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Malcolm Bailey
United Kingdom
301 Posts |
 Posted - 30/09/2010 : 14:08:45
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Whilst looking at Wikipedia for more info on Whitworth threads I came accross this paragraph
"Historical misuse
British Morris and MG engines from 1919 to 1955 were built in a factory that used metric threads but with bolts and nuts for Whitworth spanners (wrenches) and sockets."
Is this true or should we be correcting it?
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talbot
United Kingdom
718 Posts |
Posted - 30/09/2010 : 20:14:16
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Early morris engines were developed from ones manufactured by Hotchkiss in Europe. They did use metric threads but with Whit / BSF head sizes. From my MG TD ownership days I remember the metric threads were different from the ones in common use now.
Cheers
Jan T |
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mgptype
United Kingdom
709 Posts |
Posted - 30/09/2010 : 21:30:26
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Yes they did use metric threads. I re built a TC a few years ago and used metric fine bolts which had a thread pitch of 1.0 and not the more common 1.5.
Fred.. |
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Bruce Sutherland
United Kingdom
1564 Posts |
Posted - 30/09/2010 : 23:37:28
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I'm sure many others know, but I think the following explanation is worth passing on.
Here is an extract about the origins of the metric threads used on MG and other Nuffield Group engines from Neil Cairns book - "ENGINES for M.G's Their Story after 1935."
“……….The M.G. motor car comes into the picture in approximately 1923/24, evolved by Cecil Kimber, in the early days of the Automobile. The engines used before then were purchased from outside the main Morris Company, but as the Morris Empire grew and grew, so he began to buy up his suppliers. The company of Hotchkiss in Gosford Street, Coventry were purchased in 1923 to be renamed Morris Engines Branch. They supplied Morris with the engines for the later model of the Bull Nose (and M.G.) saloon cars. Hotchkiss et Cie had moved to the United Kingdom from France in WW1 to escape the Germans, to continue making armaments, and carried on using their original machine tools and equipment. They had never made an engine until they met William Morris, but had excellent machine shop facilities and a very experienced workforce, and were looking about for work after the war.
The machinery and tools had come over from France, and this included the thread cutting dies and taps used on their guns. These threads of an unusual French Metric size were used up until 1956 in the last 'X' series engine in the Wolseley 4/44, having been used in virtually all Morris and M.G. engines till then. These metric threads are not quite the same as those used today. The last M.G. to use such threads was the TF1500 in 1955. Such nuts and bolts have British BSW/BSF head sizes, so that the average British DIY owner or motor mechanics tool kit could still be used, but with these odd metric threads.”
Perhaps others can advise to what extent these metric fasteners were use on Triple-M cars?
During my PB's total strip I've only found BSF plus a few BSW nuts and bolts.
Bruce. (PB0564) (Bill = Bruce!! ) |
Edited by - Bruce Sutherland on 01/10/2010 12:33:24 |
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Oz34
United Kingdom
2538 Posts |
Posted - 01/10/2010 : 00:25:38
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I'm surprised no one has mentioned "Mad Metrics" in this context. Off Triple M topic, I came accross REAL mad metrics a year or so ago, needing a set of spring shackle bushes which Rover were selling in packs of FIVE, for a car set of EIGHT!!
Happy days,
Dave |
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ags
United Kingdom
275 Posts |
Posted - 01/10/2010 : 00:27:39
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Hi Bill and Malcolm,
The Wikipedia entry is partially true. Most Morris built engines (and as has been pointed out this includes XPAG and all the other T type variants) were built in the old Hotchkiss plant and did use the bastard-metric threads. This continued, I believe until ISO standardisation arrived when the equipment became obsolete.
However there are two exceptions to this rule for MG engines. The earliest are our own MMM engines, basically built in the Wolseley factory to Abingdon based designs. Much later come the Austin based engines A series, B series etc. The MMMs all used, as Bill has found, only standard British threads BSF and Whitworth (with the exception again of Lucas electrical parts which use BA threads (an early variant of metric sizes) because (I speculate) of the availability of small diameter fine pitched threads in this range of threads). The Austin designed engines used AF threads because in the early post war years when they were being developed it was a case of "Export Or Die".
However I have been only an interested and curious observer while all this was going on. The Man On The Spot at the time was of course Mike Allison - who may well say that I have been typing total rubbish!
More technical ramblings from
Andrew Smith MMM571 |
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bahnisch
Australia
674 Posts |
Posted - 03/10/2010 : 11:30:20
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| I remember, many years ago, reading about someone who was restoring a TC and found a number of different threads (perhaps as many as ten?), probably all with imperial-sized hexagons on the bolts and nuts (or, of course, slotted). I am currently restoring (but may not live long enough to finish it!) a 1910 Humber and the whole car (which is very original) is metric, dimensions of brake rods and other components, nuts and bolts and so on! Now that metric is in much wider use, sizes that were practically unobtainable years ago are now quite easy to get! |
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