Trapezoidal Screws

Trapezoidal Screws


The TransDev range of rolled Trapezoidal Screws and nuts are manufactured to a very high standard, yet supplied at very competitive prices. Quality Steels C45 and Stainless 316 are used for the manufacture of the screws. Nuts can be supplied in Steel and Bronze from stock. Plastic and Stainless Steel nuts can also be supplied. Nuts are supplied in flanged, round and hexagon forms. As well as our standard range of screws and nuts, we can offer fully machined components to customer’s specifications and drawings. Right hand and left hand forms can be supplied as well as multi-start forms. The quality on rolled leadscrews accuracy starts from 0.10 mm per 300 mm length of screw with straightness tolerances starting from 0.20 mm per 300 mm length.


Steel used for Trapezoidal Screws

  • Screw type KUE
    C45 – 1.0503 Carbon Steel
    – Surface hardness after
    rolling approx. 250 HB
  • Screw type KAF
    AISI 316 (Inox A4) – 1.4401
    Stainless Steel – Surface hardness
    after rolling approx. 280 HB

Steel used in Nuts

  • Nut types MLF, MZP, MES

    EN 10277-3 11SMnPb37 –

    1.0737 Steel with Sulphur,

    Manganese and Lead

Bronze used in nuts

  • Nut Types HSN,FFR

    EN 1982 CuSn 5Zn 5Pb5-C

    – CC491K Bronze with Zinc

    and Lead 60-70 HB

  • Nut types HBD

    EN 1982 CuSn7Zn4Pb7-C – CC493K

    Bronze with Zinc and Lead 65-75 HB

C45 and AISI 316 were chosen because,

in addition to their natural qualities

as good construction materials, after

rolling they give a very good surface

hardness and finish on the thread sides.

These two features are decisive factors

for qualitative appraisal of Trapezoidal

Screws, because they give very small

friction coefficients; much lower than

those obtainable with machined screws,

where other conditions such as speed,

load and lubrication are equal. Nut life

is therefore also increased


  • H1= 0,5 P
  • h3= H4 = H1 + ac = 0.5 P + ac
  • z = 0,25 P = H1/2
  • d3= d – 2 h3
  • d2= D2 = d – 2 z = d – 0.5 P
  • D2= d + 2 ac
  • ac= bottom play
  • es= top deviation for screw
  • s= 0,26795 es
  • R1 max.= 0.5 ac
  • R2 max.= ac