Plain Milling With Your Mill Drill Machine

A beginners guide to milling flat surfaces with your mill drill

What is plain milling?

Plain milling is when you mill flat surfaces with your mill drill machine. To do this, the axis of the cutter drive shaft is set up parallel to the surface you are cutting. This is usually done with the workpiece being clamped to the milling machine table so that the surface to be cut is parallel to the table surface.

Did you know? Plain milling has two other names:
  1. Surface milling
  2. Slab milling

These all refer to the same style of milling a flat surface parallel to the cutting axis

The milling cutter is mounted on a standard horizontal arbor which enables the cutter to be held firmly above the workpiece in a position where movement of the work table enables the operator to mill the surface easily. The cutter is mounted as close as space allows to the spindle to improve rigidity and control cutter deflection.

How do you secure the workpiece for plain milling?

The workpiece may be clamped directly to the work table or clamped in a vise when you are plain milling. As always, you should check alignment of the worktable before you start! If you will need to cut the surface at an angle to the plane of the base of the workpiece then you will have to mount the workpiece in a universal vice or clamp it to an adjustable angle plate.

The basic principle when cutting parallel to the base or at an angle to the base of the workpiece is that the surface being cut must be parallel to the table of the milling machine, this is why a universal vice or angled base plate will be required to make the cutting surface parallel to the axis of the cutter if you need to cut at an angle to the base plane.

What cutter should be used for plain milling?

It is very important to select the right cutting tool  for the job. Most flat surfaces are milled with a plain milling cutter mounted on the arbor. Narrow cutters are better suited for making deep cuts than wider cutters, but the choice of milling cutter should be made to suit the dimensions and material of the workpiece.

If you are milling a large surface then a wider cutter will reduce how much the tool will need to be repositioned to mill the entire surface. If you need to produce an excellent finish then a finer tooth cutter will be needed. Rough cutting a large volume of metal will be much quicker if you use a coarse toothed cutter.

What is the standard setup and process for plain milling?

In the standard set up for plain milling, the milling cutter is fitted on the arbor as close as possible to the milling machine spindle. The exact position depends on the clearance between the workpiece in the vise and the milling machine column. The cutter will be supported more rigidly the closer it is to the spindle, and this reduces torque and possible deflection of the cutter.

You should always index your mill drill machine before starting milling and drilling. Remember to check the surface for accuracy after each completed cut to ensure that nothing is moving out of alignment and your milling meets the tolerances you have specified for the job. Cutting fluid is essential for clearing chips if you are doing high quality finishing work.

Milling and feed speed need to be carefully set. For roughing you should use a slow cutting speed but fast table feed speed, the opposite of finishing work, which requires a comparatively fast cutting speed and slow table speed with the same workpiece material and cutter type.

Rong Fu Mill Drill Machines For Precision Plain Milling

A mill drill with a tilting head, like the RF-45 pictured above, is the obvious choice to give you the option of precision plain milling as well as face cutting and drilling tasks. The RF-45 is just one of the Rong Fu mill drill machines in our extended range suitable for any task you can imagine.

Contact us to discuss how our mill drill machines are suitable for all types of milling. Rong Fu mill drill machines are constructed to our excellent quality control standards and packed with features to optimize your work.

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