I am taking a paper piecing class with the hopes that one day I can make "Cinqo de Mayo" by Karen Stone. (Really ambitious I know ! ! !)

We did one block in class from a pattern the teacher gave us. She then gave us the special paper and told us to make copies at home for all the patterns we wanted to include in our sampler.

I made my copies and just finished a block, trimmed it down and held the 2 blocks together. The block made from my printer is 1/8 in bigger than the pattern from the teacher. I compared to the book. Teachers pattern is right, mine is off.

So... If I continue to use my copier for all the patterns and they are ALL slightly bigger, is that OK? Or do I need to scrap the bigger one and find a copier that makes it all exact?

When copying, you need to adjust the size down slightly by changing the enlargement/reduction control. Keep making samples until you can hold up the original and copy to some light and find that they are identical. Then make all of your copies at that reduction.

Or print them all, at the same time!

if only one block is off 1/8", i don't think you will have any problems. But yes next time use copies from the same machine....there is a difference

Also, use the same "master" copy - if you are making more copies of the same block - each time you make a copy of a copy it changes

If you have a scanner, scan the pattern in at 100% and save as a .pdf file. If you print that it should be identical. One way to check for discrepancies is to scan a ruler both longways and shortways and compare the final print to the ruler. In some paper piecing 1/8th can make a difference when it comes to matching seams in the lady liberty style patterns. Members of my guild had a class and there were many annoyed quilters who had to stretch fabric to make seams meet.

That's a great idea, then you have the pattern too

Have you tried doing freezer paper piecing instead? You can reuse the templates you print out a few times plus you don't have to worry about tearing it out when you are done :)

Yes, most definitely check both dimensions. Some older printers copy accurately across but slightly enlarge when going 'around' the drum.