Quote Originally Posted by Wabbit View Post
Hi Wotsit,

I'm kind of following you path to a CNC machine as I bought the plans from Patrick at buildyourcnc.com

I have to date - 1 week after plans arrived - failed to make a start.

Still trying to soure basic MDF in the correct sizes to match imperial plans from Patrick in the UK.

3/4 MDF on plans 4' x 2' = B&Q not correct size to start off with ...

We seem to be 18mm MDF only thickness and 3/4" is like 19.nnn

Have I made a big mistake already ??

Guys ??
You have to adapt the plans for the different thicknesses. MDF in Europe is 6, 9, 12, 18 or 25mm, while in the US its 1/4", 3/8", 1/2", 3/4" and 1". Its not a big issue; in most cases it makes no difference, in others you have to do a bit of thinking and make an allowance for the difference by adding a mm where appropriate (so for example if you were making a box, you'd need to make two of the sides 2mm longer to get the same external dimensions if that was the critical measurement). The tolerance on MDF isn't that good anyway, its within 0.5mm so the difference between 18mm and 3/4" could be as little as 0.5mm anyway.