Help converting 4ply pattern to 8ply pattern

Could anyone help me. I want to make a simple raglan sleeved cardigan in 8ply for a three year old.

I have been searching for weeks and there does not seem to be any.

There are patterns in 4ply but these only go up to size 24 months.

If I was to follow this pattern but use 8ply wool and size 4.5 needles. Would I be able to make the cardigan big enough for a three year old boy

Thanks

Welcome to the forum!
You can probably knit the pattern using the heavier yarn (more like a DK weight) but you’ll have to adjust the lengths of the cardi and armholes to suit a 3-year old. The only way to tell for sure would be to knit a swatch, determine your gauge and see if the measurements will work for the size you want.
It might be easier to do an advanced search on Ravelry for a cardigan in DK weight. Here’s an example of some of the free or mostly free patterns.
http://www.ravelry.com/patterns/search#photo=yes&craft=knitting&view=captioned_thumbs&query=free&weight=dk&fit=baby%2Bchild&sort=best&pc=cardigan&page=1

Hi and welcome

You are using my favorite needle size and yarn thickness but if the pattern is using 4 ply then it usually uses smaller needles.

If you followed the pattern as stated you will end up with a garment much larger than what you require. If you double the needle size and yarn your garment will be almost 4 times the size. I know this because this t rex was small but I wanted it big.

Do a large swatch with the pattern eg 40 X 40 stitches and then compare that with the tension recommendation in the pattern and try to use even tension and I apologise if you know but that is how tight you make each stitch. When you measure make sure that the swatch lies flat and is not stretched.

So absolutely no problem if your swatch tells you that it will be too big unless there is a pattern that needs a certain number of stitches but that can be solved too.

pm me if you want because working out sizing is just simple maths

Cheers