7mm Mickoo's Commercial Workbench
- Thread starter mickoo
- Start date
mickoo
Western Thunderer
Thanks
BTW, I've not forgotten your nameplates
should have the final etch going out in a few weeks for you 
mickoo
Western Thunderer
I did take some grubby internal shots, more for reference for the next build, so they're not squeaky clean or very professional.
But y'all get the idea of the inside motion and pick up arrangement.
The instructions make no reference that you have to cut the piston rods back......to stop them slamming into the transverse securing beam attached to the underside of the footplate.....just where that plate work is scratched.
You only find this out when the two are finally put together, and as anyone who's built one of these knows, it's not a five minute job fitting the body to the chassis
But y'all get the idea of the inside motion and pick up arrangement.
The instructions make no reference that you have to cut the piston rods back......to stop them slamming into the transverse securing beam attached to the underside of the footplate.....just where that plate work is scratched.
You only find this out when the two are finally put together, and as anyone who's built one of these knows, it's not a five minute job fitting the body to the chassis
mickoo
Western Thunderer
Back to the A2 and time to work up the frames.
The first issue was the laminated springs, cheap as chips to produce, expensive as hell to clean up and make presentable if you on power by the hour, simply not fair on the customer.
Luckily Ragstone do some very nice cast ones in both flavours, brass or white metal.
One of the issues that can be encountered when using the Hobby holidays jig is for the axle shafts to not be perfectly parallel, a trait of how the axles are fixed to the slides and the locations of the adjustment screws within the axle jig blocks.
In addition, it's quite a faff trying to solder from the inside the sprung horn blocks once the frames have all been assemble, so an easier method was tried.
Shorten the jig axles to reduce/eliminate and chance of error over their length and simply work on one side at a time. This is very easy if the engine has equi-distance wheel spacing, not so for dissimilar spacing.
I always leave one axle with a top hat bush in as the fixed reference point, in this case the rear one, the strip of wood keeps the frames clear of the big heat sink that is the jig blocks. It's much easier to solder the sprung axle guides in place on the flat and easier to ensure they are perfectly vertical.
Once the first two are done then cut out the rear one and using the same set up, solder in the last sprung unit and you should end up with something like this.
Repeat for the the side and then join together as one unit, more on that later.
The cast springs are then added, they needed to be made removable as the wheels are cast Mark Woods affairs and unlike Slaters there is only one way to remove them....downwards.
Small countersunk head 14BA screws pass through the frames to hold them in place.
These are just accessible inside the wheel rim between the spokes, the only downside with the accessibility is that they are now also visible and not hidden by the wheel rim. The solution will be to fill in the slots on final assembly and add a dab of paint to disguise them.
Not really sure why the kit openings for the horn guides are so large and I now need to add so lower axle box stops as there is currently way too much downward travel.
The first issue was the laminated springs, cheap as chips to produce, expensive as hell to clean up and make presentable if you on power by the hour, simply not fair on the customer.
Luckily Ragstone do some very nice cast ones in both flavours, brass or white metal.
One of the issues that can be encountered when using the Hobby holidays jig is for the axle shafts to not be perfectly parallel, a trait of how the axles are fixed to the slides and the locations of the adjustment screws within the axle jig blocks.
In addition, it's quite a faff trying to solder from the inside the sprung horn blocks once the frames have all been assemble, so an easier method was tried.
Shorten the jig axles to reduce/eliminate and chance of error over their length and simply work on one side at a time. This is very easy if the engine has equi-distance wheel spacing, not so for dissimilar spacing.
I always leave one axle with a top hat bush in as the fixed reference point, in this case the rear one, the strip of wood keeps the frames clear of the big heat sink that is the jig blocks. It's much easier to solder the sprung axle guides in place on the flat and easier to ensure they are perfectly vertical.
Once the first two are done then cut out the rear one and using the same set up, solder in the last sprung unit and you should end up with something like this.
Repeat for the the side and then join together as one unit, more on that later.
The cast springs are then added, they needed to be made removable as the wheels are cast Mark Woods affairs and unlike Slaters there is only one way to remove them....downwards.
Small countersunk head 14BA screws pass through the frames to hold them in place.
These are just accessible inside the wheel rim between the spokes, the only downside with the accessibility is that they are now also visible and not hidden by the wheel rim. The solution will be to fill in the slots on final assembly and add a dab of paint to disguise them.
Not really sure why the kit openings for the horn guides are so large and I now need to add so lower axle box stops as there is currently way too much downward travel.
mickoo
Western Thunderer
Onward with the chassis.
Once the driven axles boxes and springs were fitted it was onto the Cartazzi bearings and springs,the axle box has a spigot but the spring fittings do not, generally this type of arrangement is a pig to attach.
So, I drilled holes through the frames behind the spring brackets, as well as anything else that is attached to the outside, steps, brackets etc.
Then it's a simple case of dabbing a blob of solder on the inside which neatly wicks through and gives a nice clean joint on the outside.
To ensure the main frame halves are correctly aligned I extended the axle jig rods to full extension and slipped the two halves over and soldered up as normal. The already fitted axle boxes ensure that each rod remains parallel with it's neighbours.
Once the driven axles boxes and springs were fitted it was onto the Cartazzi bearings and springs,the axle box has a spigot but the spring fittings do not, generally this type of arrangement is a pig to attach.
So, I drilled holes through the frames behind the spring brackets, as well as anything else that is attached to the outside, steps, brackets etc.
Then it's a simple case of dabbing a blob of solder on the inside which neatly wicks through and gives a nice clean joint on the outside.
To ensure the main frame halves are correctly aligned I extended the axle jig rods to full extension and slipped the two halves over and soldered up as normal. The already fitted axle boxes ensure that each rod remains parallel with it's neighbours.
Phil Harding
Member
Hi
I build using the chassis jig exactly as your method described above with good results. I am also a convert to Mark Wood wheel castings. I machined some up for the Star Class and used split axles and a plastic Slater's hornblocks down one side of the chassis. Looking at your picture, is the wheel insulation on the end of each axle, can't see if you insulated the rim?
Thanks for the posts, really interesting read.
Phil.
mickoo
Western Thunderer
Phil, you're more than welcome.
The wheels are insulated on the axles, not the rims and these are the first Mark Wood wheels I've encountered, I like them
I have to say they are very nice, perfectly circular and 90° to the shaft, the only niggles are the turned crank pins which vary in dia from 2.25 to 2.48 mm and a couple haven't been pushed home correctly, easy enough to fix mind.
Splitting the chassis this way certainly makes the axle box spacing more accurate; final assembly is much faster as you're not struggling getting an iron inside the frames to fix the axle boxes.
The wheels are insulated on the axles, not the rims and these are the first Mark Wood wheels I've encountered, I like them
I have to say they are very nice, perfectly circular and 90° to the shaft, the only niggles are the turned crank pins which vary in dia from 2.25 to 2.48 mm and a couple haven't been pushed home correctly, easy enough to fix mind.
Splitting the chassis this way certainly makes the axle box spacing more accurate; final assembly is much faster as you're not struggling getting an iron inside the frames to fix the axle boxes.
Phil Harding
Member
Thanks Mickoo
So if the wheels are insulated on the axle ends, that makes the valve gear live and different polarity down each side of the frames. I had this on the Star Class and insulated the small end of the connecting rod. Is this an issue for you or do you have a cunning plan?
Cheers
Phil
mickoo
Western Thunderer
Truth is, I hadn't thought that far ahead 
or being even more truthful, even considered it'd be a problem, logical now when you take a step back 
.
Thanks for the heads up, I'll have to do something similar though small end won't work as I also have the return crank and eccentric rod to consider as well.
or being even more truthful, even considered it'd be a problem, logical now when you take a step back .Thanks for the heads up, I'll have to do something similar though small end won't work as I also have the return crank and eccentric rod to consider as well.
Dog Star
Western Thunderer
The late Paul Penn-Sayers turned the AGH castings for Peter's A4 - each coupled wheel is insulated from the axle with a Tufnol top hat bush in the rear of the wheel boss whilst each crank pin is insulated with a Tufnol bush in the wheel boss. Insulation of the axles and crank pins gives an engine frame and valve gear which are insulated from both rails.
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Richard Spoors
Western Thunderer
Hi Mick, I'm pretty sure you'll find the crank pins insulated as above.
I like the way you prepared each frame side before making up the chassis. Drilling holes to solder from the rear is a great idea too!
I think I have penguins out of my system now. Back to 60534!
Cheers
Richard
I like the way you prepared each frame side before making up the chassis. Drilling holes to solder from the rear is a great idea too!
I think I have penguins out of my system now. Back to 60534!
Cheers
Richard
3 LINK
Western Thunderer
Hi Mick,
Thank you for the tip regarding the Hobby holidays jig, I also have one of those jigs and looking back now I did have trouble with a 2-8-0 I was building. The rear axle had a slight bind once the frames were soldered up, and after measuring it was noticed the rear axle was indeed out, I was using some milled coupling rods so I had to heat up the rear hornblock on one side until it loosened enough to free the axle ( a bit unnerving at the time ) but it did the job.
But it all makes sense regarding what you say, and it is now filed away for when you guys bring out the next GWR 2-8-0,.
Regards,
Martyn.
Thank you for the tip regarding the Hobby holidays jig, I also have one of those jigs and looking back now I did have trouble with a 2-8-0 I was building. The rear axle had a slight bind once the frames were soldered up, and after measuring it was noticed the rear axle was indeed out, I was using some milled coupling rods so I had to heat up the rear hornblock on one side until it loosened enough to free the axle ( a bit unnerving at the time ) but it did the job.
But it all makes sense regarding what you say, and it is now filed away for when you guys bring out the next GWR 2-8-0,
.Regards,
Martyn.
mickoo
Western Thunderer
Martyn, that's the down side of the jig, because of the way the guides work and the adjustment screw locations you can easily twist one axle out of alignment. Previously I used a digital vernier to check each rod was parallel with its neighbour and others, but it was a right faff. This way reduces that risk of axle misalignment but does need a little more care when joing the two sides together.
Eastsidepilot
Western Thunderer
My preference with cast wheels on outside cylindered tender loco's is insulated bosses and crank pins with current collection via the tender.
Col.
Col.
mickoo
Western Thunderer
Slight diversion from the A2.
The final rendition of the 1/8th scale Bulleid nameplates came back today and I'm happy they're fit for public consumption.
A previous Mk II version.
Mk III versions, the backing plates are on another nickel silver sheet.
Two are for me, four for the first customer
The final rendition of the 1/8th scale Bulleid nameplates came back today and I'm happy they're fit for public consumption.
A previous Mk II version.
Mk III versions, the backing plates are on another nickel silver sheet.
Two are for me, four for the first customer
mickoo
Western Thunderer
Bit of a bitty plate spinning week really, the A2 hasn't progressed as much as I wanted but will get 100% attention from tomorrow (after another hospital case) until it's done, the aim is Kettering so it'll be tight.
Most of this week was spent on a new set of chassis etches for a Cambrian Bogie Tank, it's a fairly simple affair but there's no side play in the rear bogie and close fitting splashers means some tight tolerances to work to.
It'll go to the etchers now and then the builds (two of them) will appear somewhere here soon I'm sure
Tomorrows job is a simple TLC and get ready for DCC.
I have no idea of the history (builder or painter) behind this engine other than it's a Martin Finney Princess Coronation, it's nicely built and painted but appears to have been stood for a while.
It just needs a clean up, lubrication and some gentle running in; some weight and a motor fixing point will see the job done. The cab roof and tender will join it at Kettering.
Interestingly it uses the American style pick up and the wheels are all steel, possibly Mark Wood, with nice hollow axles, not all the way through but enough to give a good representation.
Most of this week was spent on a new set of chassis etches for a Cambrian Bogie Tank, it's a fairly simple affair but there's no side play in the rear bogie and close fitting splashers means some tight tolerances to work to.
It'll go to the etchers now and then the builds (two of them) will appear somewhere here soon I'm sure
Tomorrows job is a simple TLC and get ready for DCC.
I have no idea of the history (builder or painter) behind this engine other than it's a Martin Finney Princess Coronation, it's nicely built and painted but appears to have been stood for a while.
It just needs a clean up, lubrication and some gentle running in; some weight and a motor fixing point will see the job done. The cab roof and tender will join it at Kettering.
Interestingly it uses the American style pick up and the wheels are all steel, possibly Mark Wood, with nice hollow axles, not all the way through but enough to give a good representation.