Etched loco chassis

[DavidLong]

Alan,

 

I've built two of these chassis' and I'm just starting the third. In both cases I have removed the part of the gearbox that would be nearest to the motor. On the Pannier the motor is at the rear in the cab and on the 04 it is at the front in the bonnet. In both cases I haven't used the spacer method that Chris designed in that would be to the rear of the motor. I have fitted a long conventional pcb spacer that will sit directly under the motor which enables it to have more support. A piece of plastic card sits between the motor and the spacer to enable the motor to sit at the correct height. In the case of the 04 the Nigel Lawton motor is super-glued to the plastic card. Henk has recommended this in the past and, as he says, should the motor need replacement it is fairly easy to break the glue bond although it is more than adequate under normal operation. The Pannier has an Association can motor but I am so impressed with the Lawton motor that I am going to fit one to the Pannier.

As far as flexing of the gearbox is concerned I think that we are back in the realms of how much actual stress the mechanism is under in a 2mm loco and the answer is probably very little.

The 04 will be with me at Nottingham on Sunday if you want to have a look, otherwise I can bring them to the NEAG meeting at the beginning of April.

I have just started on a 14xx chassis but this may be pushed backwards by a possible Terrier conversion prompted by the imminent arrival of some of Ian Morgan's 3D printed conversion gears!

 

David

[PeteT]

Alan,

 

The 04 will be with me at Nottingham on Sunday if you want to have a look, otherwise I can bring them to the NEAG meeting at the beginning of April.

I have just started on a 14xx chassis but this may be pushed backwards by a possible Terrier conversion prompted by the imminent arrival of some of Ian Morgan's 3D printed conversion gears!

 

David

David

 

Could you enlighten us a little more regarding the Terrier conversion. Something I've been hoping for since Dapol introduced the loco.

 

Pete

[DavidLong]

David

 

Could you enlighten us a little more regarding the Terrier conversion. Something I've been hoping for since Dapol introduced the loco.

 

Pete

 

Peter,

 

Sorry, I meant to include the link to Shapeways:

 

http://www.shapeways.com/model/1396146/replacement-2mmfs-terrier-gears-with-muffs.html?li=search-results&materialId=61

 

Ian refers to the conversion article in the Association magazine which I assume is the one that you wrote.

 

David

[PeteT]

Peter,

 

Sorry, I meant to include the link to Shapeways:

 

http://www.shapeways.com/model/1396146/replacement-2mmfs-terrier-gears-with-muffs.html?li=search-results&materialId=61

 

Ian refers to the conversion article in the Association magazine which I assume is the one that you wrote.

 

David

David

 

Thanks.

 

They seem a great idea, though I'm a little dubious as to how they will wear. I will order some anyway. I was hoping for some etched frames as they would be more accurate and consistent than my hand made efforts.

 

Pete

[Tim V]

Alan

 

I felt it was important to get away from the gearbox rear bearing. IMHO it is bad practice to have a shaft running in the four bearings (in the tolerances we use in model railways) in the chassis as designed. Hence the shaft is running in the front gearbox bearing, and the two motor bearings. It works very well, and the next chassis I build ( a Dave Eveleigh 45XX) will be built in the same way.

 

As David Long says, don't worry about the stresses the gearbox is under. If it was that stressed, something else would give! I would be seriously worried if the gearbox gave way, because it would mean I had made some fundamental flaw in assembly. And because the motor is removable, I would have found that out (by pushing gently) long before putting the chassis motor under power.

[Alan P]

Alan

 

I felt it was important to get away from the gearbox rear bearing. IMHO it is bad practice to have a shaft running in the four bearings (in the tolerances we use in model railways) in the chassis as designed. Hence the shaft is running in the front gearbox bearing, and the two motor bearings. It works very well, and the next chassis I build ( a Dave Eveleigh 45XX) will be built in the same way.

 

As David Long says, don't worry about the stresses the gearbox is under. If it was that stressed, something else would give! I would be seriously worried if the gearbox gave way, because it would mean I had made some fundamental flaw in assembly. And because the motor is removable, I would have found that out (by pushing gently) long before putting the chassis motor under power.

Hello Tim

 

I agree too many bearings in one line is bad and is one reson for my interest.

You have answered my query fully.

 

Thanks

Alan

[Alan P]

David

 

Could you enlighten us a little more regarding the Terrier conversion. Something I've been hoping for since Dapol introduced the loco.

 

Pete

 

 

Alan,

 

I've built two of these chassis' and I'm just starting the third. In both cases I have removed the part of the gearbox that would be nearest to the motor. On the Pannier the motor is at the rear in the cab and on the 04 it is at the front in the bonnet. In both cases I haven't used the spacer method that Chris designed in that would be to the rear of the motor. I have fitted a long conventional pcb spacer that will sit directly under the motor which enables it to have more support. A piece of plastic card sits between the motor and the spacer to enable the motor to sit at the correct height. In the case of the 04 the Nigel Lawton motor is super-glued to the plastic card. Henk has recommended this in the past and, as he says, should the motor need replacement it is fairly easy to break the glue bond although it is more than adequate under normal operation. The Pannier has an Association can motor but I am so impressed with the Lawton motor that I am going to fit one to the Pannier.

As far as flexing of the gearbox is concerned I think that we are back in the realms of how much actual stress the mechanism is under in a 2mm loco and the answer is probably very little.

The 04 will be with me at Nottingham on Sunday if you want to have a look, otherwise I can bring them to the NEAG meeting at the beginning of April.

I have just started on a 14xx chassis but this may be pushed backwards by a possible Terrier conversion prompted by the imminent arrival of some of Ian Morgan's 3D printed conversion gears!

 

David

David

Thanks for forwarding your experience. With your reply and Tim's it seems that theory does translate into practice in this case.

By what you say I have a good idea of what you have done and mine would be the forward motor case.

I am unable to get to Nottingham but hope to be able to get to the NEAG meeting in the afternoon. 

If you have it with you maybe I could have a look then as you suggest.

 

Thanks

Alan

[Chris Higgs]

David

 

Thanks.

 

They seem a great idea, though I'm a little dubious as to how they will wear. I will order some anyway. I was hoping for some etched frames as they would be more accurate and consistent than my hand made efforts.

 

Pete

 

Pete,

 

I have thought about doing an etched chassis for the Terrier a number of times, but could not quite come up with a suitable gear arrangement using Association gears. The Dapol design works because they have very thin gears.

 

Chris

[-missy-]

You could do one using the original Dapol gears maybe?

 

I think Ians conversion is really good. I love those 3D printed gears he has done and am interested in how they perform with the muffs included.

 

M

[Chris Higgs]

You could do one using the original Dapol gears maybe?

 

I think Ians conversion is really good. I love those 3D printed gears he has done and am interested in how they perform with the muffs included.

 

M

 

Quite possibly in combination with these 3D printed gears. It is indeed interesting to see how they wear. It sounds very unlikely they would be robust, but I understand Rolls-Royce now 3D print parts of their jet enjgines, so why not.

 

Chris

[DavidLong]

 

I think Ians conversion is really good. I love those 3D printed gears he has done and am interested in how they perform with the muffs included.

 

M

 

Oh dear, no pressure there then   The gears are on the way so I better start drawing out those frames . . . and the 14xx/58xx will just have to wait.

I'm fairly confident that with the leisurely life that my locos lead (no pounding around 'Fencehouses' for them  ) that wear is unlikely to be an issue.

 

David

[bécasse]

Pete,

 

I have thought about doing an etched chassis for the Terrier a number of times, but could not quite come up with a suitable gear arrangement using Association gears. The Dapol design works because they have very thin gears.

There is a simple technique for thinning gears which I have used successfully a number of times in the past.

 

Use a piece of plastikard which is the same thickness that you want the gear to be - for example 30thou for a 0.75mm thick gear, 40thou for 1.0mm, etc - and drill a hole in it a little smaller than the diameter of the gear, then broach out the hole so that the gear is a very tight fit. (If you have a series of gears to thin, the scrooges among us will start with the smallest and work up to the largest!)

 

Use double-sided sellotape to fix the plastikard to a hard, very flat surface - I use an old mirror - and make sure that the gear is pressed very thoroughly into the hole. Then use a broad file to slowly file away the exposed side of the gear until it is flush with the top of the plastikard. You might think that the file would cut into the plastikard as well, but, with care, it will do no more than marginally abraid it.

[Donw]

If you wanted to do a fair number the same size a piece of brass or Nickel would work well.

Don

[Chris Higgs]

A bit of spare time on my holiday has finally allowed me to get the etch for the Farish J39 chassis ready to send to the etchers for test, along with a few tweaks to that for the Black 5 and a bunch of NPCS underframes which have been almost ready for over a year now. So hopefully these will be available soon. The M7 and Terrier are also almost done now, just need a bunch of another stuff to fill up another test sheet.

 

After some comments on here about etched loco chassis being easy to distort by twisting - with which I agree as I have a Fencehouses J72 chassis in the same state - I realised it should be easy enough to make the frames up from two layers of etch as a sandwich to make them more robust. Using the narrower type of Association PCB spacer (6.4mm as opposed to 7mm) works nicely in combination. The J39 and Black 5 will now have this design, and I am testing out some extra parts for the already existing chassis.

 

Chris

[Donw]

A bit of spare time on my holiday has finally allowed me to get the etch for the Farish J39 chassis ready to send to the etchers for test, along with a few tweaks to that for the Black 5 and a bunch of NPCS underframes which have been almost ready for over a year now. So hopefully these will be available soon. The M7 and Terrier are also almost done now, just need a bunch of another stuff to fill up another test sheet.

 

After some comments on here about etched loco chassis being easy to distort by twisting - with which I agree as I have a Fencehouses J72 chassis in the same state - I realised it should be easy enough to make the frames up from two layers of etch as a sandwich to make them more robust. Using the narrower type of Association PCB spacer (6.4mm as opposed to 7mm) works nicely in combination. The J39 and Black 5 will now have this design, and I am testing out some extra parts for the already existing chassis.

 

Chris

What NPCS underframes will be on the etch please?

Don

[Chris Higgs]

What NPCS underframes will be on the etch please?

Don

 

LNER Long CCT (Chivers body)

LNER Horsebox (Chivers body)

SR CCT/PMV (Dapol or Chivers body)

GWR Fruit D (Dapol body)

BR Grain Hopper (Dapol body)

GWR Loriot D/E Lowmac (BR 2/241)

 

Plus a bunch of new pre-group etched bufferstops - LYR, SECR, LSWR, NBR, GNR, GER (2 types)

 

I designed a BR 2-240 Lowmac as well, but it proved too long and flimsy to build in 2mm. It needs a major rethink, or perhaps just blowing up to 4mm scale, where it should be fine :-)

 

Chris

[PaulCheffus]

LNER Long CCT (Chivers body)

LNER Horsebox (Chivers body)

SR CCT/PMV (Dapol or Chivers body)

GWR Fruit D (Dapol body)

BR Grain Hopper (Dapol body)

GWR Loriot D/E Lowmac (BR 2/241)

 

Plus a bunch of new pre-group etched bufferstops - LYR, SECR, LSWR, NBR, GNR, GER (2 types)

 

I designed a BR 2-240 Lowmac as well, but it proved too long and flimsy to build in 2mm. It needs a major rethink, or perhaps just blowing up to 4mm scale, where it should be fine :-)

 

Chris

Hi Chris

 

Is the Grain underframe for the diagram 1/275 version? I would definitely be interested in around ten of those if so.

 

Cheers

 

Paul

[Valentin]

[...]

 

After some comments on here about etched loco chassis being easy to distort by twisting - with which I agree as I have a Fencehouses J72 chassis in the same state - I realised it should be easy enough to make the frames up from two layers of etch as a sandwich to make them more robust. Using the narrower type of Association PCB spacer (6.4mm as opposed to 7mm) works nicely in combination. The J39 and Black 5 will now have this design, and I am testing out some extra parts for the already existing chassis.

 

Chris

 

Hello Chris,

 

Being one of those who appreciates your efforts in making 2mm FS more accessible by offering a simple solution for R-T-R conversions, and based on my experience with the replacement chassis (three J94/Austerity kits and many hours of working on them) I'd like to make a suggestion regarding the motor fittings: would be possible to re-design the etches in order to accommodate a "Branchlines Motor Mounting Bush" for Faulhaber / Maxon motors i.e. instead of having a fold-up gear box with two holes for the P/B bushes, to have just one hole for the P/B bush and a bigger hole for the "Branchlines" bush? (see figures 13, 14 and 15 in the Replacement Chassis Instructions).

 

I'd like to add that I'm grateful to everyone who helped by posting here and on VAG their solutions for motor mounting.

[Chris Higgs]

Hello Chris,

 

Being one of those who appreciates your efforts in making 2mm FS more accessible by offering a simple solution for R-T-R conversions, and based on my experience with the replacement chassis (three J94/Austerity kits and many hours of working on them) I'd like to make a suggestion regarding the motor fittings: would be possible to re-design the etches in order to accommodate a "Branchlines Motor Mounting Bush" for Faulhaber / Maxon motors i.e. instead of having a fold-up gear box with two holes for the P/B bushes, to have just one hole for the P/B bush and a bigger hole for the "Branchlines" bush? (see figures 13, 14 and 15 in the Replacement Chassis Instructions).

 

I'd like to add that I'm grateful to everyone who helped by posting here and on VAG their solutions for motor mounting.

 

But that would only work if you are using one of the mentioned motors. The Class 08 kit had such an arrangement (because only the Maxon motors would really fit and not melt the body), but it did not work out too well as the relatively large hole required for the bush made it weak and too flexible.

 

Chris

[Chris Higgs]

Hi Chris

 

Is the Grain underframe for the diagram 1/275 version? I would definitely be interested in around ten of those if so.

 

Cheers

 

Paul

 

1/271. I think I may have a 1/275 version somewhere (so long since I did it that I am not too sure) but it has not been test etched as 1/275 is relatively rare, and as I recall the Dapol body was not 100% right for it. However if you want 10 I can put them on somwhere.

 

EDIT: I remember the problem now. 1/275 has 8 shoe clasp brakes and there is basically no room with the 'normal' way of doing brakes on etched chassis, what with the hopper protruding through the underframe. I will need to to think again how it can be done.

 

Chris

Edited August 25, 2014 by Chris Higgs

[PaulCheffus]

1/271. I think I may have a 1/275 version somewhere (so long since I did it that I am not too sure) but it has not been test etched as 1/275 is relatively rare, and as I recall the Dapol body was not 100% right for it. However if you want 10 I can put them on somwhere.

 

EDIT: I remember the problem now. 1/275 has 8 shoe clasp brakes and there is basically no room with the 'normal' way of doing brakes on etched chassis, what with the hopper protruding through the underframe. I will need to to think again how it can be done.

 

Chris

Hi Chris

 

Ok if you do find a way I will definitely have ten. From memory the body difference is at the ends and I was planning on modifying these.

 

Cheers

 

Paul

[Chris Higgs]

Hi Chris

 

Ok if you do find a way I will definitely have ten. From memory the body difference is at the ends and I was planning on modifying these.

 

Cheers

 

Paul

 

Yes, I managed to sort out the brakes after some thought. Like the other grain underframe, due to Dapol making the bottom of the hopper far too wide, you have to choose between two compromises to fit the underframe - choose one with the solebars too wide and using 14.8mm axles, or somehow hacking the body so it will fit between correctly spaced solebars.

 

Chris

[Donw]

Thanks Chris let us know when you are taking orders or do you need projected numbers.

Don

ps any siphon chassis available?

[Izzy]

Yes, I managed to sort out the brakes after some thought. Like the other grain underframe, due to Dapol making the bottom of the hopper far too wide, you have to choose between two compromises to fit the underframe - choose one with the solebars too wide and using 14.8mm axles, or somehow hacking the body so it will fit between correctly spaced solebars.

 

Chris

 

 Glad the grain version using the 14.8 axles is coming. The Dapol body is virtually spot on lengthways, but far too wide, however I don't think I could hack it well enough to reduce the width. As per DonW please say if you need those who asked for certain amounts before when first announced to ask again.

 

Izzy

[Valentin]

But that would only work if you are using one of the mentioned motors. The Class 08 kit had such an arrangement (because only the Maxon motors would really fit and not melt the body), but it did not work out too well as the relatively large hole required for the bush made it weak and too flexible.

 

Chris

 

 

Thanks, Chris. It makes sense what you're saying.

 

Meanwhile, inspired by Tony Simms' approach to motor mounting, here is my attempt:

 

 

 

 

 

Before seeing Tony's picture I had the PCB mount fitted at the other end of the motor. I can't say which approach is better as the running quality is about the same.