Airfix 48xx with High Level Kits chassis

[Paul Willis]

Paul:

It looks like the space for the coalbox could fit a small speaker. Are you planning sound?

Sean

Hi Sean,

I have no plans to fit sound. Unlike for diesels, such as the subtle implementation on Tatty's Porthullin, I've never been convinced by steam locomotive output. That said, with no shows for the last couple of years, I have no idea how the better quality chips and speakers may have progressed.

However, regardless of my intentions, there would definitely be room to fit a small speaker in the bunker. It's now a sealed box, but an educated guesstimate of the size suggests that it would take a speaker up to 5mm x 15mm x 25mm in size. And there would need to be an allowance for the wiring, I'm sure.

Cheers
Paul

[steve howe]

Coincidentally, this afternoon I have been fitting 'top wipers' collectors to a 'Terrier' on a Branchlines chassis using much the same technique. I agree with Paul's comment about this being one of the most tiresome jobs of a loco build. There wasn't enough room to fit pcb pads as Paul has done, I glued pcb strip between the frames and mounted the 0.4mm nickel silver pick-up wire on 0.7mm wire outriggers which were soldered to the pcb. I'm not sure if phosphor bronze wire would not have been better, or possibly spring steel wire as the wheel tyres are also steel. I'll be interested to see if the wipers either keep the wheels clean or get clogged up with dirt!

Steve

[Paul Willis]

Coincidentally, this afternoon I have been fitting 'top wipers' collectors to a 'Terrier' on a Branchlines chassis using much the same technique. I agree with Paul's comment about this being one of the most tiresome jobs of a loco build. There wasn't enough room to fit pcb pads as Paul has done, I glued pcb strip between the frames and mounted the 0.4mm nickel silver pick-up wire on 0.7mm wire outriggers which were soldered to the pcb.

That sounds a pain to do. I assume that you wanted to use the thinner wire on the ends to minimise visual impact? I have been fortunate enough to be able to tuck the wipers up out of sight on the 48xx. On other locomotives I've had to use the same route of PCB between the frames, and coiled pickups on the rear flanges of wheels.

Y14 build (53).jpg

I'm not sure if phosphor bronze wire would not have been better, or possibly spring steel wire as the wheel tyres are also steel. I'll be interested to see if the wipers either keep the wheels clean or get clogged up with dirt!

I've never tried nickel silver, but have not heard any reason not to. In a similar way, Iain Rice went through a period of using hard brass, I recall. Although that was with gold wire soldered on the tips.

If the locomotive is run regularly (i.e. more frequently than every couple of years) then I am sure it will wipe the wheels. I've always found the worst problem is crud and fluff picked up of the railhead, and then building up under the wipers. The occasional clean out with tweezers cures that.

Cheers
Paul

[Philip Hall]

I have used nickel silver on occasion, but it always seems to be too stiff for me. My standard is now 0.3mm hard brass wire wound into coils as per your last picture. They never seem to need cleaning, effectively rubbing on the cleanest part of the wheel, and have a firm but very light pressure. My only exception to the design is for RTR tenders, using a slightly thicker brass wire bearing at 45° on the edge of the flanges.

I’ve tried many times to use top acting wipers, never successfully!

Philip

[Paul Willis]

The final stage that I completed on the 48xx before it went into storage last April was to add some weight...

Unlike the etched brass kits I have built, there was no opportunity for introducing low-melt solder directly into tanks or bunkers. So it was back to the old method of placing sheet lead directly into the locomotive body.

I have an old and trusty roll of sheet lead that I have always cut bits off to weight wagons, locomotives, etc. I've never tried Liquid Lead, or similar. I suspect that I would make a tremendous mess of things. As you'll see, this roll of lead is finally coming to an end. Fortunately, at the autumn Missenden course one of the tutors had brought along a large quantity of lead sheet that they have been gifted. This was offered around, and I now have enough material to weight my modelling for the next couple of years at least.

48xx weighting (1).JPG

The best spot that I could find for the lead to go was above the driving wheels. This was by cutting lead "plates" to fit inside the side tanks on both sides.

48xx weighting (2).JPG

I was able to fit two plates into the tanks on each side, and still leave plenty of sideplay for the upper part of the driving wheels. I could have put an extra, slimmer plate or two into each side as long as I kept it above the tops of the tyres. However, it this point I didn't feel it would be necessary.

48xx weighting (3).JPG

Finally, I created a couple of rolled up sausages of lead, and slid them into the smokebox, above the front driving wheel. I also slipped some extra lead into the top of the boiler. All of this was held in place with 24 hour Araldite, giving me the chance to position the weights carefully, and then leave them to set in place. The Araldite will not only act as an insulating skin in case of any contact with electrical parts, but shouldn't give rise to the "lead rot" reported when glues such as PVA are used. The body was held inverted in my loco cradle whilst the setting process happened.

48xx weighting (4).JPG

The total weight of the locomotive and chassis now is around 135 grams. This doesn't feel too bad - by comparision, my little GER Coffeepot is around 110 grams.

So with everything so far glued and wired into place, this was the state at which it went into storage back in April. Next comes finding out what is necessary to finish it off...

IMG_7933.JPG

Cheers
Paul

[Paul Willis]

In summing up the progress on the 48xx before it went into storage, I mentioned that there was some damage to deal with. Although the locomotive, and all the associated parts, had been kept in its own box and then packed in a crate, it had still been bounced around, transported halfway across the country, etc, etc.

Fortunately, when I finally was able to take the parts back out and inspect them, the damage that had occurred was minor. All that had happened was that one of the pipe fittings on the rear buffer beam had broken free:

48xx pipe repair (1).JPG

This (and the others on both front and rear bufferbeams) had previously been glued in place. I used Slo-Zap superglue, which I like for sticking these sorts of components. It gives you time to adjust the position of what you are sticking, you can place it carefully with the end of a cocktail stick, and it can be used to build up fillets of glue to strengthen the bond. Unfortunately, like all superglues, it is brittle, and vulnerable to knocks. I suspect that is what has happened here. It's not the first time that I've knocked one of these pipes off.

This is the prototype part, and how it is mounted. The picture was taken during the setting up of the preserved 48xx at the Warley Show a few years ago. You will see that the mounting plate has very little overlap with the bufferbeam. This is what I aimed to replicate in attaching it, and what proved to be the point of weakness.

48xx pipe detail.JPG

This is the lost-wax cast part. There are a couple of lumps that replicate the fixing bolts to the bufferbeam.

48xx pipe repair (2).JPG

I decided that the strongest form of repair that I could do would be to replace the cosmetic fixings with real ones, pinning the pipe onto the bufferbeam.

The first step needed to be to file away the bolt heads. There was no way that I (or my eyesight!) could centre a drill on the top of the cast bolt, and have the drill bit stay in place on a slightly domed surface. So I popped it into the vice, and ran a needle file across it a few times.

48xx pipe repair (3).JPG

Having prepared the surface, this is how I drilled it. My trusty Proxxon TBM220, with a 0.6mm drill in the chuck, drilling into an offcut of oak bookshelf. Without the Proxxon, I wouldn't have stood a chance of doing this accurately, by hand, using a pinchuck. And it would have taken an age, given the hardness of lost wax castings.

48xx pipe repair (5).JPG

And this is the result. Two neat holes drilled through, in roughly the right places. I didn't break the drill bit either

48xx pipe repair (4).JPG

The next thing to two was to drill matching holes in the bufferbeam. This is one of those jobs that needs about four hands, to hold the model, the casting, and then wield the drill. Not being excessively endowed in the limb department (although I do have above the average number) I used the vice again. The locomotive body is clamped gently in. Being made of plastic, I was aware of the risk of marking it. So the blue rag in the background is actually by usual workbench rag (a life-expired cotton handkerchief) protecting the parts of the body within the vice jaws.

48xx pipe repair (6).JPG

I had also previously used a new and sharp scalpel blade to remove the remaining traces of glue from the bufferbeam, and generally smooth the surface ready for the casting. It looks a mess in the picture (not helped by the previous paint-stripping incident here https://www.scalefour.org/forum/viewtopic.php?f=90&t=6987&start=75#p77218) but isn't that bad. The surface is sufficiently smoothed. Here are the two mounting holes, drilled through the casting as a guide.

48xx pipe repair (7).JPG

The pins/bolts/pegs themselves were made out of straight brass wire. I get through packs and packs of this stuff. Having properly straight materials in a variety of sizes makes life so much easier when it comes to making parts, adding detail, cleaning out the nozzle of the superglue bottle, etc...

48xx pipe repair (8).JPG

The casting went back into the vice (yes, I do clean it from time to time to get rid of the flux splashes) and I then had the tickly job of soldering the two separate lengths of wire in place. The first one went in fine, nicely square and clean.

At the first attempt to solder the second wire in alongside it, it all went horribly wrong. Despite using the smallest touch of solder, the flux caused it to leap across the gap between the wires, and make the whole thing a single wire and solder lump So I had to unsolder both wires, clean up the casting, and try again. This time, I used black permanent marker on the "tails" of the wires, to ensure that the solder didn't flow on to them. It worked successfully, and this was the result:

[Paul Willis]

The final steps in repairing the damage of the broken off pipe were straightforward.

I trimmed back the lengths of wire protruding through the front of the casting to a length suitable to represent the bolt heads. A few strokes with a fine needle file finished off the tops of them, and cleaned around the edges, to give them a little more definition.

I was then able to check the fit of the pegs through the holes in the bufferbeam to make sure that they were a snug fit. Despite using the same drill, I needed to open them out slightly with a fine broach. I can only assume that the Airfix plastic has a slight bit of elasticity that meant the drilled holes closed up by a tiny amount. Whatever...

48xx pipe repair (10).JPG

Having checked the positioning, etc, I mixed up a small amount of five-minute epoxy to fix it permanently. Normally, I don't like the five-minute stuff, as it never appears to fully set, and remains slightly rubbery. In this case, that was exactly what I wanted, to give that extra bit of resilience. The glue was very carefully applied to the wires and back of the mounting plate with the tip of a cocktail stick. Then a few minutes listening to the radio whilst I held it all together in alignment produced a result.

48xx pipe repair (11).JPG

This whole exercise took much, much longer to do than simply re-gluing the part back in place. But that would have still been vulnerable to knocks. Better to do the job properly, and know that it is secure

Cheers
Paul

[Daddyman]

Interesting, Paul, thanks. How did you hold the pipe to the bookshelf offcut while you were drilling it? Superglue? I don't use my Proxxon enough as I can never work out how to hold the piece to be drilled. And did you use a centre drill? If I don't use one, especially with something as small as 0.6, the bit waggles around too much to ever get a decent hole.

For the pins, it might have been easier to make both pins as one U-shaped piece, and then snip the bend of the "U" off after soldering. You can make the legs of the U as long as you like, and, if you use nickel silver wire, even hand hold the "U" during soldering.

[davebradwell]

I've seen drills started in a pit made by a scriber, David, even managed it myself. It needs a good "poke", though.

DaveB

[Philip Hall]

I use a sharp pointed punch made by my father 50 years ago, which I periodically sharpen on a diamond lap. A gentle tap from a small hammer on an anvil gives me a good start to a drill. I also have a little gadget given to me a year or two back which consists of a pointed punch held under a small magnifying lens; quite useful for getting the point precisely where you want it.

I’ve never used a centre drill in a vertical drill as I’m not sure it’s the right tool in that application. I believe its correct use is in a lathe where it actually cuts on the side to achieve a hole precisely centred in the work. I think that’s how it works!

Philip

[Winander]

The correct drill to use to start a twist drill is a spot drill that has a single short shallow flute making it rigid. https://www.cnccookbook.com/when-to-use-a-spot-drill/

A lot of lathe users use a centre drill for this purpose and since so many do, it must be effective, although the angle of a centre drill is usually 60o. A jobber twist drill has a point of 118o and the spot drill's point angle of 90o is much closer to this than a centre drill.

It sounds like you are describing a centre punch Philip, which should have a 90o tip and can be used to start a twist drill.

[Jeremy Suter]

Interesting, Paul, thanks. How did you hold the pipe to the bookshelf offcut while you were drilling it? Superglue? I don't use my Proxxon enough as I can never work out how to hold the piece to be drilled. And did you use a centre drill?

The correct drill to use to start a twist drill is a spot drill that has a single short shallow flute making it rigid. https://www.cnccookbook.com/when-to-use-a-spot-drill/

A lot of lathe users use a centre drill for this purpose and since so many do, it must be effective, although the angle of a centre drill is usually 60o. A jobber twist drill has a point of 118o and the spot drill's point angle of 90o is much closer to this than a centre drill.

It sounds like you are describing a centre punch Philip, which should have a 90o tip and can be used to start a twist drill.

I must say I didn't know they made centre drills that small or spot drills either. If you need a hole that small centring would it not be easier to use a point of some sort like a scriber. I have always made my own Pivot or Paddle drills for this sort of thing.

IMG_6933[1].JPG

Stoned to a Screwdriver shape then sharpened on the right hand corner to about 45 o on each side so it cuts when twisted clockwise.

[Paul Willis]

Interesting, Paul, thanks. How did you hold the pipe to the bookshelf offcut while you were drilling it? Superglue? I don't use my Proxxon enough as I can never work out how to hold the piece to be drilled. And did you use a centre drill? If I don't use one, especially with something as small as 0.6, the bit waggles around too much to ever get a decent hole.

Thanks for the questions.

I must have been lucky, for my Proxxon gives hardly any waggle at the tip of the drill. I do mount it as high up as possible in the chuck, to replace any possible angular deviation to the minimum. That's another reason why my chunk of oak comes in useful, as it raises the workpiece. Other than that, I just use the really fine control possible from that lever on the side to pretty much let the drill find it's own place in the metal and work gently from there.

As Dave and Philip have mentioned, proper engineering practice would have been to centre pop where the drill should start, and use that to guide the tip of the drill. I am (regrettably) nothing like a proper engineer! So despite owning a centre punch, I I completely forgot that I did, and didn't use it. Doh!

And as to holding the workpiece, I just followed my usual practice of holding it very carefully between finger and thumb... It works well enough for me, for the small pieces that I drill, and if I feed the drill at it's own pace as I mentioned above, I find very little tendency to snatch.

For the pins, it might have been easier to make both pins as one U-shaped piece, and then snip the bend of the "U" off after soldering. You can make the legs of the U as long as you like, and, if you use nickel silver wire, even hand hold the "U" during soldering.

Now why didn't I think of that? It would have been perfect, and probably saved 15 minutes pfaffing about with the job!

Next time I need to do something like this (i.e. I break off the one on the front bufferbeam) I'll aim to remember. Thank you

Cheers
Paul

[Daddyman]

Thanks to everyone for the answers. I used a centre drill on the advice of this forum (though I seem to remember there was some debate on the terminology and it may be a spot drill), and I have one down to 0.5mm. But I'll try Paul's suggestion of mounting normal bits further up in the jaws.

OK, so that's bits dealt with, and how to start a hole. What about fixing the workpiece to the shelf offcut or whatever it's resting on? Do you find the clamps supplied with the Proxxon wanting, Paul? When I used them (first ever go with the machine only), I ended up with oval holes, which I assume are a result of the workpiece moving from not being clamped tightly enough. I've tended to use superglue to attach the workpiece to a bit of wood, which in turn is clamped to the coordinate table, and I've had good results with that. But I stumbled into that myself, so I'm sure there are better ways of doing it.

Glad the U-bend suggestion helped, Paul!

[Philip Hall]

Richard,

I do have a proper 90° centre punch but invariably I use the sharper one for small drills, although I guess the angle on that has changed as I’ve sharpened it over the years. I find the acute angled point makes it easier to mark the spot precisely.

Philip

[davebradwell]

It's nothing to do with being a proper engineer or not, if you have some sort of pit in the job it will encourage the drill to start there. Without one it will find its own place. If you don't mark the position you're asking for trouble.

As for pillar drills, if you want a hole through a thick block, you clamp it solidly to the machine and start with a centre drill. Because the pit is now directly under the spindle and nothing can move, the hole should go through without wandering. Same as using mill. Centre drill and spot drill are likely interchangeable under general applications. Don't think the angle is so important for us - in our precision workshop at work, I noticed that their centre punches were more pointed than the standard item so there's room for interpretation.

DaveB

[Paul Willis]

It's nothing to do with being a proper engineer or not, if you have some sort of pit in the job it will encourage the drill to start there. Without one it will find its own place. If you don't mark the position you're asking for trouble.

Dave,

The point that I was making is that having no engineering training, this sort of thing is not instinctive

Once upon a time, in a metalwork class for one term as a 14 year old, I may have been taught to use a centre punch to locate a drill. It's refreshing the old brain cells to do it these days that I need to do.

That's why the whole of this Forum is so incredibly helpful. All sorts of little tips and tricks to pick up. I hope that I can share a few that I use, and I'm picking new ones up all the time

Cheers
Paul

[Paul Willis]

OK, so that's bits dealt with, and how to start a hole. What about fixing the workpiece to the shelf offcut or whatever it's resting on? Do you find the clamps supplied with the Proxxon wanting, Paul? When I used them (first ever go with the machine only), I ended up with oval holes, which I assume are a result of the workpiece moving from not being clamped tightly enough. I've tended to use superglue to attach the workpiece to a bit of wood, which in turn is clamped to the coordinate table, and I've had good results with that. But I stumbled into that myself, so I'm sure there are better ways of doing it.

Glad the U-bend suggestion helped, Paul!

I literally do use fingers to hold everything that I'm drilling with the Proxxon. Whether it's castings, frames, complete bodies, whatever. I'm confident that this isn't how it should be done, but it works well enough for me. Even with small parts.

There are two, okay three, things that I do to make the task easier/more accurate.

The first is to always place that piece of oak under whatever I'm drilling. It's very solid (unlike softwood), and fairly heavy, so it's a good base to drill on/into. To answer your question about the clamps, I've never really found them satisfactory. My drill came with the machine vice (I think) holder, and I've never purchased any others. I've never been that impressed with it. When you sit the machine vice on top of the chromed crossbar fixed to the drill base, there as too much slack between them. They can easily slide, and even twist a degree or two. It really seems as though the vice needs top have a clamp to fix it to the drill base. Or maybe I'm just using it wrongly!

Proxxon machine vice.JPG

The second thing that I do to help is that I adjust the height of the drill up or down so that the starting position is only a few mm above the workpiece. I find that helps because I'm not having to move the operating lever through a big arc before it comes into contact. It also helps me spot or line up the drill before switching it on and drilling.

The third thing , which is kind of obvious, but still bears considering, is to make sure that I'm comfortable operating the pillar drill. In other words, it's nicely in front of me, I've cleared all the surrounding detritus of modelling away from the surrounding area, I have the best light possible for all angles of the work, and I can operate the lever to depress the drill smoothly and easily. All of this gives me the best possible control over how I drill and the feeling that I get back as to how the drill is progressing. So no leaving it where it lives, just for convenience, but bring it right forward into my working area.

The U-bend suggestion was obvious and brilliant. The challenge for me is remembering it. Perhaps I should break off and reattach the front hose whilst this is all fresh in my mind?

Cheers
Paul

[Will L]

While I'm sure all this worthy engineering, pillar drills an all, has it's place, let us not forget that twiddling a drill in a pin chuck is still the quickest and simplest way of producing small holes in thin bits of metal.

[David Knight]

While I'm sure all this worthy engineering, pillar drills an all, has it's place, let us not forget that twiddling a drill in a pin chuck is still the quickest and simplest way of producing small holes in thin bits of metal.

You might also add the safest way of doing it.

Cheers,

David

[Enigma]

I always have as little as possible of the flutes sticking out of the chuck, very easy with a pin chuck but not so with a lathe drill chuck for longer drills. Using a pin chuck I put a drawing pin in the end to act as a 'bearing' and protect my palm (when using larger drills) and finger (with smaller ones). I have an 'automatic' centre punch which I use for positioning larger holes, starting with a very low 'pressure' and increasing until I have the indentation the size I want. Its point is quite big so for smaller holes I have an old style gramophone needle (rubbed on an oilstone to sharpen it) in an old pin chuck or, for very small holes (say 0.3mm or so) I sometimes use one of Mrs Enigma's old sewing needles - again in a pin chuck with a minimum of point exposed.

[Daddyman]

Thanks, Paul. Interesting re the machine vice not holding properly. I have a coordinate table, so have different problems. I'm surprised hand-holding of parts is enough to secure the part against the movement of the drill.

[dclift]

Using a pin chuck I put a drawing pin in the end to act as a 'bearing' and protect my palm (when using larger drills) and finger (with smaller ones).

Thank you, Paul G, for the drawing pin tip. Why didn’t I think of it myself before putting a neat and very painful circular cut in my finger while using a pin vice some time ago? Now I can go back to applying adequate downward pressure the next time I use one!

[Will L]

Using a pin chuck I put a drawing pin in the end to act as a 'bearing' and protect my palm (when using larger drills) and finger (with smaller ones).

Thank you, Paul G, for the drawing pin tip. Why didn’t I think of it myself before putting a neat and very painful circular cut in my finger while using a pin vice some time ago? Now I can go back to applying adequate downward pressure the next time I use one!

I use a small jewellers screwdriver that fits in the back of the pin vice that does the same job and fits my hand better. While on this topic I know Jeremy S goes one better and has long backward extensions on his pin vices which he rests against his body? I understand this also steadies the pin vice and keeps it pointing in the right direction, so much reducing the tendency to break small drills. That's right isn't it Jeremy?

[Paul Willis]

So, after bringing the story of this build up to date, it's time for me to put the project back in a box...

Having done the work of repairing the damage from storage, I have carried out an exercise to clear the decks ready for the next stage. Just as it's necessary to clear the workbench and tidy all the tools away, from time to time. In this case, I did a check across all the parts that I had left on the fret, in the pile of bits removed from the original model, and what I needed to complete the 48xx.

After all of this, I had a few bits in the bin, the addition of some useful nickel silver pieces into my scrap box, and this:

48xx boxed (2).JPG

So to complete the model, I have:

- cab details (backhead, brake, reverser)
- battery boxes (these attach under the cab, and are best left off until the body is completed)
- body fixing bolt (for it is conveniently and securely fixed by a tongue and slot at the other end)
- four crankpin nuts (round ones, to replace the temporary 14BA nuts used during the build process)
- whistles (the original ones seem more than adequate)
- two vacuum pipes (removed during the original dismantling and ready to clip back on)
- the clip-on High Level brake gear (always a clever design element in Chris's kits that I am impressed with)

And that's it! I was amazed as to how little there is to do. Which is why the model has gone back in a box...

48xx boxed (3).JPG

The next step is going to be to spray the body, and I'm going to wait for the weather to improve just a little bit before attempting that. Whilst I'll be airbrushing indoors, I've recently invested in a new filter and hose for the spraying booth. So that will be going out of an open window of my modelling room, and I'd prefer not to be having rain coming back in the other way at the same time. It's been a miserable few weeks for the weather recently, hasn't it?

So on to other things until the sun shines...
Paul