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Whats on your 2mm Work bench


nick_bastable
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Yet another scratch-built chassis; this time a mode of a very old 0-4-2 engine (type B1-n2) built in 1869 for SA CFR of Romania:

 

gallery_11426_4216_363447.jpg

 

All I can hope is that sometime in the not very distant future to actually finish one of these many attempts...

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the 2-4-0 progresses, it now sits on it's wheels, always a mark of advancement. The basic mechanism is in place, the worm needs to be fitted along with the flexible drive shaft. Next job will be the drag bar. You never know this time next week it may be working.post-14910-0-21859700-1492953797_thumb.jpg

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Well I was going to do a bit more work on the J39 chassis this evening ...

 

post-3740-0-83115800-1493065556_thumb.jpg

 

I've built up the chassis (with full Simpson springs this time) and soldered on the crankpins, so the next step is fitting the wheels (with the quartering jig). I made the mistake of dunking the wheels in blackening fluid (Birchwood Casey gun blue), and then water to rinse it off. Despite drying them off with tissue and leaving them in bright sunlight to dry off completely, they rusted up incredibly within a few hours. Took quite a while to polish it all off with a fibreglass pencil.

 

I'm keeping the old tender chassis, with turned down wheels. What have other people done for a drawbar with this setup? Adapt the Farish one, or just make a solid one from brass and solder some permanent wire connections for pickup?

 

Justin

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Well I was going to do a bit more work on the J39 chassis this evening ...

 

attachicon.gifIMG_20170424_205412.jpg

 

I've built up the chassis (with full Simpson springs this time) and soldered on the crankpins, so the next step is fitting the wheels (with the quartering jig). I made the mistake of dunking the wheels in blackening fluid (Birchwood Casey gun blue), and then water to rinse it off. Despite drying them off with tissue and leaving them in bright sunlight to dry off completely, they rusted up incredibly within a few hours. Took quite a while to polish it all off with a fibreglass pencil.

 

I'm keeping the old tender chassis, with turned down wheels. What have other people done for a drawbar with this setup? Adapt the Farish one, or just make a solid one from brass and solder some permanent wire connections for pickup?

 

Justin

wots my Arya doing sitting in your chair ?

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Well I was going to do a bit more work on the J39 chassis this evening ...

 

 

I've built up the chassis (with full Simpson springs this time) and soldered on the crankpins, so the next step is fitting the wheels (with the quartering jig). I made the mistake of dunking the wheels injured blackening fluid (Birchwood Casey gun blue), and then water to rinse it off. Despite drying them off with tissue and leaving them in bright sunlight to dry off completely, they rusted up incredibly within a few hours. Took quite a while to polish it all off with a fibreglass pencil.

 

I'm keeping the old tender chassis, with turned down wheels. What have other people done for a drawbar with this setup? Adapt the Farish one, or just make a solid one from brass and solder some permanent wire connections for pickup?

 

Justin

Justin,

Meow! We've got one of those too.

I don't like hard wire connections, if fine enough to not impede movement, they are much too fragile. Think Dapol tender locos!

Have you thought about a drawbar made of double-sided copper-clad fibreglass PCB. Connect one pole to each side (you can use the pivot for one pole and a wire connection or a rubbing strip for the other). Alternatively, I have had success with two J-shaped phosphor-bronze wires soldered to one split-framed chassis and rubbing on the inside of the other. This seems to work fine.

Regards,

John

Edited by JohnBS
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........... What have other people done for a drawbar with this setup? .......

I made some fine tube 2-3mm long by wrapping fine copper wire round a No 80 drill and flooding it with solder.  This was then soldered to the outer face of the tender frames, holding against the frame while still on the drill (the drill won't solder).  The loco frames each have a length of 8thou p/b wire, with a coil in the centre, soldered to them.at the back.  The straight end of the coiled wire is threaded into the tubes when the loco and tender are united.  You can see the arrangement here on my 0-4-2.

 

post-25077-0-71234100-1493152338_thumb.jpg

 

It has worked well on all three of my tender locos.

 

The draw-bar is a strip of brass pivoted on the underside of the front spacer of the tender and with a pin on the other end which sits in a hole in the rear spacer of the loco and is trapped in place by the footplate when the body is attached.  The front wheels of the tender are lightly sprung and some of the weight is transferred by the draw-bar to the loco.

 

Jim

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Well, the darn thing works now. After a bit of fiddling around with the drive train, and electrical pick up it has ground its way along my test track. There is much to do before I am satisfied.

post-14910-0-25766900-1493671361_thumb.jpg

The worm shaft is supported at the front end with a plain bearing, at the rear is a tiny ball race. 4mm OD. The rear end of the shaft has two flats filed into it and is cross drilled for the thin wire flex shaft. This is very thin, and I may replace it with a thicker gauge of wire. The rear end of the drive shaft has a loop bent into it and engages with a socket made from brass, which is attached to the sagami motor. Current is transferred from the loco to the tender via two p/b springs which engage into 14BA nuts soldered to the rear of the loco frames. These also help to transfer a bit of weight from the tender to the rear of the loco, as this is naturally front heavy.

There is not enough side play in the leading axle, so I will have to attend to that. Dear old Mike Bryant used to narrow the frames a little in cases like this, so a bit of surgery is called for.

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Well, the darn thing works now. After a bit of fiddling around with the drive train, and electrical pick up it has ground its way along my test track. There is much to do before I am satisfied.

post-14910-0-25766900-1493671361_thumb.jpg

The worm shaft is supported at the front end with a plain bearing, at the rear is a tiny ball race. 4mm OD. The rear end of the shaft has two flats filed into it and is cross drilled for the thin wire flex shaft. This is very thin, and I may replace it with a thicker gauge of wire. The rear end of the drive shaft has a loop bent into it and engages with a socket made from brass, which is attached to the sagami motor. Current is transferred from the loco to the tender via two p/b springs which engage into 14BA nuts soldered to the rear of the loco frames. These also help to transfer a bit of weight from the tender to the rear of the loco, as this is naturally front heavy.

There is not enough side play in the leading axle, so I will have to attend to that. Dear old Mike Bryant used to narrow the frames a little in cases like this, so a bit of surgery is called for.

Unfortunately, I don't think it will see duty at Watford.

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I bought some from Ebay a couple of years ago but haven't got round to using them yet - the ones I got were 1.5mm ID x 4mm OD x 2mm wide cost £7 for 4, they came from "High Torque UK" in Leighton Buzzard from the invoice.

Ian

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Where did you get the bearing? That's awfully small...

Hi Gareth the little bearings are the same size as Ian's, you could try his source Thanks Ian, . In fact I got mine in 1997 at a show in Germany price 1 euro for 4 bearings ! I got 8!

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Really not happy with the Sagami motor. Imho it's not well enough balanced and vibrates badly. May have to go back to the drawing board for this. Before I give up completely I need to add some mass to the tender, if not it's a new motor and / or loco chassis.

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Is it possible that the drive coupling is causing this issue? I have a similar problem with the drive on my 2251 and had assumed that my handiwork was the problem, despite using a lathe. I haven't tried exchanging the motor, which is a small mashima flat can. Additional mass did not completely solve the problem; hauling ability diminished significantly before there was sufficient mass I to dampen the vibration.

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It's quite possible the Sagami is at fault, Denys Brownlee had this issue with one of his locos and had to exchange the motor.

 

These are very nice motors. Smooth running , good quality and with a useful mounting bracket:

http://www.ebay.co.uk/itm/2pcs-814-Coreless-With-mounting-bracket-8-14-5MM-Coreless-motor-6v-15000-rpm-/112003966488?hash=item1a13f4e618:g:Ey8AAOSwp5JWWbiK

 

Mark

Edited by 2mmMark
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  • 3 weeks later...
  • 2 weeks later...

Hi all. I'm dipping my toes in 2FS with the 08 chassis kit... so this may appear a simple question given that I have the PDF instructions sheet, and the MRJ/2FS mag articles, and I have tried to find the answer on here, but should the gears be used with the 3-112 brass bearings, which would need the holes in the frames enlarging, or, as I think the photos show and the etched holes fit, stick to the smaller pb bearings for the gears as used for the wheels?

 

Cheers in advance....

 

John S

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Hi John,

 

I have only ever used the pb bearings, and I believe these are what the etched chassis kits are designed to use. From the size difference - photo attached - I think using the larger bearings would be quite difficult given their size in both thickness and diameter, gear clearance re alignment etc.

 

post-12706-0-07969100-1496402550.jpg

 

Anyway, hope this helps.

 

Izzy

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Having made the error in the past of trying to make the brass bearings fit, I speak from experience by recommending the PB bearings.

Edited by Argos
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