Here We Go... Frateschi G-8 & Other CSB Experiments

Armchair Modeller
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Here We Go... Frateschi G-8 & Other CSB Experiments

Postby Armchair Modeller » Fri Apr 07, 2017 11:36 am

Frateschi General Motors G-8

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As you all know by now, I only ever work on one project at a time. Only when that project is completely finished would I ever dream of starting another. The subject of this topic, you may assume, is therefore strictly a proof of concept - not an actual project as such. ;)

The Frateschi model of the General Motors G-8 is to 4mm scale, despite the packaging and advertising suggesting it is HO scale. It suits me for three reasons. Firstly, I had a ride behind one (or more likely, the almost identical G-12) in Chile in the 1990s on a copper railway from Llanta to Potrerillos in the Atacama Desert. The copper ore is hauled up the side of a huge mountain to a smelter at the top. The ingots are then hauled back down and shipped to wherever. I am not making this up – see here http://www.unp.me/f44/amazing-railway-126529/ !

The second reason is that I need at least two locomotives belonging to a fictitious main line railway, to propel wagons and other stock to the ferry from the main line interchange and haul others back the other way - just to add to the operating interest, chaos and general confusion. The G-8 and G-12 were export models built in several countries and operated in many parts of the world, so not a bad choice for my totally fictitious railway.

Thirdly, it is always useful to have a few larger items of stock to ensure satisfactory clearances between stock and various obstructions I plan to install alongside the track. My tramway will have a very close and intimate relationship with the outside world – not quite as close as this, though!

https://www.youtube.com/watch?v=Dsi_ItK-j30

Here are a couple of photos of the chassis after the body has been removed

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And here, a photo of a disassembled bogie

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Keith (Grovenor-2685)referred me to his conversion of a Frateschi U20C here, but the G-8 is constructed differently. Also, I wish to experiment with CSBs. Penbits and Rumney do conversions for a number of RTR BR bogie diesel locos. Only a Class 20 bogie conversion kit would be of any use to me - and neither has any plans to do one. That means I have to invent my own conversion, whatever loco I choose. My class 20 conversion was just a straight wheel swap. It runs fine on my trackwork without springy beams. The Frateschi loco probably would too. I am introducing springiness here mainly because I want to try it, just for the experience. Time is less an issue than curiosity.

I appreciate that this is likely to be of only very marginal interest to the Scalefour population as a whole, but I seem to get lots of good ideas and advice, even when I try to do something really weird. Ideas may be useful for other similar one-off projects and may even encourage others to have a go, so here goes.... !

The wheelbase of the bogies is just very slightly shorter than scale at 31mm, but much longer than the 28mm or so it ought to be in HO scale. This 1mm discrepancy is something I can live with. Using the dreaded CSB spreadsheet, I worked out that the CSB wire needs to stretch 10.85mm outside the axles. This means the wires and supports would stick out a couple of mm beyond the bogie frames. However, the ends of the bogie frames are pretty well hidden on the prototype, so I am not going to let this little problem stop me either.

I plan to do this by making new inner frames to hold the wheels, springs, outside moulded plastic bogie frames and the Frateschi mechanism - a bit like Penbits seem to do, I guess. I will be using High Level hornblocks and Gibson wheels with 1/8" axles. The Frateschi wheels, incidentally, are made of brass and have short 1mm stub axles. I don't consider them suitable for turning down to P4 standards.

I am ambitiously hoping to get the basic P4 conversion done fairly quickly, but only time will tell...!
Last edited by Armchair Modeller on Tue Jun 06, 2017 9:19 pm, edited 1 time in total.

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Andy W
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Re: Here We Go... Frateschi G-8

Postby Andy W » Fri Apr 07, 2017 1:15 pm

Interesting project A.M. Could I suggest that any of us who thinks along the lines "I am hoping to get (fill in this blank).... done fairly quickly" donates a penny to the society funds? Within a year we should be able to buy a sizeable headquarters in the centre of London.
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Re: Here We Go... Frateschi G-8

Postby Armchair Modeller » Fri Apr 07, 2017 2:43 pm

Andy W wrote:Interesting project A.M. Could I suggest that any of us who thinks along the lines "I am hoping to get (fill in this blank).... done fairly quickly" donates a penny to the society funds? Within a year we should be able to buy a sizeable headquarters in the centre of London.


:D :D :D

My comment was tongue in cheek, of course. My real aim is to start so many projects that I never ever finish anything ;)

I am very lucky in that Neversay has two local builders I can subcontract to if necessary - Kneely Wright and May-Dupp. They are apparently very prompt, cheap and reliable.

Meanwhile, after a spot of gardening I have read the High Level hornblock instructions and am ready to start work on the new bogie sideframes...... :ugeek:

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Re: Here We Go... Frateschi G-8

Postby Armchair Modeller » Sat Apr 08, 2017 9:49 pm

A couple of evenings have seen a bit of progress on the loco. The hardest bit was working out how everything would fit together. I could only find drawing of the High Level hornblocks on the CLAG site. I suppose people normally use them in etched chassis designed by someone else these days, so they don't need all the details. Fortunately, everything should fit using standard hornblocks, with a millimetre or so to spare.

The first step was to assemble the hornblocks. Beginner's luck struck again, with no problems. Here they are, arranged to make a nice, happy face.

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For the bogie inner frames, I cut four bits of brass sheet, just slightly under 0.5mm thick. These are overlong, as I want to accommodate holes beyond the ends of the bogie sides to hold everything together when I do the final assembly.

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I soldered the brass bits together at the ends (only). A 40W soldering iron was ideal for this. I blackened the top one with a felt-tipped pen and marked the position of the axle centres and a few other bits onto the brass. I then put the brass onto a small piece of plywood and drilled out one of the the outer holes to 1.5mm. I put a piece of 1.5mm rod through the hole and into the plywood. After drilling the second 1.5mm hole, I put another piece of 1.5mm rod in this hole. These pieces of rod positively locate the brass on the plywood. The 1.5mm holes are purely for location purposes. The section of the sides with these holes in will be removed completely once the frames have been assembled, leaving just the correct length for the bogies.

I then drilled out the axle holes to 1/8". This is purely to create 1/8" holes in the plywood. These holes will hold lengths of 1/8" rod when I solder the hornblocks in place. Here is a photo showing the ply with the brass bogie sides and the 1.5mm rods locating everything correctly and with the 1/8" holes drilled - and with the moulded outer bogie frames for comparison.

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I also started a bit of work on the body. The main issue is the large coupler holes in the buffer beams. These have been filled with several layers of plasticard.

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When this is fully set, I will file off the detail on the buffer beams. This is moulded in relatively low relief and in any case represents buckeye coupler fittings and other details that I don't require. Otherwise the body is not too bad. The only other surgery of any great note should be the replacement of the moulded handrails along the long hood with a 3D equivalent.

That's probably it for the time being, as Peak District walking and other things will keep me busy for the next couple of days.

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Re: Here We Go... Frateschi G-8

Postby Armchair Modeller » Mon May 01, 2017 9:22 pm

Work is being done to complete the bogies. I decided to do one bogie first, just to see how well everything went before doing the second.

Firstly, I cut out the slots for the hornblocks, taking great care to cut the slots as accurately as I could. I then separated the soldered frames and soldered on the High Level hornblocks, using the wooden jig I had made earlier as a guide. I then drilled holes for the CSB carriers in each of the blank frames individually, using the hornblocks as a reference. This is not the normal way of doing things, but I wasn't keen on drilling the holes at an earlier stage as thin drills tend to wander from the straight and narrow when drilling through several layers of metal. I used the High Level drilling jig for this.

Then, I cut out the overall shape of the frames, leaving the end extensions in place for the time being. I soldered the 2 frames together using the 2mm Finescale loco frame jigs, using the holes at the extremes of the brass strip as with my Ruston diesel. The ends of the bogie are located so as to make the Frateschi innards a tight push fit. Here is a photo of the first bogie frame with the Frateschi inner bogie in position. There is just room for the CSBs in-between the inside of the frames and the Frateschi parts.

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Next, I will cut the frame extensions off. These were only required for locating the 2mm jigs when I soldered the frames up. A short thin bit at each end will be retained as the outer CSB carriers are located outboard of the main bogie frames - you can probably just see the holes I drilled. I must remember not to cut these off :?

There will only be a primary suspension on the bogie frames. The method Frateschi use to attach the bogie to the main loco frame is slightly springy, so should be good enough, without anything extra.

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steamraiser
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Re: Here We Go... Frateschi G-8

Postby steamraiser » Mon May 01, 2017 11:45 pm

As the diesel is a Bo-Bo had you considered swapping the original wheels with P4 Lowmac wheels with copped and shortened axles?

Gordon A

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Re: Here We Go... Frateschi G-8

Postby Armchair Modeller » Tue May 02, 2017 9:36 am

Hi Gordon,

Just swapping the wheels for P4 ones would be easy, especially with 2mm axles. The plastic muffs holding the gears on the Frateschi bogie drill easily to 2mm diameter as they already have very slightly smaller holes for the stub axles.

That would have been far too too easy though. I wanted to try a sprung chassis to see what they are like. Unfortunately, the none of the available diesel conversions are suitable for my scenario, so I had to make my own. Perverse, but true!

BTW - I am using Gibson Warship wheels, as they are the nearest to the correct diameter for the G-8.

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steamraiser
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Re: Here We Go... Frateschi G-8

Postby steamraiser » Tue May 02, 2017 12:14 pm

Thanks for the reply.
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Re: Here We Go... Frateschi G-8

Postby Armchair Modeller » Thu May 04, 2017 8:49 pm

All was going very well, or so I thought. I only realised far too late that I have soldered the hornblocks to the wrong side of the frames. I cut off the jig location holes a while back, so fixing the problem with the current frames would be very difficult. Probably best to start again.

I'm an idiot! I'm an idiot! I'm an idiot! I'm an idiot! I'm an idiot! I'm an idiot! I'm an idiot! I'm an idiot! I'm an idiot! I'm an idiot! I'm an idiot!

Sometimes you have to learn the hard way, I guess. :D

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Andy W
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Re: Here We Go... Frateschi G-8

Postby Andy W » Thu May 04, 2017 9:23 pm

Can you unsolder the spacers, switch the frames so the hornblocks face the correct way and use axle jigs like those sold by LRM to re-align them?
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Re: Here We Go... Frateschi G-8

Postby Armchair Modeller » Fri May 05, 2017 8:33 am

Thanks for your helpful advice, Andy, but in fact, the hornblocks are already the correct way round. I mistakenly soldered the wide bit to the outside of the frame, not the inside. To correct this, I have to remove them from the frames. The instructions don't actually tell you where they go, though an illustration hints at it. But then, who reads instructions? :?

It will probably be easiest I think to start again. It should take much less time this time around as I spent too much time procrastinating (about the wrong things!) with my first effort. I would now do it differently anyway.

Watch this space!

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Re: Here We Go... Frateschi G-8

Postby Armchair Modeller » Fri May 05, 2017 10:22 am

I have been scouring the Internet for ideas on how best to fit the High Level hornblocks to the chassis. I can see how people have made sure that the axles are at right angles to the chassis and with the correct spacing, but nothing that guarantees the slots are absolutely vertical when they are soldered in place.

I may just be missing something obvious here (again)! :?

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Russ Elliott
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Re: Here We Go... Frateschi G-8

Postby Russ Elliott » Fri May 05, 2017 3:26 pm

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Will L
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Re: Here We Go... Frateschi G-8

Postby Will L » Fri May 05, 2017 4:13 pm

Armchair Modeller wrote:I have been scouring the Internet for ideas on how best to fit the High Level hornblocks to the chassis. I can see how people have made sure that the axles are at right angles to the chassis and with the correct spacing, but nothing that guarantees the slots are absolutely vertical when they are soldered in place.


Try here, which shows how I do it on a chassis jig, but I think the same approch will work with a couple of steel rules so long as the top of the chassis frame is parallel with the axle center line.

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Re: Here We Go... Frateschi G-8

Postby Armchair Modeller » Fri May 05, 2017 4:46 pm

Thanks, Russ & Will. Those ideas give me food for thought. Really more important when I get around to steam locos, probably. Nevertheless, even a diesel bogie chassis should be pretty accurate, I guess.

I did a bit of work on 'Mark Two' this afternoon, cutting out one side frame and drilling holes. I decided to try marking all the holes without drilling axle holes in the frames. Axle holes are ultimately superfluous anyway, as only slots are left for the hornblocks at the end. I marked out the positions of the centre CSB carrier hole and the centres of the axles. Then, I used the High Level CSB jig to drill 0.5mm holes in all the relevant places. I drilled holes at 0.5mm diameter for the CSB carriers, the positioning holes at the top of the hornblocks, the markers for the top edges of the frame slots and also positioning holes for the aligning jigs, I will use when assembling the bogie. This seems to have worked well, despite me having to turn the jig round half way through, as I needed to use both the 1mm spacing and the 1/2 mm spacing sides for positioning the CSB carrier holes.

I recovered the hornblocks from the original sideframes. I have soldered two of these into position on the new frame. I used a piece of 0.5mm wire in the alignment hole of the hornblock to get the position correct and an engineers square to judge the vertical alignment. Here is the result...

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There is a bit too much solder for neatness! This is the result of solder remaining on the hornblocks from the original work. They both function though, so all is well enough, I think - especially as the solder will be well hidden when the bogie is fully assembled.

Next, I will cut out the remaining three bogie frames.

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Re: Here We Go... Frateschi G-8

Postby Armchair Modeller » Sat May 13, 2017 8:47 pm

Things have moved on quite a bit since the last posting, but I will have to save some photos for another time as I am having to recharge the camera battery at the moment.

I cut out the blanks for the remaining three bogie frames and drilled holes individually, using the High Level hornblock jig. I was able to successfully mark out and drill the holes for the CSB holders, the hornblock locator holes and the holes indicating the top corners of the hornblock slots just using this jig and one horizontal line to show the height of the axle centres, as in this example

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I then tested each frame against the others by using 0.5mm rod through the various holes to make sure they matched - which they did.

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For someone who generally finds it difficult to drill two holes in the same universe, never mind the correct positions on the same piece of metal, that's quite an achievement! A refinement of this idea would be to clamp or solder a straight edge along the top of the frame to give a more positive location for the vertical position of the jig. Of course, with an etched chassis the etched axle holes provide the point of location for the jig. My method is only relevant for scratch-built frames, avoiding the need to drill the axle holes altogether. Just to reiterate a previous point, I don't like drilling through several layers of brass in one go with small drills, as in my experience the drills are inclined to wander.

Using the first frame as a master, I marked the shape of the frame and cut the remaining three sides to the correct shape. I then soldered each pair together with a touch of solder at each end, using bits of 0.5mm rod through a couple of the holes to line things up correctly. Then, I drilled a hole at each end through both pieces to form the alignment jig holes. I soldered the remaining hornblocks in place using 0.5mm rod through the locating hole at the top of the hornblock and an engineer's square to get everything lined up correctly.

Handrail knobs (the CSB holders) have been soldered in position and the frames have been soldered together, using the same method as the Mk1 version in a previous posting, using 2mm FS jigs. The holes in the knobs were lined up with a piece of rod before soldering. I have also drilled out the axle holes in the driving axle gears to the correct diameter for the Gibson axles. I did this in 0.1mm steps to try to maintain concentricity - the point of no return in the conversion.

Having got my mind around fitting the hornblocks, I am also messing around with a couple of etched chassis for steam locos. More about those another time.

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Re: Here We Go... Frateschi G-8

Postby Armchair Modeller » Tue May 16, 2017 11:03 pm

Not much has been done in the last couple of days but I finally got around to photographing the bogie frames. Not very pretty but it will all be well hidden when finished. The ends have still to be trimmed too.

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Here is one of the frames with the Frateschi inner bogie parts loosely in place. Everything seems to line up!

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I have also fettled the hornblocks so they all slide smoothly. I can't hold off putting these together much longer - I am desperate to see if it all works!

Nothing to do with the G-8, but here are two other things I have been fiddling around with. Firstly, I bought a couple of these motors from China to try out. The motor is powerful, but a railway modeller would definitely need further gearing to get satisfactory crawling, I think. I suspect the output shaft has a slight wobble too, though it is difficult to tell for sure as the shaft has a flat section in it. The whole thing is very compact at 23 x 20 x 10mm, so potentially very useful. The white gear is my addition. I was hoping to use it as a direct drive in a steam railcar, but I think further experiments will be necessary before I am convinced about using it.

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The other experiment is another CSB chassis - this one a kit. It is the Mainly Trains chassis for the Sharp Stewart Cambrian 2-4-0 tank. This probably needs a topic of its own, but if I get involved in any more topics at the moment I won't have time to do any modelling. I may start a topic if and when I get the chassis running - the bodywork will largely have to be scratchbuilt.

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Suffice to say I am using jigs like I did for the G-8 bogies and the Ruston chassis. The main difference is that holes are already there in the etch for the axle positions. I was able to use the High Level jig the way it is supposed to be used to position the CSB pivot points and the hornblock slots.

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Re: Here We Go... Frateschi G-8

Postby Armchair Modeller » Wed May 17, 2017 9:38 pm

The new bogie frames for the G-8 are almost done now. The final shape of the frames was achieved with a piercing saw. I remember getting through the whole supply of the school metalwork department's piercing saw blades one afternoon as a schoolboy. This time, I didn't break one. I then soldered several layers of PCB to the inside of each side. These give a good friction fit for the Frateschi inner bogie core. The plan is to test each assembled bogie with wheels and gears before I fix the inner cores permanently. This will allow small adjustments to be made if necessary before it is too late.

Here is a photo with the cores temporarily in position

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I washed my work in hot water to get rid of any remaining liquid flux. Whilst they were drying I made further progress on the Sharp Stewart tank loco chassis. I have cut out the slots for the hornblocks. I also cut away part of the rear part of the frames where they don't match photos of what I want to build. I also soldered the hornblocks in position.

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I may need a separate topic for this one quicker than I thought :shock:

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Re: Here We Go... Frateschi G-8

Postby Armchair Modeller » Fri May 26, 2017 10:50 pm

Nothing like as much progress as I had hoped for! My 90 year old mum had a few problems last week, so I have been spending a lot of time with her.

The G-8 bogies are almost ready for final assembly though. The hornblocks have been fettled to ensure a smooth operation. They and some CSB wires have been tested in position and seem to be functioning as hoped for.

The gear wheels have been fitted to the axles. I was unsure how best to do this. My main concern was that they never come loose on the axles. In the end I hit upon the idea of sandwiching each gear wheel between a pair of 1/8" axle bearings, using epoxy as the adhesive. Here is a photo of the assemblies setting - modern art????

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Here are the more or less completed inner bogies, ready for the axles and wheels. CSBs were not in place when I took this one.

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Next, I will put the wheels on their axles (not forgetting the hornblocks, of course) and see how well the gear train on the remains of the Frateschi inner bogies mate with the axle mounted gears.

On the Sharp Stewart 2-4-0T chassis, which I am doing mainly as another CSB experiment, things have just about reached the same state. The frames have been soldered together using the EM gauge spacers provided in the Mainly Trains kit - but not necessarily in the places intended by the kit designer. I used the 2mm Scale Association chassis jigs again, as with the G-8 bogies. There are separate CSBs for the front axle. Mercifully, the chassis coupled wheelbase and coupling rods match.

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The next job here is to assemble a gearbox, ready to place on the rear axle.

I had been hoping to get the chassis for the G-8, Sharp tank and the Ruston 48DS running by the end of the month. I have probably got my work cut out now to achieve that.

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Re: Here We Go... Frateschi G-8

Postby RobM » Sat May 27, 2017 6:45 am

Like your respect for your tools........ ;)
http://www.robmilliken.co.uk
Updated December 2016

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Re: Here We Go... Frateschi G-8

Postby Armchair Modeller » Sat May 27, 2017 8:28 am

RobM wrote:Like your respect for your tools........ ;)


If you mean the rule, it was bent for a specific job, honest! I have others that have not been modified. 8-)

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Re: Here We Go... Frateschi G-8

Postby Armchair Modeller » Wed May 31, 2017 9:12 pm

Just a little more progress with the G-8 and the Sharp Stewart.

I now have a partially assembled gearbox for the Sharp Stewart tank - scratchbuilt. I am using Ultrascale 30:1 gears with a spur gear reduction of just under 2:1 at the motor end. Here are most of the bits.

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The top part, including the worm gear, will be a slide fit onto the bottom half, which fits around the axle. My idea is to just put the wheels on their axles once, complete with the lower part of the gearbox. When (if?) I am satisfied about the quartering etc, I can then just epoxy the top part of the gearbox on and I have complete drive train. Everything is made from odd scraps I have in my gloat box, including the Tenshodo motor. The whole thing is only around 20mm long and just 16mm above the axle centre. At axle level, it is only 6mm wide. For a first attempt it is probably not too bad, but I don't think High Level and others need lose much sleep just yet... ;)

The driving wheels are old fashioned Gibsons with just a dimple where the crankpins go. The next job will be to drill the holes for the crankpins. I will have to make a jig to make the holes consistent.

On the Frateschi G-8, I have now assembled the wheels on their axles, complete with hornblocks and put them in the bogies. I have also provisionally tested them with the Frateschi inner bogies - and it looks very much as if everything will work fine. The full truth will only come when everything is fully assembled and running on the track, of course - which can't be long now.

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I don't propose to do too much with the body just yet. I have recently realised though that the long hood narrows near the cab - something I hadn't really noticed before, sadly! This image illustrates what I mean...

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That is one piece of surgery I must do, as the Frateschi long hood doesn't have the recess.

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Re: Here We Go... Frateschi G-8

Postby Armchair Modeller » Sat Jun 03, 2017 12:01 pm

The CSBs and axles have now been fitted to the bogies. The Frateschi inner bogie assemblies have now been epoxied in place, after some testing to make sure that the gears mated OK with those on the axles. Not sure what I will do if the axles etc ever need removing, as getting the CSBs back in again now will be a challenge. I guess I might resort to doing a proper job with a completely new chassis TBH. I am now waiting for the glue to set thoroughly before assembling the chassis and doing further testing.

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Just one other thing I managed to squeeze into my hectic schedule, an 08 conversion.

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This must be the easiest loco conversion to date. The Ultrascale wheels just drop into place. A little bit of fiddling with the pickups and hey-presto! it runs. Given my commitment to Colonial modelling, I am not sure quite what to do with it yet. Egypt, Australia and a few others had fairly conventional bodies, very like the BR version. Others were prettier though, like this South African pre-war version

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And the streamlined version for Malaysia

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I got this chassis very cheaply on eBay, mainly because the body is in a bit of a state. It came with a cheap controller too - all for £25. The chassis runs very sweetly, so I am well pleased!

It was not just the 08 that got cosmetic treatment, of course. Here's a Jamaican 'Class 20'.

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Armchair Modeller
Posts: 1149
Joined: Thu Jan 06, 2011 7:34 pm

Re: Here We Go... Frateschi G-8

Postby Armchair Modeller » Tue Jun 06, 2017 8:47 pm

We left this project on the boil on Saturday, with the glue drying on the inner bogies.

At this point I really should employ a good PR consultant, but I can't afford the kind that might be of any real help, so here goes with an unadulterated version of progress... :?

Firstly, it quickly became obvious that the epoxy glue had got to places that even Heineken could not reach. Several of the hornblocks had seized up completely. Oops! I promise I took a lot of care with the glue application etc, but you probably won't believe me. Nevertheless, I put the bogies back into the chassis and ran the motor under power on the workbench. At least the wheels went round :thumb

Looking at the chassis from underneath showed that I had not really cured the eccentric gear wheel problem. In fact, all the axle gears were very slightly eccentric - but only the one really bad one seemed bad enough to affect performance with a distinct tight spot where the motor slowed down once every wheel revolution. At this stage I was ready to give up (polite description!) but glued some PCB for the pickups to the sides of the bogies anyway, just in case - and left everything to set overnight.

I had another look this evening after a visit to the cinema to watch 'Alien Covenant'. Filled with adrenaline, I decided not to give up. Firstly, I attacked the stray glue problem by carefully cutting between the backs of the CSB holders on the hornblocks and the Frateschi inner bogie sides with a razor saw. Where I couldn't get the saw in, I used a Stanley knife. Amazingly, within 10 minutes or so, I had cured the immovable hornblock problem completely.

Buoyed by this success, I soldered temporary pickups to one of the bogies and reassembled the chassis.

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I then put it on the layout and gave the chassis a run.... and there is only good news after this bit... :D

The loco runs AND most importantly, stays on the track. There is a definite tight spot, but a few hundred circles of a P4 circular test track may well improve things no end. I may even turn up at Scaleforum if the roundy-roundy is going to be there. Also, the chassis rides at exactly the right height. I ran it at high speed backwards and forwards for several minutes without any sign of it coming of the rails.

So then, was it worth it? As Gordon suggested earlier, a straight conversion replacing the wheels with P4 ones would have been infinitely quicker. Also, I would not have landed myself with the eccentric gear problem. That was not the point though. I really wanted some experience of building my own CSB chassis to help me understand how they work. Better to test it on a cheap and nasty chassis, that probably needs replacing in the long term anyway, rather than something more expensive and sophisticated!

Encouraged by this limited success, I shall put more permanent pickups on both bogies and do more testing. That will probably do for now, as I really ought to be getting on to more serious things.

Next, I will try to get the Sharp Stewart CSB chassis running.

Armchair Modeller
Posts: 1149
Joined: Thu Jan 06, 2011 7:34 pm

Re: Here We Go... Frateschi G-8 & Other CSB Experiments

Postby Armchair Modeller » Sun Jun 11, 2017 12:46 pm

The slow running of the diesel chassis is now getting a little better after a few runs up and down Neversay's trackwork. I am beginning to think that it might be OK after a proper workout. The big positive from this project is that the CSB system seems to work very well. Quick or slow, it hasn't derailed yet. That is really what this little experiment was all about.

Moving on to the Sharp Stewart, I have now assembled the wheel sets and installed them in the chassis. No CSB wires yet though. The good news is that the wheels do turn with the coupling rods on. There is just a very small tight spot. The crank pin holes are a very tight fit on the Gibson crankpins though. Hopefully, just easing the holes out slightly will sort it.

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As with the Frateschi diesel, this is very much a learning exercise for me. It has given me a lot of food for thought before I do my next chassis. There were so many stages where it could have gone horribly wrong. For example...

Locating the CSB hornblocks in exactly the right place - correct for the axle positions and square to the chassis.
Drilling the holes for the crankpins accurately and consistently (not necessary for most wheels)
Ensuring the crankpins are square to the wheels.
Enlarging the holes in the coupling rods accurately to suit the Gibson crankpins. The holes had to be enlarged quite a bit, leaving the possibility that the hole could wander as it got bigger.

These are all things I need to make a little more foolproof.


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