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Heath Town and other signalling diversions


5BarVT
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1 hour ago, 5BarVT said:

IT’S INTERFERENCE

But not quite how I imagined.

Each board physically separate but joined electrically, all indications work fine; joined together, the interference resumes. Sheet of A4 between the boards, works fine, so a rail /rails is/are touching across the joint and causing run round paths.

Solution, grind back to ensure a gap, starting with the most suspect.

That will be tonight’s task.

 

Paul.

Paul,

 

Not sure how you plan to grind the rail back, but my preferred method is; assemble the baseboards, mark the exact line of the cut with a marker, and then use a ~1mm grinding disk in my 'dremel' (with flexishaft drive) to make a nice vertical cut. The 'gap' is then the thickness of the grinding disk.

 

I'm assuming that the rails are already in perfect vertical and horizontal alignment.

 

Ian

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3 hours ago, ISW said:

Not sure how you plan to grind the rail back, but my preferred method is; assemble the baseboards, mark the exact line of the cut with a marker, and then use a ~1mm grinding disk in my 'dremel' (with flexishaft drive) to make a nice vertical cut. The 'gap' is then the thickness of the grinding disk.

Many thanks Ian.  Those are the key words.

I had tried with my dremel equivalent but the slitting discs had to be angled to cut the rails.  I had bought a larger diameter diamond cutting disc but it isn’t planar so cuts a 2 - 2.5mm gap. The rails had been cut with a razor saw which doesn’t give a big enough gap to cater for board flexing.

For Christmas I got a flexible drive which is smaller in diameter so the slitting discs will cut vertically. Now I have 16 x 1.a bit mm gaps in my rails and all the track sections report correctly now. With practice the gaps may become 1mm!

Need to do some track cleaning now.
Paul.

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10 hours ago, 5BarVT said:

 

Many thanks Ian.  Those are the key words.I had tried with my dremel equivalent but the slitting discs had to be angled to cut the rails.
Paul.

Paul,

Indeed yes, the flexishaft is a real necessity for this job. I did once try using a larger ~50mm cutting disc to overcome the height issue, but it wobbled so much that it was impossible to use.

Even with a flexishaft, the grinding discs need to be treated with care as they have a nasty tendency to 'explode' if you get the rotating axis 'off line', meaning the disc has to bend. Yep, I found out the hard way ...

Another issue with grinding discs is that they don't like cutting solder. I have my rail ends (at baseboard joins) soldered to brass screws driven into the top of the baseboard. Sometimes the solder 'flows' along the underside of the rail and so needs to be cut. A grinding disc will 'clog' with the solder very quickly and become useless as the cutting surface is now smooth. I did throw those discs away until I found I could sand/file off the solder using a small file, putting the disc back to cutting status again.

Ian

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3 hours ago, ISW said:

Another issue with grinding discs is that they don't like cutting solder. I have my rail ends (at baseboard joins) soldered to brass screws driven into the top of the baseboard. Sometimes the solder 'flows' along the underside of the rail and so needs to be cut. A grinding disc will 'clog' with the solder very quickly and become useless as the cutting surface is now smooth.

Useful tip, thanks.  Files don’t like filing it either!


My technique (so far) has avoided too much solder at the actual joint.

No.4 brass flat CSK about 6mm from the edge of the board (pilot hole to make sure it doesn’t split the ply that close to the edge).  Adjust the screw to interference height using a scrap piece of rail with sleepers cut away from the end, then 1/4 turn (ish) extra to allow space for solder.  File (clean) the top and tin, then remove as much solder as possible.  Cut flexitrack to length, mark screw position, remove sleepers, file the foot, tin and then remove as much solder as possible, connect and lay track, then solder the rails to the screws by putting the iron on one side of the screw and solder on the other.  As soon as solder melts it will run where the screw is by capillary action but not along the rest of the rail foot.
 

For visible areas I have some 1/2” No.1 screws which will hide under the foot of the rail but need more precision in fixing. I got as far as 12 of them on the old layout, I will have 60 on this layout.

 

Paul.

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52 minutes ago, 5BarVT said:

Useful tip, thanks.  Files don’t like filing it either!


My technique (so far) has avoided too much solder at the actual joint.

No.4 brass flat CSK about 6mm from the edge of the board (pilot hole to make sure it doesn’t split the ply that close to the edge).  Adjust the screw to interference height using a scrap piece of rail with sleepers cut away from the end, then 1/4 turn (ish) extra to allow space for solder.  File (clean) the top and tin, then remove as much solder as possible.  Cut flexitrack to length, mark screw position, remove sleepers, file the foot, tin and then remove as much solder as possible, connect and lay track, then solder the rails to the screws by putting the iron on one side of the screw and solder on the other.  As soon as solder melts it will run where the screw is by capillary action but not along the rest of the rail foot.
 

For visible areas I have some 1/2” No.1 screws which will hide under the foot of the rail but need more precision in fixing. I got as far as 12 of them on the old layout, I will have 60 on this layout.

 

Paul.

Serious question - do you orientate the slot in any particular direction and, if so, why?

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Not any more.

I used to align the slot across the rails so that I could put the dropper in the slot and the rail on top.  Now I prefer to go for the almost interference fit.  If the slot is aligned suitably I may well use it for the dropper when I have short rails at the board joint but I don’t fret about it.

Paul.

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I am entirely new to this but I had planned to go across joints like this:

1) insert DCC dowels to allign boards and then bolt or clip boards together

2) mark track position and insert brass screws just short of the joint at the correct height, lightly tin the screw tops

3) lay the track down across the two boards and glue or pin in position ensuring screws are in the correct position

4) solder to the screws

5) cut the rails (following advice above)

Does this make sense to you guys?

Andy

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5 hours ago, St Enodoc said:

Serious question - do you orientate the slot in any particular direction and, if so, why?

I 'try' to align the slot perpendicular to the track centreline as this provides a nice 'groove' to insert the solder. I place the soldering iron on the opposite side of the rail, thus ensuring that the solder gets under the full rail foot width.

 

As I don't bother with tinning either the rail foot (too much of a hastle) or the top of the brass screw (I 'imagine' that it might upset the vertical alignment while gluing the track down), I paint some flux between the rail foot and the brass screw with a small paintbrush.

 

I'm also a bit 'over enthusiastic' or 'heavy handed' with the solder, as I really don't want it to come apart. Thus, in a number of instances, the solder has actually 'bridged' between the brass screws on either side of the baseboard joint. Hence the resulting 'issues' with cutting of the solder.

 

I have quite a few curves running across the baseboard joins, and so place the brass screws as close as I can to the edge of the baseboard. This usually means <5mm. The longer the 'overhang' the more pronounced the resulting 'kink' is in the curve.

 

Ian

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3 hours ago, Andy Keane said:

I am entirely new to this but I had planned to go across joints like this:

1) insert DCC dowels to allign boards and then bolt or clip boards together

2) mark track position and insert brass screws just short of the joint at the correct height, lightly tin the screw tops

3) lay the track down across the two boards and glue or pin in position ensuring screws are in the correct position

4) solder to the screws

5) cut the rails (following advice above)

Does this make sense to you guys?

Andy

Andy, 

 

I'd add a couple of QC checks. I'm sure you'd check the horizontal alignment before gluing, but it's equally important (possible more so?) to check the vertical alignment. Just use a steel ruler and look for any 'rocking' over the brass screws.

 

If you are using cork underlay you'll not get the next problem, but I did find that using foam underlay can easily result in a vertical 'kink' due to the track lowering under the weight of any load placed on the track to keep it in place during gluing and then staying like that.

 

Ian

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12 minutes ago, ISW said:

Andy, 

 

I'd add a couple of QC checks. I'm sure you'd check the horizontal alignment before gluing, but it's equally important (possible more so?) to check the vertical alignment. Just use a steel ruler and look for any 'rocking' over the brass screws.

 

If you are using cork underlay you'll not get the next problem, but I did find that using foam underlay can easily result in a vertical 'kink' due to the track lowering under the weight of any load placed on the track to keep it in place during gluing and then staying like that.

 

Ian

Yes indeed - I did not include my full check list but I suffer from paranoia over such thing so check and measure endlessly before glueing or cutting.

I would deliberately not allign the screw slot since this might enforce a slight sideways dislocation in the position.

I have also wondered about using pairs of screws when dealing with curves to try and ensure there can be no kink forming after the cut - does anyone do that?

Andy

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32 minutes ago, Andy Keane said:

I have also wondered about using pairs of screws when dealing with curves to try and ensure there can be no kink forming after the cut - does anyone do that?

Andy

Andy,

 

I'd only consider it in a non-scenic element of the layout as it's hard enough trying to disguise 4 brass screws, let alone 8.

 

I suppose if you have a really tight curve, say, less than 2nd radius, then it might be necessary. Myself, I have a couple of 2nd radius curves at baseboard joins (yes, I know, poor planning on my part) and I've had no problems with just the usual 4 brass screws.

 

Ian

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1 hour ago, ISW said:

it's equally important (possible more so?) to check the vertical alignment. Just use a steel ruler and look for any 'rocking' over the brass screws.

Effectively, I’m doing that with my ‘interference fit’ step.

 

1 hour ago, ISW said:

If you are using cork underlay you'll not get the next problem, but I did find that using foam underlay can easily result in a vertical 'kink' due to the track lowering under the weight of any load placed on the track to keep it in place during gluing and then staying like that.

That is my learning point from this layout!  Last time, I used sealed cork tiles and have enough left for the scenic section this time.  My interference fit step worked fine.

This time I’m using foam and discovered the hard way about being careful not to press down when doing my interference check or when soldering.

Always the need to learn new mistakes when trying a new method.  Good job it’s ‘only’ a hobby.
Paul.

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5 hours ago, ISW said:

I suppose if you have a really tight curve, say, less than 2nd radius, then it might be necessary. Myself, I have a couple of 2nd radius curves at baseboard joins

For tight curves like that I'd use sectional track, not flexible.

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On 23/07/2021 at 00:25, St Enodoc said:

For tight curves like that I'd use sectional track, not flexible.

Previous layout had 4th radius setrack curves across a joint (at 24 degrees) and was no problem at all.

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QUARANTINE

No, not COVID.

After a ‘no work’ weekend (Grandchildren for 2 nights without parents) board 2 has had the point and all remaining track fitted. (Apart from the piece I have temporarily lost!).  Droppers added and wired, point motor wired and connected to home made drive unit and supply.  Works one way but not the other.  In the dark recesses of my mind something tells me I have had that fault before.  Is the ‘spare’ I had used actually a reject that needed further investigation?  Probably, and thus one that should have been quarantined.

 

I need to add serial numbers so I can positively record use and failure etc which I am now away to do. Perhaps there was something in BS5750 after all!

 

I had a rest from home made gubbins and constructed a DCC track occupancy detector (MERG DCT2).  This time I was able to use my new pencil tip iron which made the kit even easier to put together.


Photos when I’ve sorted the home made boards. (Perhaps.)


Paul.

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FAULT FINDING

Was not as easy as I had hoped.  Changed to known good board and the fault changed.  Took another known good board off the old layout and the changed fault continued.

So I moved one of the old layout boards beside the new and drive the old board and tortoise.  Perfect!  Piece by piece is transferred back to the new and all was well until connected back one of the cables - I had cross wired it.

Anyway, the new layout board is working, with a serially numbered Point Drive and a serially numbered spare and the third is in a quarantine bag with a note of its failure mode.  As I only have one layout board with an odd number of points and there is already a spare I may just bin the faulty one.

Now I can move onto the lifting flap board.  That “only” has 12 points on it . . .

Paul.

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3 hours ago, 5BarVT said:

Piece by piece is transferred back to the new and all was well until connected back one of the cables - I had cross wired it

Paul,

 

I worked with black & red wires (and green for frog polarity ...) and simply kept to the 'back to black' mantra. When I had a short it was easy to spot the plug (dupont type PCB sockets) that was the wrong-way-round as the colours didn't line up. I kept all the wiring to the same format / layout, and religiously labelled every plug and socket as I went along. Saved me hours of fault finding, of which there were surprisingly few.

 

Ian

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PHOTOS were promised

Board number 2 complete (apart from the piece of track I have mislaid).

 

 

 

960197106_210802Y2top.jpg.3e4855357e10cafe4d1b50fedbf1fa0c.jpg

 

1016523180_210802Y2belowarrow.jpg.175a996aced7d81cdaf40ad89cdef03f.jpg

 

On 02/08/2021 at 20:48, ISW said:

I worked with black & red wires (and green for frog polarity ...) and simply kept to the 'back to black' mantra. When I had a short it was easy to spot the plug (dupont type PCB sockets) that was the wrong-way-round as the colours didn't line up. I kept all the wiring to the same format / layout, and religiously labelled every plug and socket as I went along. Saved me hours of fault finding, of which there were surprisingly few.

Which is (allegedly) more or less what I do . . . 

The offending lead was the short Black Yellow Grey arrowed - I had swapped the black and grey in one of the housings.  Whenever I'm inserting pins into the connector sockets I have to compare with another to make sure I've got them right.  I find it so easy to have one upside down which is what will have happened this time.  They were in the right order . . . looking from the wrong side!!!

 

Next board is going to be significantly more crowded.

 

Paul.

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2 hours ago, 5BarVT said:

PHOTOS were promised

Board number 2 complete (apart from the piece of track I have mislaid).

1678609042_210802Y2top.jpg.f64f330dae59ef526ef2d1bf30b123b0.jpg

 

590799940_210802Y2belowarrow.jpg.ee220c163d4be3ea64996ea0cc41bd38.jpg

 

Which is (allegedly) more or less what I do . . . 

The offending lead was the short Black Yellow Grey arrowed - I had swapped the black and grey in one of the housings.  Whenever I'm inserting pins into the connector sockets I have to compare with another to make sure I've got them right.  I find it so easy to have one upside down which is what will have happened this time.  They were in the right order . . . looking from the wrong side!!!

 

Next board is going to be significantly more crowded.

 

Paul.

Hi Paul

 

I am not sure how to word this post but that looks a tad more than two wires to me. I know you would like to describe what everything is but please remember I am but a simple old fella and I am sure most will just zoom over my head.

 

By the way, we all can get wires crossed. I passed a job with a pair of crossed wires when I was working as an inspector at Marconi's, in fact the batch of the cabinet draws were all like it. The test department didn't notice until they had destroyed about five expensive PCBs installed in the draws. Not the fault of the test guy, nor the bloke who wired things up wrong, or the drawing office who had cocked the drawing up but my fault as the inspector. It must have been my fault because the last time they made a batch of these draws the test department done the same thing. That time the drawing office got the blame. Now the bloke who did the wiring had been given an older drawing without the revision. I had a revised drawing with the correct wiring. Whoops.

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One bit I will explain.

The small nearly square board above the arrow almost at the diagonal.  It does nothing!

It’s a spare for its mate to the left of the arrow left over from testing and got tangled up in the wiring.  Only noticed from the photo when posting.

”It’s not there now, the board’s all flat . . .”

Good job I don’t have a bowler.

Paul.

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11 hours ago, 5BarVT said:

PHOTOS were promised

Board number 2 complete (apart from the piece of track I have mislaid).

1678609042_210802Y2top.jpg.f64f330dae59ef526ef2d1bf30b123b0.jpg

 

590799940_210802Y2belowarrow.jpg.ee220c163d4be3ea64996ea0cc41bd38.jpg

 

Which is (allegedly) more or less what I do . . . 

The offending lead was the short Black Yellow Grey arrowed - I had swapped the black and grey in one of the housings.  Whenever I'm inserting pins into the connector sockets I have to compare with another to make sure I've got them right.  I find it so easy to have one upside down which is what will have happened this time.  They were in the right order . . . looking from the wrong side!!!

 

Next board is going to be significantly more crowded.

 

Paul.

Paul, minor question, how do you hold PCBs and wires onto the underside of your boards? I guess you need to be able to remove boards if needed but I have mixed feelings about sticky back solutions when they get warm and gravity has its way.

Andy

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59 minutes ago, 5BarVT said:

One bit I will explain.

The small nearly square board above the arrow almost at the diagonal.  It does nothing!

It’s a spare for its mate to the left of the arrow left over from testing and got tangled up in the wiring.  Only noticed from the photo when posting.

”It’s not there now, the board’s all flat . . .”

Good job I don’t have a bowler.

Paul.

Good job you didn't make it round when it ought to be square.

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22 minutes ago, Andy Keane said:

Paul, minor question, how do you hold PCBs and wires onto the underside of your boards? I guess you need to be able to remove boards if needed but I have mixed feelings about sticky back solutions when they get warm and gravity has its way.

Andy

So do I, it’s only the Wago terminals (grey/orange blocks) that are stuck with double sided tape and a few do come loose.

I use 6mm ply baseboards and all PCBs are fixed with 9mm no.4 pan head self taps with 5mm spacers. Wiring is held in place by the terminations at each end (possibly not best practice!), the holes in the bracing and a bit of careful running under other wires for longer runs.  I also use P clips sometimes (see the black cable at the top) to give a bit of extra restraint.

Paul.

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Just now, 5BarVT said:

So do I, it’s only the Wago terminals (grey/orange blocks) that are stuck with double sided tape and a few do come loose.

I use 6mm ply baseboards and all PCBs are fixed with 9mm no.4 pan head self taps with 5mm spacers. Wiring is held in place by the terminations at each end (possibly not best practice!), the holes in the bracing and a bit of careful running under other wires for longer runs.  I also use P clips sometimes (see the black cable at the top) to give a bit of extra restraint.

Paul.

I use a hot glue gun to fix lightweight things like miniature connectors to the bottom of the baseboard but it's not 100% reliable.

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