SEBO Screw C 3.9 x 25 (DIN 7981) for X Series, G Series and 300/350

Twenty-five millimetres of thread is what this screw brings to the X and G series machines and to the 300 and 350 uprights. Length is exactly its purpose: it passes through a deep section and still buries enough thread in the boss beneath to hold the assembly rigid. Part 104 supplies it singly, in the DIN 7981 form, a cross-recessed pan head on a self-tapping thread.

Deep fixings are also the ones most often cross-threaded, because the point of the screw is out of sight long before it is fully home. If a 3.9 x 25 spins without pulling down, back it out, clear the hole and start it square by hand rather than pushing harder. The extra length gives a crooked screw more opportunity to carve a second path alongside the first, and once that has happened no fastener will hold in that boss again.

• Part number: 104
• Fits: SEBO X series and G series machines, plus the 300 and 350 uprights
• Specification: C 3.9 x 25 to DIN 7981
• Head and drive: cross-recessed pan head
• Size: 3.9 mm diameter, 25 mm long, the longest in this family
• Sold: each
• Shorter 3.9 mm DIN 7981 screws: part 102 at 13 mm, part 103 at 16 mm and part 105 at 19 mm

Shorter 3.9 mm screws appear elsewhere on the same machines, so check the length you pulled out before ordering rather than after. A 25 mm screw driven into a 16 mm seat will bottom out and jack the panel back off the housing, which reads through the driver as a screw that has gone tight.

The symptom that usually leads here is a housing that has developed movement at a seam, a screw that spins without ever drawing down, or a recess rounded past the point where a driver will grip. On a deep fixing the damage is often in the boss rather than the fastener, so look into the hole before assuming a new screw will solve it.

This part answers searches for a SEBO long chassis screw, a SEBO 300 or 350 deep fixing, a DIN 7981 3.9 x 25 replacement and a genuine SEBO 104. Genuine SEBO hardware from an authorized dealer, dispatched in 2-5 business days.