中文（繁體字）
English (international)Definition of Mill Drill Head Tilt
Head tilt is used to drill angled holes, machine chamfers and bevels, and mill inclined faces without an angle vise or tilting fixture. Its practical value lies in flexibility on one-off and small batch work. The trade-off is that, once tilted, the head must be returned to exactly 90 degrees to the table, a process known as tramming, before normal vertical work can resume. The graduated scale alone is not accurate enough for this.
Why it Matters for Band Saw and Mill Drill Machines
Accuracy also depends on how the angle is set. The scale on the head flange typically reads to one degree, which is adequate for clearance holes or deburring chamfers but not for features with angular tolerances. For precise angles, the head should be set with a protractor, sine bar or dial indicator against a reference surface.
Every use of Mill Drill Machine head tilt carries a resetting cost. Even a small error in returning the head to vertical leaves the spindle out of tram, which produces stepped faces and tapered bores. Misalignment of this kind is one of the causes of rough cutting listed in our guide to troubleshooting a mill drill. A tramming check with a dial indicator swept around the spindle should be part of the routine whenever the head has been moved.
Related Terms
Tramming, Spindle PerpendicularityMill Drill Dovetail Column
Mill Drill Column Rigidity
Quill Feed
Mill Drill Machining Accuracy
FAQ
When is Mill Drill Machine head tilt a better choice than an angle vise or tilting table?
Mill Drill Machine head tilt is the better choice when the workpiece is large, awkward to clamp at an angle, or already located on the table for other operations. Typical examples are an angled oil hole in a bracket, a chamfer along a plate edge, or an inclined face on a part too heavy for a tilting vise. Tilting the head keeps the workpiece flat and fully supported. An angle vise or tilting table is preferable for repeat work, for compound angles, or where vertical operations follow in the same setup, because the head stays in tram. As a rule, we would suggest tilting small parts in a vise and tilting the head for large ones.
How do you re-tram the spindle after using Mill Drill Machine head tilt?
Re-tramming after Mill Drill Machine head tilt starts with returning the head to zero on the scale and tightening the clamp bolts lightly. Mount a dial indicator in the spindle on an arm giving a sweep diameter of about 150 to 200mm, and bring the stylus onto a clean, flat surface such as a ground parallel resting on the table. Rotate the spindle by hand and compare the readings at the left and right positions. Tap the head in the direction that halves the difference, recheck, and repeat until the readings agree within about 0.01 to 0.02mm across the sweep. Tighten the clamp bolts progressively, then take a final reading, since tightening often moves the head slightly.
Which cutting parameters should change when Mill Drill Machine head tilt is applied?
With Mill Drill Machine head tilt applied, the structure is less able to resist cutting loads, so parameters should be more conservative than for the same operation with the head vertical. Reduce the depth of cut and radial engagement for milling, typically by a third to a half, and lower the feed rate to limit side load on the head clamp. When drilling at an angle, start with a spot drill or end mill to create a flat entry, since a twist drill will wander on an inclined surface. Lock the quill when milling, keep quill extension short, and check that the head clamp bolts are fully tightened. Chatter indicates that the setup has reached its rigidity limit.
