Rotary Toolholders & End Mill Performance
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Controlling TIR is CRITICAL to maximizing metal removal rates with our end mills. Here's our order of preference for using various types of Rotary Toolholders when using our end mills.
Destiny Tool end mills are designed for high speed machining. We perform best under optimal conditions where centerline deviation (TIR) is controlled very tightly. We prefer to run in conditions that enable to you make more chips faster wit better quality parts than your competitors. Below please find an overview of the best ways to hold our tools in your machining center. |
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Here is our list of choices for Toolholder Types. The TIR values in parenthesis below are based upon shank diameter tolerances for our Viper End Mills (-0.0001" to -0.0003")
- Shrink Fit - (-0.0001" to -0.0003") The most accurate for TIR as the toolholder engages completely around the shank of our tools
- Hydraulic Holders (-0.0002 to 0.0004") Generally most Hydraulic Holders hold a TIR value of 0.003mm (0.0001181").
- Milling Chuck - (-0.0001" to - 0.0006") Generally a milling chuck holds a Bore tolerance of -0.000" to +0.0003". Many of the hydraulic holders in use prohibit the use of Weldon Flat tools. Adding a Weldon Flat to our tools voids the warranty.
- SK/SX Collet Chuck - It becomes a bit more tricky to set up as you need to know both the TIR of the Toolholder and the TIR of the collet as an assembly. This style collet is becoming more popular with our tools. It has twice the gripping power and a lower required tightening torque, due to it's 8° included angle, longer shank engagement. Most manufacturer's guarantee 0.0002" (5μ) @ 4 x D run-out for standard collet. If you are going to use SK/SX collets, we recommend using the ‘A’ type collet with 0.0001" (3μm @4X D) TIR.
- ER/RD Collet Chuck - The ER style has a 16° included angle just like your steep taper holders such as CAT 40 or BT40. It becomes a bit more tricky to set up, as with the SK style as you need to know both the TIR of the Toolholder and the TIR of the collet as an assembly. TIR for tool holders ranges from 0.0001" to 0.0002" and ER collets range in TIR tolerance from 0.0002" to 0.0004" and, even in the best case, that depends on if you are using the proper torque spec on the collet. The best way to determine TIR with a collet holder is with the tool loaded in the spindle. (If you are going to use ER collets we recommend "on-size' collets up to ~1.000" diameter)
- TG/PG/RDG Collet Chuck - RDG/TG Collets are within .0005 T.I.R.. The collet chucks are within .0002 T.I.R. from the cone to the collet seat bore. The nuts are designed to float to allow for centering of the collet. TG systems when properly cleaned and assembled can achieve approximately .001 T.I.R. on a cutting tool shank in the assembly at a checking point length of about 2-3 times the diameter of the cutting tool. The collapse range of the TG Collets are 1/64”. As with all Collets it is recommended that the collet be used at the nominal or largest diameter. (We generally prefer NOT to use TG style collets under 5/8" diameter. Above 1" diameter we do recommend them as the shank engagement within the TG style is longer than an ER style.
- End Mill Holder (DO NOT USE) - Please see below.
- RDA/DA (DO NOT USE) Collets are manufactured to within .0005 T.I.R. outer diameter to inner diameter. The length of parrallelism between the two female contacting angles in the chuck controls the accuracy of the system and is held to within plus or minus .0002. The clamping nut floats slightly to allow the chuck to center the collet. Normal accuracy is approximately .001 T.I.R at the face of the collet chuck. DA collets will not work with Destiny Tool end mills. Ever.
Why we do NOT recommend End Mill Holders
We do NOT recommend that any Destiny Tool be used in an End Mill holder. Tool performance WILL be severely reduced because of the resultant TIR. There are two primary reasons: Lack of a standard on a weldon flat and variations on the bore tolerance that WILL create a uneven and unbalanced cutting.
Weldon Flats
In 1918, Carl A. Bergstrom opened the Weldon Tool Co. in Cleveland. He invented the "Weldon Flat". The Weldon Flat standard has not been changed since. The specifications for a Weldon Flat are based upon National Aerospace Standards, NAS 986 (Type 46, Type 86) a high speed steel standard and measured from the shank end.
Currently there is not a standard for Carbide Tooling and each manufacturer's weldon flat may vary in dimension, position and tolerance. That means that your run out may vary between not only different manufacturer's standards but also variations between their Weldon Flat depth.
In 1918, Carl A. Bergstrom opened the Weldon Tool Co. in Cleveland. He invented the "Weldon Flat". The Weldon Flat standard has not been changed since. The specifications for a Weldon Flat are based upon National Aerospace Standards, NAS 986 (Type 46, Type 86) a high speed steel standard and measured from the shank end.
Currently there is not a standard for Carbide Tooling and each manufacturer's weldon flat may vary in dimension, position and tolerance. That means that your run out may vary between not only different manufacturer's standards but also variations between their Weldon Flat depth.
Bore Tolerance
Different Rotary Tool manufacturer's hold different bore tolerances on their end mill holders. Loose running fit for wide commercial tolerances or allowances.
The ISO System of Limits and Fits is a coordinated system of hole and shaft tolerances for engineering and manufacturing used for cutting tools, material stock, gages, etc. If held to these tolerances, cutting tools, material stock, and gages are generally available throughout the world.
The hole basis fits have four preferred hole tolerances (H11, H9, H8, and H7); the shaft basis fits have four preferred shaft tolerances (h11, h9, h7, and h6) as shown in Table below. NOTE: Shaft tolerances are now covered in the new ANSI B32.100- 2005 standard.
Different Rotary Tool manufacturer's hold different bore tolerances on their end mill holders. Loose running fit for wide commercial tolerances or allowances.
The ISO System of Limits and Fits is a coordinated system of hole and shaft tolerances for engineering and manufacturing used for cutting tools, material stock, gages, etc. If held to these tolerances, cutting tools, material stock, and gages are generally available throughout the world.
The hole basis fits have four preferred hole tolerances (H11, H9, H8, and H7); the shaft basis fits have four preferred shaft tolerances (h11, h9, h7, and h6) as shown in Table below. NOTE: Shaft tolerances are now covered in the new ANSI B32.100- 2005 standard.
- Hole H11/c11 - Loose running fit for wide commercial tolerances or allowances on external members.
- Hole H9/d9 - Free running fit not for use where accuracy is essential, but good for large temperature variations, high running speeds, or heavy journal pressures.
- Hole H8/f7 - Close running fit for running on accurate machines and for accurate location at moderate speeds and journal pressures.
- Hole H7/g6 - Sliding fit not intended to run freely, but to move and turn freely and locate accurately.
- Hole H7/h6 - Locational clearance fit provides snug fit for locating stationary parts; but can be freely assembled and disassembled.
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