Jacob":2re9lfhb said:
Metal scrubs are scarce (not counting the modern LN/LV offerings - which are oddities) probably because they didn't catch on. I guess it was because of the weight (and the price).
OTOH the light woodies are a pleasure to use and remove a lot of wood very fast. Light weight, lighter work.
I wonder whether metal scrub planes in the UK at least, didn't catch on in the late 19th/early 20th century because everybody had access to older woodies to modify into 'fore planes' if they needed one.
The weight claim slightly surprised me, since I'd never noticed the LN scrub being 'heavy' to use - rather the reverse, in fact. In comparison to most planes, wood and metal, it feels quite light. Just out of interest, I weighed it (the wierd things I do for this forum!) and it's 2lb 10oz. For comparison, I weighed a small woody smoother (7 1/2" body, 2" iron) which came in at 2lb 2oz. Both of those are well to the 'light' end of the bench-plane scale.
I can't imagine a circumstance in which one would use a scrub for an extended period, given that they shift a lot of wood very fast - if there's so much to remove, you'd either choose thinner stock to start with, or saw most of it off. I've certainly never suffered fatigue whilst scrubbing, since the job is done before fatigue sets in. Trying-up stock is another matter - that can sometimes take quite a long time with a big, heavy plane, and pacing yourself can be a necessity after a while.
If making an 'infill scrub', I might be tempted to use stock steel for the sole and sides a bit thinner than usual for an infill - say 1/8" sole and 3/32" or even 1/16" sides. That should give a body that's light but more than strong enough for duty, given that absolute flatness and straightness are not really needed in a scrub, and neither is the 'heft' of an infill smoother or panel plane.
Edit to add:
Just watched Corneel's video. He tends to use the scrub rather faster than I do; I tend to assess where the humps are and take the highest spots off, assess again - and so on. I probably use a stroke rate about half his, with a depth of cut depending on what the wood will allow for a reasonably easy stroke with maximum stock removal, and on how much needs to come off. (I don't often have boards that big to work - if I did, I'd pace myself a bit!). By the way - that is in no way a criticism of Corneel - different approaches suit different people, and judging by the heaps of chips, his technique works fine for him!