Adjustable Spanner.

skooter Posts: 264
edited March 2019 in Workshop
I have just bought an old Triumph road bike 79/80 ish and I need to undo the top lock nut on the steering I have a 32 mm spanner and it's too small and a 32 mm spanner and its too big.
Queston. I have seen some adjustable spanners that open to 36/38 mm so plenty big enough but they are the pipe fitting type will these be strong enough the the big nut on the forks.