Bouch's workbench - 7mm Jinty

[MarkNJ]

Hi Mark,

 

Have you found this one?

 

Jinty_footplate.jpg

Hi Mike,

 

Thanks to Marshall5's lead I managed to find a web site with lots of cab interior and other useful pics. I can post a link later if you are interested. At least I now know for sure the cab detail in my kit is wrong. The instructions and etches have it mirrored.

 

Best wishes

Mark

[MarkNJ]

On the link you mention it says "As built the boiler/firebox height seemed a little low".

 

Before going down that path I would consider what evidence that is based on. Do you have a drawing to check it?

Cheers,

Peter

Hi Peter and Mike,

 

I believe the centreline of the boiler is 7' 4" above rail head. I will check this when I get home and have access to the GA in the Wild Swan book.

 

Keep up the good work

Mark

[N15class]

Look very nicely made. I try to compensate or spring the frames and then keep the loco as light as possible. You want the wheels to slip if it comes to a holt, or the motor will burn out.

[Mike Boucher]

Hi Peter and Mike,

 

I believe the centreline of the boiler is 7' 4" above rail head. I will check this when I get home and have access to the GA in the Wild Swan book.

 

Keep up the good work

Mark

Essery and Jenkinson LMS locomotives Volume 4, page 130 says the centerline is 7' 4 1/4".  That's the closest thing to a plan I have.

 

I think before I do anything here I need to a) build the firebox/boiler/smokebox assembly and b) get the chassis on its wheels.  Then I'll be able to measure.  Looks like I'm soldering in the inner tank sides and shimming later (if required).

 

One of the next things to put on is a overlay on the cab front for the flange that bolts the cab front to the firebox.  But it also seems like I should have the firebox built there, and set to the right height, before applying that overlay.  Two choices.  1) do things out of order, that is, stop work on "the body" and work on the boiler and chassis before putting on that overlay and 2) say "screw it, the number of people on this side of the Atlantic that would see a problem is negligible" and build just the firebox before applying the overlay...

 

Strongly leaning towards #2, if I hadn't seen that note on the other web site, I wouldn't even have this question...

[PAD]

Hi Mike,

If my calculations are correct, 28 thou (0.71mm) is about 1.2 inches in 7mm scale.

You wouldn't notice the difference on the real thing, let alone the model. I built one of these some years back and put the boiler/firebox where it was designed to go. It looks just fine to me so if I was you, I'd ignore the 28 thou and crack on with the build.

I'll take a picture tomorrow and post it.

 

By the way, very nice work so far.

 

Cheers,

Peter

[Mike Boucher]

Hi Mike,

If my calculations are correct, 28 thou (0.71mm) is about 1.2 inches in 7mm scale.

You wouldn't notice the difference on the real thing, let alone the model. I built one of these some years back and put the boiler/firebox where it was designed to go. It looks just fine to me so if I was you, I'd ignore the 28 thou and crack on with the build.

I'll take a picture tomorrow and post it.

 

By the way, very nice work so far.

 

Cheers,

Peter

Hi folks,

 

I have a corresponding build thread on the Gauge O Guild's website.  I heard back from Adrian, who did that build I reference.  I'll quote his text here, leaving out the photos...

 

I suppose I should explain this - as it was my build. It's not essential but I think it improves the look considerably even though it seems a small adjustment.

 

If you look at the full size loco the angle beading around the firebox virtually touches the bottom of the window bezels.

 

Fortunately there are plenty of Connoisseur build on t'internet so exhibit a: a standard build of the kit. There is a noticeable gap between the firebox angle and the window bezel.

 

By applying the small shim on the tabs it raises the boiler and firebox so that the relationship with the window bezels looks better - IMHO.

 

At the front end the shimming of the smoke box is hidden by the dummy frame etchings and casting in front of the smoke box. Personally I think it was worth the modification but it's not essential.

 

Adrian

Looking at photos of the prototype and the models, both the ones he posted and others I then went to look at, he's absolutely right.  The difference is obvious if you know where to look.  With this information, I think raising the boiler/firebox is the right thing to do, as its easy to do at this stage and it does improve the looks of the model.

[PAD]

Hi Mike,

Can't argue with that. I didn't get a chance to check the one I built, but no doubt it will be as Adrian describes. As you say, easy to correct at this stage.

Cheers,

Peter

[Mike Boucher]

As I mentioned earlier, I diverged from the order of instructions a bit to build the firebox, to get the height correct (in relation to the cab front windows).  Only took 2 hours to get 4 pieces soldered together...

After cleaning up the etches, I soldered the two front formers together, and then tacked them to the "top" of the firebox wrapper, careful to make sure the etched in centerlines matched.  I used my radius gauge set against the rear former to determine the radius of the curves was 1/8".  Took a piece of 1/4" rod and bent the curves around the front former.  I used my mini-torch to try to anneal the brass where it needed to bend.  I didn't want it incredibly soft, so I didn't get it quite hot enough, but it still bent easily enough.

If you're not familiar with radius gauges:

 

If you don't have one of these sets, they're very useful.  My set is imperial, from 1/64" to 1/2" radiuses, by 64th up to 9.32, by 32nd from there up to 1/2, but you can also get them in metric by 1/2mm increments.  High quality sets aren't exactly cheap, but you can find a "budget" set for $25 or so, and for hobby purposes the cheap set is sufficient, IMHO.  They're very nice to have!

Another great use for sets like this is then I can file the radius on the front edge of the firebox, and use the gauge to make sure its the same radius everywhere, even around the compound curve at the corners.  To my eye, 1/32" radius looks about right.

I then soldered the side of the wrapper to the front former, and then soldered in the rear former.  Here it is, test fit in the loco.

 

 

Now I can measure how low it is, and add appropriate shims to the supports on the inner tank sides.  And then progress along with permanently attaching the tanks

 

As with the tank tops, there's gaps. (the firebox is in the right location, as the etched holes in the tank tap and boiler for the tank straps are aligned, and if they're at an angle, it'll be obvious.)  Need to add a little shimming to the rear of the firebox.

I put the pre-rolled boiler in place, and that looks to far back, as the etched line for the boiler band is right in line with the tank fronts, and photos show it should be the rear edge should be right at the front edge of the tank.  So this may need to be shimmed as well.  Once the firebox is fit to location, I'll test fit that again.

[Mike Boucher]

Did a little more work this weekend on the Jinty.  I took some .025 thick brass shims and added them to the support brackets on the inner tank side.  I cut them to close to the size of the support brackets, and tinned them.

 

Ran into a bit of a problem here.  On the first one I did, I was pushing down on the shim when the heat got to the point of melting the solder, it also melted the solder I used to strengthen the fold.  And the bracket bent down to about 30 degrees from the side, rather than the needed 90 degrees.  When I went to straighten it, it of course snapped off...

 

 

I was a little more careful on the remaining, only bending (and breaking) this one.  I soldered a small piece of 90 degree channel brass from inside the tank and re-attatched the support bracket.  I then attached the inner tank sides to the footplate.

 

Next was the half-etched riveted beading to attach to the cab front.  I tinned this, held it in place so its just about touching the cab windows, and soldered it in place.  Since its higher than designed, this left a noticable gap where it meets the tank top.

 

 

Since its 1/2 etched, I couldn't use scrap etch to fill it.  I had some .010 thick brass shim stock, so I cut two small pieces to fit the gap (and small is an understatement!), and soldered them in place.  Once cleaned up, you're really going to have to look to notice this..

 

 

I've also added some scrap etch to the rear of the firebox, to fill the gap mentioned in my earlier post.  With this shimming, test fitting the firebox and boiler shell, the boiler now sits in the correct place.  Jim etched in slots where the boiler meets the tank ends, and everything looks good.

 

Finally I added the beading at the top of the tank front/sides.  Next step is cab rear and sides.

[N15class]

Coming on nicely.

Going back to the wieghts of a model. I had my Beattie well tank out over the weekend and had a play. It only weighs in at 510gm and it will push 2000gms of white metal wagons with just a hint of slip at the start. So it would seem that an 0-6-0 at a kilo should move the house.

[Mike Boucher]

Hi folks,

 

Now that I have the boiler height straightened out, I started work on the cab rear and sides.

After installing the cab window trim rings, I needed to add the coal bars which protect the glass.  These are made from brass wire, bent to fit.  I made a small fixture from styrene to bend multiple pieces the exact same size, figuring that there would be 4 “small” ones (the outermost and innermost on both windows), 4 “medium” ones (next ones in) and 2 “large” ones (centers on both windows).  Turns out, that wasn’t completely a correct assumption.  The outermost on both were the same, but they weren’t the same size as the innermost.  The 2^nd in from the edge were close enough, as were the centers.  So, I really needed 4 different lengths.  Not a big deal.

Next was to get them installed so they were a consistent distance from the cab rear.  For this, I took two pieces of scrap etch, put them against the cab rear.  I then put the coal bars in place, and place a 3^rd piece of scrap etch across them.  Using wooden clamps, this made a “sandwich” which held everything where I wanted it to be.  A photo is worth 1000 words…

 

 

I soldered everything in place from the inside of the cab.  After cleaning up, I tacked the cab rear in position on the rear bunker.

 

 

Now the fun starts...  I took the cab sides, cleaned them up, and put them in position…

 

This doesn't look too bad.  But...

 

 

                

 

And as they say in Massachusetts, “Light dawns on Marblehead”  ( https://www.waywordradio.org/light-dawns-on-marblehead/ ).  Clearly, the reason I had gaps between the tank sides (and firebox) was because, despite my best efforts to jig it up so it was square to the footplate, the cab front is at a slight angle, tilting towards the rear.  It’s REALLY obvious in the 2 ^nd photo above.

 

If this was a Gauge O Guild Gazette review of the kit, I think the appropriate statement would be “any shortcomings of the model are due to the inexperience of the builder, not the quality of the kit.”  Another phrase which comes to mind is “experience is what you get when you don’t get the outcome you wanted.”  Lesson learned to double check EVERYTHING and don't move on until you're sure everythings square.

Looking at it from the side…

 

 

It’s obvious that I shouldn’t just file it shorter, as then the front edge of the cab opening is too far forward.

Looks like I have two choices…

1) Tear half the engine apart, get the cab front square, and reassemble, hoping I do it better the 2^nd time.

2)  Carefully cut the cab sides in half, remove the appropriate amount, file square, and solder back together.

Strongly leaning towards #2, as no one is going to measure the cab opening to find it 1-2mm short, and while it’s not trivial, it’s a lot less work than #1.  Of course, that also means I'm going to have to shorten the casting for the roof as well.  Still seems the better choice.

I think while I ponder that (and repeatedly kick myself), I’ll work on the boiler.  My club has a show next weekend, and I would rather display the body with the boiler at least test fit than have no boiler but the cab sides in place…

[PAD]

Hi Mike,

Is there any chance you can scribe a horizonal line across the cab front at tank top height? With careful bending you could then snap off the cab front at the tank tops which would allow you to square it up with the cab sides. That would leave a slight step in the cab front but would be hidden by the firebox. That way you don't have a major strip down or any change to the cab dimensions.

 

The difficulty would be in holding a straight edge in place to scribe the line.

One option would be to solder a strip of waste etch on the cab front between the tank tops and then scribe. After you have scribed the line sufficiently, desolder the "straight edge, and then carefully start bending. A little bit each way gradually increasing until it snaps. You'll need to scribe the line several times to get it as deep as possible but as I recall the brass is not too thick and quite soft.

 

Best of luck with whatever ever you do and I hope it works out OK.

 

Cheers,

Peter

[John K]

Hi Mike,

You have done brilliantly so far, and so I think you might never be happy if you bodge it by filing bits off or snapping the cab front in half.

I would select your option one, and carefully dismantle and clean up the components until you get to a stage where you can build the whole thing straight and square.

You may also have problems fitting the roof if it's not right.

John K

[PAD]

Hi John,

I agree, bodging would  be  a  poor solution.

 

What I am suggesting  is  a possible  solution to correct the  error, square the  joint  between the  cab front and side while  maintaining the  correct cab dimensions, all without a major  strip down and  back tracking.  The  resulting joint  in the  cab front will be fully hidden by the firebox on the  outside and  mostly (if  not  completely)  hidden by the  boiler back plate casting inside. That I would  suggest is  not  bodging.

 

Now  cutting the  cab side, shortening, moving back and  re-fixing, well that is  another matter.

 

Cheers,

Peter

[Mike Boucher]

To quote the Kinks...

 

"Give it all up and start all over

You say you will but you don't know when

 

Then its back where you started

Here we go 'round again

Day after day I get up and I say

Come on do it again..."

After putting the Jinty to the side while I pondered how to fix the situation I was in, I kinda lost a bit of my "modelling mojo", the weather was getting nicer so I was spending more time outside, I worked on other projects, etc...  Now that the summer's over, I've picked up the Jinty project again and decided to fix it the right way by taking it apart to get the cab front vertical, so its time to wake up this thread.

 

I removed as little as I could get away with.  I removed the flat trim on top of the tanks, the inner tank walls (and tank tops), and a few pieces in the cab.  I loosened up the cab front and made it vertical.  I also had to get rid of all the shim pieces I added to the various pieces.  

 

Then got everything back together.  Removing the long, thin trim pieces really bent them to hell, so it took some work to get them reasonably flat and smooth again.  And I had to add new shims to the rear end of the tank tops (at the cab door) since I had filed some of that away previously when things weren't fitting right. 

But, after about 8 hours of re-work, I'm back to the point I was when I discovered my out of square screw-up.

 

 

Now the cab sides fit much nicer.  It may look like they're too long, but a) the 1/2 etched edges fit nicely between the cab front and rear and b) you can see the "gap" is consistent size over the whole height.  and , the camera makes it look bigger than it is, that "gap" is less than 1mm.

 

 

 

Next step will be to attach the cab sides, and remove the shimming I added to the boiler/firebox to make sure that fits correctly.  (and yes, I need to clean up some of that tarnish.  also, I've cleaned up that huge glob of solder where the cab rear is attached to the tank)

[Fastdax]

Now the cab sides fit much nicer.  It may look like they're too long, but a) the 1/2 etched edges fit nicely between the cab front and rear and b) you can see the "gap" is consistent size over the whole height.  and , the camera makes it look bigger than it is, that "gap" is less than 1mm.

 

Next step will be to attach the cab sides, and remove the shimming I added to the boiler/firebox to make sure that fits correctly.  (and yes, I need to clean up some of that tarnish.  also, I've cleaned up that huge glob of solder where the cab rear is attached to the tank)

 

Great build Mike! I have only just found your thread and it reminds me of where I was a couple of years ago:

 

 

If I may make a couple of suggestions:

 

I think most Jinties did not have the circular blanking plates on the tank tops. These were left-overs from the rarely-fitted condensing gear. Certainly 47327 did not have them when I photographed it recently. I filled the etched circles with Squadron Green and sanded them smooth:

 

 

Regarding the back of the tank tops not quite meeting the cab front plate, I made up a couple of baffle plates (which stop water spilled on the tank tops from running back into the cab under acceleration) which might help cover any gap:

 

 

This is 47327 (at the Midland Railway Butterley) and you can see the lack of tank top cover plates and also the slosh baffle (or whatever its proper name is!)

 

 

I'll be following your build with interest.

[Mike Boucher]

I've made a little progress on the Jinty over the weekend.

 

First was to add the cab sides to the body.  This turned out to be trickier than I thought it would be.  My 30W iron didn't have enough power to get enough heat into the parts, and the 80W was too big to solder from the inside of the cab.  So, it took quite a bit of time to clean up afterwards.  But, I have them on, and hopefully I won't find any more massive mistakes...

 

One thing I did "in advance" was to cut slots in the folded-in tops of the cab sides.  To make the cab roof removable (hopefully), I plan on doing what I've done on other projects.  Cut slots in the folded over tops, and then attach "tabs" to the inside of the roof.  When everythings aligned right, you can drop the tabs through the slots, slide them ahead, and the roof stays nicely in place.  (see post #67 of this thread to see the principle: http://www.rmweb.co.uk/community/index.php?/topic/18405-bouchs-workbench-7mm-jinty/page-3&do=findComment&comment=1148813)

I figured it would be easier to cut the slots before bending/assembling.

 

 

We'll see if I can get the cast roof to slide into place.  If not, then those slots won't be noticeable anyway.

 

I also went back to working on the boiler.  I had previously assembled the firebox, now I worked on the smokebox.  With the changes made to the boiler height, I have some work to do to get the boiler level.  Here's the former for the smokebox, I still need to add the riveted wrapper.

 

Back to an older project.  I had finished assembly on my C&O caboose a while back, but needed to get decals made for it.  I have a friend who does custom decal work, so I gave him the original decals which came with the kit, which are now completely unusable due to age.  He made me 4 sets of new decals.  I put the decals on, sprayed the entire caboose with dullcote, and then gave it some light weathering.

 

 

With it lettered and weathered, there's nothing else to do, so I'm declaring victory on it.  One more project off the "in progress" pile.

[Mike Boucher]

And we have most of a boiler.  Still need to adjust the height in the smokebox so the boiler sits level and put the washout plug castings in the firebox, but its looking like a boiler.

 

In preparation for shimming/adjusting the smokebox, I've also added the front splashers to the footplate.

 

 

Hopefully next update will have the boiler attached to the footplate.

 

I'm getting close to having major construction done on the body, so I'm pondering what to do about the chassis.  There's part of me that wants to compensate the chassis, but there's another part of me that says on an 0-6-0 its not really going to make a huge difference.  The main advantage will be in electrical pickup, not tractive effort.  I also have to deal with the fact that the loco is designed that the center axle is the one with the motor mounted, and there's no reasonable compensation scheme which keeps the center axle fixed, which definitely complicates things.

 

I have no question that I could do the work (I have a fairly decent machine shop, and my father has 4 milling machines in his basement), the question is do I want to or not.  Lots to consider there.

[Fastdax]

 

I'm getting close to having major construction done on the body, so I'm pondering what to do about the chassis.  There's part of me that wants to compensate the chassis, but there's another part of me that says on an 0-6-0 its not really going to make a huge difference.  The main advantage will be in electrical pickup, not tractive effort.  I also have to deal with the fact that the loco is designed that the center axle is the one with the motor mounted, and there's no reasonable compensation scheme which keeps the center axle fixed, which definitely complicates things.

 

Mike, if I may offer another opinion:

 

I used the "Jazz" method* of providing a half-way house compensation on my Jinty, which does have the motor/gearbox on the centre axle.

 

This method allows the centre wheel bearings to move upwards and downwards in elongated slots in the chassis frames. The weight of the motor and gearbox keeps the axle pressed downwards but the axle will "float" and follow trackwork undulations (of which I have many!). Optionally, two springy wires attach to the inside of the frames and locate into holes in the bearings to stop them rotating.

 

In this picture of the chassis, you can just make out the springing wire in the far centre wheel bearing hole. Its end is turned downward to fit into a corresponding hole in the bearing.

 

 

I know it's not full compensation but it should give at least 5 point contact with the track at all times.

 

*Named for the prolific loco builder Jazz, who uses this method on most of his creations (for example - see here).

[Mike Boucher]

Mike, if I may offer another opinion:

 

I used the "Jazz" method* of providing a half-way house compensation on my Jinty, which does have the motor/gearbox on the centre axle.

 

This method allows the centre wheel bearings to move upwards and downwards in elongated slots in the chassis frames. The weight of the motor and gearbox keeps the axle pressed downwards but the axle will "float" and follow trackwork undulations (of which I have many!). Optionally, two springy wires attach to the inside of the frames and locate into holes in the bearings to stop them rotating.

 

In this picture of the chassis, you can just make out the springing wire in the far centre wheel bearing hole. Its end is turned downward to fit into a corresponding hole in the bearing.

 

 

I know it's not full compensation but it should give at least 5 point contact with the track at all times.

 

*Named for the prolific loco builder Jazz, who uses this method on most of his creations (for example - see here).

Hi Duncan,  I'm familiar with Jazz' work, I follow his workbench thread.  His is one of the methods I'm considering (I pretty certain Sandy Harper uses the same technique as well)  I'm glad to see that you've successfully used it.  

 

I think the biggest "mental block" is that Jim designed the motor mount to be fixed to the chassis sides (at least, that's how it appears to me by reading the instructions), which means I'll have to modify the motor mount.  Getting the gearbox aligned correctly is one thing that can make or break a model.

[PAD]

Hi Mike,

I'm glad to see that you got out of jail with the cab.

 

On the motor mount, why not discard it and go for an ABC gearbox and motor. Not cheap but worth it. If you look on the ABC website you can download full size drawings of the various gearboxes, print, cut them out, and then check against the model which will fit. If you email them they are very helpful in suggesting the best gear ratio for your chosen prototype. I've bought seven over the years and have never regretted the outlay as they are top class. I've got another one on order for my Duchess.

 

Cheers,

Peter

[Fastdax]

I think the biggest "mental block" is that Jim designed the motor mount to be fixed to the chassis sides (at least, that's how it appears to me by reading the instructions), which means I'll have to modify the motor mount.  Getting the gearbox aligned correctly is one thing that can make or break a model.

 

I didn't actually realise that at the time or until you mentioned it. As you can see in my photo above, the motor is mounted to Jim's gearbox. This sets the mesh of the cogs. The whole unit isn't fixed to the chassis of my Jinty though.

 

I can't recall doing anything special to mount the motor. As I said, the motor/gearbox/axle unit floats. To stop the motor twisting about the axle I have it tethered loosely to a frame spacer with a thin wire looped round the motor casing. I think there's a foam pad under the motor to cushion it from said frame spacer. This still allows the motor to rise, fall and roll a millimeter or so with the track.

[Shez]

I have used Jazz's method on the Pickersgill 4-4-0 I am building and I am pleased with the results. I was going to message him with a question about six coupled locos that are designed to drive on the centre axle, but it looks like Fastdax has answered my question for me!  

[Mike Boucher]

I've reached the first "major milestone" in this build.  "Major body construction" is done.  What's left on the body is all "detail parts", do be done after the chassis is done and fitted to the body.

 

 

 

Note that the castings for the smokebox door, stack, dome, and cab roof aren't permanently attached, only thing holding them there is gravity.

 

Few interesting bits in the past week getting here.  Around the front splashers there's trim pieces.  The instructions say to file to fit.  Well, when I put them in place they were quite oversized, about 2mm too long.  So I cut them in half, soldered one half in place, then filed the other half shorter to get a good fit.  I suspect that means I installed the splashers incorrectly, but I can't check that until I have the wheels in the chassis.  Hopefully that won't mean the front wheel rubs on the inside of the splasher.

 

 

If you look at the 2nd photo you can see the joint (photos are more cruel that the naked eye), but once painted I'm sure it'll all but disappear.

 

And, one of the most fiddly parts I've dealt with, the "boiler infill" between the tanks and the boiler.  Few things here.

1) It was designed to also fit between the firebox and the tanks.  My firebox is a tight fit to the tanks, so that extension was simply cut off and discarded.

2) It was significantly oversized, I had to file about 1/2 of it away to get it to fit, in addition to filing small notches where the boiler bands are.

3) There's no support underneath, so if it twisted just a little, it would drop down between the boiler and tank.

4) The instructions didn't state how "recessed" this was supposed to be, and I couldn't find a photo either in my books or online.  So, I "winged it" and recessed it about 1mm, so it doesn't look like an extension of the tank top, but it clearly fills in the gap between the boiler.  This may be wrong, but at this point I'm not terribly concerned since the number of people on this side of the Atlantic that would a) know its wrong and b) notice is pretty low.  (I'm also justifying this by thinking how many people have built this kit and don't notice the boiler height issue, which is quite obvious when you know where to look!)

 

It took about an hour to file to fit, get it to sit flat in that small gap, and then solder in place.

 

 

One thing that seems to have developed, probably when I fixed the cab front, is there's a bit of a twist to the body.  If one buffer beam sits flat, the other one has one corner about 1mm off the surface.  You can see it if you look closely at the 3rd photo above.  Not sure how I did that, as I had been checking along the way.  While I'm annoyed about it, I'm not horribly concerned as long as I keep the chassis square.  I can add small shims where the body and chassis meet to make sure that when I attach it I don't twist the chassis to match the twist in the body.  But, its another thing I have to be more careful of on my next loco build.  (spoiler: probably a "City of Truro" from David Andrews)

I gave it a good scrub with "Bar Keepers Friend" to remove much of the tarnish.  To my surprise, this also affected the solder, it really "jumps" now where before it was a lot less visible.

I've been keeping track of how much work I've done on this, just for my own edification.  Right now, including the 8 hours it took to fix the cab front issue, I've been at it for about 43 hours.  Still a long way to go before I get to "Jazz speed".    

My club has a show next weekend, and I'll have this on display.  Since the etch has a small plate to identify what it is, I took this and used it to make some "signage" as to what it is.  Took some Humbrol crimson, painted in, and then sanded the extra off.

 

 

(once again, close up with the camera is cruel, it looks a lot better to the naked eye!)  If anyone asks, I'll tell them that PMK is what Jim used to call his kits, I have a LMS brake from him that says that as well.

Next update we'll have started on the chassis.  Lots to think about there, and also be a LOT more careful to not get things out of square.

[Mike Boucher]

Hi folks,

 

I've started work on the chassis, but in a different order than Jim suggests in the instructions.  He says to build the chassis up "solid", with axle bearings in place, and then make the rods and make sure they fit.

Many builds I've seen online build the rods first, and then make the chassis to fit the rods.  That approach seems more reasonable to me, so I skipped ahead and started on the rods.

 

I've learned there's a LOT more work involved in making the rods than I thought.  The rods for each side are made of of 10 etched parts and 1 piece of copper rod.  6 laminations for the body of the rods, and then 4 small overlay pieces to give the ends more thickness.  The copper rod is to represent the joint where the rods would articulate in real life.  On the model, its a dummy and the rod articulates on the crankpin of the center axle.

 

What I did was this:

1) Tin the surface on 4 of the laminations and all 4 overlays while still on the fret.

2) After cooling, cut them out, making sure to keep them organized so they get assembled in the right order.  I didn't clean off the cusp that was left from etching, as I figured that would give me some room for error when stacking them.  I did clean off the tabs where each piece was attached to the fret.

3) Take 2 drills that fit the holes in each "half" of the rod and mount them in holes on my soldering board.  (I used #44 drills (.086) for the crankpin holes, #50 (.070) for the dummy joint hole).

I made each "half" of the rod separately, so I wouldn't accidentally solder them together...

4) Put the "inner two" of the laminations over the drills, and solder them together.  (that is, the two pieces which would be closest to the wheels)

5) Put the 3rd lamination (the outer rod, which is fluted) over the other two and solder it on.

6) Put the 2 overlays over the ends and solder them on.

7) Repeat steps 4-6 for the other "half" of the rod.

8) Clean up the cusp on the assembled rods

7) Add the copper rod in the appropriate location, overlength, and then file smooth on the back and a little proud of the rod on the front.

8) Tin the top and bottom surfaces of the rods, filling in the visible gaps between each lamination

9) Let it cool, then using a file and sanding stick, finish the tops and bottoms

 

And, after that, I have the rods for 1 side of the loco.  Only took almost 2 hours, if you include the cleanup time in step 9.  I can't wait to build a loco with outside valve gear...

 

Here's what I have now.

 

 

 

 

The "end" on the center axle looks a little rough in the closeup photo of the joint, hopefully once they're mounted on the drivers it won't be as obvious.

 

In hindsight, I probably should have put the fluted lamination down first, fluting against the soldering board.  This would have made cleanup a little easier as I wouldn't have had any solder on the outer surface.  I would have had to flip the rod on the fixture to install the overlays, but that seems easier.

 

I still have to clean up the holes, enlarging them to take the Slaters crankpins.  I'll do that once both rods are done.

 

Next step is the rods for the other side...