Terry.
Have a look at this extract from the official "Nottingham Myford" parts list for all Super 7's.. No mention of change in headstock rear bearing alteration so undoubtedly metric bearings have always been specified.
The correct bearing is , as you have been advised 7205 BEP from SKF or other reputable maker. I bought a matched pair from Lathe Parts at a very reasonable price made by SKF in Austria.
Don't fash yourself about why Myford chose a Metric size bearing as they were probably the best overall dimensions for the headstock design. Hoffman , later RHP were the premier UK bearing supplier in the 1950s together with SKF who had 2 large manufacturing plants in Luton. My wife worked as SKF Luton for several years and was able to get me a substantial staff discount on bearings.
Popular Spare Parts For Pre-Power Feed Super 7,
Power Feed Super 7 and ML7R Lathes
History:
The Super 7 lathe, was introduced in April 1953 to compliment the already, very successful ML7 lathe. Whilst virtually identical in capacity, the Super 7 incorporated a number of features within its standard specification that made it a truly outstanding machine, these were:-
A spindle, supported in a taper bronze front bearing and a pair of angular contact ball races at the rear, which for its size gives outstanding performance, this coupled to 14 spindle speeds give an excellent and progressive speed range of 27-2105r.p.m. Over 40 years later there are many machines being marketed as screwcutting lathes, which have bottom speeds of 200 r.p.m. or so. This is just too fast for screwcutting. Other features are backgear engagement by lever, a countershaft clutch unit, a larger cross slide with block type gibs, a fully swivelling topslide, resettable friction dials on both cross and topslides, a self ejecting tailstock and a leadscrew handwheel. Over the years there have been a great number of modifications made to the original design as part of our continual policy of planned improvement. The major additions and changes are as follows:-
The first quick change gearbox became available in 1955. The gearbox used soft gears and the leadscrew drive was on the right hand side of the gearbox. In 1956, hardened gears were fitted to the gearbox.
In December 1956 the gearbox design was completely revised and from box No. QC 2501 the leadscrew passed through the gearbox and the drive was taken from the left hand side.
In June 1958 from machine No. SK 8128 the expanding sleeve clutch mechanism was changed to the current cone clutch. The change involved redesigned motor and headstock belt guards.
Customers are asked to note that we regret we are no longer able to supply spares for the early gearbox and clutch units.
In May 1959, from machine No. SK 9167 the drip feed lubrication to the headstock was replaced with a wick feed system.
In August 1972 from machine No. SK 108891B the broad guide bed and saddle were introduced in preparation for the launch of power cross feed models in March 1974 from machine No. SK 115830.
In February 1975 from machine No. SK 120965 swing head oilite bushes were ground on the outside diameter.
In June 1975 from machine No. SK 122657 the bronze cross slide feed nut on power cross feed models was changed to hardened steel unit.
In December 1975 from machine No. SK 126004 the power cross slide feedscrew was modified requiring a larger counter bore in the corresponding micrometer dial.
In November 1977 from machine No. SK 136311 the power cross feed apron was redesigned incorporating an adjustable cam for the leadscrew half nuts.
In April 1977 from machine No. SK 142981 the colour of machines was changed from grey to green.
Today over 40 years after it was first launched we are continuing to improve the Super 7. Apart from those items previously stated we can supply almost every spare part for these lathes.
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