rotation comes from the middle 11mm of movement. The reasoning here is that, no matter how hard you try, there will always be slop / rattle / sticktion / wear / expansion affecting the underbaseboard gubbins, and this must never be transmitted to the blades. In other words, provided you can get a reliable movement of 11mm mid stroke, the total movement can vary by 2-3mm without having any impact on the positioning of the blades against the stockrail. Even better, the form of the escapement crank causes the blades to be locked at each end of their throw.

Now let me say that the Ambis PALM gives exactly the same functionality - my only reasons for going my own way being that the PALM is a bit of a fiddle to assemble (with about a dozen or so parts) and it did not have much in-built adjustment of throw beyond a choice of operating cranks. But it does work well and I commend it as an off-the-shelf-solution'

Here is a shot of what mine looks like from underneath:-

Underbase board drives [small].jpg


(ignore those cranks at bottom left, they just work the rodding to drive the FPLs - which are a lot less critical than the blades - and so are located together under the signal box.)

In terms of what the bits look like....

Pointdrive 2 small.jpg


The escapement crank itself is the one with the three-pointed slot in the end. The crank with the three holes is the one which is soldered to the bottom end of the drive shaft - the three holes being the means of providing an adjustable throw and work with the other slot in the escapement crank.

The brass tube with the collar on the end is the drive shaft which transmits the rotary motion to the above-basboard crank. The idea is that this can be properly soldered up "off the job" (for strength) then pushed down through the unit, then soldered from below. That way (a) the result should have enough strength and durability (b) there is scope for some adjustment (c) there is plenty of metal to resist loss of motion in torsion. The shaft itself is made up of bits of telescopic brass tubing the smallest of which is a sliding fit on a Duchesse pin to which the top crank has been soldered and which in turn can then be soldered into the tube. Thus there is a decent area of solder on both sides of the crank to transmit the load - this is tricky thing to make strong yet of scale appearance. You can see that above base board I used a scale "adjustment crank" for the final bit. Not everyone will be as fussy as me! I would have to confess that I did have one of these joints fail on me - so much for my soldering skills - but it was easily fixed by removing the shaft and re-making the joint. (I think in hindsight, I just pushed the pin into the tube and forgot to solder it up!)

The hardest bit of the whole job is minimising the lost motion AFTER the escapement crank and this requires a fair bit of care but it can be done and is certainly easier than trying to eliminate lost motion on the whole under-baseboard rodding run! A LITTLE bit of over travel to keep some pressure on the blades is no bad thing but don't over do it or a failure is just round the corner somewhere.

I have never actually tried using one of these with a Stall point motor, but, in concept it should be easy since the slot for the drive provides an ideal way of limiting the travel of the motor without transmitting any force to the blades.

Hope that is reasonably clear (it is not easy to describe!)

Best wishes,

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Re: Starting out in P4

Postby Colin Parks » Tue Nov 04, 2014 3:46 pm

Hi Howard,

Thanks for the photos and explanation of the workings of your escapement crank mechanisms. I don't know how you managed to design such a thing, but it does look very effective. Having the extra 2mm of travel at each end of the throw makes life a lot easier for operation. Does the brass tube used in the units come form Eileen's by any chance?

I have just noticed the extra pieces of wire soldered onto the rodding which activates the micro-switches - as shown in the first picture. It is all very neatly arranged.

Colin

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Re: Starting out in P4

Postby JFS » Tue Nov 04, 2014 4:13 pm

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,

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Re: Starting out in P4

Postby Martin Wynne » Tue Nov 04, 2014 4:46 pm

JFS wrote:There is slightly more to the micro switch operation than might meet the eye.

Hi Howard,

Micro-switches are fiddly to fix and keeping them adjusted is always a pain because the internals are so flimsy. I would have connected the whole rodding assembly to ground, put an insulated bit of bent springy phos-bronze wire where your micro-switch rollers are, and used the contact to operate a relay for polarity switching. Nowadays you can get a small sealed relay for not much more than the cost of a micro-switch, and it is a fit-and-forget component requiring no adjustment. Easily fixed anywhere with a dab from the hot glue gun.

Having to adjust a micro-switch underneath a baseboard is a cruel punishment in contravention of the Geneva convention.

regards,

Martin.
40+ years developing Templot. And counting ...

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Re: Starting out in P4

Postby JFS » Tue Nov 04, 2014 7:20 pm

Martin Wynne wrote:
JFS wrote:There is slightly more to the micro switch operation than might meet the eye.

Hi Howard,

Micro-switches are fiddly to fix and keeping them adjusted is always a pain because the internals are so flimsy. I would have connected the whole rodding assembly to ground, put an insulated bit of bent springy phos-bronze wire where your micro-switch rollers are, and used the contact to operate a relay for polarity switching. Nowadays you can get a small sealed relay for not much more than the cost of a micro-switch, and it is a fit-and-forget component requiring no adjustment. Easily fixed anywhere with a dab from the hot glue gun.

Having to adjust a micro-switch underneath a baseboard is a cruel punishment in contravention of the Geneva convention.

regards,

Martin.


Hello Martin,

Many thanks for a very interesting interesting idea!

I have a lot of sympathy with what you say - I have not personally had one of these fail but I know a man.... and I do know that they are certainly not any kind of panacea. Also agree about having to make adjustments underneath and that is why I made the whole unit replaceable (but I did not go so far as to have detachable connections!!)

But of course, I made life more complicated by having working point rodding - so all this lot is electrically connected to the above baseboard stuff. And a short circuit by accidental contact to both running rails is a real risk - so the whole lot is very carefully electrically isolated. Of course that does not negate your principle as a fully independent supply could be used - but it would be an additional complication. So perhaps for next time...

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
Signal Box.JPG (67.57 KiB) Viewed 9478 times


Best wishes,
Last edited by JFS on Tue Nov 04, 2014 8:42 pm, edited 2 times in total.

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Martin Wynne
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Re: Starting out in P4

Postby Martin Wynne » Tue Nov 04, 2014 8:18 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?

Hi Howard,

It depends how miniature. Image

On Adavoyle Junction we had well over 100 of these "little men" (as Tony Miles called them) scattered about under the baseboards and in the control panel:

http://uk.rs-online.com/web/p/non-latch ... s/7933777/

(Actually they were 24volt, but essentially the same thing.)

In 20 years on the exhibition circuit the only one which ever failed was the one Tony rested his soldering iron on.

regards,

Martin.
40+ years developing Templot. And counting ...

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Re: Starting out in P4

Postby Terry Bendall » Wed Nov 05, 2014 7:26 am

Very nice and neat Howard, but I would not have expected anything else. :) The drive to the micro switches is a very useful idea.

Terry Bendall

Simon Glidewell

Re: Starting out in P4

Postby Simon Glidewell » Wed Nov 05, 2014 8:05 am

Colin Parks wrote:Oh, if only it were all this easy!

On the workbench today is my Hornby class 73 which has had Ultrascale P4 wheels installed in place of the same maker's 00 ones. The conversion probably took less time this time than with the 00 ones as there is no need to carve away any of the power bogie's plastic moulding. The wheels will remain shiny until the loco has been tested. There is the forthcoming Dapol class 73 of course, but having spent quite a bit of time on the chassis detail (though not to the standard of Simon Glidewell's '73), I shall stick with this old 73. It also has a spare body with the later BR livery and TOPS code which can be swapped for this body in a few minutes. The P4 wheels do make the loco look hefty and just right, rather than having the appearance of standing on tippytoes with the 00 wheels.

IMG_1684.JPG


It was interesting to note that the 00 wheels that came out of this loco were quite fine. I seem to recall Brian Rogers of U/scale saying they were to 'Pendon' profile, which his father had developed with Guy Williams (at least I think he said that - it was eight years ago).

Not that I want to open any old wounds, but the 00 flanges are just 0.6mm deep and the tyre width only 0.4mm wider than the P4 wheels. So, if this loco ran on 00 track that was thrown together with not much care on its rather fine profile wheels, it looks promising that it will now run well on P4 track (which hopefully will not be thrown together) on wheels that are not much finer (famous last words etc., etc.!). It does weigh quite a bit, which must help too.

Colin


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

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Colin Parks
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Re: Starting out in P4

Postby Colin Parks » Wed Nov 05, 2014 10:26 am

Thanks to Howard and Martin for your input re. micro switches v. relays.

I have no experience of these matters, so am willing to take advice. What ever ends up being the type of device used, they shall be made to be removable units, which can be easily changed if a fault develops. That avoids the adjusting under the base board which martin so dislikes.

Colin


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