Etched loco chassis

[justin1985]

 

The new metric worm/wheel sets should have both 1mm and 1.5mm bore worms supplied with them, so the problems of sleeving to different motor shafts should be reduced.  The specification I worked out with our Polish manufacturer included both bore sizes, and I expect the shop is sticking with that specification.

 

Hi Nigel, I don't suppose frame bushes with a 1mm ID are also in the works to go with these? 

 

Justin

[2mm Andy]

Justin,

 

I'm not aware of any plans to get 1mm bore frame bushes made at the moment (unless the 2mm Sales Officer is planning a pleasant surprise!).

 

However,Exactoscale (now part of C&L Finescale I believe) sell 1.5mm OD, 1mm ID bearings if that's any use. PM me with your address and I'll send you a few if you want.

 

Andy

Edited January 22, 2013 by 2mm Andy

[Chris Higgs]

Justin,

 

I'm not aware of any plans to get 1mm bore frame bushes made at the moment (unless the 2mm Sales Officer is planning a pleasant surprise!).

 

However,Exactoscale (now part of C&L Finescale I believe) sell 1.5mm OD, 1mm ID bearings if that's any use. PM me with your address and I'll send you a few if you want.

 

Andy

 

Actually, I have mentioned it to the sales officer. And he promised to look into it.

 

Chris

[2mm Andy]

Well it will be a pleasant surprise if they do appear then...

[Pixie]

Ok - own up! Who outbid me on that collection of Dapol Pannier bits on eBay with a rechassis-ing project in mind?!

 

 

Pix

Edited January 23, 2013 by Pixie

[richbrummitt]

Someone asked but I can't find the post so I'm going to bung the answer here: 

 

How I made the cardan shaft: 

 

Ingredients: 0.3mm ID 0.8mm OD tube, 0.3mm wire, solder and flux.

Tools: 2 pin chucks, small file, soldering iron.

 

1, Fix the tube in a pin chuck to allow you to hold it with a small amount of the tube protruding from the jaws. 

2, Touch the file to the diameter in one place to make a small flat so the drill will centre on the tube. 

3, Cross drill the tube close to the end 0.3mm diameter. Be extra careful when the drill breaks through into the bore it will try to catch and you need to go very gently to avoid catching and breaking the drill.

4, Cut off any excess tube protruding beyond the hole close to it. This bit is scrap.

5, Cut again about 1 to 1.5mm from the hole.

6, Solder some 0.3mm wire through the cross drilled hole. Leave about 1mm on either side it can be trimmed to final length later.

 

You should have a small length of tube 2-3mm long with a hole close to one end that has a short length of wire in it. Repeat steps 1-6 to make a second piece. 

 

7, Solder these ends onto a length of wire fitted into the longer ends of the tubes. This step is easier if you use solder paste. 

8, Clean up any excess solder.

 

It will hopefully look something like this

 

 

The ends will fit in a 1.0mm hole with some clearance to get you around the corners. This can be tube sized to join to a shaft by fitting over or joined with a sleeve. It could also be a centre drilled piece of axle steel. Either requires a slot cutting down it's length with a fine saw to receive the wire. The wire can be cut off if it protrudes too much from the slots.

[autocoupler942]

The photos for the 08 replacement chassis show half etched recesses on the inside of the frames for the axle bushes but there are none on the actual etch. This would, I suppose, affect the amount of sideplay between bush face and muff. What should the between-faces dimension be . The yearbook wheel and muff standards does not illustrate frame bushes!

[Chris Higgs]

The photos for the 08 replacement chassis show half etched recesses on the inside of the frames for the axle bushes but there are none on the actual etch. This would, I suppose, affect the amount of sideplay between bush face and muff. What should the between-faces dimension be . The yearbook wheel and muff standards does not illustrate frame bushes!

 

The photos are from the original 08 kit. As with all the other replacement chassis, the between frame distance should be 7mm - the jig will ensure that pretty much. 7.5mm over the outside of the frames. 

 

The yearbook standards (more like guidelines for frame settings) were drawn a long time ago for hand made frames, which were typically thicker than the etched ones and did not use frame bushes.

 

Chris

[autocoupler942]

Thanks Chris.

I've got types of frame bush - Brass with a 0.1mm flange  or PB with 0.3mm flange. Using the pb ones will leave me with 6.4 between faces (the info I was actually asking for!) which seems to be the dimension between the solid frames in the yearbook. So all should be ok leaving 0.2mm each side of muff for Mick's springs. I could use the brass ones I suppose for extra clearance (as I don't foresee excessive mileage/wear) or shorten the muff.

[JohnBS]

Rich (post 356) and all,

Again, perhaps not the right place but here is my take on a quickie cardan shaft.

Yesterday I decided to reduce the loco to tender gap on the Dapol 2884. The existing draw bar link is of plastic so was unadaptable and I replaced with a shorter scratch-built version in 0.25 copper clad fibreglass - easy and took about 30 minutes and I didn't even need to undo the fragile jumper cables.

Then moved on to the cardan shaft. The Dapol drive doesnt have an outer sleeve so the shaft is centred by the bore of the sockets. As such, you can't just use a dumbell-shaped piece of bent wire. So I picked out a length of nickel-silver wire (Eileen's) about 0.50 diameter and bent one end into a J shape. In the J, I soldered a short section of the same wire at right angles and then moved on to the other end. Using the existing Dapol plastic shaft as a gauge, I bent another J shape (in the same plane as the first) and soldered a similar length of wire at right angles. After a minimimum of tidying-up and trimming back the cross bars to suit the sockets in the loco and tender, a working cardan shaft. The solder joints were sufficiently small to fit inside the sockets and centre the shaft. Then dipped the thing in gun blue and rinsed.

All in all, this took about an hour, including making one to the wrong length! And no drilling involved.

The shaft is in the loco at the moment but I will post a photo when I next take it apart.

John

[richbrummitt]

The Dapol drive doesnt have an outer sleeve so the shaft is centred by the bore of the sockets. As such, you can't just use a dumbell-shaped piece of bent wire. 

 

That is not to say you could not add one from a suitably sized offcut of tube. The solution you outline is easier to make than my suggestion.

[Chris Higgs]

Here is the latest replacement chassis being test built. LMS Black 5 chassis for the Farish body in the assembly jig ready to have the frame spacers added

 

 

[Valentin]

A new replacement chassis for the Hunslet Austerity 0-6-0ST (Grafar):

 

The springs and the supports for the brake shoes are in place:

 

 

 

Before painting the chassis I have to solder the sandboxes / sand-pipes and add protection for the P/B bushes (cocktail sticks?) and for the brake shoes supports (grease or wire insulation).

[Tim V]

Nasty bit of swarf round that front bearing - remove that before going any further. Suggest you twist a large (say 4mm) drill in all the holes to take off the machining marks.

[Valentin]

All the bearings are perfectly clean. What you see through the opening is the spring.

 

And then, 4 mm drill!? Really!?... isn't it a "bit" too large?...

[PaulCheffus]

All the bearings are perfectly clean. What you see through the opening is the spring.

 

And then, 4 mm drill!? Really!?... isn't it a "bit" too large?...

Hi

 

It's only used between the fingers to just take the edge off the outside not drilling all the way through.

 

Cheers

 

Paul

[Valentin]

Now I understand what you mean and I think both of you are right. I can see the swarf at the front-right bearing.

 

Thank you!

Edited April 15, 2013 by Valentin

[Valentin]

Ready for painting with black acid primer:

 

 

After painting, a detail of the drive axle with the 1.5 mm hole and the springs:

 

 

After quartering the wheels the chassis has been tested for free running on a tilted board. Also the brake shoes have been soldered in place.

 

 

 

I don't know where to solder the brake rod: between the wheels and the chassis (not to much room) or inside the frame? Where are the brake rods fitted on the prototype?

[Adam]

Very impressive - especially given the size. The pull rods on the prototype are postioned between the springs which underhang the wheels, i.e., under the chassis. Hope that helps.

 

Adam

[Valentin]

Thanks Adam!

 

Nearly finished:

 

 

[queensquare]

Nearly finished:

 

 

 

 

Great stuff Valentine, you've made fantastic progress since I saw you at Nottingham. Make sure you bring the Austerity along next time you are attend a show Kim and I are exhibiting at.

 

Jerry

[Alan P]

Hello

 

Some time back Tim V built the J94 conversion chassis with a removable motor and worm.  This seems a good idea

I am interested in this as I did not like the idea of a captive motor and worm that puts extra extra pressure on the box during assembly. 

 

How did this work out in practice?  Was the single bearing gearbox rigid enough to maintain adequate contact between the gears or did additional strengthening have to be added?

 

Alan

[oily]

Hello

 

Some time back Tim V built the J94 conversion chassis with a removable motor and worm.  This seems a good idea

I am interested in this as I did not like the idea of a captive motor and worm that puts extra extra pressure on the box during assembly. 

 

How did this work out in practice?  Was the single bearing gearbox rigid enough to maintain adequate contact between the gears or did additional strengthening have to be added?

 

Alan

Worth looking at Magazine for Feb 2012 p 18 and April 13 p 37. There was also either an article by same author on making both motor and worm gear replaceable but I cannot quickly find it. It's possible that it was described on this site but would take a bit of finding. It even included a description of a very neat aluminium jig for ensuring alignment during assembly. I borrowed it recently and can vouch for its value.

Oliver

[Tim V]

Hello

 

Some time back Tim V built the J94 conversion chassis with a removable motor and worm.  This seems a good idea

I am interested in this as I did not like the idea of a captive motor and worm that puts extra extra pressure on the box during assembly. 

 

How did this work out in practice?  Was the single bearing gearbox rigid enough to maintain adequate contact between the gears or did additional strengthening have to be added?

 

Alan

Yes, note that the rear of the motor was bracketed to the frames. I posted some pictures earlier, do you need some more? It was a pannier by the way, but the principle is the same!

[Alan P]

Yes, note that the rear of the motor was bracketed to the frames. I posted some pictures earlier, do you need some more? It was a pannier by the way, but the principle is the same!

Thanks Tim.  I saw the earlier pictures in this forum where the complete motor, worm shaft and worm come out as one unit which is a sound principle.  This is the type I am hoping to try rather than the seperate motor that Olly guided me to. I have four J94's, actually one J94 and three Hunslet Austerity industrials built for the Fence Houses layout, all chipped. On has been running over three years using Neals wheels and three more were built quickly as spares for Glasgow show. Of these one has the Assn conversion chassis we are talking about with motor at the front and a flywheel on the rear of the gearbox leaving the cab clear.  The other two are now having the full replacement Assn chassis built and currently being detailed.

 

So this brings us to the question: The standard chassis has the gearbox hung off the left frame by means of a front and rear support frame each holding a bearing for the worm shaft. Your idea of removing the front bearing in my case so the entire motor worm unit is easily removed is good, with the motor supported at the outer end.  The question was this satisfactory in practice (before i cut the etch)?  Only using one gearbox worm bearing support makes the gearbox less rigid. I am trying to find out your experience as I know several people who with two bearings (not J94) have had the gearbox flex and have had to solder an insulated pcb support across to the opposite frame to maintain rigidity and gear mesh. Hope you can advise.

 

Thanks

Alan