the finer and coarser details of bolts!

After struggling with grubby bolts and missing bolts from key pieces of the tractor.

I have spent some time trying to understand the finer points of nuts and bolts on the tractor.

My tractor has a combination of imperial and metric fixings, which I suppose has been bodged together over the years of ownership. I am trying to standardise on imperial to keep in line with how the tractor started off.

The parts list was essential in putting me in the right direction here, especially with the problem of connecting the engine to the transmission case. The parts list has Ferguson codes and a look up table. The codes that I have been looking to find are the:

353 564X1

353 426X1

353 702X1

353 707X1

etc

These can be looked up against the following types:

A bolt as I understand has three key metrics. Firstly the head type defines the bolt type- the Ferguson uses Hex heads, which makes it straight forward.

Using common sense the three metrics define the width and length of the bolt and the coarseness of the thread. 

The coarseness is defined by the UNx acronym. UN stands for UniFied, and there can be a F for Fine, a C for Coarse and also a EF for Extra Fine. The Ferguson only seems to have UNC and UNF bolts on it.

The following bolts seem to be the essential widths on the Ferguson TEF 20, with a variety of lengths.

5/16 UNF

7/16 UNF

5/16 UNC

7/16 UNC

I did a bit of web searching, and I have found these master sets for each of the above sizes with a variety of lengths and associated washers and nuts. Nice and easy, but not cheap. The following website is excellent for these sets. I have bought a master set for each of the dimensions, with a hope to covering off most of the required fixings for the tractor!

http://www.aseriesspares.co.uk/index.php

and, as always the wiki- for a better explanation!

http://en.wikipedia.org/wiki/Unified_Thread_Standard

I am planning on filling the gaps and replacing the metric bolts where possible!

I have also won a Ferguson plough spanner on ebay! It has a inch ruler on one side and a cm ruler on the other. It was part of the original tool box, which is detailed in the parts list. Supposedly it is a fuel gauge, and plough ruler!