Instructions for Wire EDM Machining of Somma Throwaway Quick Change Inserts 1/8" Thick for Use in RQCDS-A, RQCDS-SL, RQCDS-DV, RQCMS-0 and RQCMS-1 Shave Tool Holders with Zero Degree Top Rake

These RQC Style Shave Tool Holders are designed for a zero degree front clearance angle and zero degree top rake, therefore, inserts must be set at zero degrees in relation to the top and bottom faces when being EDM machined and step corrections calculated accordingly.

Also inserts must be a parallelogram form, therefore, back surface must also be at zero degrees parallel to formed face.

Inserts are oversize on length and width to allow for EDM wire thickness and are recessed on back end for mounting in the grinding fixture so that back edges can be machined at the same time as formed surface without removing from fixture.

Fixture is supplied with a wedge clamp for holding 8 inserts.

Inserts should be carefully mounted in fixture with appropriate clamp and tightened securely with clamp screw. Be certain that inserts are fully seated in bottom base of fixture. This is important because if face angles are not exactly zero degrees, there may be diametral difference errors in the workpiece.

Also, inserts should be in alignment with each other and clearance angle cutout in insert should be centered on fixture with equal space on both sides of fixture body.

When wire EDMing, we recommend placing the spacer in the middle position and machining all the way around the form starting on the left side in the space between the fixture and the recess in the insert and ending in the groove on the opposite side (see sample print attached). This groove prevents outer shell from breaking off and jamming wire. Shell should be broken off manually and any remainder ground away so that it does not interfere with seating of insert in holder.

For RQCDS-A, RQCDS-SL, RQCDS-DV and RQCMS-0 Holders:
In order to simplify adjustment of the insert slide when changing over from job to job, holders are designed so that a .875" long insert will cut to center of the part (.000" base diameter). Therefore, all inserts should be designed using .000" as the base diameter. This will cause the insert to be correspondingly shorter for all other diameters, or slightly longer if facing past center. See sample insert design.

For RQCMS-1 Holder:
This holder is designed so that a .875" long insert will cut .125" diameter on the part. Therefore, all inserts should be designed using .125" as the base diameter instead of .000".

Enclosed are master insert design sheets for 1-1/8" wide inserts. Additional sheets are available upon request.