Special M20 x 400 Csk Bolts for a Canal-Side Project
We recently worked on an interesting job involving a batch of unusually long countersunk bolts, made to the customer’s own spec. And when we say long, we mean it!
The bolts were manufactured by our Wigan-based factory, Smith Bullough, who handled the process from raw material to finished product.
THE SPEC
These were M20 x 400mm long Csk bolts, threaded 200mm and finished with hot-dip galvanising.
Not your everyday stock item, but nothing we couldn’t handle.
THE PROCESS
It was quite the process from raw material to finished bolt. Here's how it went:
- Started with round bar – good old-fashioned steel, cut to length to get things rolling.
- Next up: forging – this is the noisy part! The bar ends were heated up and forged to form the countersunk head.
- Then it was over to machining – chamfered and threaded to spec with precision.
- Final step: galvanising – off to the galvanisers to give it a tough, corrosion-resistant finish.
And that was that!
From a bare bar to a finished fastener that’ll stand the test of time along the canals.