Trapezoidal Screws and Nuts

Trapezoidal Screws and Nuts

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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