Sunday, 18 December 2011

Winter project - Chassis awaiting hornblocks

Below is the current state of play:

I've used Alan Gibson short handrail knobs for the CSB fulcrum points. All holes were drilled for the breakgear assembly and frame spacers adapted to fit their locations. These tasks were all completed before soldering the chassis together. High Level's hornblocks were very easy to fold up. My soldering could be a little tidier but so far for my first attempt I'm feeling happy


If anyone wants to follow my stumbling progress in a little more detail I'll try and illustrate below.....

Before cutting the frames out of the etch I marked the position for the CSB fulcrum points using High Level's CSB jig. A 0.4 mm drill was used to mark the centres, as this size drill seemed the best fit for the holes in the jig and I was reluctant to do any alterations to it at this early stage. The jig was then removed and a 0.7mm drill used to drill through the frames. The holes were still very tight for the handrail knobs so a 0.8mm drill was used to open them out. At this stage I also drilled though all the pre-marked locations on the frames for the brakegear hangers using a 0.5mm drill.

The frames were then carefully cut out of the etch. Then, in accordance with Comet's instruction sheet, the etched springs were removed in preparation for the fitting of the hornblocks. The handrail knobs were then soldered into position using a length of 0.4mm straight brass wire to align them. I must admit to making a bit of a mess here, accidentally soldering the brass wire to one of the handrail knobs (it was rectified at the second attempt). Where required the frame spacers were shortened as per my previous diagram. Also a couple of holes were drilled in one of the end spacers to help with threading the CSB spring wire through the handrail knobs at a later stage. The frames were then soldered together using Comet's P4 chassis jigs giving the result shown in the photo above.

Progress has stalled a little over the last couple of weeks but, when a little time has been available, I've been working on getting the bearings to be a smooth fit in the hornblocks.

With Christmas fast approaching this may well be my last posting until the New Year. So
may I take this opportunity to wish you all a very enjoyable Christmas and thank you for persevering in reading this blog.


Flymo said...

That's looking very good - nice to see that you're using CSB for the suspension. I'm convinced that it's the most effective and smoothest running method currently available.

One comment on the opening out of the holes for the handrail knobs. You say that you used a series of small drills to increase the size of the holes. One of the problems with this is that the drill can snag, and tear the metal, or even possibly break.

You would get more control if you used a broach to open the size up. You can get the small sets of five or six for about a tenner at various stands at exhibitions.

They have a multitude of uses. Try colouring the side with black marker pen, and you have an instant size gauge for the second and subsequent holes that you make of the same size.


Iain Robinson said...

Looks like a very sound job indeed. Merry Christmas to you, and here's to lots more modelling in the New Year!

Geoff said...

An excellent post Yan and I am now considering using CSB suspension on my Dean Goods.
In the past I have always favoured a simple beam compensated chassis as I don't really care for individually sprung hornblocks.
So CSB certainly seems the way to go in future.

Flymo has certainly given you good advice regarding broaches. I have a set of both cutting and smoothing broaches and they are well worth the small sum asked. How I ever mangaged without them I will never know.

Wishing you a Merry Christmas and a Happy New Year.