Any Question Answered

[Nigelcliffe]

9 minutes ago, Donw said:

 

Nigel for clarity which Loctite is recommended ?

 

Don

 

I have no recommendation, other than something for retaining metal inside metal.   I have a bottle of out-of-date 603 or 601 in my cupboard, and I use that.   Reason being its not safety critical, unlike say, gluing the wings to an aeroplane.   There are 3M products which do the same as Loctite ones, and no doubt other makers.  

 

- Nigel

[Doncaster Green]

Well - first attempt was an abject failure!  With the wheel firmly held in a block, I tried to press a crankpin in and only succeeded in managing to break it off!  Luckily I was able to poke the broken bit out with a 0.35mm drill - one less crankpin but no damage to the wheel!  I have two ideas for the next attempt.  Firstly, I'm going to put the pin in a minidrill and lightly file a tiny chamfer on the end to ease entry.  Secondly, I have some brass tube with a 0.5mm bore which I will try to use as a kind of press.

 

Do either of these sound feasible?  I'm working on the basis that crankpins are cheaper to replace than drill bits and certainly cheaper than wheels!

 

John

 

Edited May 20, 2022 by Doncaster Green
Missing word

[Caley Jim]

How about gripping the crankpin in a pin vice right up to the flange and using that to push it in?  I make my own crankpins, turned in the minidrill from piano wire, which go in from the back.  They are made with an approximate Morse taper on the bit that goes into the wheel and have a countersink 'head' on them sitting in a countersink in the back of the wheel.   I sit the wheel on a piece of plywood with the crankpin hole over a hole in it, push the crankpin in from the back as far as it will easily go and then tap it in using whatever suitable tool comes to hand, usually a small screwdriver, as a nail punch.

 

Jim

[Doncaster Green]

18 minutes ago, Caley Jim said:

How about gripping the crankpin in a pin vice right up to the flange and using that to push it in?  

 

Thanks Jim - I hadn't thought of that.  I think I'll still give them a spin in the minidrill just in case the turning has left a small burr on the end where they are parted off.  Also the pin vice can be given a light tap of encouragement!

Regards

 

John

[Doncaster Green]

Well - the second attempt was a success!  Rather than trying to chamfer the day of the pin, I twiddled a drill bit (about 1mm I think - I just picked up what was handy) in the hole in the wheel to create a (very small) countersink and, using Jim’s tip about using a pin vice, pushed a pin home.  The counter sink made the pin centre in the hole squarely and is completely hidden by the flange when the pin is fully home.  I didn’t use any loctite, but the pin seems to be firm enough as is for free running rods without wiggly bits.  Perhaps a tiny drop in the countersink when the pin is pushed home would be sufficient.  Seems to me an engineer could design some sort of miniture drill press that would ensure the down force is even and vertical - not me, I’m an accountant!

 

Nigel mentioned above that he uses an out of date bottle of loctite.  How out of date is acceptable?  I appear to have an unopened bottle of 603 with a date on the bottom of May 2011!

 

Regards

John

[Nigelcliffe]

9 hours ago, Doncaster Green said:

Nigel mentioned above that he uses an out of date bottle of loctite.  How out of date is acceptable?  I appear to have an unopened bottle of 603 with a date on the bottom of May 2011!

 

 

Mine is at least 20 years old, possibly 25+ years.     Loctite requires a small gap to work - in theory there's a tiny grove printed in the bore of the holes for crankpins and axles for the Loctite to sit in.  But I have my doubts that the grove is always present in the crankpin holes. 

 

- Nigel 

 

[Alex Duckworth]

My bottle of Loctite is easily as old as the one that Nigel uses - still works fine.

[Nick Mitchell]

Just poking my head up from an enormous pile of exams I'm in the middle of marking...

 

I had a 50% failure rate with Loctite 603 retaining compound - which is my go-to green juice for jobs like this. There seems to be no rhyme or reason to it.

Loctite 243 threadlocker (which in theory is less strong) has worked every time, however.

 

I'm a big fan of soldering, but I've never had joy soldering to stainless steel, and wouldn't even attempt it with these wheels. Hats off to those who make it seem easy! 

 

P.S. My 603 "expired" in 2007, and the 243 in 2012.

Edited May 22, 2022 by Nick Mitchell
Added Loctite expiry dates

[Donw]

Nick could it be due to differing viscosity. I would expect the thread locker would be less viscous so it can flow between the threads.

 

Don

[5944]

29 minutes ago, Donw said:

Nick could it be due to differing viscosity. I would expect the thread locker would be less viscous so it can flow between the threads.

 

Don

It's the other way round - 243 is medium viscosity, 603 is low viscosity. 

 

We use various types of Loctite at work (a north London train maintenance depot), and 243 is generally the go-to stuff if you don't want something coming loose. Generally a little spot is all that is needed, but it can be enough to make removal of bolts etc very difficult. Gearbox drain plug bolts are torqued to 120Nm, but it's often at least double that to crack them off again afterwards to undo them. 

 

So it should be fine for 2mm scale crank pins!

 

[CF MRC]

There are special fluxes and solder for soft soldering stainless steel: I got some from Germany. It works well - quite ‘oily’ - but is quietly corrosive in a subtle sort of way. A well respected engineer at the local model engineering society suggested boiling all joints made with very corrosive fluxes, such as Bakers fluid, in water to remove any excess. 
 

Tim

Edited May 25, 2022 by CF MRC

[John Brenchley]

DC Controllers

 

I'm looking to upgrade my current controller (an ancient H&M Executive) and would welcome some suggestions.

 

I have a mixture of motors including Maxon and the Association's more recent can motors.

 

One that I have found online is a Morley Vesta N Gauge Crawler Zero Two Controller.  Does anyone have experience of this?

 

Thanks for any suggestions - at this stage, I'm not proposing to move to DCC.

 

Best wishes

 

John

[2mmMark]

2 hours ago, John Brenchley said:

DC Controllers

 

I'm looking to upgrade my current controller (an ancient H&M Executive) and would welcome some suggestions.

 

I have a mixture of motors including Maxon and the Association's more recent can motors.

 

One that I have found online is a Morley Vesta N Gauge Crawler Zero Two Controller.  Does anyone have experience of this?

 

Thanks for any suggestions - at this stage, I'm not proposing to move to DCC.

 

Best wishes

 

John

I'm quite keen on the inexpensive PWM speed controllers available from ebay & other sources. They work well with a variety of motors.  I'm using one on British Oak and it copes very well with my locos which have motors ranging from the traditional open frame Tenshodo to Tramfabriek coreless.

Here's how I built a controller:

It's important to find one with a 0 to 100% duty cycle. Some are not zero which in simple terms means that the power is not off completely so a loco with a very efficient motor can creep slightly with the control at its lowest point.

I have tried a Morley Vesta controller but I found it didn't give the very fine slow and steady running I was after.

Mark

 

[Graham108]

Another vote against Morley. Nice controllers (I have  both 2 & 4 control options) but the wiring connectors are awkward as the wires go in from the bottom and the screws are at the back - which means you have to stand the box on its front in order to make the connections (unless you're a lot cleverer than me). It would be a whole lot easier if the wires went in from the back and the screws were at the top

[John Brenchley]

21 hours ago, 2mmMark said:

I'm quite keen on the inexpensive PWM speed controllers available from ebay & other sources. They work well with a variety of motors.  I'm using one on British Oak and it copes very well with my locos which have motors ranging from the traditional open frame Tenshodo to Tramfabriek coreless.

Here's how I built a controller:

It's important to find one with a 0 to 100% duty cycle. Some are not zero which in simple terms means that the power is not off completely so a loco with a very efficient motor can creep slightly with the control at its lowest point.

I have tried a Morley Vesta controller but I found it didn't give the very fine slow and steady running I was after.

Mark

 

 

Thanks Mark

 

I have just read your description on British Oak.

 

It sounded quite interesting till I got to this paragraph :-

 

For British Oak, I tapped into the 12vAC feed already provided for the plug-in controllers I use, like the Pentroller. The AC feed is taken to a small solid state bridge rectifier

(the black box at the bottom of the case) and from there, the rectified feed is fed in the controller, which has screw terminals to make the job easy. The output from the controller is taken into a DPDT reversing switch with a centre-off. This serves to isolate the controller when a plug-in unit is in operation. If this is not done, there is a strong possibility the two controllers will interact with each other.

 

For someone with no electronics knowledge, this caused heart palpitations and a cold sweat - tapping into 12vAC feeds, bridge rectifiers etc - help!

 

I could probably solder together a set of components if I had a shopping list and a wiring diagram but without, I haven't a clue.

 

Anyone have suggestions for a really good off the shelf unit?

 

thanks

 

John

 

[2mmMark]

3 hours ago, John Brenchley said:

 

Thanks Mark

 

I have just read your description on British Oak.

 

It sounded quite interesting till I got to this paragraph :-

 

For British Oak, I tapped into the 12vAC feed already provided for the plug-in controllers I use, like the Pentroller. The AC feed is taken to a small solid state bridge rectifier

(the black box at the bottom of the case) and from there, the rectified feed is fed in the controller, which has screw terminals to make the job easy. The output from the controller is taken into a DPDT reversing switch with a centre-off. This serves to isolate the controller when a plug-in unit is in operation. If this is not done, there is a strong possibility the two controllers will interact with each other.

 

For someone with no electronics knowledge, this caused heart palpitations and a cold sweat - tapping into 12vAC feeds, bridge rectifiers etc - help!

 

I could probably solder together a set of components if I had a shopping list and a wiring diagram but without, I haven't a clue.

 

Anyone have suggestions for a really good off the shelf unit?

 

thanks

 

John

 

 

You can ignore that paragraph if you use a 12vdc plug-in power supply of something like 500ma. This will be written on the power supply.

Here's a very simple schematic for you. 

http://davidksmith.com/modeling/projects/throttle.htm

The LED Dimmer can be replace by this or something very similar
https://www.ebay.co.uk/itm/275254025141
 

I'm well out of touch with what's available on the market. Gaugemaster are OK but their feedback handheld (HH) is still based on a very crude circuit. All Components offer one but I know nothing about it except that it costs £60.

A good ready-made unit would be the Stapleton 852B.  I have a couple bought secondhand from ebay, already set up for N scale.  Don't let the 1.5amp output worry you, it's up to 1.5amp. Use a lower amperage power supply and it'll give a suitably reduced output.
http://www3.sympatico.ca/kstapleton3/851.HTM

 

As for basic electronics, I highly recommend the first 8 chapters of this as an excellent primer on the subject.
https://www.merg.org.uk/content/ebook

Mark

[John Brenchley]

Thanks very much Mark

 

I'll follow up all those links

 

Much appreciated

 

John

[Sithlord75]

MERG do some useful kits for the novice electrical engineer John.  I seem to have not had the magic smoke come out of mine yet.

[Donw]

I would recommend a Switched Mode Power Supply  SMPS similar to that used for laptops. I would also look for the square within a square symbol that indicates a double insulated unit. MERG do indeed provide some good ones I use a 12v 5A one to provide 12v for servos etc. and a 15v3A for the DCC.

However you may find old chargers and the like which are 12v double insulated at suitable currents.

 

Don

[Ian Morgan]

3 hours ago, Sithlord75 said:

MERG do some useful kits for the novice electrical engineer John.  I seem to have not had the magic smoke come out of mine yet.

 

For those not familiar with magic smoke, it is what is inside electronic components that make them work. If you let the magic smoke escape from them, they stop working. (OK, my university lecturers gave different explainations, but ...)

 

 

[John Brenchley]

On 05/06/2022 at 16:30, 2mmMark said:

 

You can ignore that paragraph if you use a 12vdc plug-in power supply of something like 500ma. This will be written on the power supply.

Here's a very simple schematic for you. 

http://davidksmith.com/modeling/projects/throttle.htm

The LED Dimmer can be replace by this or something very similar
https://www.ebay.co.uk/itm/275254025141


Mark

 

Thanks Mark and others for your suggestions.

 

If I go for the PWM route, would something like this also work - specifications seem the same as in your link above have the control knob separate is a bit more versatile for fitting in a control box.

 

https://www.ebay.com.au/itm/254692769428?chn=ps&_ul=AU&_trkparms=ispr%3D1&amdata=enc%3A1grW0IFPgQ8Sj5PKYSLIpag45&norover=1&mkevt=1&mkrid=705-139619-5960-0&mkcid=2&itemid=254692769428&targetid=&device=c&mktype=pla&googleloc=9070549&poi=&campaignid=15984321586&mkgroupid=&rlsatarget=&abcId=9300814&merchantid=263026884&gclid=EAIaIQobChMInuqnttSf-AIVT5NmAh1HJgbSEAQYCyABEgIVoPD_BwE

 

If my understanding is correct, I need a 12v DC power supply.  A local electronics shop has one like this - suitable?

 

https://www.altronics.com.au/p/m8932b-powertran-12v-dc-1a-fixed-2.1mm-tip-appliance-plugpack/

 

They also have versions at 12V but higher amps ie 2A, 3A, 4A - do I go for the lowest amps?  Is the fact that most of the PWM units are 2A or higher relevant?

They also have a  9V DC, 0.66A version - would this be better for slow speed control?

 

Thanks

 

John

[Donw]

One of the things with these PWM units is just how slow can it go.  They work by adjusting the ratio of the pulses to the spaces.  They give good motor control but some will not go slow enough for our use. The only way you can tell is to try them as far as I know.

 

Don

[John Brenchley]

4 minutes ago, Donw said:

One of the things with these PWM units is just how slow can it go.  They work by adjusting the ratio of the pulses to the spaces.  They give good motor control but some will not go slow enough for our use. The only way you can tell is to try them as far as I know.

 

Don

Thanks Don

On that basis, my simple electronics brain says having a lower voltage DC supply would give a slower speed - though would this mean they just stall more often at the lowest speed?

John

[Donw]

John  the supply voltage affects the top speed.  Control is done by adjusting the mark space ratio , at full speed the pulse becomes a continuous steady voltage at low speed pulses may only amount to power 10% of the time or less.  Dropping the voltage will reduce the slow speed pro rata but that affects the whole speed range. It may also make a loco more susceptable to dirt .

 

Don

[John Brenchley]

Given the low cost of these PWM units, I think the easiest plan is to order one and hook it up to the rear terminals of the H&M Executive, turn that controller up to full 12v power and see how the PWM unit works at slow speed control.  If happy, I can then buy a dedicated 12v supply, and build the PWM unit into a controller box with direction switch etc.

 

Thanks for everyone's help.

 

Best wishes

 

John