PIVOTS, PINIONS & SHAFTS
(Click on the pivot images below for more details)
True Point (UK) Ltd is a leading international manufacturer of precision pivots, pinions and shafts for scientific instruments. Our pivots are being utilised in numerous precision instruments including navigational compasses, panel meters, flow meters, tachometers, fuel and pressure gauges .... to name a few.
Construction: True Point (UK) Ltd can manufacture pivots in Nickel Silver, Brass, Stainless Steel, Tungsten Carbide, Tool Steel and propriety alloys such as. All our pivots are available with or without bi-metal construction i.e. The body of the pivot being either of the previous metals listed, but may also having an Iridium or Tungsten Carbide tip.
Selection: The base metal of the pivot should be selected for the environment that it is going to operate in (Brass or Nickel Silver are the most popular). Whilst the choice of metal for the tip often comes down to cost, i.e. Tungsten Carbide is more economical to produce and is much harder than Iridium, but Iridium has the special property of self polishing its contact surface. In either case the tip of the pivot is highly polished during manufacture.
Other considerations are: Magnetic qualities, Corrosion, Hardness, Surface finish, Dimensional stability and tolerance.
True Point (UK) Ltd's pivots are generally used in conjunction with 'V' or Cup type Jewels. The radius of the pivot must be smaller than that of the jewel i.e. 1.5:1 or less. When alignment of the assembly is important this ratio should be reduced.
Notes: When used horizontally, the pivots should not bottom against the radius of the jewel. A degree of looseness is required which is called 'end shake'.
'Pivot roll' results when excessive 'end shake', in combination with the radii of the pivots and jewels and their respective angles combine to allow the pivot-tip radius to roll against the conical edge of the jewel. This causes added friction which sometimes shows up on meters as a resistance of the needle to return to zero. Correct selection of pivot and jewel combined with the correct amount of 'end shake' can reduce this friction to a point where it does not cause a problem.
To Select the type of Pivot that you require click on the image below.
These are the most common shapes, but we can make the pivots to your own design.
Please let us know what your requirements are.
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