Dapol N Gauge Class 73 Replacement Drive Shafts

This week I have another new replacement part to share with you, this time for an N Gauge Dapol Class 73.

The Dapol Class 73 (Pre DCC-ready version), as shown below (stock Dapol photo), has a central motor which powers both trucks or bogies.  This is now common practice on all N gauge diesels.  Because the motor is fixed to the chassis and the bogies rotate a linkage or drive shaft is needed to transfer the power.

The drive shafts connect the brass fly wheels on each end of the motor to worm gears on top of the gear towers in the trucks.  The drive shafts have a ‘cross’ on each end which fit into slots in the fly wheels and worm gears.  This arrangement allows the gear towers to rotate while still being driven.  Below you can see one of the original drive shafts with the crosses on the ends.  The particular model I’m working on came to me with a missing drive shaft.

The drive shaft was then drawn up for 3D printing and designed for Shapeways Smooth Detail material (formally known as FUD).  I use this for its accuracy and strength as it’s a hard acrylic plastic.  As there are two drive shafts in each model I made a set joined together by a figure 8 loop to keep them together while in production.  The loop is not actually connected to the drive shafts but the holes are not big enough for the crosses to pass through.  The loops can simply be cut off.

The test print came out very well with nice crisp detail.  As the material is translucent its somewhat hard to photograph.

With the loops removed you can see the drive shafts are almost identical to the original injection molded part.

The new shafts can then be fitted into the locomotive.  As their the same shape and size their a direct replacement and work perfectly.  You can see the drive shaft replacement on the right is also sloping down.  This shows how this method of connecting the drive shafts allows of a lot of flexibility in the alignment of the two ends.

A pair of drive shafts for the Dapol Class 73 are available here.

Normally drive shafts are different lengths for different locomotives even though they are made by the same manufacture.  This is because when locomotives have a different wheel base its easier to change the length of the drive shaft than alter the motor design.   If you have a locomotive which needs a replacement drive shaft and you can’t find one send me a message via the contacts page and I can probability help.

N Gauge Peppercorn A1 Replacement Bell Crank Covers

This week I have another new replacement part to share with you for an N Gauge Bachmann (Graham Farish) Peppercorn A1.

These locomotives, as pictured below (Bachmann stock photo), are fairly new and therefore not a lot goes wrong with them.  They are fantastic runners.

But from time to time parts can come off and get lost, and that’s what happened to this one.  Where the eccentric rod connected to the bell crank Beckman have secured the rod with a plastic molded part with two pegs as shown below.  These parts are opp-handed so they are different for each side.

Drawing the part is fairly simple, as I had one to copy, and I’ve joined both parts together to make them cheaper to print and keep them in pairs.

The new parts, which being transparent are very hard to photograph, came out very well and are almost identical to the original.

On the locomotive below you can see the eccentric rod hanging down.  The two holes under the running board receive the pegs on the bell crank cover.  The hole nearest the front of the loco pins the eccentric rod.  At the end of the rod is a plate with three holes; the middle hole is oversized to allow the plate to rotate in on the pin.

With the original cover fitted, as shown below, you can see how it all fits together.

On the other side the new 3D printed part fits in the same way.

This 3D printed part has one of the pegs ever so slightly, and I mean 0.3mm, too low on the cover.  This causes it to appear to be at an angle.  I’ve corrected this in the model file.

Once painted with a matte acrylic black, the new cover fits right in with the locomotive.

For symmetry I changed the other side for a 3D printed part as well and again it fits right in.

Upon test running, the locomotive is as smooth as when it was new.  A pair of replacement N Gauge Bachmann (Graham Farish) Peppercorn A1 bell crank covers can be found here.

Next week I’ll have another new replacement part to share with you and then it’s back to the projects in hand.

Minitrix 9F Replacment Drive Gear

This week I have another new replacement part to share with you for the N Gauge Minitrix 9F.  I’ve already made replacement parts for this locomotive such as the eccentric rod crank pin which you can read about here and the cross head, which you can read about here.

The Minitrix 9F has always been a good runner but, apart from the eccentric crank pin and cross head, it suffers from wear in the plastic gear after lots of running.

The worm gear on the motor shaft is metal and drives a plastic gear, this in turn drives two metal gears which drive the metal gears between and on the axles.  The first gear is made from plastic, I believe, because it’s a double gear and it’s cheaper to make it in plastic than metal.  A double gear means it has a large and small diameter gear moulded into one piece as illustrated below.

Because the original gear is plastic and is driven by and drives metal gears, over time it wears down and looks like this.

Sometimes a slight wear can be overcome by slipping a pack under the rear of the motor, tilting it forwards, causing the worm gear to push down onto the plastic gear but eventually it will wear out.

You can see the larger gear, which is driven by the worm gear, has lost its points and the bottom left side has worn more than the rest.  This may be because the side rods jammed, stopping the gear, but the worm gear carried on turning, chewing the plastic.

The new 3D printed part, as shown below, is printed in Shapeways Fine Detail Plastic.  This is a hard material and long-lasting which has been proven with the O Scale gears I made a few years ago.  You can read more about those here.

The plastic gear spins on a metal axle which fits into the new gear without enlarging the hole.

Fitted back into the chassis before the motor is re-fitted, the new gear can be seen in the top of the tower.  At this stage the gear can easily be tested because the worm gear is not stopping all the gears from turning.  Running the wheels along the work bench turns all the gears, including the new one.

With the motor re-fitted, along with the weights and shell, the locomotive can be tested on power and it runs nice and smoothly.

The gear is available here.

Next week I’ll have another new replacement part to share with you.

Bridging the Gap Between Kits and Production Models

As you may have read on my blog before I often do commission work for companies allowing then to mass produce models using 3D printed parts.  And in this week’s post I have the latest release to share with you.

Three good examples of other projects which have been created this way are:

The Pennsylvania Railroad (PRR) F22 flatcars & naval gun load.

The 4 vat open pickle car.

And the enclosed tank pickle car.

All three of these were drawn for the N Scale Architect who sells them as kits.  However, sometimes the projects are only sold as ready-to-run models and this new project is one of these.

My brief for the project was this photo of Pennsylvania Railroad gondola G26 #440375 taken around 1951. (Andrew J. Hart collection from “Pennsylvania Railroad Gondolas,” PRRT&HS).

The concept is to have a bridge girder load carried on or in a gondola car with the ends removed.  The overhang spans over flat cars, or idlers, at each end. I found it particularly interesting that the girder is not symmetrical;  I have seen this type of load modelled before in HO scale but never as an asymmetric girder.  This makes it unusual as the center of gravity will not be in the center of the car.

As well as making the girder I also had to work out how it was supported and strapped down in transit, taking into account the offset center of gravity.  And, as with all my projects, this work is all done in a 3D model.

The red parts are separate, allowing easy painting, and represent wooden blocks which brace the girder.  The black bars are just that, bars which clamp the girder between the blocks.

All five bottom wood sections will be fixed to the gondola car deck.  The two sets of vertical timbers prevent the girder from rolling over.  Two of the timbers clamps are positioned either side of the largest part of the girder, each one pulling towards the other, preventing the girder from sliding up and down the gondola.  The third clamp simply holds that end down.

And just to make sure it all fits I also modeled in the cars with just enough detail.

The next step was to order a test print to see how well it all worked, and I think you’ll agree from the pictures below that the actual girder looks good.

The supporting wood blocks are hard to see without any color, so the girder and the wood blocks took a trip to the paint shop and now they looks like this.

And here is a video of the train crossing the road, just as if you had stopped in your truck!

So where can you get one from?  These are on sale as a special run in limited numbers from the N Scale Enthusiast.  They have been painted and assembled by The N Scale Architect as a Union Pacific load from Kaiser Steel as shown below.

All three cars are made by Micro trains and include the shipping crates on the flat cars.

This was a great project to work on and really shows how 3D printed parts can help ‘bridge the gap’ between kits and production models.


Pennsylvania Railroad (PRR) F22 Flatcars & Naval Gun Load

Several weeks ago I posted about the N Scale Architect’s new kit for a set of Pennsylvania Railroad F22 Flatcars & Naval Gun Load.  This kit, which was still in development, was announced at the Amherst Railway Society Show 2018, in West Springfield, Massachusetts.

And I spoke about it again two weeks ago as the sample came to the Bournemouth N Trak convention here in England.

Well, this kit is now complete and it looks amazing.

Here is what the N Scale Architect has to say about them:

“The Naval Gun Load kit is based on the Mark VII Naval Gun designed in 1939 and first used aboard Iowa-Class Battleships during World War II.  Measuring 16” in diameter, these guns could fire a 2,400 lbs projectile up to 24 miles. Each of these 68 foot guns weigh nearly 270,000 lbs and were shipped (breech first) across two(2) heavy weight flatcars with a third flatcar used as an idler. Many of these guns were manufactured by Bethlehem Steel in Pennsylvania and transported via the Pennsylvania Railroad across three(3) F22 flatcars. This kit comes complete with Frosted Ultra Detail (FUD) 3-D printed parts, full-color illustrated instructions, sixteen(16) inches of phosphor bronze rod and a ‘DO NOT HUMP’ placard sheet.

The Pennsylvania Railroad (PRR) F22 Flatcar 3-Pak Kit builds three(3) of these wood-decked 30 foot heavy-duty flatcars which had a loading capacity of nearly 200,000 lbs when upgraded to the Crown 2F-F1 cast steel trucks modeled in this kit. These flatcars were originally designed in 1913 and, at their peak in the 1940’s, there were over 100 in use on the Pennsylvania Railroad (PRR) roster with some of them surviving into the 1960’s. This kit comes complete with Frosted Ultra Detail (FUD) 3-D printed parts, full-color illustrated instructions, photo-etched stirrups & cut-levers, brass car weights, Micro-Trains brake wheels & body-mounted couplers, Fox Valley metal wheel sets and a PRR F22 decal sheet that features nine(9) verified road numbers, pertinent car data and prototypical reporting marks.

The ‘Naval Gun Load’ kit (#20100) retails for $39.95, the ‘Pennsylvania Railroad (PRR) F22 Flatcar 3-Pak’ kit (#20101) retails for $69.95 and the ‘Box Set’ (#20102) retails for $89.95… a $20.00 Savings !!!  These kits are available exclusively at the THENARCH.COM.  Additional 3-D printing material options are available at our Shapeways Shop: https://www.shapeways.com/shops/the-n-scale-architect.”

This was a project I really enjoyed working on as it’s such unique load. It was great to get everything correct from the trucks to the length of the gun barrel. The lack of restrictions, which are often caused by donor chassis and other parts that I have to use when designing a locomotive, are what made this easier to do. Only the wheels and couplings are bought in items.

As The N Scale Architect says the kits are available direct from their website or via their Shapeways shop if you want to order them in Frosted Extreme Detail (FXD).  If you do purchase a kit from Shapeways don’t forget to contact the N Scale Architect via their website (THENARCH.COM) or e-mail (thenarch.com@gmail.com) to obtain the additional pieces and instructions needed to finish the kit.  Be sure to include your name, mailing address and Shapeways order number in this message. These items will be mailed to you at no additional charge (including international orders). Please allow 7 to 10 business days for delivery (international orders may take longer).

For me it’s back to the virtual drawing board and on with my current projects, and I hope next week to have some more progress to share with you.

New Axles for a Bachmann HO 4-8-4 Northern – Part 2

Last week I shared with you my designs for a set of replacement Bachmann HO 4-8-4 axles as shown below.

The locomotive was tested and ran smoothly with new axles fitted: the set of four axles are available in my Shapeways shop here.

One thing which I wasn’t sure of last week was one of the original axles has a square center section rather than circular as the other two.  I have since been informed by a fellow modeller that the orignal version of this locomotive also had smoke but the smoke unit had a section which was driven from this square axle to create the puff effect.  As the model was improved this feature was removed but the square axle was never updated.

This coming weekend, 9th to 11th March 2018, is the N Trak convention in Bournemouth, England and again it’s at The Trouville Hotel.  You can read a bit more about last year’s convention here and the 2014 convention here.  I’ll be there over the weekend if you are in the area and want to come by and say hello.