The 1926 colours were quickly replaced by the well-regarded Burgundy red and dark green by mid-1927, and applied eventually to all but the brass and small nickel-plated brackets and washers - nickel-plated parts were still available to order, however, until the mid 'thirties. The later 1920s was a period of prolific introduction of new parts. These included the small Flanged Wheels, several additional Pinions and Gear Wheels, Bevel Gears, Motor Tyres, the Channel Bearing, Fan, Ball Race, the steam-related parts, and such specialised items as the Ships' Funnels (25, no less!), Crane Grab, Digger Bucket, Pulley Blocks, Signal Arms and the Circular Saw - with the exception of just one Ships' Funnel and two of the three Pulley Blocks, all of these latter were to disappear permanently after 1941. With the introduction of the Circular Saw in 1927, the 51/2" x 21/2" Flanged Plate was provided with a saw slot and guide fence slot - these were deleted along with the Saw itself in 1934.

In 1928 the Geared Roller Bearing was introduced, at one pound much the dearest item in the Meccano parts inventory. This was finished in a new colour - battleship grey - along with the Pulley Blocks, the steam-related parts and the Digger Bucket. Single-tapped bosses became double-tapped from 1928. In 1929 the stained finish for the larger outfit cabinets gave way to enamelled two-tone green, and the second vertical steam engine was introduced. The Meccano Magazine regularly featured No. 7 Set - and larger - models, sometimes over more than one issue. These were subsequently published in leaflet form as the Meccano Supermodels. There were ultimately 37 of these, but several underwent subsequent improvement and reissue to bring the final total up to 42. The model featured in Supermodel Leaflet No. 4, the famous Giant Blocksetting Crane became the average Meccano boy's ultimate modelling aspiration. The Depression resulted in some downsizing of the No. 7 Outfit in 1930. The early 'thirties saw the introduction of a plethora of new items: the Motor Car and Aeroplane Constructor Outfits, Hornby Speedboats, the X Series Outfits, Kemex, Elektron, Dinky toys and Dinky Builder. The 1927 red and green Meccano parts finishes were replaced by lighter shades by 1933 - rather similar shades of red and green were to be reintroduced again after the war.