I have some questions regarding router bits?
I am looking to use a roud over bit for my box, which is made using 3/4 in mdf
I notice for router bits it give you a few measurements
Radius, Large Diameter, Cutting length.
Can anyone tell me how these measuremnts will effect the results.
The rule of thumb is that the maximum radius should be less than, or equal to, the thickness of the material. You can use a larger radius if the material is reinforced but it will tend to make the corners weaker if you don't. It's really a matter or proportions and smaller radius usually looks good on smaller pieces, so a 1" radius on a 4"x6"x8" piece often just looks dated, wrong and weird. Some companies sell sets of bits and if you plan to do much more woodworking, having a good selection of bits comes in handy. If you don't want to spend a lot (or can't), go to an art supply store and buy a circle template. That way, you can draw the piece and try different radii to find what looks best.
3/8" is a good, general use radius. Subtle is usually better. Sometimes, a slight chamfer (bevel) looks "right", too.