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22 hours ago, MisterT said:

Hi All,

For my first 2mm loco conversion I've started working on the Dapol 57xx conversion, as detailed by Pete King in the Feb/Mar 2016 Magazine. However, whereas that article described pressing normal drive bushes (3-112) into the original Dapol bearings, I am using the Dapol Pannier Conversion Bearings (3-225), which presumably are intended for this job and were introduced after that article was written.

I actually have 2 issues/questions:

 

1) I'm finding that the Conversion Bearings are a bit of a loose fit; they measure about 3.8mm, whereas the original Dapol bearings measure about 3.82mm. It's a tiny difference, but it means that some of the Conversion Bearings actually fall out the side of the chassis while I am handling it. (I haven't yet fitted any muffs, gears, wheels, etc. - I'm just having an initial look to see how the parts fit.)
Do you think I maybe need to knurl the outside of the bearing, or the inside of the chassis, so that the bearings are a tighter fit in the chassis?
Or won't it matter?

 

2) When I insert one of the gear muffs (3-102b) into the Conversion Bearing inner recesses, and measure across the outer faces of the bearings, I get about 8.22mm. In the article, it says that the distance across the bearing outer faces should be a maximum of 7.75mm to allow for a bit of side play. So it sounds like I need to shorten the muffs by about 0.47mm (from 6mm to 5.53mm). Does that sound right? Or do I need to shorten the muff a little more, so that the muff has a bit of side play within the bearings?

 

Hope someone can advise,

Thanks,
Ed

 

1) I would just glue the bearings in.

 

2) the bearings should be pushed into the chassis (check that 7.75mm dimension). The muff should be made as short as is needed to then fit between the bearings with some sideplay. Those conversion muffs will almost certainly be needed to shortened when used in the RTR conversions, I doubt that there any that provide enough room for the full 6mm length.

 

Chris

 

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Hi Chris,

Thanks for your reply. However, are you sure about glueing in the bearings? Isn't the current pickup via the bearings? Surely the glue won't help?

Sorry in advance if I'm missing something.

Ed

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58 minutes ago, MisterT said:

Hi Chris,

Thanks for your reply. However, are you sure about glueing in the bearings? Isn't the current pickup via the bearings? Surely the glue won't help?

Sorry in advance if I'm missing something.

Ed

 

As I understand it, our loco wheels (not the very latest type) were partially glued between the rim and brass centre and they still conduct fine. So the key would be to use it very sparingly. Once glued, give it a continuity test. I would also file down around the hole on the chassis to ensure good electrical contact with the bearing.

 

Chris 

 

 

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On 22/02/2020 at 19:24, MisterT said:

1) I'm finding that the Conversion Bearings are a bit of a loose fit; they measure about 3.8mm, whereas the original Dapol bearings measure about 3.82mm. It's a tiny difference, but it means that some of the Conversion Bearings actually fall out the side of the chassis while I am handling it. (I haven't yet fitted any muffs, gears, wheels, etc. - I'm just having an initial look to see how the parts fit.)
Do you think I maybe need to knurl the outside of the bearing, or the inside of the chassis, so that the bearings are a tighter fit in the chassis?
Or won't it matter?

 

Hope someone can advise,

Thanks,
Ed


I’m afraid I have no experience of this loco conversion, but since the size difference is about a thou how about coating the outside inner face of the bearings with solder paste, and applying some heat while they are in the chassis? Might just hold them in place and also keep electrical conductivity.

 

Izzy

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The Dapol 57xx conversion works fine with bearings glued in sparingly to hold them in place.  My recollection is that they need narrowing once in place.  Not a very tidy conversion, because the chassis isn’t the simplest to start with. 
 

Tim

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Very interesting - along those lines, I now have the components required to convert a modern Farish Jinty to 2FS (in addition to the chassis for the older model, which is to be tackled again, next) - i.e. the conversion bearings, muffs, and a set of wheels and rods - is there anything untoward I should be aware of before cracking on? I'd have thought someone would have put together an article or guide (even as simple as I get the impression it can be, I'd rather not make an easily avoidable mistake on an expensive new model.

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perhaps this might help a bit:

 

https://www.rmweb.co.uk/community/index.php?/topic/82934-farish-jinty-4f-2fs-dcc-with-stay-alive/

 

Izzy

 

 

 

 

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Thanks all for the feedback about the 57xx pannier conversion. I got a few different responses, via here and also talking to others: glueing, soldering, do nothing. I think I may start by doing nothing - i.e. just leaving the bearings as a loose fit and see how that works out. If that gives problems then I can take it apart again and try again with glueing or soldering. Anyway, it will probably be a while yet before I can press on ... I am waiting for 9.5mm wheels to come back in stock, and also I need it to get a bit warmer out in the shed!

 

Thanks again for all the input,

Ed

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3 hours ago, Lacathedrale said:

Very interesting - along those lines, I now have the components required to convert a modern Farish Jinty to 2FS (in addition to the chassis for the older model, which is to be tackled again, next) - i.e. the conversion bearings, muffs, and a set of wheels and rods - is there anything untoward I should be aware of before cracking on? I'd have thought someone would have put together an article or guide (even as simple as I get the impression it can be, I'd rather not make an easily avoidable mistake on an expensive new model.

 

The conversion of the new-style Farish Jinty is covered in the 'Getting Started in 2mm Finescale' booklet (P-102 from Shop 1). Alternatively, Nigel Ashton wrote an article on converting the 64xx pannier in the February 2017 2mm Magazine (available as a download from the member's area of the 2mm website) - the conversions are almost identical to do.

 

Andy

Edited by 2mm Andy
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12 hours ago, Izzy said:

 

9 hours ago, 2mm Andy said:

The conversion of the new-style Farish Jinty is covered in the 'Getting Started in 2mm Finescale' booklet (P-102 from Shop 1). Alternatively, Nigel Ashton wrote an article on converting the 64xx pannier in the February 2017 2mm Magazine (available as a download from the member's area of the 2mm website) - the conversions are almost identical to do.

 

Andy

 

That's wonderful, thank you both - OMWB post shortly!

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I found the rods supplied for the conversion very flimsy. The etched set of generic Farish conversion rods are more robust and easy to handle. 
 

Tim

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On 27/02/2020 at 09:02, CF MRC said:

I found the rods supplied for the conversion very flimsy. The etched set of generic Farish conversion rods are more robust and easy to handle. 
 

Tim

 

I managed fine with the coupling rods, no problems at all.

 

Julia :)

2mmSA farish convs jinty top assy exploded.jpg

jinty-01-09-14.jpg

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So I'm trying to press the Dapol worm off their motor, to use on an association motor, but having no luck, any suggestions? All my pullers are too big for the 1mm shaft.

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58 minutes ago, -missy- said:

 

I managed fine with the coupling rods, no problems at all.

 

Julia :)

2mmSA farish convs jinty top assy exploded.jpg

jinty-01-09-14.jpg

The thing that makes them flimsy, in my hands, is that they are half etched on both sides, so only 10thou over that dimension.  The standard rods are 5 thou thicker. 
 

Tim

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Have you tried them Tim? I honestly didn't have any problem using them.

J.

 

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1 hour ago, Tim V said:

So I'm trying to press the Dapol worm off their motor, to use on an association motor, but having no luck, any suggestions? All my pullers are too big for the 1mm shaft.

 

If you're junking the motor I'd stick a big soldering iron on the worm to expand it relative to the shaft. 

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I've never had to do that, but have you tried cutting a slot in a piece of brass or such like which will fit between the worm and the motor, using this to hang the motor over the jaws of a vice by the worm (not gripping anything), placing a rod of the same, or preferably slightly smaller, diameter as the shaft on the end of the shaft and giving that a sharp tap or two?

 

Jim

Edited by Caley Jim
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58 minutes ago, -missy- said:

Have you tried them Tim? I honestly didn't have any problem using them.

J.

 

Of course. There perhaps wasn’t a need to half etch the back half of the rods. 
Tim

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I think they were reverseable to cover the 4f as well as the jinty hence the half etch. They worked out fine for me, I'm happy with the results. I guess they just don't suit everyone.

 

Julia :)

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14 hours ago, Caley Jim said:

I've never had to do that, but have you tried cutting a slot in a piece of brass or such like which will fit between the worm and the motor, using this to hang the motor over the jaws of a vice by the worm (not gripping anything), placing a rod of the same, or preferably slightly smaller, diameter as the shaft on the end of the shaft and giving that a sharp tap or two?

 

Jim

Tried that! I'm suspicious it has been glued on. As I am junking the motor, I'll try the soldering iron trick, and if that doesn't work, I'll try a blow lamp.

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19 hours ago, CF MRC said:

The thing that makes them flimsy, in my hands, is that they are half etched on both sides, so only 10thou over that dimension.  The standard rods are 5 thou thicker.

If I am soldering two flimsy etches together, I use a high melting-point silver-content solder which adds a surprising amount of extra strength - although to be fair the solder is specifically aimed at amateur jewellers needing strong joints. In practice, I use that solder as a matter of course when making up coupling rods as its higher MP makes it much more "ping" resistant when broaching out the pin holes.

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Posted (edited)

Now it appears the medvend controllers are gone, may I ask what the best DC controller for use with 2mmFS is, that won't cost an arm and a leg? As part of the process of massaging my first 2FS layout into shape I am getting well and truly fed up with DCC and would like to try the original method but finding it very hard to spend three figures on a DC power supply whose design hasn't changed in half a century!

Edited by Lacathedrale

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Posted (edited)

These Mehano lightweight hand-held controllers are very popular on the French exhibition circuit. I picked one up secondhand for about € 15 at a bourse. Reversal was initially a bit of a puzzle, as you turn the knob past the zero point and then back, but one quickly gets used to the arrangement and it does ensure that one never tries to reverse something under power.

Edited by bécasse

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Not sure why you are having such a problem with DCC possibly the system you are using is not the best. As for DC controllers one thing to watch is some PWM types which do not suit coreless motors. The DCC decoders use high frequency Pulses which seem to avoid problems.  Simple emitter flower type circuits give  a steady DC output but will be unlikely to match a PWM type for slow running, the simple type are good for testing asPWM and feedback can conceal problems.

The DC controllers I have are old and no longer available I think besides I am using DCC more these days.

 

Don

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I have found that DCC overcomes a lot of the problems inherent in the control of 2mm models. 16v on the track at all times, instead of 1-2v - that is just not going to cut it.

 

Decent controller? How about decent chips - there is no such thing as a cheap DCC chip, you get what you pay for.

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