ASME B5.50-2009 pdf free download.7/24 Taper Tool to Spindle Connection for Automatic Tool change.
This Nonmandatory Appendix is intended to provide informative content pertaining to the use of the 7/24 taper spindle-to-toolholder connection. These are general recommendations which if followed should maximize performance and minimize maintenance difficulties. Nominal operational values for 7/24 taper toolholder shanks are shown in Table A-i. All of this content is derived from decades of practical experience with the subject toolholder interface in aerospace, automotive, and general machine shop practice Items to consider when specifying either the toolholder or spindle side of the interface are
(a) age, condition, and service requirements of the machine tool
(b) the ability to either maintain toolholder interface integrity or repair and replace worn-out equipment
(C) updated training for machinists and programmers
(d) the knowledge of your machine tool supplier on the subjects of machining dynamics, allowable machining forces, and maintenance of drawbar mechanisms
(e) the degree to which a given spindle taper can be reground without exceeding the depth of the hardened case
The cone tolerance system as historically described by ISO 1947 is presented to the extent that it pertains to this Standard (see Nonmandatory Appendix B).
7/24 taper tool to spindle connections require sufficient force pulling on the retention knob to achieve the following operational characteristics. These characteristics are directly affected by the amount of pulling force and, because of this, performance characteristics of the toolholder-to-spmdle connection will change if drawbar force changes. At tool change, the drawbar pull force elastically deforms the mating tapers until enough surface area contact is made to distribute point contact forces and seat the taper. The performance characteristics affected by drawbar pull force are
(a) positional accuracy and stability of the machine
(b) resistance to torque-induced slippage at the toolholder—spindle interface
(C) resistance to pulling out (unseating the taper) during heavy cuts
(d) vibration characteristics of the machining system (e) resistance to damage between mating tapers
NOTE: A poor taper fit will degrade any or all of the above pei-ormaiice characteristics reganlless of drawbar pull fone.
Balance should not be pursued to unnecessarily high quality levels. For additional information, see ISO 1940-1 and ISO 1940-2.
A-4.1 Care of the Tool-to-Spindle Connection
In order to guarantee the minimum runout error and a long spindle and tcolholder life, special care must be taken to keep this area clean. The person loading and unloading tools from the machine should visually inspect each toolholder for wear and signs of corrosion.
Below is a description of each item involved in the process.
A-4.IJ Spindle. The spindle nose must be kept clean and tree from deposits of any kind. Depending on the application, the user must establish regular cleaning intervals. Occasionally, a special taper cleaner (commercially available from tool manufacturers) should be used to clean the seating surfaccs A high-resolution indicator can be used to measure the taper runout. If the runout is excessive, the spindle may need repair. A runout test arbor can be used to check the runout at a certain distance from the spindle nose.
A-4.1.2 Toolholder Care. Toolholders must be replaced when the taper starts to wear or when excessive corrosion is noted. Minor blemishes can be repaired with a stone or crocus cloth. ckcasionally, the runout of the cutting tcol seat should be checked with an indicator on the machine. Toolholders that will not be used for some time should be treated with a rust preventative.