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Parts 30-30c: Bevel gears

The first bevel gears were introduced in 1920, adding a much-needed and elegant alternative to the use of contrate wheels for transferring drive through right-angles.  In 1927, the range was extended, showing yet again the complete lack of engineering skill at Meccano despite their lofty claims for the system. Three new sizes of bevel gears were announced in the October 1927 issue of Meccano Magazine, along with the note that they "will enable several different speed ratios to be obtained" and describing how to mesh completely inappropriate gear combinations.

Very soon after their launch, someone pointed out to Meccano that bevel gears only mesh correctly when their cone angles meet and coincide with where the lines of their axles meet.  Part 30b, the ¾'' bevel gear, was discontinued and the parts 30a and 30c were re-cut to the correct angles and supplied as matching pairs.

 
30Bevel gear, 7/8'' 26t 1920-448N°10
30aBevel gear, ½'' 16t 1927-221N°9
30bBevel gear, ¾'' 24t 19271927n/an/an/a
30cBevel gear, 1½'' 48t 1927-221N°9
Three standard bevel gears: 26, 16, and 48 tooth
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Loading picture Bevels

The parts

The three standard bevels are shown in the picture to the right.  As explained above, bevels can only mesh when the teeth are cut correctly.  Because of this, the 45° bevel part 30 (left of the picture) only meshes with another part 30, and the 30a and 30c pair can only work together as a pair.

Chronological variations

Early 45° cut bevels appear to mesh
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John Nuttall
Loading picture Bevelsat45

The first bevel gear, part 30, existed on its own to begin with.  In 1927, the three other varieties were introduced.  As shown in this photograph, these gears were all incorrectly cut with their teeth at 45 degrees, and were advertised as being able to mesh with each other or with themselves.  They do mesh correctly with themselves.  The pair of 30a's to the left of this photo work well, but the combination to the right doesn't.  The part 30b was dropped only months afterwards.

Pointed, correct, and flat teeth versions of 30a
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Loading picture 30acutteeth The second phase of gears has the teeth correctly angled, but cut in a point like the left-hand one in this picture -- that is, they were wider at the outside of the gear than at the inside (not just wider at the bottom of the tooth than the top).  The easiest way to spot this is to look at the end of the part, particularly the small 30a.  In the earlier parts, the teeth are almost triangular at this end.  Later versions have differently cut teeth: clearly involute and they have the same profile along their entire length, as per the middle gear above.  Post-war gears have flat tops, as shown on the right-hand gear above.

Wider and narrower post-war part 30 gear teeth
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Loading picture 30cutteeth The post-war part 30 had flats on the teeth, as per the left-hand part in this photo.  Later on (anyone know a date?) the teeth became slightly thinner, as you can see from the right-hand part.

There were variations on the depth of recess in the face of part number 30.  It is difficult to date these, although it is agreed that the non-recessed versions are early.  Examples of this non-recessed version can be found both single-tapped and double-tapped, implying that it was current around 1927/28.  A slightly recessed version with heavier teeth profiles is shown in the table below, single-tapped, and it is assumed that this part was earlier (because it has not been found in a double-tapped variant).  These classifications are very tenuous, but have been divided into non-recessed, recessed, and heavily recessed.  "Heavily recessed" is where the depth of recess below the bottom of the teeth is greater than the height of the tooth.

Difference in tooth widths on part 30c
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Loading picture 30cfacedifference John Nuttall has pointed out differences in the tooth width of pre-war part 30c's, as shown by the two examples in this photograph.  It is not yet known whether these are two distinct types of gear or whether there are just slight differences in each batch, nor what dates these gears are from.

The Meccano builder needs to be aware of the variations in the teeth, as pairs of bevel gears do not mate satisfactorily unless they have the same tooth type.  I try to make sure I use exactly matching pairs, although some combinations do work.

Variations and oddities

None known
Examples of spare parts boxes for bevel gears
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Loading picture 30spareparts

Dealer spare parts boxes

The pair of 45° bevels part 30 to the left are early post-war, probably 1950-53.  They are shown with a picture of the pre-war parts without flats on the teeth.  Misleading pictures like these are quite common on spare parts boxes. The 30a and 30c bevel gear pair were sold as a set in a single box, as shown by the later 1960's box to the right.

Two types of box label for the parts 30a and c
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Loading picture Bigbevelspareparts
Later plastic bagged bevel gears part 30
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Loading picture Bevelsparepartspack Above we can see two different box labels for the bevel gear pair 30a and 30c.  To the right, a later (probably 70's) plastic bag containing bevel gears part 30. 

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).

More about bosses More about stampings More about paint colours
Descriptionfrom30
30a
30b
30c
Centre slightly recessed, heavy pointed teeth20.br2   
Incorrectly cut 45° teeth, single-tapped, no holes27 .br2.br.br2
Centre not recessed, pointed teeth, single-tapped27.br3.br3  
Centre not recessed, correct teeth, double-tapped27.br4.br4 .br4
Centre recessed, double-tapped??.br4a   
Deeply recessed (> tooth size), double-tapped??.br4b   
Flats on teeth, double-tapped post-war stamping47.br.br .br
Flats on teeth, teeth slightly narrower??.br1   
Sintered brass, double-tapped71 .br1 .br1
ALLALLALLALL

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!

Further information

Richard Payn      (at 10:07am, Mon 24th Jun, 13)

Yes - part 30 produced during the 1970s weren't stamped.

Andrew      (at 4:10am, Mon 24th Jun, 13)

Hi does anyone know if there were ever any unstamped bevels part 30 that came out of Binns Road? Thanks

Peter Bentley      (at 5:03am, Tue 19th Feb, 13)

Hi, I have some part 30 double tapped with a recess. My dad started collecting in the late 20s. I can only presume that these would be from the very early 1930s

Alan Esplen      (at 12:56pm, Sat 14th Apr, 12)

Charles, I have several sintered brass p/n 30 that came with a 1973 ten set. I note you do not show this as an option, would you like a picture?

Regards Alan

Stephen Jeavons      (at 11:08am, Thu 15th Mar, 12)

All the part 30 bevels in my 70's BYZ no.10 set had their axle holes drilled skew and are unusable as they wobble when you tighten the grub. Poor QC at Binns Road.

Robert Kay      (at 12:49am, Sun 29th Jul, 07)

Hello. Do you still need a picture of 30b? I have one on a model but can extract it if the picture would be of use.
Yours,
Robert Kay

Reply: Yes, very much so. Anything that there isn't a picture of would be most appreciated. As big as you can, please. Cheers...


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