Lathe Static Tool Holders - CNC tooling

The cutting process in a lathe is carried out by rotating the workpiece in the spindle and feeding the lathe carriage, in which the cutting tool is securely fixed. In most modern lathes, all types of tools like cutters, drills, and taps are mounted through tool holders, which in turn are mounted in the turret. You can read about the types of turrets in our article on this article.

Tool holders for CNC lathe have undeniable advantages:

• Global standardization and versatility. The same tool holder can be used on any other CNC machine with the same type of turret.
• The ability to set up and preset outside the machine = saving auxiliary time = saving your money.
• Lathe tool holder is relatively inexpensive (compared to the cost of the lathe turret), and in the event of tool and holder collisions with the workpiece, it is often only these elements that get damaged, rather than the expensive components of the CNC machine.
• And most importantly. The ability to configure the lathe turret for each specific job. The engineers are limited by previous setup or pre-engineered positions in the lathe turret, but only by number of positions/posts in the revolver of the CNC machine.  For example, for part X today, you need a long boring bar mounted in position No. 1, and tomorrow, due to the geometric constraints of part Y, you can place a parting tool or any other turning cutting tool in the same position. 

Types of tools holders

CNC tool holder is classified by the type of machining and/or the type of tool to be mounted in the fixture and size. The main types include:

• Radial turning holder (OD)

The most common type of holders for mounting tools with a square shank for machining the outer diameter of the workpiece. The tool in such holders is positioned perpendicular to the axis of rotation of the part (radially). The holder design always includes a slot for the tool and a clamping plate for fixation.

• Axial turning holder (OD/FACE)

Structurally identical to radial tool holders, except that the tool is positioned parallel to the axis of the spindle rotation (axially). Mainly used for holding tools for face grooving. They can also be used for external and internal turning.

• Boring bar holders (ID)

Used for mounting round shank boring bars for inside diameter (ID) machining. The bar is positioned against the face of the workpiece. Usually they have three clamping screws because the tool often needs to be clamped along a longer length. Typically, two nozzles for coolant supply are located externally.

• Indexable drill bodies holders

Used for mounting indexable drill bodies incl. U drills with interchangeable inserts or heads. They usually have two screws in a row and an additional positioning screw another side. Designed for shanks with a large flat and internal coolant supply through the drill. This one can universal and also hold boring bars.

• Cut off blade holders

Used for mounting flat parting blades. They replicate the design of radial tool holders, except for the square cross-section. The slot and clamping plate form a "dovetail" type mount.

• Morse taper holders

Used for mounting tools, mainly drills with a Morse taper shank. The hole in the holder matches the Morse taper standard. There are Morse taper holders with side windows for access to the clamping screws of the adapter.

• Holders with collet chuck

Used in lathes for mounting small diameter drills and taps. Collet chucks typically range from ER16 to ER32 standards. The precision of tool clamping and positioning highly depends on the runout of the collets used.

• Holders with drill chuck

Used for mounting drills in a classic jaw chuck. When the tail part rotates, the screw moves axially, giving the chuck jaws radial-axial movement. The jaws slide within the body and along the collar, securing or releasing the tool from the clamping force.

• Holders with quick change tapping chuck

Used for mounting taps and provide compression and tension compensation. A reliable mechanism compensates for possible misalignment between spindle rotation speed and feed movement (especially important during reverse).

• Special Fixtures and accessories 

This category includes bar pullers, stop blocks, plugs, and blank blocks for custom manufacturing.

We mentioned in the first paragraph that it is essential to know the type of turret your lathe has.

Next, there are two ways to select tooling: purchasing a universal set of holders if you work in a general job shop or selecting tooling for a specific technology, i.e., a part or group of parts.

• Universal approach

If you are unsure what orders you will receive tomorrow, simply choose the most common holders from lates catalogue. For example, if your CNC lathe has 10 positions for BMT65 holders, we recommend starting with the following:

1. 4 pcs radial turning holders (OD) – the primary function of a lathe is OD turning, threading, and external grooving, so this type of holder will certainly be used.
2. 2 pcs axial turning holders (OD/FACE) – for additional universality in OD turning and must have for face grooving 
3. 4 pcs universal holders for boring bars (ID) and indexable drills – you can't perform lathe machining without internal diameter turning, drilling, and other ID operations. Additionally, you can insert a wide range of accessories (collet chucks, bar pullers, tap holders, etc.) into the cylindrical holes of these holders.

• Selecting holders for specific technology/part

This method simplifies the selection of tooling to some extent. After receiving the process map from the technologist, you only need to ensure that each cutting tool has the corresponding holder. An important aspect of this selection is the correct placement of tools in the lathe turret. For example, a long boring bar might interfere with OD turning, so these types of holders are better positioned in opposite locations in the turret, and so on.

Keep monitoring suppliers newsletters to get latest holders and please always remember, if this is not your first CNC machine, first check your existing stock of tool holders. It is quite common for shops to purchase new tool holders that they already have. This will save you money and make your operations more sustainable.