Monday, 15 February 2016

Boxpoking about


So what have I been upto since my last post I hear you all ask. Well, I have been mostly CNCing stuff.

I have a Dapol Q1 which has been treated to a conversion a while ago. For those of you who remember it I ended up writing an article for the Model Railway Journal which ended up in issue 211. The problem was that I was never happy with the results. While the engine did run it wasn't upto my standards as the wheels were a kind of hybrid of dapol and 2mmSA.

As with many things in life, the older you get, the more knowledgeable you get and this is a classic case. Since my last attempt at conversion I have rethought an approach to producing the wheels for another attempt at getting something I am happy with. This time armed with a CNC mill I made a start...

This is how the wheel started off. A 3D model of a scale wheel with a 2mmSA rim attached, from this I can generate a CNC programme. In my previous post I showed how I turned up the blanks from Paxolin and added the association rims.

The wheel blanks were clamped in a rotary table and clocked with a dial test indicator to ensure they were centred correctly. I had a frustrating time getting the DTI to fit the milling machine because of the depth on the Z axis wasn't enough. This meant I had to make a little bracket (seen clamped to the mill chuck) which was a pain.
Once the wheel was centred the programme was then run. The milling cutter is a 0.5mm slot drill which conveniently was suitable for all the milling and drilling operations. The programme took about an hour per wheel. It seemed to take forever to do all 7 (6+1 spare) spread over a number of evenings.
And these are the result to date. The backs need tidying up a bit on the lathe but other than that the next step is cutting some axles and fitting them to the chassis.

Am I happy with them? Definitely, they look like Boxpok wheels and fingers crossed they are an improvement on the previous attempt.



  1. Seriously clever stuff.....

  2. Very nice Julia. Let's hope that they run as good as they look :-)


  3. Hello Julia, they look great. Looking forward to seeing the reborn Q1.


  4. With pedant-mode 'on', I should point out that these are not Boxpok wheels but Bulleid Firth Brown (BFB) wheels. The American Boxbok wheel was made of sections fitted together, whereas Bulleid's design was a single casting. See for more info.

    Whatever the name, that's a wonderful bit of small-scale milling that you've done :)