P4 conversion work

Colin Parks

Re: Starting out in P4

Postby Colin Parks » Tue Oct 14, 2014 12:11 pm

JFS wrote:
Colin Parks wrote:I hadn't seen the downloads on the Ambis website. I have had a look at the instructions and still do no understand how the longer etched bracket should look!

Colin


Hello Colin,

I think I get it - the long extensions with the hole in the end are bent back double against the sides of the bracket. They then form an eye-end under the stock rail. It is not the best way to do a double slip in truth, but many prototype turnouts are done that way - I will see if I can dig up a photo or two.

Very Best Wishes,


Hi Howard,

Well, I tried them idea of folding the long ends back on themselves and they got in the way the 'twisted' ends. I have abandoned using the long version on the etch. I think having the drive rod connection between the blades rather than under one of them would be better in terms of maintenance if anything goes wrong in the future. having looked at the pictures in your article on stretcher bars in a recent S4 News 9forget the number!), it is clear that the Mk 4 version of the bracket is definitely bigger/wider than the type you have used on your track work.

Meanwhile there are still eight of the little blighters to solder in place

All the best,

Colin

Colin Parks

Re: Starting out in P4

Postby Colin Parks » Tue Oct 14, 2014 12:20 pm

James Moorhouse wites:

Me too! After a quick trawl through the 'library', here's what I have on end ramps:

Image

From the same folder (the contents of which emanated from the late Joe Brook Smith), here's something on side entry/exit ramps too. This drawing is why I suggested using nickel silver angle to model them.

Image

HTH. Sorry if this info is cluttering your thread, Colin![/quote]

Thanks James.

I shall be looing into the matter of side-entry ramps more closely now. The use of nickel-silver angle would appear to be the best material as you suggest. This double slip requires one side-entry ramp. As I said before, the are quite a few on the junction I am modelling, so I will have to study the old photos again and compare the cast ramps to the SR ones.

All the best,

Colin

Colin Parks

Re: Starting out in P4

Postby Colin Parks » Thu Oct 16, 2014 3:30 pm

The double slip is now loosely arranged on its template again after trial-fitting the stretcher bars.

IMG_1675.JPG


This has not been easy. The Ambis brackets are really too wide for the space available between the sleepers on a double slip - even after much filing of the parts. Even after studying the downloaded instructions, the result was the same as my effort of bending the brackets up without instructions! After a lot of fiddling with the soldering iron and burning my fingers, The stretchers are in line as best that they will go, given the fact that they have to be spaced too wide apart for the reasons mentioned above. (But, conversely, not far apart enough for my liking to give a sufficient gap for insulation purposes.)

IMG_1680.JPG


It remains to be seen if this arrangement can be made to work without short-circuiting occurring if the brackets should touch each other. should this happen, Plan B is to scrap the brackets and fit the Mike Norris 'Preston' type of stretcher bars with brass wire soldered to gapped PCB strip.

Colin
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JFS
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Re: Starting out in P4

Postby JFS » Thu Oct 16, 2014 4:50 pm

Well done Colin, these things can be a battle but it looks like you have done a good job at getting everything in.

It seems that the design of the Ambis MkIIII brackets results in them bending up rather wider than the MkIII which I used and certainly makes it harder to "tweak" them into line with each other. Also, I had my insulation gaps by the K crossings which eases the electrical clearance issue.

I am sure the clearances will work out - and if they only touch occasionally a smear of epoxy might help (not that I would ever have to resort to such tactics...)

All downhill from here...

Very Best Wishes,

Simon Glidewell

Re: Starting out in P4

Postby Simon Glidewell » Thu Oct 16, 2014 5:11 pm

That looks jolly good Colin, especially as a first piece of complex P4 track work. If it were me I'd test the point ASAP with electricity and polarity switches then run a loco up and down. The clearances between some of those stretcher bars do look horribly close for comfort, short circuit wise. You'll need to be absolutely certain that everything works reliably before glueing it in place and ballasting it; trying to sort it out afterwards would be a nightmare. Maybe plan B?

All the best
Simon

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Will L
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Re: Starting out in P4

Postby Will L » Thu Oct 16, 2014 5:22 pm

Colin Parks wrote:...It remains to be seen if this arrangement can be made to work without short-circuiting occurring if the brackets should touch each other. should this happen, Plan B is to scrap the brackets and fit the Mike Norris 'Preston' type of stretcher bars with brass wire soldered to gapped PCB strip.


As you can only set one rout through a double slip, is it not reasonable for both sets of blades at one end to move together and therefore always be the same distance apart and not be at risk of an accidental short circuits?

Will

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Re: Starting out in P4

Postby grovenor-2685 » Thu Oct 16, 2014 6:26 pm

As you can only set one rout through a double slip, is it not reasonable for both sets of blades at one end to move together and therefore always be the same distance apart and not be at risk of an accidental short circuits?
The usual case is for all 4 blades at one end to move together in the same direction, there are exceptions and the GWR was rather fond of such exceptions, but that still leaves the stretcher brackets very close together and at risk of touching, aspecially with the Ambis or Masokits etches. Note the photo does not show the blades in the correct position as all the blades are closed (almost). The suggestion to move the insulated joints to the heel end of the switches makes life a lot easier. There is a set of fishplate joints in all 8 rails just before the K crossing which allows the prototype to be seperated into 3 pieces for transport.
Regards
Keith
Regards
Keith
Grovenor Sidings

Colin Parks

Re: Starting out in P4

Postby Colin Parks » Thu Oct 16, 2014 6:38 pm

Will L wrote:
Colin Parks wrote:...It remains to be seen if this arrangement can be made to work without short-circuiting occurring if the brackets should touch each other. should this happen, Plan B is to scrap the brackets and fit the Mike Norris 'Preston' type of stretcher bars with brass wire soldered to gapped PCB strip.


As you can only set one rout through a double slip, is it not reasonable for both sets of blades at one end to move together and therefore always be the same distance apart and not be at risk of an accidental short circuits?

Will

Hi Will,

That's what I am hoping!

All the best,

Colin

Colin Parks

Re: Starting out in P4

Postby Colin Parks » Thu Oct 16, 2014 6:49 pm

grovenor-2685 wrote:
As you can only set one rout through a double slip, is it not reasonable for both sets of blades at one end to move together and therefore always be the same distance apart and not be at risk of an accidental short circuits?
The usual case is for all 4 blades at one end to move together in the same direction, there are exceptions and the GWR was rather fond of such exceptions, but that still leaves the stretcher brackets very close together and at risk of touching, aspecially with the Ambis or Masokits etches. Note the photo does not show the blades in the correct position as all the blades are closed (almost). The suggestion to move the insulated joints to the heel end of the switches makes life a lot easier. There is a set of fishplate joints in all 8 rails just before the K crossing which allows the prototype to be seperated into 3 pieces for transport.
Regards
Keith


Hi Keith,

The blades are being set apart like that as the wisdom with thin stretchers is to keep them under tension. I might have to follow your advice and move the insulated joints to the K-crossing position. It would certainly make life easier in the long run.

All the best,

Colin

Colin Parks

Re: Starting out in P4

Postby Colin Parks » Thu Oct 16, 2014 6:59 pm

Simon Glidewell wrote:That looks jolly good Colin, especially as a first piece of complex P4 track work. If it were me I'd test the point ASAP with electricity and polarity switches then run a loco up and down. The clearances between some of those stretcher bars do look horribly close for comfort, short circuit wise. You'll need to be absolutely certain that everything works reliably before glueing it in place and ballasting it; trying to sort it out afterwards would be a nightmare. Maybe plan B?

All the best
Simon


Thanks Simon.

I certainly will be testing the point as soon as I can! Nothing is fixed yet and the thing will be staying on the assembly board for the foreseeable future, even once all parts are permanently glued down. There is no base board for the point work to go on, in fact the rest of the junction has not been drawn up yet on Templot. But that's another story...

All the best,

Colin

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Re: Starting out in P4

Postby grovenor-2685 » Thu Oct 16, 2014 7:22 pm

The blades are being set apart like that as the wisdom with thin stretchers is to keep them under tension.
Yes, start with both blades sprung against their respective stock rails, as in your pic, then put a gauge in one side to hold it open the required 1.4 mm and fix the stretcher in place. When you take the gauge out the blades should spring approximately central. I assume you have not fixed your stretchers yet.
Regards
Keith
Regards
Keith
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Colin Parks

Re: Starting out in P4

Postby Colin Parks » Thu Oct 16, 2014 9:54 pm

Hi Keith,

Yes that is the plan and thanks for your advice. Nothing is fixed yet so nothing is too hard to change. All the parts are shown just laid to see how the stretchers would line up. Just as well this was not left until later!

All the best,

Colin

Colin Parks

Re: Starting out in P4

Postby Colin Parks » Fri Oct 17, 2014 7:21 pm

Well, with a bit of cutting and tweaking, the insulation gaps have been sited at the K crossing joints:

IMG_1683.JPG


The locking fishplates are Loctited in place on the rails. The outer switch blades are still separate of course.

At the common crossing ends, locking fishplates have been temporarily used just to ensure that the stretcher bars still line up. The next riddle is how to supply power to the inner switches and their closure rails. I have some two-part brass etched fishplates, but soldering them into position is going to be very hard to get right - I think it's going to have to be by adding droppers to each rail = eight more droppers. I am not leaving anything to chance: two switch anchors broke in the process of altering the assemblies. This alarmed me somewhat. I replaced the broken anchors with wire that was less thinly filed than before and strengthened the rest of them with filets of solder from underneath. It all looks robust enough, but it seems best not to rely on the anchors to conduct current just in case they break in the future.

IMG_1682.JPG


The brackets on the centre switch blade ends are now free to touch each other without risk of short circuit. Having made certain that all was well, I filed off the folded tab which holds the two parts of the bracket together. (This does not show up in the photo as well as I had hoped.) It is a one-way process, as the brackets cannot be un-soldered to adjust their position any more - or they will fall into two parts. It had to be done though, as they were too deep even when using the thick timbering. Still a little tweaking to do on those bars!

IMG_1681.JPG


It does now look more like a piece of point work that might work, which is the whole point of the work. Actually glueing the assemblies down is looming ever closer, but I wonder if I have enough gauges for this. I have looked at several articles on the subject and people seem to use up to four at a time. I have just one, unless the check gauge can be pressed into use. Then there is the question of gauge widening through the switches in the stock gauge area. Lots to learn yet.

Colin
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Re: Starting out in P4

Postby JFS » Fri Oct 17, 2014 9:35 pm

Colin Parks wrote: The next riddle is how to supply power to the inner switches and their closure rails.



Actually glueing the assemblies down is looming ever closer, but I wonder if I have enough gauges for this. I have looked at several articles on the subject and people seem to use up to four at a time. I have just one, unless the check gauge can be pressed into use. Then there is the question of gauge widening through the switches in the stock gauge area. Lots to learn yet.

Colin


Hello Colin,

Looking good - albeit it sounds very hard work.

The check gauge is actually the correct one for gauging the two Ks apart and also for gauging the Stock rail / check rails from the Vees. So you should be alright.

If you have some Exactoscale lost wax brass fishplates, these would solve your electrical continuity issue as you could solder the joints up solid. The etched one are a bit weedy by comparison.

No doubt your switch anchors gave way under attack from the piercing saw - in normal use they are not subject to any real strain. But if you worry about them being a bit brittle, you could always anneal them - before fitting of course...

Given that you are not building this D/S in situ, how are you proposing to extract it from the template? Solvent bonds to ply sleepers are quite strong enough for normal running, but if your timbers are well stuck down the the jig, there might be an issue ahead. Perhaps cyano would be better in such a case.

Very Best Wishes,

Colin Parks

Re: Starting out in P4

Postby Colin Parks » Sat Oct 18, 2014 10:11 am

Hi Howard,

I had thought of using the brass locking fishplates at the joints, but it would be hard to lay the common crossings with them on once the K crossings and the attached switches are fixed. Due to all the droppers, the crossing have to be laid vertically if you see what I mean. I could use brass etched fish plates on the inside face of the joints and plastic cosmetic ones on the outside where they are more prominent.
The switch anchors that gave way might have been down to bad shaping on my part with the files. However, the point blades pivot on the anchors, so they do have job to do and I want to take no chances with failure of parts once the track is operative.
The GEL material for the stretcher bars seems to work well now that the brackets have been fettled. Where did you/do you get the drive rod brackets from for your point work? I suppose I could scratch-build something in extremis. The C&L double slip chairing diagram shows the stretcher bars are linked together before connection to an operating crank. It isn't clear what sort of fitting is needed for that, so again, if you have any ideas let me know!

You asked about extracting the point from the template. Well the sleepers are only held down by thin strips of double-sided tape. But having said that, if the point is chaired-up to completion on the template, the slide chairs could all suffer from being levered off the tape.

Now that I have got this far with the slip, it would be good to see it finished, but I am now wondering if the best policy would be to develop the track plan in Templot for the whole junction formation next. The the base boards could then be built and the point work laid as per your method, laying and ballasting the sleepers first then installing the rail assemblies in situ.

All the best,

Colin

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Re: Starting out in P4

Postby grovenor-2685 » Sat Oct 18, 2014 10:42 am

However, the point blades pivot on the anchors,
They should not pivot on the anchors, this effect is a result of your not having fitted the chairs on the switches yet, the blades should be held firmly in the heel chairs and flex, not pivot in order to move. The anchors are there to stop the blades moving longitudinally with respect to the stock rail.
You asked about extracting the point from the template. Well the sleepers are only held down by thin strips of double-sided tape.
How is the template held down to the building board? I attach mine by double sided tape outside the area covered by the timbers, then on completion it can be cut along the timber ends and the point simply lifted complete with template. Then by turning it over the template can be peeled off carefully without risk of damage. Levering off the tape was OK with ply and rivet, but not with cosmetic chairs and glue construction.
Regards
Keith
Regards
Keith
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Re: Starting out in P4

Postby Phil O » Sat Oct 18, 2014 1:25 pm

I use super glue gel to stick slide chairs to the rail and the plastic weld to stick the chair to the sleeper, if one or two got missed during construction, I only find out when extracting the turnout from the template, they can be done afterwards as it is possible to judge the position from the rest.

Phil

stevecarr

Re: Starting out in P4

Postby stevecarr » Sat Oct 18, 2014 5:27 pm

I am surprised you stick rail to the chairs?

The advantage of plastic chairs is the allowance for expansion/contraction, or so I thought.

Simon Glidewell

Re: Starting out in P4

Postby Simon Glidewell » Sat Oct 18, 2014 6:24 pm

stevecarr wrote:I am surprised you stick rail to the chairs?

The advantage of plastic chairs is the allowance for expansion/contraction, or so I thought.


Slide chairs are supposed to hold the rail in position Steve, unlike the general stock rail chairs. As slide chairs only have half a chair, on the outside (model wise), some form of adhesive ought to be used to be on the safe side. Presumably that's why some choose brass slide chairs so that they can solder the stock rail securely to them to avoid gauge narrowing.

Best wishes
Simon

Colin Parks

Re: Starting out in P4

Postby Colin Parks » Sat Oct 18, 2014 6:44 pm

grovenor-2685 wrote:
However, the point blades pivot on the anchors,
They should not pivot on the anchors, this effect is a result of your not having fitted the chairs on the switches yet, the blades should be held firmly in the heel chairs and flex, not pivot in order to move. The anchors are there to stop the blades moving longitudinally with respect to the stock rail.
You asked about extracting the point from the template. Well the sleepers are only held down by thin strips of double-sided tape.
How is the template held down to the building board? I attach mine by double sided tape outside the area covered by the timbers, then on completion it can be cut along the timber ends and the point simply lifted complete with template. Then by turning it over the template can be peeled off carefully without risk of damage. Levering off the tape was OK with ply and rivet, but not with cosmetic chairs and glue construction.
Regards
Keith


Hi Keith,

Perhaps I should have been more careful in my use of words when describing what happened to the switch anchors. I' m sure they won't pivot once fitted with all the appropriate chairs, but the damage occurred when the parts were being rather roughly handled whilst cutting the rail assemblies into ever-smaller sections(!)

To be honest, there is no discernible pivoting now, with just the locking fishplates glued in place at the insulating joints. The thing I didn't want was to get close to laying the rails then find that the anchors broke just at the point of laying. In the case of this particular model double slip. the anchors were fitted only for the purpose of conducting current. The real slip at Newhaven has no anchors!

Re: How the template is held down: I used a Pritt stick to attach the paper to the ply base, admittedly more liberally applied than might have been sensible with hindsight. I am hoping that the paper will come away in one piece as it will be useful for marking out the holes for the droppers - when the time comes for that. Next time I make any track work on paper templates, I shall follow your advice and keep the area under the timbers free of adhesive.

All the best,

Colin

Colin Parks

Re: Starting out in P4

Postby Colin Parks » Sat Oct 18, 2014 6:49 pm

stevecarr wrote:I am surprised you stick rail to the chairs?

The advantage of plastic chairs is the allowance for expansion/contraction, or so I thought.


Hi Steve,

If there is one place on the track where things have to be held securely it is at the position of the slide chairs on point work. The rest of the rail can be left to expand and contract either side in their plastic chairs. (At least that is my understanding of the situation.)

All the best,

Colin

Colin Parks

Re: Starting out in P4

Postby Colin Parks » Sat Oct 18, 2014 7:14 pm

Simon Glidewell wrote:
stevecarr wrote:I am surprised you stick rail to the chairs?

The advantage of plastic chairs is the allowance for expansion/contraction, or so I thought.


Slide chairs are supposed to hold the rail in position Steve, unlike the general stock rail chairs. As slide chairs only have half a chair, on the outside (model wise), some form of adhesive ought to be used to be on the safe side. Presumably that's why some choose brass slide chairs so that they can solder the stock rail securely to them to avoid gauge narrowing.

Best wishes
Simon


Hi Simon,

I am hoping that there will be no need to use brass slide chairs and have soldered joints - though it would be a belt and braces approach.

Having to prise off some cosmetic plastic fishplates from rail 'joints' yesterday proved to be a surprisingly hard job and gave me cause for optimism that glued joints are going to be up to the job of holding plastic slide chairs and rail to gauge effectively. The bond was so strong that the fishplates to be removed were damaged as they had to be sliced off, leaving some plastic still embedded in the Loctite 435 which was itself still stuck tenaciously to the rail web.

All the best,

Colin

Simon Glidewell

Re: Starting out in P4

Postby Simon Glidewell » Sat Oct 18, 2014 8:33 pm

That sounds amazing Colin! I was speaking from bitter experience where I super glued the slide chairs on my three way point only to find a few weeks later that the gauge had changed with derailments happening, and that the stock rail on the curved side had come away from the chairs. My intention is to replace the plastic chairs with some new brass ones (which I have now); removing plastic chairs from plywood sleepers is not too difficult but a tad fiddly cleaning up afterwards. By the way, your double slip looks really good and will be a great start to your layout.

All the best
Simon

JFS
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Re: Starting out in P4

Postby JFS » Sat Oct 18, 2014 9:57 pm

Colin Parks wrote:Hi Howard,

I had thought of using the brass locking fishplates at the joints, but it would be hard to lay the common crossings with them on once the K crossings and the attached switches are fixed. Due to all the droppers, the crossing have to be laid vertically if you see what I mean. I could use brass etched fish plates on the inside face of the joints and plastic cosmetic ones on the outside where they are more prominent.
The switch anchors that gave way might have been down to bad shaping on my part with the files. However, the point blades pivot on the anchors, so they do have job to do and I want to take no chances with failure of parts once the track is operative.

Where did you/do you get the drive rod brackets from for your point work? I suppose I could scratch-build something in extremis. The C&L double slip chairing diagram shows the stretcher bars are linked together before connection to an operating crank. It isn't clear what sort of fitting is needed for that, so again, if you have any ideas let me know!


Now that I have got this far with the slip, it would be good to see it finished, but I am now wondering if the best policy would be to develop the track plan in Templot for the whole junction formation next. The the base boards could then be built and the point work laid as per your method, laying and ballasting the sleepers first then installing the rail assemblies in situ.




Hello Colin,

Yes, all the sub assemblies do have to to go in vertically - and it is a bit of a fight to enable the functional fishplates to be fitted - you end up with a fair few of them strung together above the baseboard just supported by the droppers until you can start to lower them in. I managed the whole lot with only one of the fishplates breaking - they are tougher than they look! Having said that, I don't think having the switches united with the Ks makes it any more difficult - after all, with a 1:7 I had no option but to do it that way.

As Keith says above, there is no real movement in the switch anchors - you can rest easy there. What do you mean by "drive rod brackets?" The eyes on the ends of my drive rods are Ambis and they came free with the Mk III stretcher brackets. You will need something different as the drive on the MkIIII are vertical rather than horizontal. If you get stuck (and there is not much from the "trade" to help) I do have a few Ambis bits and pieces left over

As you know, the pairs of switches on mine are linked under the closure rails (can be done with the Ambis Mk III) but probably for you, the easiest would be to contrive something like that on the Exactoscale plan. A lot ultimately depends on how you intend to drive the switches so that would be worth some consideration before too long.

Of course having got this far you must get it running! But in truth, if you were building it into the whole formation you would do it differently - making somethings easier and others less so... But knowing you want to get something running for test purposes, maybe this one finds its way onto a plank - after all, you might want to further experiment with the ballast, detailing, third rail, switch drives etc... And, good as this one is, the next will be even better - this is a skill after all!

Very Best Wishes,

Colin Parks

Re: Starting out in P4

Postby Colin Parks » Sat Oct 18, 2014 11:32 pm

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

Despite appearances at the moment, I'm sure the slip will work in the end and I don't do 'planks'.

Re. switch drives there is nothing on the Ambis etch that I have that inspires me with confidence. I have not really got that far in my mind as to how the points on this new layout will be operated, but some form of mechanical drive rather than slamming everything about with solenoids would be kindest due to the delicate nature of the parts being used. (Not even sure what the 'Exactoplan' is for such things.)

Having just read your fine article in the latest MRJ, I can see some forward planning is now needed before going any further. This particular piece of point work is quite separate to the rest of the formation to be built - no overlapping check rails or interlaced sleepers. But the rest is going to have to go down as one giant metal, plastic and wooden puzzle. That does call for getting it all planned in advance to a great extent. That means working out the rodding runs, third rail positions and all that stuff from photos. Then there is all the wiring underneath. All those droppers - aagh!

All the best,

Colin


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