Newbie router question

[eRiCdWoNg]

I finally bought myself the Ryobi RE180PL plunge router after thinking about it forever as well as the 2 jig's from Parts Express. I am using it to primarily cut perfectly round holes for speakers etc. Taken me some time reading all the directions and just playing with it but I think it should be well worth the investment considering I love building speakers and I hate the non-perfect cuts of a jigsaw, not to mention the guessed method using string and nail.

Question: Are 1/4" bits with a 2 peak HP router supposed to be able to cut through 3/4" MDF from one side? If so, should I do it in multiple passes or just one pass? MDF to me seems a "soft" material compared to solid oak.

Or should I turn the material over and finish the cut from the other side?

First project- 6 15" woofers in my car. Then probably some sort of dipolar sub for the house.

[mitch808]

With a very high quality bit that is sharp, you could very well do it all in one pass. However, some people have the tendency to go faster then the bit can work, and burn the wood and prematurely dull the bit.

I like to make two passes on 3/4"+ MDF. I usually don't go more then 1/2" in each pass. I feel that the bit stays cooler this way.

Yesteryday I was cutting some construction grade plyboard and went through the whole thing in one pass. But that wood is pretty poor in quality and density. For my last few 3/4" + MDF enclosures, I made two passes.

[jamesj]

It's not a matter of power but waste ejection that is going to be a problem in cutting 19mm MDF in one pass. If your 1/4-inch bit is also 1/4-inch wide, then I would do it in 3 or 4 passes. You'll get a cleaner cut, save your bit from blunting too quickly, and prevent your bit breaking off completely if it got snagged.

The benefit is worth an extra few minutes.

James