Manufacturing Specifications

Material and Heat Treat:

All tapered products are manufactured from 8620 alloy steel. 8620 steel is the ANSI standard for retention knobs because of its good core strength and its long wear life. Tapered shanks are case hardened to RC 56-60 or RC52-56 and have a core of RC 35-40. The case hardness is designed to give maximum wear life without compromising the RC 60-62 spindle. Retention knobs are case hardened to RC 56-60 with a core of RC 35-40. HSK products are manufactured from a through hardened material to eliminate stress and fractures on the surface. These fractures are often present in case hardened materials because of continual compression of the HSK taper. Shrink Fit Toolholders are manufactured from H13 or equivalent material. This ensures long continuous service, heating cycle after heating cycle.

Feature End:

All feature ends (end mill seat, collet seat, shell mill pilot, etc.) are ground to <.0002” TIR. Diameters are held to a nominal +.0002”/- .0001” on the inner diameters and +.0000/-.0002” on all OD features. All features are ground in a taper pot chuck to insure close runout specifications between taper and the feature. All end mill holder ID’s are air gauged and all diameters under 3/8” are diamond honed to avoid barreling at the cross hole.

Boring Tools:

All boring tool tapers and shanks are manufactured to the same exacting tolerances as above. The PC modular connection is ground to an ID tolerance of +.0000/-.0002. for sizes PC2 – PC4 and +.0003”/ .0000” on PC5 – PC7 with a maximum of .0002” TIR. The face of the connection is ground to .0001” TIR with between .0001” to .0003” concave surface to insure maximum contact at the largest diameter. This yields maximum rigidity in the connection. All components with the male PC connection have the feature end ground in a PC pot chuck to eliminate any stack up of connection shift. All finish boring heads are inspected for adjustment accuracy, range, and for brake movement. Any error of more than .0001” is rejected.

Manufacturing Specifications

Tapers:

Parlec tapered toolholder shanks are manufactured in accordance with ASME B5.50 – 1994 (Per ISO-1947).

• Angle deviations are allowed only in the direction that increases the rate of taper.
• The attached histograms illustrate the results of measurements taken on Parlec manufactured tapered toolholder shanks. These represent typical manufacturing process output results.
• The horizontal axis of each histogram represents cone angle deviations from 3.500” nominal.
• Cone angle tolerance grades, as defined by ISO 1947-1973 (E), have been drawn on the histograms to illustrate the relative location of the tolerance limits for each grade level. The placement of the grade level lines represents the allowable cone angle deviation from the specified 3.500” taper per foot nominal.
• Additionally, the placement of the grade level lines represent the allowable angle tolerance deviation at Parlec’s taper gage contact lengths.
• Based upon the observed manufacturing process variation and the location of the process averages, as illustrated in the histograms, the following process performance can be summarized:

Process Performance