Times Jumbo 1140

[stevenj]

Wow! This was a tough one. I should have paid more attention to my biology teacher, that's for sure! And not helped by SWMBO not allowing any extension to bath/ bedtime because of the change in the clocks. Still, I have just about got there but, being me, inevitably there's one clue I can't crack.
Tools not so powerful for cutting stone up (8)
I have ? w?a?e?s. The only word I can think of is sweaters but I just don't get it.
Please help. Sorry it's yesterday's problem...
steven

[Lie-in King]

28d Tweakers (tools) - 'weaker' (cutting; inside) 'st(one)' (up)

[stevenj]

Thank you Sir! As so often, my Master counsellor. I am so grateful. It would have been awkward still thinking of the answer when I am on the altar for the Palm Sunday service. Done one already!
Steven