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On 07/07/2020 at 11:32, queensquare said:

Great minds and all that Laurie - I was also inspired by last weeks ZAG meeting to dig out some pictures of my tie bar. Its been said before but there are probably almost as many tie bar variations as there are active members!

I use a moving sleeper  - fibreglass for strength. I use it copper side down and pass a couple of pins through holes in the tie bar and through little chairplates. The pin/chairplate is soldered to the closure rails but is obviously free to pivot. A quick wipe with a rat tail file (something a bit less course than the one I grabbed for the photo) to put a little concave curve on the joint to clear flanges and job done. The hole for the operating wire has a washer or bit of etch scrap soldered on the underside for added strength and in practice Ive not had one break yet.

They are very easy to make (I have a little jig for drilling the holes) and fit and have proved to be reliable and unobtrusive in operation.

 

Jerry

 

IMG_0002.JPG.26b09622f0c432b3edbd25c56af22d89.JPG

 

IMG_0003.JPG.00bb8cf23cea02cd1a5f2bc789af4060.JPG

 

1208069902_IMG_0004(2).JPG.d5e4bd1c9f58189798125805fa9477ef.JPG

 

578220825_IMG_0006(2).JPG.ae4b146ef6e7a88da0270dd95c9b2601.JPG

 

IMG_0008.JPG.ec253f81b253d5c9f10f8520978e3af5.JPG

 

I like that Jery I did somehing similar in 7mm but without the chair plates and using a timber sleeper (4mm point timber I think). In 7mm I could leave enough pin sticking up to solde to the blade. I only had one break in a few years of shows it boke at the operating pin hole. I tied a piece of black cotton round to hold the two halves together. It was still there at the next show as I had forgotten about it and lasted another 2 days. Anyway I shall try the chair plates when I do some 2mm ones. 

Don

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The level crossing.

 

I thought I should just explain the forward diode voltage issue I had for anyone interested. The motor used was a Mitsumi which is fairly slow running and the total gear reduction involved is 456-1. Here is a shot of the setup. The gears are old Airfix/MRRC 64dp ones I’ve had for, well, decades. They were originally meant for use in slot racing cars, which I played around with back in the day.

 

1076749528_RMwebTSELC11.jpg.794c0adc7791772f86627cdcc3be129c.jpg

 

The one on the main shaft is 48t and driven by a 12t on the next shaft. This is attached to a 36t which is again driven by another 12t. This is mated with an old Gibson 38-1 100dp wormwheel while the worm is one of the 2mmSA’s black 100dp worms cut to half it’s length.

 

Even with this reduction the motor only needs to turn over very slowly. With hindsight - a wonderful thing - I should have added another reduction stage. My feeling is that somewhere between 900 /1200-1 would be a better reduction, to allow the motor to spin faster at the slowest disc rotation speed needed. Especially for use with plain/simple DC.

 

But anyway, at the reduction used not much voltage to power the motor was needed, and when the diodes that allow the motor to be reversed kicked in they dropped the voltage to below that which allowed the motor to turn over. Increasing the voltage to compensate meant that when they were bypassed the motor speed jumped up too much. I used IN4001’s which I think drop 0.7v. The easy answer has been kindly posted, add diodes the other way to balance things out, but of course not being that bright that didn’t occur to me!

 

Izzy

 

 

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Posted (edited)

Sometimes in model making you take one step forward and 2 steps back.

Recently I took so many steps back so quickly that I nearly fell over.

Somehow I managed to kill a decoder (I think there was a short between motor terminals when under power, but I'll never be certain).

Yes, it was a precious CT decoder made from pure unobtanium (unless you are prepared to pay €20 to have one posted form Austria).

In taking things to bits to extract the lifeless corpse of said decoder, I managed to stop the motor from working.

The wheels have somehow ended up out of quarter too, but that is another story... all told, it was one of those days I wish I'd stayed in bed!

 

The motor is the subject of this post, and is one of the Farish-like 7mm coreless ones which were available fleetingly for very low prices on eBay a few years ago.

How I wish I'd bought more of them, with currently available equivalents being 10 times the price (though still only half the price of the decoder... grrr...).

I soon worked out what the problem was - one of the wires had broken inside its plastic sleeving. Typically, the break was exactly at the point the wire emerges from the motor casing.

Given what I'd paid for it, the obvious thing to do would be to bin the motor and replace it... but living so close to the Yorkshire border, I thought I'd pull it to bits and see if i could replace the broken wire.

 

Here are a few pictures of what is on the inside of these motors in case anyone is curious.

After prising off the end, this is the view down the case. The little bead on the end of the commutator rubs against the plastic end cap.

 

IMG_0721.JPG.838f235183d71cdd8e2603202837d26e.JPG

 

Sliding out the coil reveals the fixed magnet that it spins around. You can also see the brass bearing that the shaft runs in.

 

IMG_0723.JPG.9bfc39fe213d5f46763f0259ba41d571.JPG

 

The coil itself is a thing of beauty:

 

IMG_0724.JPG.16a76c34403f7d979c5714d1f17c244a.JPG

 

IMG_0725.JPG.b24ba5d2f31ec311369881ba2ad3bdb9.JPG

 

The plastic end cap contains the brushes, which are soldered to the terminal wires.

Here I have cut off the broken red wire. The plastic sleeve is pretty well secured with glue (presumably some sort of epoxy?), but the wire inside it is very fragile. The Achilles Heel of the design, really.

 

IMG_0727.JPG.169f6421525b9cf7eca611d6a227db0f.JPG

 

On the inside, the glue covers the soldered joint.

In the photo below I have removed the brush for the red wire, carved away the glue, and drilled through the hole. What is left is the brush for the black wire unmolested... for now.

As well as being held by the glue, you can see the brush is located in a slot in the plastic moulding.

 

IMG_0726.JPG.496dbdb405611a48a01bb12df876972f.JPG

 

Obviously the brush is very delicate. Somehow I managed to extract it without mangling it. This was achieved by gently prising it upwards from underneath next to the plastic slot with a very small watchmakers screwdriver.

I attempted to measure the thickness of the metal with my digital spanner and got 1 thou.

 

IMG_0729.JPG.56c0e602be83afd19da7a8af09071a94.JPG

 

Soldering wires onto decoder pads for stay-alive has been good training for soldering the replacement wire onto the brush spring.

Since taking the picture below, I have trimmed the excess wire.

The wire I used is decoder wire. I save all the bits that get cut off when I'm installing decoders for occasions such as this.

 

IMG_0731.JPG.624bc44e9a6f7a01da5d909964dc1e36.JPG

 

I had trouble getting the brush to go back in its slot in the plastic, and was in danger of crushing it. In the end, I used a scalpel to open out the slot a bit, then after fitting the brush, touched it with a soldering iron to try and melt it secure. It looks a bit messy, but seems to have done the trick.

 

IMG_0733.JPG.29e1714bcfd75c8a33efefdf84289321.JPG

 

I put a blob of epoxy over the end of the wire, and once it had set reassembled the motor.

The trickiest part was getting the commutator between the brushes without bending them out of shape - and holding it there with the case was slid on.

The orientation of the end cap is important, so that the brush contacts and the magnetic field are in alignment. The cap itself has markings, but the metal case does not. What I should have done is mark the case before I removed the end cap. 

Trial and error established the correct orientation and the motor once again ran sweetly... and intermittently.

Of course, with all the handling, the black wire has now broken in exactly the same place. It was inevitable that it would, and far better now. I would have probably replaced it anyway, but the option of laziness has been removed.

With the second one, the brush went back into its slot much more easily. I'm now waiting for the second lot of epoxy to harden before it all goes back together yet again. This time I did mark the outer case.

The postman has just been, but nothing from Austria today - only bills.

 

I wonder what the pioneers of 2mm modelling who had to knit their own motors from cobwebs would think of this?

 

 

Edited by Nick Mitchell
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Sorry to hear your woes. Nick. As you say, one of those days when you wish you'd never started!  Might it be worth putting some epoxy (or vinyl sealant?) around the wires where they emerges from the casing to reduce the chance of it fracturing there again?  Possibly something to do proactively for the next time any of us use one of this type of motor?  That way if the wire fractures where it emerges from the reinforcement you'd be able to attach a new one without having to dismantle the motor.

 

Jim

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My commiserations, Nick. 
Coreless motors virtually have no user serviceable parts, something I found out about 40 years ago - when they were relatively much more expensive! Denys Brownlee made his own for a Jinty that I now have, but it didn’t work very well and he replaced it with a standard iron cored motor.  
 

The Tramfabrik motors seem very good and not too expensive. 

 

Tim

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I've tried what you have attempted, with a Nigel Lawton motor, Nick. My success was much lower and it only kind of worked afterwards. It was not good and I binned it. It was first damaged by trying to remove or refit a worm and I separated the casing accidentally. 

 

I agree with Tim that the Tramfabriek motors seem good. Certainly better than the ebay 7mm coreless motors I bought from a similar referral link. Based on my current experience in chassis building the latter have less torque available. I bought cheap and ended up buying twice in this instance: the chassis got a Tramfabriek motor.

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21 hours ago, Izzy said:

The level crossing.

 

I thought I should just explain the forward diode voltage issue I had for anyone interested. The motor used was a Mitsumi which is fairly slow running and the total gear reduction involved is 456-1. Here is a shot of the setup. The gears are old Airfix/MRRC 64dp ones I’ve had for, well, decades. They were originally meant for use in slot racing cars, which I played around with back in the day.

 

1076749528_RMwebTSELC11.jpg.794c0adc7791772f86627cdcc3be129c.jpg

 

The one on the main shaft is 48t and driven by a 12t on the next shaft. This is attached to a 36t which is again driven by another 12t. This is mated with an old Gibson 38-1 100dp wormwheel while the worm is one of the 2mmSA’s black 100dp worms cut to half it’s length.

 

Even with this reduction the motor only needs to turn over very slowly. With hindsight - a wonderful thing - I should have added another reduction stage. My feeling is that somewhere between 900 /1200-1 would be a better reduction, to allow the motor to spin faster at the slowest disc rotation speed needed. Especially for use with plain/simple DC.

 

But anyway, at the reduction used not much voltage to power the motor was needed, and when the diodes that allow the motor to be reversed kicked in they dropped the voltage to below that which allowed the motor to turn over. Increasing the voltage to compensate meant that when they were bypassed the motor speed jumped up too much. I used IN4001’s which I think drop 0.7v. The easy answer has been kindly posted, add diodes the other way to balance things out, but of course not being that bright that didn’t occur to me!

 

Izzy

 

 

I think that your solution with a decoder is much better because it gives the motor more torque at such a low speed.

 

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5 hours ago, Nick Mitchell said:

Sometimes in model making you take one step forward and 2 steps back.

Recently I took so many steps back so quickly that I nearly fell over.

Somehow I managed to kill a decoder (I think there was a short between motor terminals when under power, but I'll never be certain).

Yes, it was a precious CT decoder made from pure unobtanium (unless you are prepared to pay €20 to have one posted form Austria).

In taking things to bits to extract the lifeless corpse of said decoder, I managed to stop the motor from working.

The wheels have somehow ended up out of quarter too, but that is another story... all told, it was one of those days I wish I'd stayed in bed!

 

The motor is the subject of this post, and is one of the Farish-like 7mm coreless ones which were available fleetingly for very low prices on eBay a few years ago.

How I wish I'd bought more of them, with currently available equivalents being 10 times the price (though still only half the price of the decoder... grrr...).

I soon worked out what the problem was - one of the wires had broken inside its plastic sleeving. Typically, the break was exactly at the point the wire emerges from the motor casing.

Given what I'd paid for it, the obvious thing to do would be to bin the motor and replace it... but living so close to the Yorkshire border, I thought I'd pull it to bits and see if i could replace the broken wire.

 

Here are a few pictures of what is on the inside of these motors in case anyone is curious.

After prising off the end, this is the view down the case. The little bead on the end of the commutator rubs against the plastic end cap.

 

IMG_0721.JPG.838f235183d71cdd8e2603202837d26e.JPG

 

Sliding out the coil reveals the fixed magnet that it spins around. You can also see the brass bearing that the shaft runs in.

 

IMG_0723.JPG.9bfc39fe213d5f46763f0259ba41d571.JPG

 

The coil itself is a thing of beauty:

 

IMG_0724.JPG.16a76c34403f7d979c5714d1f17c244a.JPG

 

IMG_0725.JPG.b24ba5d2f31ec311369881ba2ad3bdb9.JPG

 

The plastic end cap contains the brushes, which are soldered to the terminal wires.

Here I have cut off the broken red wire. The plastic sleeve is pretty well secured with glue (presumably some sort of epoxy?), but the wire inside it is very fragile. The Achilles Heel of the design, really.

 

IMG_0727.JPG.169f6421525b9cf7eca611d6a227db0f.JPG

 

On the inside, the glue covers the soldered joint.

In the photo below I have removed the brush for the red wire, carved away the glue, and drilled through the hole. What is left is the brush for the black wire unmolested... for now.

As well as being held by the glue, you can see the brush is located in a slot in the plastic moulding.

 

IMG_0726.JPG.496dbdb405611a48a01bb12df876972f.JPG

 

Obviously the brush is very delicate. Somehow I managed to extract it without mangling it. This was achieved by gently prising it upwards from underneath next to the plastic slot with a very small watchmakers screwdriver.

I attempted to measure the thickness of the metal with my digital spanner and got 1 thou.

 

IMG_0729.JPG.56c0e602be83afd19da7a8af09071a94.JPG

 

Soldering wires onto decoder pads for stay-alive has been good training for soldering the replacement wire onto the brush spring.

Since taking the picture below, I have trimmed the excess wire.

The wire I used is decoder wire. I save all the bits that get cut off when I'm installing decoders for occasions such as this.

 

IMG_0731.JPG.624bc44e9a6f7a01da5d909964dc1e36.JPG

 

I had trouble getting the brush to go back in its slot in the plastic, and was in danger of crushing it. In the end, I used a scalpel to open out the slot a bit, then after fitting the brush, touched it with a soldering iron to try and melt it secure. It looks a bit messy, but seems to have done the trick.

 

IMG_0733.JPG.29e1714bcfd75c8a33efefdf84289321.JPG

 

I put a blob of epoxy over the end of the wire, and once it had set reassembled the motor.

The trickiest part was getting the commutator between the brushes without bending them out of shape - and holding it there with the case was slid on.

The orientation of the end cap is important, so that the brush contacts and the magnetic field are in alignment. The cap itself has markings, but the metal case does not. What I should have done is mark the case before I removed the end cap. 

Trial and error established the correct orientation and the motor once again ran sweetly... and intermittently.

Of course, with all the handling, the black wire has now broken in exactly the same place. It was inevitable that it would, and far better now. I would have probably replaced it anyway, but the option of laziness has been removed.

With the second one, the brush went back into its slot much more easily. I'm now waiting for the second lot of epoxy to harden before it all goes back together yet again. This time I did mark the outer case.

The postman has just been, but nothing from Austria today - only bills.

 

I wonder what the pioneers of 2mm modelling who had to knit their own motors from cobwebs would think of this?

 

 

 

I suspect Stewart would have admired your perseverance. I dont think anyone ever made their own coreless motor winding a coil like that would be like knitting cobwebs.

 

Don

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2 hours ago, Donw said:

 I dont think anyone ever made their own coreless motor winding a coil like that would be like knitting cobwebs.

See Tim's post above.

 

Jim

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1 hour ago, Caley Jim said:

See Tim's post above.

 

Jim

 

Missed that Jim. Mind you Denys was one of those people to whom normal rules didn't apply rather like yourself. I was actually thinking back to the 60s when the Association started and making your own wheels gears and motor was often essential.

Don

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Having suffered the same issues as Nick with wire breakage on coreless motors I now always glue them on the ends in a half circle with a drop of cryno to try and prevent it. Pity they don’t just come with all-metal tags as most more expensive ones do. Perhaps the moulded plastic end caps can’t take any real heat.

 

I do see that although there has been no mention I have seen in recent shop notes, shop 3 is now stocking two sizes of 12v coreless, 6x15 s/s & 7x16 d/s.

 

Izzy

Edited by Izzy
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On 07/07/2020 at 20:32, queensquare said:

Great minds and all that Laurie - I was also inspired by last weeks ZAG meeting to dig out some pictures of my tie bar. Its been said before but there are probably almost as many tie bar variations as there are active members!

I use a moving sleeper  - fibreglass for strength. I use it copper side down and pass a couple of pins through holes in the tie bar and through little chairplates. The pin/chairplate is soldered to the closure rails but is obviously free to pivot. A quick wipe with a rat tail file (something a bit less course than the one I grabbed for the photo) to put a little concave curve on the joint to clear flanges and job done. The hole for the operating wire has a washer or bit of etch scrap soldered on the underside for added strength and in practice Ive not had one break yet.

They are very easy to make (I have a little jig for drilling the holes) and fit and have proved to be reliable and unobtrusive in operation.

 

Jerry

 

Proof is in the eating as they say - following said ZAG meeting and having some time today...

 

IMG_4343.jpg.94f50679a312c2888bb2abdcc23ff15a.jpg

 

Needs gapping but a wagon runs fine through it.  No chair plates nor anything fancy was used in the making of this B7 point - bullhead straight on the sleepers.

 

Two posts in one day - I think I may need to go and have a bex...

 

Cheers

Kevin of Oz

 

 

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I always use a pair of lightweight wagons to test a point. Push one along very slowly using the second one and see if the pushed wagon rises, jumps or kicks anywhere.

 

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3 hours ago, Sithlord75 said:

Two posts in one day - I think I may need to go and have a bex...

I take it this will be off-limits for the duration?

 

image.png.c67adfef975b34d6f82f5b7d9dfd9838.png:jester:

 

Jim

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7 minutes ago, Caley Jim said:

I take it this will be off-limits for the duration?

 

image.png.c67adfef975b34d6f82f5b7d9dfd9838.png:jester:

 

Jim

Apparently they also get brewed in Queensland... 

 

But as for the "real stuff" - trucks and freight are allowed across the Murray owing to a little thing called Section 92 of the Constitution of the Commonwealth of Australia.  It's just people - other than footballers and politicians - who aren't allowed out.

 

Cheers

Kevin of Oz

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2 hours ago, Sithlord75 said:

But as for the "real stuff" - trucks and freight are allowed across the Murray owing to a little thing called Section 92 of the Constitution of the Commonwealth of Australia.  It's just people - other than footballers and politicians - who aren't allowed out.

Politicians always manage to get round the rules!  My friend in Melbourne (retired hospital Medical Director) is somewhat less than impressed with Victoria politicians!

 

Jim

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12 hours ago, Lacathedrale said:

All of my stock to-date has been grouping era - which is odd seeing as I'd never really intended to build a grouping-era layout. I've had three wagon kits knocking around half built since autumn last year, so I figured it was time to get them done - the first is an RCH 7-planker. I'm really really impressed by it - the bolt detail on the inside, the knees on the inside, the correct position of the diagonal washer playes - all really lovely stuff. I decided on a whim to paint this in post-nationalisation condition - it needs the BR detail box in the corner and some remnants of an earlier paintjob, but overall I'm quite happy with it!

 

image.png.50a58b67ce63c60567308c926fc7297f.png

 

Where's the kit from?  The 'interior' detail is great, and worth saving for a rake of empties just to show it off.

 

 

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Looking good @Atso, how did they go together? I have several sitting in my gloat box...

 

22 hours ago, Geordie Exile said:

 

Where's the kit from?  The 'interior' detail is great, and worth saving for a rake of empties just to show it off.

 

 

 

Hi there, I don't know the true origins, but it's listed as 2-552 in Shop2 - I've no idea where I bought it, as I only have a single one and I thought they were only sold as pairs.

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15 minutes ago, Lacathedrale said:

Looking good @Atso, how did they go together? I have several sitting in my gloat box...

 

Thanks William, I didn't find any problems assembling them, even when I regauged them to N! It took around 90 minutes to assemble the pair while half watching TV.

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Here are some pics of the test track I have been building. The District Engineer has been out to have an early look after hearing of construction problems and poor workmanship.

 

734399054_Testtracktesting.JPG.b9eb3bac035b93e613999a7ebfcaa1a0.JPG

 

1057984432_Testtracktesting(4).JPG.de0f5fd4359fe3a2948d6cb9807281ab.JPG   

1449053716_Testtracktesting(5).JPG.d3da7b2cc1b2ec9acc9b70a6508c6518.JPG

 

In an initial assessment, the DE commented, 'Carpentry abysmal, baseboard will probably just about do, track laying needs more care to ensure joints line up accurately, turnouts satisfactory as far as they go at the moment. Recommend carpentry and baseboard construction be outsourced if standards cannot be improved significantly'.

 

Oh!

 

This is my first attempt at serious layout and track building and on a positive note I think I've learnt  quite a lot, mainly don't bother. No, but I can see my standards will need to improve considerably to achieve something satisfactory to run stock on.

 

For information, the outer radius is c. 30" with Easitrac except the turnouts which are soldered (no chairplates) construction. I used a Templot printout for the latter. I've yet to fit TOUs etc, so plenty of scope to screw things up even more before I try ballasting and adding the inner circuit.

 

Nigel Hunt

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Members of the VAG may recall a discussion I started a few weeks back about what model the Australasian Supermeet should look at doing for this years get together (still planned to be happening in September - PM for up-to-date details) and one of the suggestions was the SDJR/MR 25' Milk and Fruit van as found on p105/6 of Tatlow's NPCS book.  

 

The attached is the test print - very pleased with the result.  Just waiting for the wheels to churn on the chassis (although I completely understand the extenuating circumstances which will delay same).

 

It is actually blue in the picture - not the correct shade as I don't have a handy tin but putting something on was better for seeing the details rather than the black resin off the printer.   I've got to work a bit on the support and printer settings to remove the slight banana.

 

61674270817__59BB1C68-B1BB-4910-978E-10CC6CFE01B8.JPG.b26037ac4d16534ae2567b4d6883c2a2.JPG

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Well, my gloatbox is rapidly becoming slimmer with the completion of these three wagons:

 

uQ3KVpt.png

 

I'm a little frustrated by the overall finish, honestly - it seems whenever I looked at them under the lense it was fine (it being the paint finish, the wash coverage, etc. etc.) but when photographed looked like a right pig's ear. Oh well!

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