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Part 19b: 3'' pulley

19b	3'' pulley with boss	1918	-	4	4	6	N°4

The parts

The very first of these pulleys had four separate spokes, rather like an enlarged version of the 2" pulley.  You can see an example at the top left of this photograph.

For a while the part was one of the few with a larger ½'' boss (as kept on the 3'' sprocket and 6'' pulley), but that was replaced with a standard 3/8'' boss in 1928.  As you can see from this photo though, the part has been through many colour combinations, including several reds and a couple of blues.

Chronological variations

Pulley width

Other than colour variations there is one major difference over the years: the width.  There appear to be five different widths for the 3'' pulley over the years:

• Medium-wide.  From the very first (spoked) pulley right through to 1928, the pulleys were all a medium width, around 9/32'' or 7mm (centre of picture).
• Medium. For a short time around the late 20's they narrowed slightly to 1/4'', just over 6mm.
• Wide. After 1928, they got significantly and noticeably wider (as per the one one the left of this picture), 5/16'' or 8mm, until the war.
• Medium-narrow.  Almost all post-war pulleys are much narrower, 7/32'' or about 5½mm (right of picture).
• Narrow.  Some 70's pulleys are found even narrower, 3/16'' or about 4½mm.  More information pending on these.

Boss size

Most 3'' pulleys have the standard brass 3/8'' boss.  Some early nickel-plated pulleys were plated after adding the boss, so the boss is nickel-plated too.  The earliest brass bosses are longer than the later (post-1930) ones. During the early 20's, however, they had a larger ½'' boss, also brass but occasionally overplated with nickel.  During the start of the war, pulleys were also made for a short while with a 3/8'' boss made of Mazac (an alloy of zinc and aluminium).  This dates from 1940/41 or perhaps even later.

Symmetry

It will be seen that early pulleys were made from two different stampings, one has four rivets which pass through four holes on the other side of the pulley and hold the pair together.  Stampings on these pulleys are often on only one side, and then the boss is added.  From around 1928 or perhaps later, the pulleys are made from two identical stampings, each with two rivets passing through the other side.  The markings on these pulleys are generally identical on both sides of the pulley.  There are some difficulties here – the example of the 19b.re shown below is believed to be mid-30's by its width and colour, and yet is asymmetrical and so doesn't fit with the other examples.

Overall size

Earlier pulleys are in fact slightly less than 3'' overall diameter.  They tend to be approximately 2 31/32'' (about 75mm).  Later pulleys, from the 30's onwards are 3'' overall, just over 76mm.  It may be that this variation coincides with the symmetry change above.

Variations and oddities

In the "don't try this at home" department, Clive Weston has noticed that early red pulleys are found with both round central holes and slightly rounded square holes. This variation is presumably part of the developments in securing the boss of the larger circular parts, and the asymmetrical stampings would also tend to date these parts to the late 1920s. See the discussions on the central hole in the hub disc (part 118) and the boss changes to the sprocket wheels (part 95) for more related information.

Dealer spare parts boxes

Individual part numbers

Part 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.

You don't need to worry what the codes are, just click on any one for a photograph.

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).

Description	from	19b	Boss	Width
Black steel, four spokes, eight holes, 9/32'' wide	18	.bk1	standard	9/32'' (7mm)
Slots instead of spokes, black	??	.bk2	standard	9/32'' (7mm)
Nickel plated	20	.ni	standard	9/32'' (7mm)
½'' boss, nickel plated all over	22	.ni1	½'' nickel	9/32'' (7mm)
Nickel plated, ½'' boss in brass	??	.ni2	½'' brass	9/32'' (7mm)
Dark red with ½'' boss	26	.dr1	½'' brass	9/32'' (7mm)
Dark red, standard boss, narrow groove, ¼'' wide	28	.dr2	standard	1/4'' (6mm)
As above with dark green rims	??	.rg1	standard	1/4'' (6mm)
Dark red, widest groove, 5/16'' wide	??	.dr	standard	5/16'' (8mm)
As above with dark green rims	33	.rg	standard	5/16'' (8mm)
Navy blue	34	.nb	standard	5/16'' (8mm)
Red	37	.re	standard	5/16'' (8mm)
Red with black rims, otherwise as above	38/39	.re1	standard	5/16'' (8mm)
Red with mazac boss (early wartime)	41/2?	.re2	mazac	5/16'' (8mm)
Bright red, as above, post-war stamped	45-47	.re3	standard	5/16'' (8mm)
Black, widest groove	??	.bk3	standard	5/16'' (8mm)
Black, post-war, narrowest groove, 7/32'' wide	46	.bk	standard	7/32'' (5mm)
Blue	58	.bl	standard	7/32'' (5mm)
Yellow (crane kit only) †	76-80	.ye	standard	7/32'' (5mm)
Dark yellow	78	.dy	standard	7/32'' (5mm)
Dark blue (very unusual) #sup1;	79	.db	standard	7/32'' (5mm)
		ALL

Notes:

¹  This very rare dark blue 19b is overpainted from dark yellow, including the boss, and found by Rob Mitchell.  It appears to be genuine, and John Ozyer-Key agrees. Does anyone else have one of these we could confirm for sure?

Please send us pictures of missing parts! Hints and tips for pictures
Take a picture of the part in very good light, preferably on a plain yellow background, without a flash but with a tripod.
Ideally, trim the picture to about 150 pixels per inch of the Meccano part (unless the part is particularly big or small), save it as a reasonably good quality jpg file with a filename of exactly the part number, for example 19b.ni1.jpg, and email it to us by clicking on 'Contact us' at the top of the page. Thanks!

• A greyed-out box shows that no part exists for that colour combination.
• Part number codes with a green background have an attached picture of the part, just click once on the code to show a photograph of that part in a separate window.
• Parts marked "†" were temporary or economy parts, or existed only within specific themed outfits. The previous part continued throughout or afterwards.

Further information

Total number of messages on this page: 10.  This is page 2 of 2.   

derek willetts      (at 1:44pm, Sat 30th Jan, 10)

I have found two part 19b pulleys in green with a small single tapped boss, the boss is 1/4" diameter and the thread is not 5/32 whitworth. I initially thought these were not meccano due to the colour and boss but they are clearly stamped' meccano'. Have you come accross these before ? Derek derekwilletts@tiscali.co.uk

Kendrick Bisset      (at 5:49pm, Tue 3rd Nov, 09)

I suggest that 19b was introduced in 1917. It was announced in the March-April issue of The Meccano Engineer, the US Meccano Magazine. I doubt that it was introduced in the US before it was in England - but I could be wrong! Note also that the four-spoke version was used in the US until 1927, so appears in nickel and red. See http://www.usmeccano.com/parts/parts.htm

Brian      (at 11:03am, Fri 31st Jul, 09)

How about the black crackle version - 1998?

D Buckley      (at 11:46pm, Fri 4th Apr, 08)

I have in my possession 2 navy blue with Mazac bosses Reply: ...and is there any chance you could send us a picture of these?

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