Skimming heads is a common job for machine shops that service auto shops. When it comes to flycutting, the CNC flycutter is the best tool for the job. Therefore, step away from the face mill and the head won't get hurt.
use a fly cutter to machine a head Mercedes head

Why Use a CNC Flycutter to Skim Heads

You refinish the deck surface of the head or block when it is isn’t smooth or flat. It's cheaper than replacing it. Welds or other repairs cause warping or unevenness. Or, you may mill a head to increase the compression ratio. Clean up the manifold surfaces on a head with a flycutter if they are corroded or eroded. Sometimes the angle isn't perfect on an aftermarket intake manifold. Stuff happens. A CNC flycutter is the tool to get it right. And there's no room for mistake with a head. Mistakes are costly. Because once metal is removed it is gone. You can't put it back.

Doing it Right

Do the first things first. Fix warps in aluminum heads before you skim them. It reduces the amount of metal you need to skim. Next, check flatness. Flatness specs depend on the application and the engine. For example, performance engines need as flat as possible for the best performance possible. Make sure you’ve got the block squared up before the first pass. Because the surface of the head must be completely parallel to the cutter. Then, once it's aligned perfectly, ensure it is rigid. You can't tolerate movement here.
Before you start, verify engine and head gasket recommended specifications. In order for the gasket to properly seal, the recommended specs must be met. It's specified in Ras. The Ra (roughness average) in microinches varies depending on the metal (aluminum or cast iron) and the type of gasket. So, check the gasket manufacturer’s recommendation first and then check your results using a profilometer. Like any other job, make sure the feeds and speed are correct and use plenty of fluid. Now, get ready to skim.

Use the Right CNC Flycutter

 CNC flycutters CNC Flycutters
Don't forget, use the right flycutter for the job. And you can get the right flycutter at The Tool Company. Each CNC flycutter is perfectly balanced for higher RPMs and long life. You pick. Buy one individually in 1 ½”, 2”, and 2 ½” diameter sizes or get a multi-size sets. Skim with stability. The ¼-20 alloy set screws add rigidity. The Tool Company only sells products made right here in the USA. Get a full 5-year warranty with every CNC flycutter purchase. If you aren’t skimming with a Tool Company flycutter, you aren’t skimming with the best. Buy now and experience the difference in the skim.