I definitely think having a separate set of metric tools is a must.

Google has a function that if you type in the search field "millimeters per inch" or any such phrase of conversion, it will give you an answer. It is a pretty cool tool. It works with all kinds of things, like teaspoons in a tablespoon or teaspoons in a gallon or ounces in a ton. Have fun!

__________________
85 300D 75K Anthracite Grey 0-60 in 13 seconds **For Sale**
84 300D 333K Black (The Velveteen Rabbit) 0-60 in 14 seconds
00 Toyota Sienna 208K (Sold)
15 Subaru Outback 43K
11 Subaru Outback 67K
98 Ford Taurus 100K (Gertie - Was Grandma's - drove it to church and shopping - really) Daughter's car now.
30 Model A Ford 2 Door Sedan (Sold) 0-60 in . . . Never reached 60