Monthly Archives: January 2021

Bachmann Mainline Replacement Wheel Centers – Part 2

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In December last year, I shared with you my designs for a set of Bachmann Mainline Replacement wheel centers, you can find the post here.  This week I received the first test prints, so I want to show you how they came out.

I printed them in Shapeways Smooth Fine Detail Plastic as this material is very accurate and cost-effective.  They were printed on a sprue, and as they are transparent, you can see the circles on the far side where the sprue was cut off.

Initially, I was very happy with them, although they still need to be cleaned ready for painting, they looked perfectly round, and all the detail, such as the raised counterweight edge and rounded spokes, have come out well.  But I’d made a mistake; the offset hole which fits over the connecting rod fixing peg didn’t fit.  Looking at the wheel below you can see this fixing peg has two diameters.  The wheel center fits over the larger section and I measured the smaller.

Consequently, as you can see below, the hole in the 3D printed wheel center was too small.

But I still needed to see if the wheel center fitted in the actual wheel, so I used a drill in a pin vice to open out the hole.

This didn’t go so well.    The Smooth Fine Detail Plastic, unlike the original flexible injection-molded plastic, is hard and therefore brittle so the wheel center cracked as the drill went through.  To be fair the material was very thin at this point and was never designed to be drilled out.  But this did allow me to test fit it in the wheel, and it fitted perfectly.

I also wanted to test the wheel center with the smaller counterweight, although it should be the same size.  This time, to make the hole for the side rod peg larger I used a round needle file.

I just about managed to keep the wheel center in one piece; I had to file it down so it was only 0.3mm thick.  Again the wheel fitted, so once the hole is increased these will work.

I’ve now modified the 3D computer model to allow for the larger pin.  I also added a small radius to the rear edge to ensure any discrepancy in the wheel inside corner would not affect the wheel center.

I’ll do another test print to ensure these modifications work. This material, although it doesn’t always respond well to being drilled or filed, is perfect when the design is right. That’s the beauty of test prints, it allows me to perfect the design so the material is never compromised.  I can then spray them a flat black and permanently fit them into the wheels, ready for reassembly of the locomotive.

A New Year and Look Back

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Happy New Year to All!

2021 is here, and despite wanting to look forward rather than back at 2020, for the first post of the year I wanted to reflect on some of the positive things from last year, mainly the new parts and kits released.

The year started out well with the Bachmann N Scale Doodlebug getting a new set of gears and axles to replace the cracked ones.  You can read about these here.

The esteemed N scale MRC/Rowa Y6b 2-8-8-2 also had some new parts in the form of a replacement bell crank. These also fit the 2-8-4 Berkshire and you can read about them here.

Stepping up the scale to OO, the Bachmann and former Mainline brand locomotives received replacement chassis fasteners.  Given that these are a common part to fail with split chassis locomotives they have proven to be a great aid in repairing lots of them.  The parts can be found here.

Returning to N Scale, the UK Britannia 4-6-2 locomotives made by Dapol received a replacement driveshaft.  These tender-driven loco powered models suffered from the same cracked plastic problem as other models I’ve fixed such as the Atlas 4-4-0.  You can read about the Britannia here.

Speaking of Atlas models, the N Gauge diesels also suffer from cracked drive parts.  The universal connecter inside the flywheel often cracks, leaving the locos underpowered.  But new 3D printed parts are now available and you can read about them here.

In a similar way to my Bachmann/Mainline OO replacement axles, the locomotives of the Replica Railways OO range also received a new set of gears and axles.  These are smaller than the Mainline ones, but again come in a set of three.  You can read about these here.

As well as axles and gears I also released a set of dummy knuckle couplings that work with Kadee couplings.  These have NEM fittings designed to fit into European trains forming a permanent coupling that can be easily separated.  You can read about them here.

After the earlier releases of the OO Gauge Bachmann/Mainline fasteners & washers, I was asked to do the same thing for the Bachmann N scale range, so I did.  You can find them here.

One of the older British locomotive models is the iconic Class 14xx made by Airfix.  However, given the huge amount of miles some of these have now clocked up the main drive gears are wearing out. But a new one can be found here.

The final release for 2020, and literally the largest, was the HO Baldwin DT6-6-2000.  This behemoth of a locomotive has been on the drawing table for a long time and I know many of you have been following its progress throughout the year.  You can read about its release here.

So what next, what will 2021 bring?  There are lots of projects in the pipeline and several to finish off.  The HO Baldwin RT-624 will be next as it’s almost ready, and then I want to finish my N Scale 900081 Rotary Snow Plow project.

And I’m sure there will be lots of gears, parts, and other interesting bits along the way which I’ll share with you as we go.

Thank you for your continued support throughout 2020. I hope 2021 is a good year for all and I look forward to sharing my 3D printing projects and modeling adventures with you.