Think & Tinker, Ltd.
CNC router bits and carbide cutting tools with tutorials and technical guides

Depth Setting Rings

Depth setting rings are plastic collars that are securely pressed onto the shank of a drill bit, end-mill, router bit, or similar rotary cutter. Their purpose is to accurately, and repeatedly, set the distance the collet face to the tip of the cutter. The shank side of the ring (top side in the picture to the right) is accurately positioned (d ) relative to the tip of the tool. If the shank-side of the ring is pressed against the collet when the tool is loaded, the tip of the bit will be a known distance (d) from the face of the collet. Knowing this distance, the programmer can plunge the tool, confident that the depth of cut will be as expected and will remain the same no matter how many times the tool is changed.

The thickness and positioning of the rings are chosen to insure that the shank of each bit is inserted into the collet (or chuck) deep enough for proper engagement and clamping between the shank and the collet bore. This serves to insure that the collet correctly centers during tightening and minimizes the chance that the tools will "walk out" of the collet under heavy cutting loads. There is nothing worse than a solid carbide ballistic missile zipping across your shop.

Make sure that you press the ring firmly against the collet / chuck face as you tighten the nut!

If all of the tools in the programmer's magazine have been fitted with depth setting rings, an automatic tool changer can load and unload tools with the tip of each one the same distance from the face of the collet.

This is especially helpful with micro-tools where "touching-off" on some reference surface to calibrate the tool height can damage or break the tip of the tool. Rings also find widespread use in inlay pocket cutting where relatively large diameter cutters are used to "hog out" basic shapes, followed by much smaller diameter finishing bits that clean up the edges, sharpen the corners and add fine detail to the finished part.

Depth rings are available on both 1/8 in. and 1/4 in. shank tools.  There is no charge to add the rings, but the user is cautioned to make sure that their equipment is compatible with their use.

Ringset

Common Ring Settings

1/8 in. Shank

SHANK
DIAMETER
(inch)
OVERALL
LENGTH
(inch)
RING SET
(inch)(±0.004)
COLLET
ENGAGEMENT
(inch)
RING
DIA. X LONG
(inch)
NOTES
0.1250 1.50 0.800 0.70 0.30 X 0.18 drills, routers, end-mills, V-tip cut-out, counter sinks
0.1250 1.42 0.800 0.62 0.30 X 0.18 some stub end-mills
0.1250 1.42 0.800 0.62 0.30 X 0.18 V-tip engraving, tapered-stub

1/8 in. Shank (tools for PCB fabrication)

SHANK
DIAMETER
(inch)
OVERALL
LENGTH
(inch)
RING SET
(inch)
(±0.004)
COLLET
ENGAGEMENT
(inch)
RING
DIA. X LONG
(inch)
NOTES
  drills/routers/other v-tips/stubs drills/routers/other v-tips/stubs      
0.125 1.50 1.50 0.800 0.800 0.700 0.30 X 0.18 STANDARD
0.125 1.50 1.42 0.800 0.720 0.700 0.30 X 0.18 T-Tech RINGING
0.125 1.50 1.42 0.787 (20mm) 0.709 (18mm) 0.700 0.30 X 0.18 LPKF RINGING
Notes:
  • LPKF and T-Tech users must specify the make and model number of their CNC routers to insure that the rings are properly positioned!
  • Applying rings to LPKF and T-Tech specifications may delay shipping
  • Depth rings should NOT be used on end-mills and other side cutters less than 0.005" (0.127mm) dia.. Think & Tinker will not apply rings to these tools.
  • Because of the limitations of our 1/8" shank ring setting equipment, we cannot apply rings to:
    • 1/8" shank tools longer than 1.50"
    • 1/8" shank tools with flute lengths or necked cutting depths greater than 0.50"
    • 1/8" shank tools for steel rule die fabrication

1/4 in. Shank

SHANK
DIAMETER
(inch)
OVERALL
LENGTH
(inch)
RING SET
(inch)
(±0.0015)
COLLET
ENGAGEMENT
(inch)
RING
DIA. X LONG
(inch)
NOTES
0.250 2.50 1.60 0.900 0.50 X 0.25 T&T PROPOSED STANDARD
0.250 3.00 2.000 1.00 0.50 X 0.25 T&T PROPOSED STANDARD
0.250 3.50 2.500 1.00 0.50 X 0.25 T&T PROPOSED STANDARD
0.250 4.00 2.750 1.25 0.50 X 0.25 T&T PROPOSED STANDARD
0.250 4.50 3.250 1.25 0.50 X 0.25 T&T PROPOSED STANDARD

1/2 in. Shank

SHANK
DIAMETER
(inch)
OVERALL
LENGTH
(inch)
RING SET
(inch)
(±0.0015)
COLLET
ENGAGEMENT
(inch)
RING
DIA. X LONG
(inch)
NOTES
0.500 4.00 2.750 1.25 TBD T&T PROPOSED STANDARD