7mm Mickoo's Commercial Workbench

[mickoo]

All nicely cleaned up and running smoothly.

The motor mount is a U shaped bracket from 0.7 mm etch waste strip with two tabs folded over, underneath the tabs are two 10BA nuts. The bracket was fixed to the ashpan with Devcon and then a simple strap from 1.0 mm copper wire formed and held in with two 10BA screws with washers, simple is as simple does.

Lead in the usual places, it may need some more but this'll help it along in the mean time.

 

[mickoo]

Saturday update, not as much as I'd of liked, but progress none the less.

The majority of the footplate is done and the cylinders need the pressure relief valves and then slide bars fixing and setting up.

 

[mickoo]

And so to the cab....hmmph.

This is where the kits age and simplicity really come to the fore.

The basic core is complete and plonked on the footplate for the photos, just the details to add, gutters, vents (all closed position), handrails, turn ins, roof rear support rib etc.

Then it'll be a case of working around the shell to fill in all the gaps with milliput

 

[mickoo]

Slowly slowly catchy monkey.....

A week I'd rather forget, a whole week on just the boiler and firebox and still no where near finished.

The boiler was pre-rolled, badly (I understand why it's shipped rolled, if flat, it wouldn't fit in the box) and such thick gauge it's near impossible to straighten or work with, in hindsight I should of just flattened it as best possible and copied it to thinner material and then binned it; but it ended up reasonably good in the end.

One hurdle was fitting the speaker, or as I'm a maintenance engineer, being able to get it out in the future if it fails, thus a tube was formed inside the boiler to hold the speaker.



The copper wire ring prevents it falling into the smokebox, it'll be held in place from the rear with the weight and some sort of devised bracket to hold that in place.

Having a big hole in the forming rings does mean you loose the alignment holes which can be used for screws to hold it altogether for soldering up, thus another copper wire ring was fitted to the smoke box rear and aligns with the boiler front. Each former ring is set back from the wrapper edge anyway, so the wire ring just sits nicely and equally in each end.

Progress to date.









The white metal is just placed on to give an idea of how the whole engine looks.

The firebox was time consuming, I actually built the rolling chassis quicker and it still has it's niggles, there are nice brass castings for the firebox front corners, but as can be clearly seen, they're too short.

If you raise the footplate up by adjusting the swept bends then it'll be higher than the front and tip forward.

If you remove some of the firebox base then the crown will be too low in relation to the cab front. A big blob of Milliput will be wedged in there and then blended in, not looking forward to that at all.

The wash out holes are in the wrong place, the instructions tell you this so they have to be plugged and new ones drilled 5 mm lower.

There are no hand rail knob holes in any of the kettle bits, cheers, thanks for that extra work load

However, the biggest issue is the profile of the firebox wrapper at the rear, woefully wrong and after many days of teasing, filling and adding thin fillets and wedges to close up the gaps you realise it's also a whopping 5 mm too narrow at the shoulder. The cladding should just butt up to the inside edge of the spectacle window frames.

Of course there's no way of knowing that until it's virtually finished and all the formers and joints are soldered up.

There are three options going forward;

1: Leave it as it is and given the time expenditure already involved accept it and live with it. This fits the build out of the box criteria.

2: Totally remove the wrapper and start with a new one and then add back all the castings and details, that'll add a week onto the build easily.

3: Slit the top of the firebox from front to rear, widen at the rear the require amount and then plug the slot in the top with a brass wedge and make good. Once the top is widened it'll then create a gap down the sloped sides to the base, that'll have to be filled as well.

Time for a stiff drink I think.

 

[Richard Spoors]

Hi Mick, it's rather disappointing to see such an error in the firebox wrapper. This is what it should look like. A screen dump from a video on youtube of Blue Peter.
You might be heading for option 2!

 

[jonte]

Slowly slowly catchy monkey.....

A week I'd rather forget, a whole week on just the boiler and firebox and still no where near finished.

The boiler was pre-rolled, badly (I understand why it's shipped rolled, if flat, it wouldn't fit in the box) and such thick gauge it's near impossible to straighten or work with, in hindsight I should of just flattened it as best possible and copied it to thinner material and then binned it; but it ended up reasonably good in the end.

One hurdle was fitting the speaker, or as I'm a maintenance engineer, being able to get it out in the future if it fails, thus a tube was formed inside the boiler to hold the speaker.

View attachment 118485

The copper wire ring prevents it falling into the smokebox, it'll be held in place from the rear with the weight and some sort of devised bracket to hold that in place.

Having a big hole in the forming rings does mean you loose the alignment holes which can be used for screws to hold it altogether for soldering up, thus another copper wire ring was fitted to the smoke box rear and aligns with the boiler front. Each former ring is set back from the wrapper edge anyway, so the wire ring just sits nicely and equally in each end.

Progress to date.

View attachment 118486

View attachment 118487

View attachment 118488

View attachment 118489

The white metal is just placed on to give an idea of how the whole engine looks.

The firebox was time consuming, I actually built the rolling chassis quicker and it still has it's niggles, there are nice brass castings for the firebox front corners, but as can be clearly seen, they're too short.

If you raise the footplate up by adjusting the swept bends then it'll be higher than the front and tip forward.

If you remove some of the firebox base then the crown will be too low in relation to the cab front. A big blob of Milliput will be wedged in there and then blended in, not looking forward to that at all.

The wash out holes are in the wrong place, the instructions tell you this so they have to be plugged and new ones drilled 5 mm lower.

There are no hand rail knob holes in any of the kettle bits, cheers, thanks for that extra work load

However, the biggest issue is the profile of the firebox wrapper at the rear, woefully wrong and after many days of teasing, filling and adding thin fillets and wedges to close up the gaps you realise it's also a whopping 5 mm too narrow at the shoulder. The cladding should just butt up to the inside edge of the spectacle window frames.

Of course there's no way of knowing that until it's virtually finished and all the formers and joints are soldered up.

There are three options going forward;

1: Leave it as it is and given the time expenditure already involved accept it and live with it. This fits the build out of the box criteria.

2: Totally remove the wrapper and start with a new one and then add back all the castings and details, that'll add a week onto the build easily.

3: Slit the top of the firebox from front to rear, widen at the rear the require amount and then plug the slot in the top with a brass wedge and make good. Once the top is widened it'll then create a gap down the sloped sides to the base, that'll have to be filled as well.

Time for a stiff drink I think.

To my uneducated eye, this all looks tremendous, but my word, isn’t this kit building lark fraught!

Good luck with the solution.

Incidentally, Mick, when you mention abandoning say the boiler and re-fabricating from thinner material, from where (and what thickness/gauge) would you obtain it? Is it a sheet of K&S brass that you’d find in most model shops?

Please forgive my ‘thickness’ once again.

Jonte

 

[Eastsidepilot]

There are three options going forward;

1: Leave it as it is and given the time expenditure already involved accept it and live with it. This fits the build out of the box criteria.

2: Totally remove the wrapper and start with a new one and then add back all the castings and details, that'll add a week onto the build easily.

3: Slit the top of the firebox from front to rear, widen at the rear the require amount and then plug the slot in the top with a brass wedge and make good. Once the top is widened it'll then create a gap down the sloped sides to the base, that'll have to be filled as well.

Time for a stiff drink I think.

To be honest Mick if it's meant to be a build out the box I'd use filler, I know it's not 'proper building' but maybe the easiest way out for the money
As they say 'you can't build a Mona Lisa from an instagram photo of Katie Price' !
I've often had success filling with soft solder (70 degree stuff) but you need to tin the brass first as you know.

Back to the scratch build or semi scratch v kit build thing again

Good luck mate. Nice build.
Col.

 

[oldravendale]

Very sorry to learn about these problems, Mick. The photos you've provided don't suggest the magnitude of the errors you report and the build looks lovely.

As you know I can offer no advice (!) but just express my surprise that a David Andrews kit has these errors - they are of such a fundamental nature that I'd associate them with certain other manufacturers, but not DA. The few DA kits I've built have gone together really well, out of the box. There may be occasional errors but the builds have been enjoyable.

You will reach your own conclusions about how to deal with the firebox but I suspect we may see a new one attached to a future fret........

As for missing hand rail knob holes, I've used a scriber block on glass (I don't have a surface plate) to set the vertical position, and frankly I'd rather have none than have them etched wrongly.

B

 

[mickoo]

Brian,
A scriber block is on order as regards to the errors, you've been lucky, there are lots of errors in these parts, not so bad that you cannot make do, but bad enough to keep on stumbling over and wasting time correcting, the tender suffered the same in some areas. I've attached a couple of pictures below to compare with Richards screen grab, once seen it cannot be unseen.

For the record the DA A3 kit I built was pretty much the same and required a lot of remedial work, so much so that Richard Lambert mused at Telford that I might as well design my own, that was 12 months before Finney7 was born

Col,
Get your drift, but I think the resultant gap is going to be too big even for low melt, lets see what some discreet plugs of brass sheet will conjure up

Jonte,
Yes any old sheet brass will do, make sure it's half hard though, you choice of supplier is your's to make, sometimes you can bet better deals on Ebay. Myself, well we use half hard brass sheet to shim crane motors to match the gearbox centre lines The little post card scraps we get are god enough for small fill in bits and pieces, but large pieces like a new firebox wrapper would have to be sourced commercially.

Okay having slept on the problem it's clear it cannot remain, once seen it cannot be unseen.







Which ever way you turn it, the gap between the firebox cladding and front spectacle frames is just too great, so out with the safety valves and in with the slitting disc, I'll take photos as I go along and post later, they may be of use to others in the future.

 

[oldravendale]

Commiserations, Mick.

B

 

[P A D]

Hi Mick,
Leaving the kit errors aside it's a superb piece of work. I won't even consider trying to think of solutions as I don't want a migraine and in any case you don't need me to teach you how to suck eggs. I'm sure that whatever you decide to do (even leaving it as it is), it will be gob smacking when it's finished. Good luck.
Cheers,
Peter

 

[Sparky]

It may be just the camera angle of the screenshot at post 645, but the windows in the spectacle plate on the model look to be on the small side.
Increasing the size of these slightly would help to reduce the apparent error?
Shame to have to take a cracking build apart after so much effort.

Bob

 

[Dave Holt]

Again, it might the angle of the photos, but it looks to me as if the firebox is too narrow at the bottom. On Blue Peter, the firebox looks to come much closer to the sides of the cab?
Dave.

 

[jonte]

Thanks, Mick.

Jonte

 

[mickoo]

Okay, brief update and a disclosure, what ever is done will never be 100% accurate, as noted above there are errors elsewhere which have an impact on what we're doing here, all we can do is the best we can and minimise the errors to acceptable levels (that in it's self is subjective).

Bob is right, the spectacle plates are probably the wrong size and profile.

Dave is also right, sort of, whilst the base of the firebox was slightly under, it's also the cab which is slightly too wide, this could be the way it's folded up with the angled front sections and would explain why the cab floor is a loose fir inside with a gap down each edge. However, the slots in the footplate determine where the cab sides will go and that is where the error lies, they're too wide by 0.5 mm or so.

Peter, cheers, it's not hard, you just cut it open and then 'monkey see monkey do' fill the resultant holes

Col, don't know about the Mona Lisa, at work we say "you can't make a roast dinner out of dog scraped off the pavement".

So off to work we go, it's not totally complete but we're nearly back where we were this morning.

Step one, get rid of the incorrect bulkhead at the rear and then space the base to the correct width.



Step two cut along the top of the firebox.



I've already started to open it out at this stage, note it's pulling away from the boiler, this is not an issue. Simply heat that joint with a micro flame and gently ease the rear end outward, the lower you work the flame the wider the rear end will go.

Once you've got the right width at the back you end up with this.





Nice big gaps either side that will need filling....but maybe not, you'll note that the widening has forced the rear at the top to an angle, this is artificially forcing the whole assembly forward.

Next the gap filler, it's formed to the right curvature but is over wide, half will become the base plate inside the fire box, the other half is trimmed to fill the resultant gap on top.



Like thus.





Once the plug is in and dressed then the rear edge was squared up, this pulled the firebox back toward the cab, a few tweaks hear and there to the base has allowed the whole lot to settle and the big gap up front in the corners twixt firebox and footplate is greatly reduced; it'll still need filling but it's down from 4 or so mm to just over 1 mm.

I may also be able to 'ease' the swept footplate section toward the rear a little and close up the gap that has appeared at the front end of the firebox.

The next step are the crinoline bands, these are brass 5 thou strips, a little over thick but the usual lined tape will not cover these underlying issues.

These will cover the gap at the top between the boiler and firebox and bridge the final gap at the rear with the cab, once those are on then the true effect of the widening will be apparent, hopefully it'll be close to where we need to be....given what we started with.....and the possible errors elsewhere.

 

[P A D]

Very crafty Mick. It looks a whole lot better.

As you have widened the base of the fire box it appears to have lowered it slightly. The top edge is not so close to the whistle hole in the cab front. Has that had a negative impact on the view from side on?

 

[mickoo]

Very crafty Mick. It looks a whole lot better.

As you have widened the base of the fire box it appears to have lowered it slightly. The top edge is not so close to the whistle hole in the cab front. Has that had a negative impact on the view from side on?

Triggers broom!

In all fairness, the original firebox was a little too close to the whistle hole, mind who's to say the whistle hole is in the right place? Once the cab angle is added and the safety valves (which are the wrong type) are added it'll look much better.

It's about ½mm out at the moment, if necessary I'll add a strip along the bottom of the firebox base to jack it up, but i'm not going to do that until the other bits are done as they tend to throw the eye out and alter perceptions etc.

 

[Richard Spoors]

Hi Mick, thanks for sharing how you are solving the problem. I have a DA A1 to build, so no doubt I'll be referring to this page when the time comes. I'm not sure if there's a better way to tackle the problem other than building it up, hoping it's right, as you need the basic shape to know it's wrong!

Well done!

Richard

 

[oldravendale]

Mick - a masterful recovery. I'll add it to my book of "fings wot I 'ave learnt".

Brian

 

[Eastsidepilot]

............Col, don't know about the Mona Lisa, at work we say "you can't make a roast dinner out of dog scraped off the pavement"............

Agreed ....wait for the dog to turn up, prefer my food hot !

As for drilling holes for handrail knob I always scribe parallel to the foot plate, even if the loco sit out of level or the boiler is they will look right in relation to the foot plate

Col.