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Building a Backwoods Miniatures DHR Class B

Compiled by Pieter Roos

A thread started on the lefties list about building the DHR class B kit recently released by Backwoods Miniatures.

Because there’s been a number of us who have bought this kit and said, “What have I gotten myself into?”, we’re forming a little ‘support group’ in the form of this thread.

The intent of this thread is to work together to get our kits assembled. If you post on this thread, please honor that and not take the thread off on a tangent.

Harry Symonds and I were discussing the first step in the assembly, which is to install the bushings for the loco into the chassis. Here’s the relevant post, quoted for those just joining us. Quoted material is Harry, unquoted is me.

Annie

PBL sells both a low temp solder and a solder paste, if you want 
an easy supplier. I saw some in a hobby shop the other day.

Re 'variable voltage iron' - there are two variants of this 
creature. The look the same, but act differnt.
Both come with the iron permanently attached via cord to a base. 
the base has a holder to hold the iron, and usually a sponge. 
there's a knob on the base.


The cheaper, but less useful kind is simply a resistance soldering 
iron with a thyristor control. Weller makes one of these.
I don't recommend one, as for only a little more you can get what 
they imitate in appearance (but not in performance), which is -

A thermostatic temperature controlled iron.
This is what Al has. The idea is that there's a temperature sensor 
in the tip of the iron. When the iron is below the set temperature, 
it turns the heater on. The heaters in these are usually enormous 
by conventional iron standards, so they heat up quickly.
Say you have 145 degree solder. You need to heat the part to 145 
deg. C, plus a bit to make the solder flow freely.
With a conventional iron you put the iron to the metal, heat flows 
in and the temp. goes up until you pull the iron away. Given human 
reaction time, the temp. can get way above the melting point of 
the solder. More heat in means more heat to damage small parts, 
esp. in electronics. Failing to regulate the heat in per unit time 
is what you're doing if you solder your side rods with an 
oxyacetylene torch.
The conventional solution is to limit the amount of heat the iron 
can produce. Hence 25W iron, 40W iron, etc. This works, but ties 
the time to  complete joint to the heat put in. If you're slow 
making the joint, the iron dumps a lot of heat in.
The thermostat solution is to have the iron quit dumping in heat 
as soon as it's 'hot enough'.

A good technician with a thermostatic iron can solder a series of 0.005 dia. wires
on 0.020 spacings to a series of pads under them without any shorts, and without
frying the integrated circuit.

-- 
Anne Ogborn

> Anne,
> 
> I think you have hit the nail ( RR spike) on the head. The Backwoods
> kits are a very different animal-- very British-- in the complexity
> and approach.  I think part of the approach to this kit is to sit
> down and try and think like the manufacturer.

There are a couple good books on making etched metal kits. I have one 
of them,
but it's out in the container. I'm going to try to unearth it here 
soon.

> The problem here is
> that there are no extra parts, you loose a rivet, you are in trouble.
> with regard to "practicing on other kits",  I do not have other white
> metal kits to work on.

Yes, but you can get one of the little Woodland Scenics white metal 
kits for
around $10. Why not try soldering one of those together first?

 I think the mind set is to work on this kit
> very very slowly. The DHR kit has mabe 200-500 parts?? Maybe we are
> looking at 200-500 Hrs to assemble the unit. Like the proverb, a
> journey of a 1000 miles begins with a single step. With this kit, you
> need to do it a couple of pieces (mini-steps) at a time and make sure
> it is right before you preceed and setting up the parts is as
> important as doing the actual work.

Looking at the instructions, I note that the first assembly step is to install the 
wheel bearings. I want to make sure those run true, so I'm going to do this -

purchase two long pieces of 2mm shafting, and 2 3/8" square pieces of 
lathe bit stock.

Assemble the chassis per the first step in instructions, including 
putting in the bushings, but not filing them off.

insert the shafts through the bushings. I'll probably have to reheat 
one of the bushings to get the shaft through the matching one.

Place lathe bits on either side of loco chassis and set on glass plate,
so the chassis is supported on the shafts. Use a dab of 'goop' adhesive to
temporarily lock the lathe bits down (weight them, no floating allowed). 
weight the rear shaft over each bit so
they make contact (chassis may be skewed at this point) and goop down 
rear shaft.

Measure the distance between the shafts *at their extreme ends* using a dial
caliper.
Reheat one of the forward bearings and adjust so both ends of the forward shaft
rest on the lathe bits, the inside distance between the shafts is the same at 
both ends of the shaft, and the chassis isn't hiked. 
Since the shaft is a lever, when these are the same within 0.001 the wheelbase will
be the same on both sides within 0.0001 or less. Since the lathe bits 
will be accurately ground to size, and the glass will be flat, the bearings should be 
quite parallel, square, and coplanar. 

Write down the distance between the shafts somewhere where you'll keep it.

Now saw the ends off the rear shaft with cutoff tool, deburr, remove,
and continue to assemble chassis per instructions, starting with filing 
bushings flush.

That's my plan. the reason I want to know the interaxle spacing is so I 
can adjust the siderods to that later on.

> The "gang assemble" idea is a good one. The one nice thing with the
> digital world is that it is easy to snap a photo and share it with
> the group as you go along. With the majority of my Xmas  presents out
> of the way, I hope to get something started this weekend or before.

----- Original Message -----
From: "Anne Ogborn" 
To: 
Sent: Tuesday, December 04, 2001 6:20 PM
Subject: Re: [HOn30] Building a Backwoods Miniature DHR Class B

> Well, I got to a hobby shop today.
>
> Things I've learned since last post:
>
> 1. 2mm shaft is available as piano wire, 0.078" is available.
> It's not marked 2mm, it's just marked 0.078", but it's the usual
> brand (is that K&S??) in every hobby shop.

NWSL sells 2mm shaft material at $1.00 for a package. Al has or can get it.
Much more precise (straighter and truer in diameter) than piano wire. 
Also piano wire is hard to cut.

Siles

Hi folks,

It's been a long time since I last joined a thread on this list but I can't
resist this one, especially as I have a Class B waiting to be built 
too. I agree one has to be careful assembling the outside bearings, but I 
think you are overdoing it a bit.
Up till now I've built about half a dozen Backwoods kits and in my
experience dropping the bearings into their holes and securing them 
with a little bit of solder is accurate enough. Tolerances aren't that tight,
especially after a bit of running-in. Also, the siderods normally will fit
without any adjustments. The only important thing is to ensure the frames
are perfectly square. That's what you need the glass plate for -  to check
that your engine is resting on all four wheels.
I agree there are many kits on the market that require a lot more attention
but the Backwoods etchings tend to be accurate enough to fit together
without fuss. I personally would be very disappointed if the Class B 
poses any problems.

Hope this helps,

Arjen,
Delft, The Netherlands.

Another gem from the 'additional instructions':

The screws/nuts used in our kits are good ol British BA sizes. If you 
lose a screw it's no big deal. Just use the nearest US
equivalent (whatever they are!). We can easily supply spares if you 
want'em. Same goes for valvegear rivets, drain cock
turnings, handrail knobs, etc.

-- 
Anne Ogborn

OK, I just did the first step.

After Siles' admonishment that the whole 'alignment' business wasn't
needed, I went ahead and just soldered the bushings into the chassis
while it was still in the fret.

The bushings are in the bag with the wheelsets. I almost got the wrong 
ones.

You have to open the holes out quite a bit.
I have the same small set of 5 sided reamers many of us have. The 
largest one is too small to get to the bushing size. So once I'd reached the 
top of the reamer I opened the opening with an x-acto knife, tracing the 
periphery and shaving a small chip.

There's some half etched detail on the outside side of the chassis. The
blind holes for the rivets to be embossed is on the inside.

If I had it to do over again I'd emboss the rivets first (I didn't), 
before soldering. that way if I'd goobered a rivet hole with solder it 
wouldn't have made it impossible to push the rivet.

The soldering wasn't as bad as I thought it would be. What I did:

I used 145 degree solder (per B.M. recommendations - the 'extra 
instructions' are well
worth getting), rosin flux, and a 40 W iron with a large (1/4")  chisel 
tip. I found solder wick immensely useful.

I worked inside the box lid so I'd not lose parts. 

I put two aluminum blocks I usually use to keep buildings straight 
inside the lid and laid the fret between them. I dropped the bushing 
into the hole.

You have to do this a number of times, as you keep checking fit and 
reaming the hole.
Be careful not to put the fret down backwards! (Don't ask me how I know 
- it came out with a lot of prying with an xacto while heating with the iron.)

When the bushing is a push fit in the hole, you have to turn the fret 
over and 'seat' the bushing. 

Now, make a final check that you don't have it in backwards and that 
the flange is down tight agains the fret.
Take a toothpick and put a small amount of rosin around the edge. If you goober it,
wipe with alcohol, don't just use a rag (again, I know because I have a tinned spot
inside one of my frames). I discovered I was being way too careful to get it all around
the bushing. When it melts capilary action will carry it around.

Get the iron good and hot, and clean the tip. This trick definitely 
doesn't work unless the tip is really clean.

Touch the 145 deg. solder to a corner of the chisel tip and remove. You should end up
with a small blob of solder hanging like a droplet from the very corner.

Now touch the edge of the bushing at some point with the solder blob. Since the metal
is cold, it will bead up. Keep going and touch the flat of the chisel 
to the metal. When the metal
reaches the melting point of the solder it'll flow around by capillary 
action. You
may need to spread it around with the corner of the chisel.

I goobered up a little bit around the joints, but they were suprisingly 
clean. I'm sorta delighted - I didn't know I could do that!

To clean up the goobers I used solder wick. If you haven't used this, 
it's a braid
made of copper (with some flux on it, I think). You hold it over the 
solder you want
to pick up and heat the back side with the iron. The solder gets sucked 
into the copper wick. Then you cut off the wick and it's ready for the next 
time.

I had my piano wire and a piece of 2mm shafting (NWSL) I found in my 
scrap box.
The piano wire didn't fit into the bearings, so I tried the shafting. 
It didn't fit either, so I deburred the bushings, inside and out. Then it fit. 
It's obviously a tight tolerance fit. 

Tomorrow I'll try assembling the chassis.

So, Andreas, are we on the right track or are we headed for perdition?

Annie

-- 
Anne Ogborn


   From:           "dachur"  
    Date:         Thu, 06 Dec 2001 15:32:57 -0000
  Subject:         [HOn30] Building the Backwoods Class B
 Reply-to:         HOn30@yahoogroups.com

Interested to see this thread starting - and I will be keen to take 
part. I can't add much for a few days as our home computer is away 
being up-graded. 

My Class B ran for the first time under its own power on Sunday- but 
I do have the advantage of a few weeks start as i collected it 
straight from the manufacturerin October.

I will add more next week but a few general thoughts
Everything fits and locates nicely- if you think you need to file a 
lot off you are doing it wrongly.
145 deg solder is ideal for most assembly . I use 70 deg for most 
whitemetal assembly but epoxy is as good is slower.
If anyone wants the reference to UK books on assembly I will find it.

More will follow later

David churchill

OK, summary of the little time I had to spend working on it today -

I fitted the wheels in the chassis. They turn stiff. I tried
removing them and inserting the wrong end of the axle into
the bearing to see if it was the bushing size or the chassis alignment.

It's the bushing size.

Any recommendations of how much clearance they should have, and how I 
should
obtain it?

-- 
Anne Ogborn

I built there Sn3 porter and I seem to remembering I had to use a ream 
on
the axle bushings. The size and type was called out in the 
instructions.
Mike Ryan

Annie and all,

One way to open the bushings up, and I know the machinists out there will
criticize, is to coat a spare axle shaft with tooth paste (the gritty kind)
and using a pin vice or other hand drill (not electric) turn the shaft in
the bushings and at the same time move the shaft in and out. The paste will
wear out before removing too much material. Of course a proper size reamer
will be quicker and no where near as messy.

You can make a home made reamer by putting a point on the axle material and
then filing a flat of half the diameter on the shaft. The edge of the flat
will scrape the hole larger. If you have access to the 1950/1960 RMC check
out Dick Andrews columns for scratch building techniques. Also the NMRA
library may have copies of Mel Thornburo's (spelling ?) articles in MR on
scratchbuilding.  Dick's later articles in Gazette may also prove helpful.

OH YES!! If you use the tooth past or jewelers rouge be sure to clean ALL
traces from the bushings before using them. I doubt that you put enough
pressure on the bushings by hand pressing them into the frame to shrink 
the holes.

Siles

Tonight I decided to go boldly forward, and reamed out the
bushings with a taper reamer. This made the wheels free-er when I 
inserted the wheels in their proper position and soldered piece # 2 (of which
more in a minute) in place.

I tried rolling the engine on a length of track, and it hunted very badly.
I checked the wheel gauge, and the wheels were quite narrow compared to
an N scale NMRA gauge. I adjusted one out .010, the other out 0.011.
This would have been easier to do before assembly!

After adjusting the gauge the wheels again were binding. I determined that I was
pressing in on the insulating washers with the frames. Judicious bending of the 
frame solved the problem.

As for part #2, I was puzzled that the part on the fret was two sections with
a half etched 'fold line'. I decided that the folded tab goes to the 
rear and down.

The instructions go on to say, "attach the other parts in numbered order".

The next part is #3, the cylinders. They have to be folded up. I didn't 
find making the folds difficult, but had to struggle to solder the cylinder wrapper 
to the curved front and rear plates. I did it by soldering it part way, then 
soldering the lower part in 'wrong' position, then pushing the
wrapper in with long nose pliers and reheating.
I cleaned the blob of solder off with solder wick.


--
Anne Ogborn

Regarding low melting point solder - This is commonly used here in 
the UK with a variable temperature soldering iron. My iron is the 
'cheap' thyristor type but I have found it perfectly OK for this job 
after a bit of practice to get use to the settings needed. I use it 
now for all but the very smallest white metal joints. The solder is a 
70 deg type which is easily available here I can get some technical 
details if anyone wants. I use a liquid phosphoric acid flux for this 
work. If you are soldering white metal to brass the brass has to be 
tinned first with a more conventional solder. If anyones wants more 
data ask - I am sure that I can sort out some references in UK 
magazines or books and possibly to websites also.

I have used the same iron for most of the other soldering on the kit 
also. I do have a resistance soldering unit which has been useful in 
some places but I am confident that I could have managed quite well 
without it. 

Regarding Annes questions 
> Tonight I decided to go boldly forward, and reamed out the
> bushings with a taper reamer. This made the wheels free-er when I 
inserted the
> wheels in their proper position and soldered piece # 2 (of which
> more in a minute) in place.

I have used a taper reamer also on other kits ( although I cannot 
remember whether I needed to with this one) - but only to take off a 
very small amount.
 
> I checked the wheel gauge, and the wheels were quite narrow 
compared to
> an N scale NMRA gauge. I adjusted one out .010, the other out 0.011.
> This would have been easier to do before assembly!

Yes, I forgot also. I have a suspicion that most of our wheelsets 
over here tend to be on the tight side compared with the NMRA 
standard. 

> As for part #2, I was puzzled that the part on the fret was two 
sections with
> a half etched 'fold line'. I decided that the folded tab goes to 
the rear and down.

>From memory I think this is right.I am not at home at the moment so I 
cannot check directly. 

> 
> The instructions go on to say, "attach the other parts in numbered 
order".

The instructions are a bit vague here - they could be a lot clearer 
with only a little bit extra added.
I have proceeded by building the various sub-assemblies (chassis, 
footplate/bunker, boiler and cab interior/roof) in parallel and 
keeping on checking that everything fits together properly.

> 
> The next part is #3, the cylinders. 

I also did not find folding up the cylinders difficult, but the 
angles are quite subtle and it is important to keep checking with 
pictures that everything looks right. I assembled the motion brackets 
and slidebars before fitting the cylinders to the frames so that I 
could be sure that everything lined up properly. 

One other addition I have made here was to add a bit of detail to the 
springs which seem very plain. I have used a a little bit of brass 
shim in the centre and a bit of wire and tube for the hanger at 
either end. I think the prescence of a bit of relief is what is 
needed rather than precise detail. The front springs in particular 
are quite prominent.

Moving on a bit, another change I have made was to fix little brass 
angles to either side of the gearbox so that it could be screwed to 
the 'motor bracket' and therefore removed and adjusted if necessary. 
I was uneasy about gluing it in position. The brackets are positioned 
so that the screw heads (which are 14 BA) are hidden in the back of 
the boiler. If you want to do this solder the brackets after the 
gearbox is folded but before the gears are assembled.


David Churchill

Assembly is slowly progressing. 

The cylinders were reasonably easy to fold up. Soldering them was 
difficult
because I kept filling the holes with solder. I'm waiting to finish the 
rest of
the chassis before I put the white metal parts on.

I soldered the cylinder heads in place while holding a scriber through 
the central hole.

Now I'm assembling part 9 (boiler saddles) to part 10 (pilot deck).
This has turned out to be an incredible pain. Fixturing parts to hold 
them for soldering is something I'd appreciate advice on.

I tried using a little Hob-E-Tac (woodland scenics glue) to hold the 
rear one on while I soldered it, but the heat popped the joints.

Subtle point in the instructions. There are two 1.5mm 'pipes' coming 
out of the cylinder and running to the boiler. If I had it to do over I might have 
soldered these before attaching the cylinders.

Part 7 is some teeny tiny angles. Fixturing these was a pain - I ended up putting
a pool of solder, then using the iron in one hand and the part in 
tweezers in the other.

Part 8 is a big part that solders to 7. I was afraid I'd unsolder 7, 
but it didn't turn out to be a problem. I soldered 7 to 8 with the by now usual 
'solder on iron' method.

So, I'm having trouble assembling theseboiler saddles. They have tabs 
on bottom. Front one, tab goes into a slot. The rear one is worse - tab goes into a 
recess at rear of part.

-- 
Anne Ogborn

The clay trick works great. I used the same modeling clay I use
for moldmaking.

I was able to solder the boiler saddles on easily.

So I went on to part 12, the pilot front. This definitely was not
easy - I kept melting the little lumps of clay. In fact, I eventually
loosened the rear boiler saddle as well.

At this point I'm sufficiently disgusted that I've put it away for the 
evening.

-- 
Anne Ogborn

Tonights entry.

I soldered the pilot on. This turned out to be pretty straightforward.
I filed away a bunch of solder in the way, slipped the deck in place, 
and put a spot on either side where the front crossmember is.

Soldering on the part 14's turned out to be ...uh... difficult.
My recommendation to the next soul - ACC!

In soldering them on I loosened an 11. Soldering it back on it went
'zing' into the carpet.  Just as this happened my housemate phoned.
I was, uh... less than diplomatic... Amazingly, I did find it.
Soldering it back on the 14 got cockeyed & I took
it off. Soldering THAT back on, it too went 'zing'. I even had an 
anti-zing device in use (I was doing this in the folds of a much used paper 
towel).
Didn't find the 14. Fortunately it's one of 4. I won't need a 
replacement until I get to the rear of the loco.

8cP

At some point I did begin to ask if I was having fun.

Model Railroader (ma-del rA-lruder) (n) 
1. A person who likes to crawl about on the floor and look for small items.
2. A magazine that won't tell you about #1

-- 
Anne Ogborn

Tonights saga:
  Crosshead guides!

  I soldered the two pieces together. This turned out to be only 
moderately
painful. I clamped them with a hemostat and soldered.
On one side the hole the conn rod goes through got filmed over with 
solder. I rewarmed the part and poked the center of the hole with a scriber. It 
worked just like popping a soap bubble. 

After I soldered the parts together the part without the tab interfered with the
part with the tab. So I had to carefully file the part back.

I also found a use for those small metal burrs with my dremel. If you 
hold the tool rather loosely they'll carve away great huge chunks of solder without 
cutting the brass.

In the process of handling the parts I broke the crosshead guide off of 
the hanger.
So I epoxied the guide back in place (I didn't think I could solder it 
without everything coming apart). We'll see if this holds up. If it doesn't 
(and if I can get the cylinder end of the guide loose, I epoxied it as well) I'll 
silver solder it off the model. That'll be exciting.

I also managed to knock off a part 11. Advice to others

1) before installing these put a solder fillet in to reinforce the part. 
Wick away enough to not be unsightly, but it'll still fill the weak 
half etch fold.

2) install these later. I've nearly knocked them off a couple times. 
Now I've totally done it.

My plan is to put on part 18 with epoxy to avoid dealing with solder 
here. This isn't a part that has to be strong.

-- 
Anne Ogborn

Tonights saga -

  I completed assembly of the chassis. I've left the sanders handrails
off until later to avoid breakage, but I've attached all the other 
parts, including the white metal.

I started on the linkage. The rivets for the valve gear I assembled per 
their instructions.
That turned out to be really trivial. For those without the kit in front of them,
the prescribed method is to place rivet on work surface, put first part over rivet,
put typing paper with a hole punched in it over rivet, then second part. apply a small
amount of flux. Hold stack down firmly with screwdriver and transfer a little solder on the tip of 
the iron.
(I wish somebody had shown me this 'tip of the iron' trick a long time ago).
clean off flux with alcohol and file flush.

It's not obvious from the instructions how the lifting link is to be 'plumbed'.
After looking at other parts of the instructions I realized that a reverse link
is provided on the superstructure. So part 29 (lifting link) solders to one end
of a rod that runs across the chassis to the opposite side, where it's soldered
to part 38, the reverse link.
On the prototype this is the connection to the Johnson bar in the cab.

Also not obvious is how the coupling rod is assembled. The bushings are
NOT to be soldered, merely put in place and their excess length filed down. 
I soldered them in place. The only place this is important is the front of
the coupling rod. This bushing has to be soldered to the flycrank pin 
to keep the coupling rods on.

Also not obvious from the diagram is the way the flycranks attach to 
the axles.
This is described in the written instructions, but not in a good place. 
They attach via plastic bushings. I'm not sure why, as the valve gear will be 
electrically connected to the rightside of the wheels like everything else on the model. 
The plastic bushings don't help, as the piston rod and reverse lever ground things anyway.

-- 
Anne Ogborn

--- In HOn30@y..., Anne Ogborn  wrote:

> I started on the linkage. The rivets for the valve gear I assembled 
per their instructions.
> That turned out to be really trivial. For those without the kit in front of them,
> the prescribed method is to place rivet on work surface, put first part over rivet,
> put typing paper with a hole punched in it over rivet, then second part. apply a small
> amount of flux. Hold stack
> down firmly with screwdriver and transfer a little solder on the tip of the iron.
> (I wish somebody had shown me this 'tip of the iron' trick a long time ago).
> clean off flux with alcohol and file flush.

This 'trick' helps a lot with a lot of the smaller parts in etched 
brass kits. In my kit I found that the hole in the cast crosshead was 
much too big for the rivets provided - I used a larger rivet which I 
happened to have to hand with the head 'turned' down somewhat.

 
> It's not obvious from the instructions how the lifting link is to be 'plumbed'.
> After looking at other parts of the instructions I realized that a reverse link
> is provided on the superstructure. So part 29 (lifting link) solders to one end
> of a rod that runs across the chassis to the opposite side, where it's soldered
> to part 38, the reverse link.

In reality the cross shaft runs across the chassis and bends down to 
clear the boiler.
 
> Also not obvious is how the coupling rod is assembled. The bushings are NOT
> to be soldered, merely put in place and their excess length filed down. 
> I soldered them in place. The only place this is important is the front of
> the coupling rod. This bushing has to be soldered to the flycrank pin to keep the
> coupling rods on.

The instructions seem to recommend gluing which I have been a bit 
wary of but seems to have worked at the front.
I am hoping to finally attach to the rear crankpin using a 14BA nut 
soldered to the rear of the return crank and thinned down as much as 
I dare. At present it is test running retained by a 14BA nut without 
all the valvegear.

David Churchill

rear crankpin will solder to the return lever, won't it?

Your technique might work in front. You might have luck making
a nut - drill and tap 14BA in brass sheet, then cut the outside of the
nut around it?

Having made more progress over the last few days here are some more 
comments.

Valve gear
The lifting link part 29 is on the nickel silver chassis etch - but 
there is only one. Surely there should be one on each side of the 
loco. It is quite prominent so I will make another one from the etch 
scrap. However this will need some change to the fitting of the 
reversing rod [part 38). I will leave thia to sort out later.

Superstructure
There is nothing in the instructions about fitting the cast boiler 
section to the brass bunker/footplate assembly. I have drilled down 
through the base of the bunker and tapped the boiler section 12BA. 
This allows the boiler assembly to be separated for work /painting 
etc. It also allows access to the screws I have used to retain the 
gearbox rather than glue it in position.

In comparison with pictures the backhead (part 59) does not seem to 
me to project far enough back into the cab. I wanted my loco to have 
a round topped boiler anyway so I will replace it with one bent from 
approx 5mm X 1mm brass - and use the detail fittings provided in the 
kit.

When forming the rear section of the left hand bunker side overlay 
(part 35) note that the curve at the rear reaches right to the back 
of the footplate and does not neatly follow round slightly inset from 
the footplate edge. Hopefully my meaning is clear. I got mine wrong 
to begin with so will have to detach the rear and re-bend it. 
Fortunately this section gets very battered in service so it will 
actually be better if it is a bit untidy.

The handbrake assembly provided is a not a good representation of the 
actual one - the tube is far too large in diameter. I will replace 
mine with one fabricated from wire.

If you are ultra-pedantic the rivet pattern on the right hand bunker 
overlay is wrong. On this side the rivets along the bottom of the 
bunker are always (I think) along the bottom edge and not at an 
angle. Having noticed this I corrected it by filing away the rivets 
and replacing them using a riveting tool. A bit nerve racking but it 
seems to have  worked OK. 

Hopefully these are not too detailed to be of interest. 
Best wishes

David Churchill

> Valve gear
> The lifting link part 29 is on the nickel silver chassis etch - but
> there is only one. Surely there should be one on each side of the
> loco. It is quite prominent so I will make another one from the etch
> scrap. However this will need some change to the fitting of the
> reversing rod [part 38). I will leave thia to sort out later.

oooh... this looks tricky. I guess I can try drilling the holes, then
filing the part down around them. It looks scary. Bet I ruin a few.

The idea of attaching the boiler with a screw is a good one. Forgive me
though, I'll be using UNF threads, not BA.

> 
> In comparison with pictures the backhead (part 59) does not seem to
> me to project far enough back into the cab. I wanted my loco to have
> a round topped boiler anyway so I will replace it with one bent from
> approx 5mm X 1mm brass - and use the detail fittings provided in the
> kit.

I'mnot sure what you mean by a round topped boiler in this context.

> 
> When forming the rear section of the left hand bunker side overlay
> (part 35) note that the curve at the rear reaches right to the back
> of the footplate and does not neatly follow round slightly inset from
> the footplate edge. Hopefully my meaning is clear. I got mine wrong
> to begin with so will have to detach the rear and re-bend it.
> Fortunately this section gets very battered in service so it will
> actually be better if it is a bit untidy.

Once again I'm slightly stumped. I can see how it's supposed to curve 
from pg. 16
of Badawy and Crow's DHR book, but I'm not sure where that puts in on 
the footplate.
Does a piece of the footplate stick out beyond it, or is there a gap in 
the floor?

Thanks for the report. I was beginning to feel like an only voice, nice 
to have a
wiser head about.

Annie

> > Valve gear
> > The lifting link part 29 is on the nickel silver chassis etch - but
> > there is only one. Surely there should be one on each side of the
> > loco. It is quite prominent so I will make another one from the 
etch
> > scrap. However this will need some change to the fitting of the
> > reversing rod [part 38). I will leave thia to sort out later.
> 

It looks like the reverse link is inside the bearing for the crossbar,
while the lifting link is outside. This is shown clearly on inside back 
cover
of badawy.

OK folks, 

       Since y'all were so wonderful about the missing link question,
       I've got another for ya.

       I'm soldering my valve gear rivets on using the Backwoods
       Miniatures method.
       Their method is basicly to assemble the parts with a piece of
       paper with a hole
       punched in it between them, solder, and tear away the paper.

       This usually works great, but in a couple instances I've
       soldered everything into a solid mass. 
       I've reheated and disassembled and used lots of solder wick,
       but the parts, notably
       the rivet, are still thinly tinned. The tinned rivet has a
       real tendency to solder itself again when I try again.

       Any cure for this?

       -- 
       Anne Ogborn

Anne:

Paint the joint, you don’t want soldered with yellow ochre. It is a solder resist. Sold at
Jewelry suppliers. It is poisonous, so caution should be used. I cannot recall a time, a
solder joint hasn’t been made workable, after applying yellow ochre, working the joint free
while heating it. Carbon is another solder resist.

If neither of these methods will work for you, try oxidizing the metal by overheating it and
then polish it the area you want soldered.
Doug MacLeod, Roseville,CA

Anne –

I use ordinary straight pins, which come in various sizes, and are quite
abundant and cheap. I insert them from the rear and solder on the front
side. Then I clip off the excess pin length and trim the stub with a
fine needle file.

Dick Karnes

Anne

An alternative here is liquid gun blue. Just blue the parts, and you get the solder resist effect Doug describes
plus you get blackened parts.

I use the Birchwood Casey product. The instructions suggest it does not work on non-ferous metals, and
while this may have some truth for the manufacturers intended purpose, it works very well as a brass blackener
and solder resist. Buy it from your local firearms purveyor. Works well for blackening whitemetal too.

I don’t bother about rivets. I use plain wire with a forked joint or, like Dick, lacemakers pins for a lap joint.
Rivets are OK if you use them as rivets (ie hammered closed) but if you want to solder, a long length of wire is
far easier to handle.

Happy Christmas

Lawrence

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