Printed from www.nzmeccano.com
Part 20b: Flanged wheel, ¾''
|20b||Flanged wheel, ¾''||1927||-||10||10||4||N°7|
In this picture, the large flanged variety is shown to the left, and the more common one to the right. There is plenty of variation in the flange size, and you should make sure you have a 'matching set' of wheels if possible.
The small flanged wheel came in at almost exactly the same time as bosses became double-tapped. It is thought that all of them are double-tapped, although we can only expect to prove the opposite.
Double tapping is presumed to have started in early 1928. The GBSC requires double tapped collars in the Fidler's gear. The leaflet refers to them as "recent" and points out that people who don't have them can use spiders from universal couplings instead. 20b was introduced in late 1927. The MM anouncement of Dec 1927 shows no visible tapping in the boss, which suggests it is single. However the Boiler announcement in Jan 1928 MM shows a double tapped one used with a sleeve piece as an oscillating cylinder.
These MM pictures, however, are notoriously unreliable. The same picture shows the sleeve piece with a single hole on all three sides, instead of having two holes opposite the slit.
I do not have, and have never seen, single tapped ¾'' Flanged Wheels. They may have been single for a month or two before going double, I don't know. We need someone to say, "I've got some," and send a picture.John Nuttall
Although there may possibly be pre-production or sample parts with single-tapped bosses, I would expect them to be exactly that. The author has an almost mint outfit 4 from December 1927, right on the cusp of the change to double-tapped bosses. Most of the common parts are stamped "Meccano" and double tapped. The gears are stamped "Fabrique en Angleterre" and single tapped, as was the case from 1921 to 1927. It seems that in this outfit there was still a stock of certain parts being used up in the older single-tapped style. The outfit has no small flanged wheels, which were introduced to the outfit 4 in the following year. It seems very unlikely that it would be introduced single-tapped.
Variations and odditiesNone known
Dealer spare parts boxes
Individual part numbersPart numbers for the parts on this page are as follows: Unique part numbers
For identification, each variation has been given a suffix to the main Meccano part number. These suffixes consist of a two-character code for the colour, and if there are many variations, a further number and sometimes letter code to identify each variation. See the bottom of the 'Parts' page for further details.
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The button above turns on and off the display of DMS numbers (where they are known). The DMS (Development of the Meccano System, Hauton and Hindemarsh) published in 1972 and added to in 75 and 82, suggested part numbers for every variation of every Meccano part. These numbers aren't perfect, but they are recognised and also referenced in the EMP (Encyclopedia of Meccano Parts, Don Blakeborough).
|Brass, deep rim for GRB. 31/32'' overall diameter||27||.br1|
|Brass, standard rim for outfits, 3/4'' overall diameter||27||.br2|
|Steel face, enamelled blue||34||.nb|
|As above but red||37||.re|
|Nickel-plated, pre-war stamping||??||.ni|
|Plain brass casting, post-war||46||.br|
|One-part alloy casting, painted black (Korean) ||51||.bk|
|One-part alloy casting, matt brass plated, boss attached||73||.bm|
|One-part alloy casting, matt brass plated including boss||73||.bm1|
|One-part alloy casting, zinc||78||.zn|
|One-part alloy casting, iridescent||79||.ir|
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Peter Sullivan (at 4:31pm, Mon 16th Apr, 18)
I'm just sorting through a large lot of French Meccano I've recently acquired of wildly differing vintages. Amongst the parts are some 20b flanged wheels with an aluminium, or aluminium alloy boss - maybe a wartime economy measure? I'll send you a photograph of one.
kbisset (at 9:07pm, Mon 5th Aug, 13)
As discussed in the Rust Bucket (collectors), a single tapped version (tapped UN #7-32!) was made in the US. A comparison picture is in my gallery...