Sandy's Workbench 7mm Scale

[Sandy Harper]

This is my new project. It will be finished in late BR livery and will have split axle tender pickup only. This model will have the 5000gal bogie tender fitted, which is going to be a first for me. A split axle/frame 6 wheel tender is fairly straight forward to construct but a pair of bogies is gong to be a bit more interesting.

The North Star tender bogie deign has an outside frame with U shaped inner frames to hold the axle bearings. The inner frames are attached to the outer cross member (bolster) by nuts and bolts and I will need to isolate the two sides of the inner frames and also the outer frames from the inner frames. Then I need to transfer the wiggly amps from the bearings to the inside of the tender body where the DCC chip will be located.

I have spent a few idle moments over the last few weeks studying the etches and trying to figure out the best options and this is what I have come up with.

I first assembled the inner frames complete with bearings and glued a length of fiberglass copper clad between the vertical parts of the frame. I will gap the copper and use it to attach the electrical connections. I strengthened the half etch join between the vertical and the horizontal parts. The bearings were reamed out to fit the axles which I have already 'split' using the tried and tested 'drill, cut and glue method. All eight Slaters wheels have been 'de-insulated. The wheels came with the kit otherwise I would have gone with a set of JPL un-insulated cast wheels and have saved my self a job!

This photo does not relate to the project below.












Next I made a cut through one side of the brass inner frame with a piercing saw, down to the fiberglass, to provide the electrical isolation between the two halves of the inner frame. The fiberglass, plus Devcon 2 tonne, have maintained the rigidity of the unit.




Next I needed to prevent any power reaching the outer frame so I covered the mating surfaces between the inner and outer frames with a thin layer of plastic.The nut and bolt connection between the inner and outer frames will be made with nylon bolts and nuts.



That's it for now
Regards
Sandy

Edited February 4, 2019 by Sandy Harper
Change title

[Donw]

Looks like you are making extra work for yourself but I will be interested to see if the result makes it worthwhile.

Don

[Sandy Harper]

Hi Don

It is not a grea deal of additional work at this stage but when I come to the loco there will be no pickups or shorts to worry about! Now that is a big saving!!

REgards

Sandy

[JeffP]

Watching this with interest, as it's something I've thought on doing.

[Ressaldar]

Hi Sandy,

 

I take it that you are building a Maunsell Arthur or S15? Best of luck with the build, looking forward to seeing it at Llanbedr early in the New Year

 

cheers

 

Mike

[Sandy Harper]

Hi Sandy,

 

I take it that you are building a Maunsell Arthur or S15? Best of luck with the build, looking forward to seeing it at Llanbedr early in the New Year

 

cheers

 

Mike

 

Hi Mike

It is the S15 but as for the new year!!!! You might get the tender!

Sandy

[dikitriki]

Hi Sandy

 

Any particular reason for not using double sided copperclad and soldered it to the frame?

 

I have one of these in the store cupboard, so I too shall watch with interest.

 

Regards

 

Richard

[Sandy Harper]

Hi Sandy

 

Any particular reason for not using double sided copperclad and soldered it to the frame?

 

I have one of these in the store cupboard, so I too shall watch with interest.

 

Regards

 

Richard

 

Hi Richard

I have had some copperclad delaminate on me in the past, probably too much heat, so I thought I would give the Devcon a try. It;s bloody strong!!

 

Sandy

[Sandy Harper]

I have completed the bogie's and the isolation system works, Yippee!!

 

The nuts on the top have nylon bolts to ensure there is no transfer of wiggly amps from the inner sub frame to the cosmetic outer frame.

 

The white metal castings are of good quality with very little cleaning up required and are attached with 2 part epoxy.

 

Next job is to continue with the rest of the tender.

 

Regards

Sandy

 

 

[JeffP]

Following this with interest........

[Sandy Harper]

I spent a busy day at our local Model Railway Exhibition today and, by way of relaxation, I have done a bit more on the tender this evening. Not that a Model Railway Show is stressful but when your new layout is being exhibited and the paint is not yet dry, well, I was glad it all went well. Considering I was ballasting track yesterday it was amazing that we only had one point stick and one isolation gap that closed up without us noticing and caused a worrying short that had us confused for about 10 minutes just before the show opened. Note to self, 'Don't leave it so late to complete a project!!'

 

Anyway here is the tender body so far. The brass is a delightful 18thou. and is easy to solder and get square. It is recommended that the rear internal spacer is drilled to allow an air gap into the rear of the tender and enable cleaning to be carried out so I have not yet soldered it in place.

 

Sandy

 

 

 

 

 

 

[ozzyo]

Anyway here is the tender body so far. The brass is a delightful 18thou. and is easy to solder and get square. It is recommended that the rear internal spacer is drilled to allow an air gap into the rear of the tender and enable cleaning to be carried out so I have not yet soldered it in place.

Sandy

 

Hello Sandy,

 

nice looking build. Looking at the build it looks like you have four big holes in the base so you should have no problems there, so where does this rear spacer fit? If you do have to drill it, I always try and drill four holes, two in the top corners and two in the bottom corners, all about 3mm. This will let the fluid (ultrasonic cleaner?) in and the air out.

 

OzzyO.

 

PS. it's very shiny and makes working out some of the photos a bit hard.

[Sandy Harper]

Hello Sandy,

 

nice looking build. Looking at the build it looks like you have four big holes in the base so you should have no problems there, so where does this rear spacer fit? If you do have to drill it, I always try and drill four holes, two in the top corners and two in the bottom corners, all about 3mm. This will let the fluid (ultrasonic cleaner?) in and the air out.

 

OzzyO.

 

PS. it's very shiny and makes working out some of the photos a bit hard.

 

As you notice the brass is almost like a mirror it is so smooth. It needs a trip around your sand blaster! The final spacer fits in about 1cm from the rear. In the end I took the slitting disk to it and cut out a rectangle. It won't be seen.

 

I have now fitted the top plate and the rear coal spacer along with the bogie bolsters

 

It is a b****y big water cart!!

 

 

 

 

Now here is something from your part of the world.

 

They were both scratch built by a friend of mine but he has a habit of not finishing off the detail before he moves on to his next build. He is now trying to build just about every class of loco from the Caley and NB built before 1880!!!! THese are now surplus to his requirements and I am going to put them on ebay for him. He makes a very nice job of the upperworks but as an ex Art teacher he has no engineering skills and I usually end up making them run!!

 

 

 

 

Regards

Sandy

[Sandy Harper]

Tender now complete except for wiring for the pickup and DCC Chip. There are issues with clearance of the swing of the front bogie which fouls the operating levers for the brakes. I am going to have to fettle this a bit to prevent this. (Location A on photo) Allowance was already made with small cutouts in the linage brackets but not enough.(Location B on Photo) Once it has been painted and attached to the loco it is unlikely that this area will be seen from a normal side view so I may remove the uprights altogether.

 

Next, the loco coupling rods.

 

Regards

Sandy

 

 

 

 

[N15class]

I really like your idea for the insulation of the bogies. These with the H15 are my favourite of the large LSWR/SR locos. I have long term plans to build the stepped running plate H15.

 

Your tender looks great. When I built one of these tenders in 4mm to EM gauge I also had trouble with bogie clearance.

 

Just noticed you seem to be a lamp iron missing above the buffer centre.

Edited December 3, 2012 by N15class

[Sandy Harper]

Thanks Peter, when I was sorting out the box to start on the loco, there was a spare lamp iron!!! Well spotted.

 

The 'stepped footplate' H 15 is a very handsome engine with the inclined cylinders. I was admiring Peter Trigwells model in LSWR livery on the tech stand at Guildex in September.

Sandy

[Sandy Harper]

I have started the chassis and here it is in the Chassis jig

 

 

 

This close up shows what kind of joint you can get using a torch rather than an iron.

 

 

Sandy

[JeffP]

How come you can't get that with a decent iron? Say 100W?

[Barnaby]

Very nice work Sandy looks like you're using several different soldering methods, irons. resistive and flame.

Exquisite.

 

 

Regards

[dg40014]

I agree, why rely on any one single method for soldering when we are skilled builders? Use what works best.

[3 link]

How come you can't get that with a decent iron? Say 100W?

 

Hi Jeff,

 

You would get the same result with say a 100W iron, but if you think of the amount of heat sink in the chassis sides and the thick axle bushes you would have to keep the iron in place longer than you would with a torch. And it would be a much more "local" heat so you do not have to worry about adjoining parts suddenly dropping off .

 

Martyn.

[JeffP]

Hmmmmmmmmm.

And yet, when I asked, last year, about flame soldering, I was told unequivocally to "leave it alone".

[Sandy Harper]

Hmmmmmmmmm.

And yet, when I asked, last year, about flame soldering, I was told unequivocally to "leave it alone".

 

Now that does surprise me as it has become a popular and efficient way of soldering. Like anything else it needs a bit of practice to develop the skills but the results are good.and clean which is a big bonus.

 

I don't think I can agree with the 100watt iron requirement for general soldering. I have found, over the years, that it is not the Wattage rating in an iron that is the determining factor in an iron, it is the ability of the iron to replace the energy/heat loss quickly that matters. You can have a 100w iron that takes several minutes to reach maximum temp.but when applying the tip to the work the heat dissipates, especially with brass, so quickly that the iron does not have the capacity to return the energy used to keep the solder molten and able to flow. Good quality Temp. Controlled Irons will do this, but at a cost, where as the gas torch maintains the heat irrespective of the work you are doing. Good torches will have adjustable flames to control the required temperature for the job in hand.

 

It doesn't replace the soldering iron as I still find that useful for tinning etc but it is a great addition to our tool range.

 

Regards

Sandy

Edited December 7, 2012 by Sandy Harper

[Sandy Harper]

No soldering this morning just a lot of drilling, tapping and fitting!

 

I cleaned up the driving wheels yesterday and blackened them with Birchwood Casey Blue after degreasing with meths. I also riveted and fitted the balance weights using epoxy.

 

This morning I tapped and counter-sank the crank pin holes to take 10BA and also tapped 8 top hat bearings. The extra two bearings are for the middle axle where they will be fitted face to face to accommodate the connecting rods. The photo shows the centre axle, outer, bearing the wrong way round but that is just to hold the rod in place temporarily. Eventually they will be trimmed and a washer fitted between the coupling and connecting rods.

 

I had already made up the coupling rods and, as you'd expect after using the jig, they fitted perfectly and I already have a sweet running chassis.

 

The motor/gearbox that came with the kit is a Ron Chaplin item fitted to a Cannon Motor which are superb units and thankfully, now available again through MSC.

 

The spacers for the main frames, I think, are a bit too narrow and I am going to have to use a ruck of washers to take up the enormous amount of side play. I have the wheels pushed right over in the photo so the amount of play can't be seen.

 

Regards

Sandy

 

 

 

 

Edited December 7, 2012 by Sandy Harper

[Sandy Harper]

I built the bogie frame yesterday afternoon. Nice design with sprung side control, vertical spring control and provision for adding a little extra weight. This went together without any issues.

 

This morning I tackled the cylinders. Don't be tempted to bash on with your own agenda here as it is quite important that you follow Adrian's build schedule otherwise things can get a little difficult. I've had it apart twice!!

 

I am not happy with the butt joint between the rear cylinder casting and the slide bars. This appears to be a weak bit of the design and I am going to have to have a think about how I proceed from here. The N/S castings for the slide bars and the cylinder rear covers are all superb and it will look good when completed but I don't think that a soldered butt joint will stand up to the stresses in this area.

 

 

Regards

Sandy