Dumb knitting question - if I use 8mm needles instead of 4mm, would the garment be twice as big?

[COCKadoodledooo]

I knitted this sweater for ds2. Dh would like me to make one for him. I have looked and looked and I can't find an equivalent in adult size. I am not confident enough to adapt the pattern aside from simply knitting it longer, but sadly dh although skinny does not have a 22" chest! I doubt his arms would get through the sleeve holes comfortably at the size they are on ds2's jumper either..

I've found this one which is a similar rib, and I could adapt the collar to the roll-neck style fairly simply I guess, but I'm not sure on the raglan sleeves (dh has distinctly sloping shoulders and I don't think that style is particularly kind to him!).

So - if I knitted the original in super-chunky wool on 8mm needles, is there any chance it could work?!

ooh, that's lovely I wonder if you'd be better off finding a plain pattern like this one that's the same style but using the rib stitch from your ds' jumper rather than knitting plain? Although knitting in rib may mean you're better off going up a size, it'd be worth knitting a tester square to check.

No, it would not work.

As NinjaGoose says, find a plain sweater in your DS's size, it should have a multiple of six as in 5 knit, 1 purl on right side and 5 purl and one knit on the reverse side. You may need to increase or decrease it slightly... although as this is a version of rib which knits more tightly, you probably need to think about going up a size.

No, it wouldn't work, but sizing it up is not as difficult as it seems and requires no more than simple arithmetic. The pattern goes up by two inches each time, so just measure your husbands chest and say for instance it is 34". The largest size on your pattern is 26", so just add 4x more stitches to the pattern all along.
So if your 22" size says cast on 50 stitches and the 24" 56 and the 26" 62, (for instance) then for a 34" you would cast on 86 (4x6 stitches for each further size. And so on. It may seem daunting, but it is a fairly simple T-shape pattern without much shaping.
The raglan jumper is also nice and would suit most people.
Best of luck

Don't just size up because the proportions will be all wrong! I'm going to throw you some links now but it may be over several posts because the iPad keeps reloading the page and losing my post.

www.ravelry.com/patterns/library/mr-darcy

www.ravelry.com/patterns/library/brigade

www.ravelry.com/patterns/library/leo-2

www.ravelry.com/patterns/library/ski-sweater-3

Just some ideas. I used an advanced search on Ravelry, for an adult men's pullover, and then searched for ribbed - in case you want to look for more.

You will need to size up the rows as well as the stitches. The patterns are nice though.

Thanks all for your help. He's decided that he likes the look of the one that I found so I shall make that one and hope it suits him!

Invader I looked all over Ravelry but failed to come up with any of those ones, clearly have to work on my searching skills!