Project 14: Geneva Gear

This project teaches the following skills:

Work holding using double-sided tape.

Some parts can be held using double-sided tape. This eliminates the need for making a complex fixture and works quite well if cutting pressures are low and surface area is large enough to form a sufficient bond.

Aluminum and Medium Density Fiberboard (MDF) are commonly used fixture plate materials. Prepare an aluminum plate by clamping it to the table and facing it smooth and flat to form a good surface to bond to. Don't use coolant because its residue will inhibit good bonding.

To ensure a good bond with the tape, a good practice is to place a heavy weight on the part and let it set for at least 15 minutes after taping. The longer this weight is in place, the better the bond, so leave it for several hours or overnight if possible.

Figure A.42: Geneva Gear

Table A.25: Geneva Gear Setup
Geneva Gear: Machine Complete

Datum: G54 XY is at the approximate center of stock. G54 Z is top of stock material.
^Op-1 Contour	^{Tool (inch)} .25 End Mill	^{Speed (rpm)} 1800	^{Feed XY (ipm)} 18.0	^{Feed Z (ipm)} 9.0
	^{Rough XY (in)} 1.0	^{Rough Z (in)} .25	^{Finish XY (in)} 1.0	^{Finish Z (in)} .005
	^{Stock to Leave XY (in)} 0.0	^{Stock to Leave Z (in)} 0.0

Tips for Using Double-Sided Tape

Use a high quality industrial quality double-sided tape. Avoid using old tape because bonding strength decreases with shelf life.

Avoid using coolant because it will loosen the tape.

Weigh down the part with a heavy object to improve bonding.

Use light cutting forces to keep the part from moving or coming completely loose during machining.

Removing the part after machining without deforming it can be a challenge. Methods used depend on the material, but can include the use of heat or a solvent like WD-40©.