Monday, August 6, 2012

J Class Tyre

Hi All,

An unhealthy combination of work, together with a far more healthy dose of family and holidays has put a ‘go slow’ on the J class.

I’ve been developing my machining skills over the last couple of weeks, which has resulted in the first trial J Class tyre profile. I was not able to machine the bore, as I need to purchase a drill bit.
As can be seen, I removed as much material (stainless steel) I could, leaving around 10 thou on the tread and flange. I then used the Proto87 form tool, I finished the tyre surface by slightly feeding in the tool and rotating the chuck by hand.

The Proto87 form tool takes up a considerable amount of room on either side of the tyre. I removed enough material to accommodate. However, this will be time consuming and wasteful when it comes to machining all wheels. Consequently, I am considering machining several tyres to the basic shape, followed by boring the centre, then parting off each unit. I can then mount each tyre on a mandrel and finish off with the Proto87 tool.


1 comment:

Anonymous said...

This is a very helpful post re the use of the P87 profile tool. I had my own P87 tool produced by Dave Doe of DD Wheelwrights which appears to be narrower than yours, so not so much material may be wasted. It was quite expensive, though.

I am also having a look at whether Roco German steam loco wheels - the current generation are all metal - might be usefully modified to P87 profile where there are no specialist wheels available, e.g. from Teichmann or Holger Graler. Things like the one-off ex-DR 18.201, which has 7'6"(2.3m) dia. drivers and which is not - as far as I know - covered by any of the finescale wheel producers.