As I needed the pillars for the battery tray to be tapped as opposed to having a through hole I made a new set from stainless.

After cleaning and etch priming various parts of the running gear, thought I would do a test assembly of the rear left mudguard where the convoy light fits.

At first I noticed a 4mm bolt would not fit in the threaded portion of all the mudguard hinge blocks (CE0327).

After a measurement of the thread it was found to be oversize. Used a 4mm die to get the proper threads. As this part is made in aluminium, I took extra care that the die picks up the old thread.

Next thing I noticed was that the lower bolts in the frame might be a bit too large.

I could solve this by either using a 3mm bolt instead of the 4mm one or else use a 4mm bolt with what is called a one-size smaller head.

I finally started the final assembly of the lower hull but ran into a problem.

I decided to fit the O-rings also when bolting the suspension bar to the side of the hull. Just by chance I thought I would try one of the assembled swing arms in the various holes to see how they fit. One side of the hull was not a problem but on the other side, the swing arm would not go in as much as the other side.

Had a look inside the holes with the problems and saw this:

Dismantled everything and found the reason for this problem. The counterbore for the O-ring was not concentric with the shaft hole. Two options:

- Leave the O-ring out.

- Counterbore the holes and use a different thickness of ring.

Prior to considering any of those two options I was going to try centring the counterbore with a boring head. Took the boring head out but was not looking forward to setting it up. I had a look in my box of milling cutters and there it was at the bottom of the box. A 19mm end mill. The diameter of the counterbore was measured to be around 19.5mm. No harm in trying 19mm with the cutter first and see how it goes.

Centred shaft hole with a 16mm bar.

Blued up the counterbore to see what is happening.

Adjusting the position of the counterbore with 19mm endmill.

Another trial fit with the swing arm. Perfect. The other seven holes took less than 30 minutes to correct.

This is the spacing on both sides between the swing arms and the hull; the shoulder of the shaft just touching the brass bush.

Next was the assembly of the lower hull. Assembled the suspension bars to the side plates. Tested again all the holes for the swing arms and then masked the brass bushes. Also loosely fitted the two brackets which will hold the rear plate.

Bolted up the front sloping plate. Used the glacis plate for alignment purposes only.

Fitted the rear plate and turned it around to fix the hull floor with countersunk screws.

Next time: the ‘official’ build begins.

Part 2 here  Part 4 here