N Scale Fixed Coupling Drawbar Update

This week I have another product update to share with you.  Unlike last week’s update, for the Minitrix eccentric rod crankpin, which was driven by improving the part, this time it’s simply about reducing the cost to you.

For many years I’ve offered N scale and N Gauge fixed link couplings or drawbars to use between rolling stock or, as I like to use them, between multiple diesels that stay coupled together.  This is really useful if you install a DCC decoder in one locomotive which drives both motors, you can read more about that here.  These drawbars are designed to fit into the Rapido style coupling pockets as you can see below.

To start with these couplings were offered in Shapeways FD (Frosted Detail) material but as that was removed from the available materials they automatically became available in FUD (Frosted Ultra Detail) and sadly the cost went up a bit.  When Shapeways restructured their material pricing again back in June of 2017 these became rather expensive.  However, just as with the Minitrix crank pins from last week I’ve combined the fixed links or drawbars into one piece making them much cheaper to order, as you can see below.

And I’ve also made the primary material BNVP (Black Natural Versatile Plastic) formally known as Black Strong & Flexible.  This is one of the cheaper materials; it’s already a good color for a coupling and can be used right out of the box.  Below you can see a set I’ve already ordered.

These are available in a variety of lengths and all come in packs of 6:


And if you’re not sure which lengths you need I do have two sample packs available:

Basic Sample Set – Containing 4mm, 5mm, 6mm, 6.5mm, 7mm, 8mm & 9mm.

Full Sample Set – Containing 4mm, 5mm, 6mm, 6.5mm, 7mm, 8mm, 9mm, 10mm, 11mm, 12mm & 13mm.

The length refers to the distance from the inside of the coupling pocket, for instance the 12mm is measured like this:

Next week I’ll have some real steam to share with you as I spent a day at ‘The Great Dorset Steam Fair 2018’.

N Scale Minitrx Eccentric Rod Crank Pin Replacement Update

This week I have an update to share with you regarding my N Scale Minitrix eccentric rod crank pin replacements.

Back in September of 2015 I wrote a post about repairing Minitrix steam engines which had suffered with broken eccentric crank pins.  You can find the post here.  These fit A3, A4, 7P (Britannia), 9F, US K4 and US 2-10-0 Decopod steam locomotives.

The crank pin, as illustrated below, has a square peg which fits into the actual wheel and a hole which receives a steel rivet linking it to the eccentric rod.

Although these worked and allowed the repair of the locomotive they did have a few issues.  Their small size made them rather delicate and it was easy to break one when attempting to refit the rivet.  So I originally offered spares in each pack as it was almost certain to happen on your first attempt.

This lead me to improve them by slightly increasing the size of the loop and the size of the rivet hole as shown below, the newer Mk2 pin is at the back.

This did help and made it much easier to reinstall the rivet.  But the issue of re-flaring the rivet was still a problem and I was finding it hard to do as I couldn’t get a supply of new rivets.  This lead me to start cutting part of the loop away to leave a ‘C’ shape which could be forced over the rivet.  As it is a ‘C’ shape it would not fall back off the rivet and the rivet didn’t need to be un-flared in the first place.  The original peg, what was left of it, could be cut away and the new one could simply be clipped in.

But it was hard to cut the hoop in just the right place without braking the hoop.  This lead me to upgrade the model again to include three Mk2 parts with a complete hoop and three Mk3 parts with a ‘C’.  Below you can see the Mk2 and Mk3 crank pins.  Supplying both, I thought, would give you the option as I was unsure as to how well the Mk3 ‘C’ type would work .

Then in June 2017 when Shapeways restructured their pricing system this model became rather expensive as each individual part had an additional $1 handling charge added to the cost.  But the answer is my new Mk4 version of the crank pin which you can see below.

The crank pins are now supplied in a frame.  Although they are not attached to the frame they are 3D printed in the configuration shown above and the loops prevent the cranks from falling out.  The whole model is therefore treated as one piece.

There are eight cranks in each model, allowing for spares, and all have the ‘C’ shaped end which I’ve now used successfully on every loco I’ve repaired since printing the first ‘C’ shaped crank.  Also having spoken to several of my customers they confirmed they didn’t use the cranks with the full hoop at all.

And as the cranks are now held together it makes them easier to not lose!  When you need one simply cut the restraining hoop.

The new Mk4 crank pins can be found here.

Next week I’ll have an update on some of my 3D printed couplings.

A Small Fix for the N Scale Alco C-855B

My most recent locomotive shell is the N scale Alco C-855B, the companion locomotive to the C-855 released a little bit earlier.  The C-855B is almost the same as the C-855 with the exception of the missing cab.  Along the sides of the locomotive are the iconic sandboxes and it’s with one of these that I’ve picked up an error in my model.  In this post I will show you what that error was and how it can be fixed.

The front end of the shell, as shown below, where the cab would normally be has a similar setout to the rear end.  The walkways, sandboxes and railings are the same and simply mirror the details already drawn.  However, the front sandboxes on the C-855 are different and also have a different fitting location.

Alco C-855B Sand Box Fix 1

When I drew the C-855B I took the model of the C-855 and modified it.  I did the front right-hand side first, followed by the left.  And it was at this point that I forgot to adjust the sandbox fixing.  In the image above it looks like there’s nothing wrong but in the image below you can see the long slot for the sandbox locating pin and the frame sticking down.  This slot should have been further to the left and a bit shorter.  Also the frame should have been pushed back all the way to where the walkway steps out.

Alco C-855B Sand Box Fix 2

To show this below is a screen shot of the rear of the C-855B with the correct detail.

Alco C-855B Sand Box Fix 3

So how is this solved.? Well, fixing the 3D model is easy and that has already been done.  The C-855B that’s available on Shapeways is correct and all the sandboxes fit.

If you already have a C-855 then there are three choices.  Firstly, you can cut or sand the locating nub off of the back of one of the sandboxes.  Then trim back the lower section by 3.5mm (1/8th inch) as shown below and it will fit.

Alco C-855B Sand Box Fix 5

Secondly, if you don’t fancy cutting the 3D printed material, I have made a replacement sandbox available on Shapeways, which will be a perfect fit.  In the image below you can see it on the right compared to the original on the left.  The locating nub has been moved over to fit into the hole in the shell and the lower section has been cut back to make way for the frame.

Alco C-855B Sand Box Fix 4

This replacement part can be found here.

The third option is to replace the shell and as with the C-855 I have made the C-855B shell available on its own with no other parts, which can be found here.  This is a bit extreme but if you have had an accident with your shell this is cheaper than buying the whole kit.

Hopefully those who have already purchased a C-855B can make the existing sandbox work without too much trouble.  However, I am happy to help so please feel free to get in contact me and ask any questions.

I know some of you are still waiting for the dummy chassis for this locomotive and I am hoping to have something to share with you very soon.

Geared Up and Ready To Go

At the beginning of June I shared with you some drawings for a replacement cup gear to be used with a Con-Cor U50/Turbine chassis.  That post can be found here. In this post I’ll show you the 3D printed result.

This new gear is a part used to extend the chassis for use with my Alco C-855 kit.  And this particular gear was designed for the rarer chassis made by Sekisui which has 26 teeth in the gear.  The normal one has only 20 teeth.

Below you can see a render of the two gears.

Alco C-855 Extra Gear

And below you can see the actual 3D printed gear.

New C-855 26 Tooth Cup Gear 1

In truth there isn’t much to see.  The priority was to make sure it fitted into the existing gear and matched the motor teeth, which it did, but it was a very tight fit.  So I decreased the diameter of the tooth section by just a fraction and reprinted the gear.  Now, as you can see below, it fits into the cup gear.  It’s a nice gentle fit and the motor teeth matched the other side.

New C-855 26 Tooth Cup Gear 2

So the last thing to do is to tell you where you can get them, and as usual it’s through the Shapeways shop.

Here is a link to the set of two 26 tooth cup gears for Sekisui-made U50/Turbine chassis.

So, a nice short post this week!  I’ll have something a bit bigger to share with you next week.

A Difference in Gears

This week’s post is about a replacement gear set for my C-855 model.  In particular it’s for the very early Con-Cor U50 chassis and the difference it has with later models.

The Con-Cor U50 and Turbine chassis has a centered motor powering two drive shafts.  Each drive shaft has a cup gear on the end which looks like this.

Con Cor 4500-U50 Chassis Render 2

The motor has a small gear which fits inside the cup.

In the rendered image below you can see the two drive shafts either side of the motor.

Con Cor 4500-U50 Chassis Render 4

My C-855 locomotives required this chassis to be extended and therefore the drive shafts as well.  In the image below you can see the white drive shaft extenders inside the extended chassis.

Alco C-855 Chasses 2

Up close you can see the drive shaft extender is simply a cup gear that plugs into the existing gear.  The tooth set out is the same with twenty teeth in total

Alco C-855 Chasses 8

So far in all the U50 and Turbine chassis I have seen the cup gears have all been the same.  But last month I had an email from a fellow modeller who had a U50 chassis with different cup gears.  His had 26 teeth per gear.  So I searched through all the U50 chassis I had to hand and eventually found one as well.  It looks like the very first U50 batch were made by Sekisui on behalf of Kato and it is these models that have the different gears.  Both the Kato made and Con-Cor “Rail Baron” version have the same motor gear and cup gear.

So not wanting to let anybody down I have drawn a replacement cup gear extender.

Alco C-855 Extra Gear

The new cup gear is on the left and you can see the teeth are finer, and there are more of them.

Before I release this gear I want to do a test print and check that it really does fit the 26 tooth cup gear in the Sekisui chassis.  Then it will be available through the shop should you wish to convert your Sekisui U50 into a C-855.

Also while searching through all the chassis I noticed the gears in the trucks and worm gear are different between the Kato made chassis and Con-Cor “Rail Baron” versions so I would not recommend mixing up the trucks, I tried it and the loco run very lumpily indeed!

Adding Window Glazing and Wipers to the Alco C-855

Last week I showed you how I added lighting to my C-855s.  The final details to add to the locos are the window glazing, and to keep those clean, the windscreen wipers.  In this post I will share with you what I did.

The glazing is fairly simple.  A use clear plastic sheet which can be cut with scissors or a sharp craft knife.

C-855 Glazing 1

I designed the inside if the window areas to be flat so the plastic need only be larger than the window and glued in place. For the front four windows I use one strip of plastic measuring 18mm by 6mm.

C-855 Glazing 2

For the two side windows you will need one square piece each measuring 6mm by 6mm.

C-855 Glazing 3And don’t forget the windows in the doors, that piece needs to be 5mm by 3mm.

Before you attempt to glue anything test fit each window with a pair of tweezers to make sure it fits.  This also helps to work out the best angle to put them in at because it’s a bit tight on maneuvering room.

I like to use Gel Control superglue made by Loctite.  Not only does this superglue give you about 12-15 seconds before it sets it also doesn’t run allowing you to get it where you need it.  However if you simply try to put it around the window frame or on the actual plastic with the nozzle it wont go well.  You will get two much and in the wrong place.  It’s best to put a drop into a bit of scrap paper, then use a toothpick to put an even smaller drop on the window frame.  You don’t need much as it will spread out under the plastic.  Also you don’t need to go all the way around, two or three places will be fine.  The more glue you put on the higher the risk of it spreading out or smearing over the part you want to be the window and that doesn’t look so good.

Once all the windows are in place, and stuck, its time to add the windscreen wipers.  I sprayed the brass parts before removing any from the fret, it’s much easier that way.  The wipers are in pairs and handed.  Looking from the front of the fret, the wipers below are for the right hand side, the longer one is for the outer window.

C-855 Wipers 1

Once the wiper is removed you will notice a small half etch on the back of the arm.

C-855 Wipers 3

This is where you bend the arm to fit it into the hole in the shell above the window.

C-855 Wipers 6

Then it’s simply a matter of adding some glue to the arm and pushing it into the hole.  As the glue sets you have a few seconds to rotate the arm, the normal resting place is on the out side of each window.

C-855 Wipers 7

The last thing I wanted to share with you is a little fix to solve a problem that has been annoying me.  Because the fuel tank on the C-855 is sloped on the under side, not square like the Turbine or U50, the peg on the back of the trucks has to be cut off.  When the loco is on the tracks this causes no problem at all but if you pick up the loco the trucks swing out and hit the ladders.  It also makes it a pain to put back onto the track.

To solve this I have used a piece of plastic sprew from an old kit.  Any thing of a similar size will do.  In the shot below you can see the lug protruding out of the back of the truck with out its peg.

C-855 Truck Swing 1

I simply glued a short section of the plastic onto the top of the lug.  This will still allow the trucks to move freely but wont allow it to swivel out.

C-855 Truck Swing 3

In order to get the truck in without unscrewing the chassis you can simply unscrew the truck and separate it from the geared section.

C-855 Truck Swing 2

Once everything is reassembled the loco is ready for service.

Finished Alco C-855

And just as the C-855 cab units were completed the postman delivered the next bit.  Here is the 3D printed C-855B kit in its raw state. The plastic parts will shortly be going into their cleaning bath and later this week will be off to the painters.

C-855B Kit - Raw

The C-855B brass Additions have been ordered and will also be arriving this week so hopefully I will be able to show a bit more in next weeks post.