Stationary Self Opening Die Heads SDH

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Stationary Self Opening Die Heads SDH

External Threading Stationary Self Opening Die Heads SDH

Self-Opening Die-Heads: SDH

📌 Purpose:

Self-Opening Die-Heads – Model SDH (Stationary Type) For High-Precision Snap Threading.

‘TACO’ Self-Opening Die-Heads are engineered for precision thread cutting and are ideally suited for heavy-duty applications and mass production. Designed for mounting on centre lathes, capstans, turret lathes, and similar machine tools, these die-heads automatically open when the desired thread length is reached eliminating the need to reverse the machine spindle.

They are especially recommended for high-volume production of components such as stay bolts, adjusting screws, and more.

Each die-head is normally supplied with a straight shank, secured in position with three screws. If required, it can be adapted with other types of flanged shanks (e.g., Morse taper) to suit specific machines.

🏗️ Machine Compatibility:

Model SDH Die Heads can be seamlessly mounted on:

v  Centre lathes

v  Capstans and turret lathes

v  Semi-automatic machines

v  Drilling machines and Milling machines

v  Radial drilling machines

v  CNC, VMC and HMC machines

🎬 Video Highlight Summary:

The provided text outlines the assembly and operation of a Model SDH die head, a tool used for cutting threads. It begins by describing the initial setup, including attaching handles, adjusting screws, and inserting the chases in a specific order for right or left-hand threads. The instructions then guide the user through setting the thread size with a gauge and preparing the die head for use, emphasizing the importance of locking a double nut before cutting. Finally, the text details the process of mounting the die head onto a lathe, positioning it over the workpiece, and executing two-stage cuts a roughing cut followed by a finishing cut while advising on proper speed and gentle pressure to prevent damage.

🛠️ SDH Die Head Technical Data

Model

Model Size / Chaser Set

Capacity (mm)

Capacity (inch) [BSW, UNF, UNC]

ØD

L

ØC

Ød2

M [Expansion]

L2

Short Cutting (Dia x Length)

Pipe Capacity (inch)  [BSP, NPT]

Shank Options –  O.D. /d

Shank  –  I.D. /d1

SDH - Approx Weight (Kg.)

SDH-1

5/16"

2–8 mm

3/32" – 5/16"

48

58

48

10

3.5

12

11 mm × 12 mm

—

5/8” or 20 mm

3/8”

0.800 Kg. / 0.900 Kg.

SDH-2

1/2"

4–14 mm

3/16" – 9/16"

65

78

42

17

4.5

24

16 mm × 24 mm

1/8" – 1/4"

1” or 30 mm

5/8”

1.900 Kg. / 2.000 Kg.

SDH-3

3/4"

6–18 mm

1/4" – 3/4"

88

99.5

56

24

5

35

22 mm × 35 mm

1/8" – 1/2"

1-1/2” or 40 mm

24 mm

4.200 Kg. / 4.300 Kg.

SDH-4

1"

10–24 mm

3/8" – 1"

102

109

63

34

5

40

30 mm × 40 mm

1/8" – 3/4"

1-1/2” or 40 mm

11/16”

5.500 Kg. / 5.600 Kg.

SDH-5

1-1/4"

12–30 mm

1/2" – 1-1/4"

120

126

72

36

5.5

45

35 mm × 45 mm

1/4" – 1"

2-1/8” or 60 mm

1-3/8”

8.800 Kg. / 9.300 Kg.

📝 Important Ordering Note: When placing an order for SDH models, please specify the required shank size [ e.g., SDH-1: 5/8" or 20mm] to ensure compatibility with your machine spindle. Additionally, kindly purchase the appropriate chaser set based on the material you intend to process. [ Special MT Shanks: Supplied on request at an additional cost, depending on the availability of the required MT shank size. ]

Engineered for reliability, speed, and precision in high-performance threading operations.

🤖 Smart Function:

🧭 Function	📖 Description	🎯 Benefit
🔓 Auto-Release Thread Stop	Built-in cam disengages locking pin at preset thread length	Enables precise thread length control without spindle reversal
🎯 Precision Diameter Control	Knurled screw with engraved calibration lines for micrometric adjustment	Ensures consistent thread sizing across production batches
🔄 Two-Cut Threading Mode	Rear handle toggles between roughing and finishing cuts	Improves surface finish and reduces chaser wear
🧰 Universal Machine Compatibility	Mounts on lathes, drilling, milling, CNC, VMC, HMC machines	Maximizes operational flexibility across setups
🔁 Thread Direction Flexibility	Supports both right-hand and left-hand threads with dedicated chasers	Expands threading capability for diverse applications
🧲 Snap-Action Opening Mechanism	Die-head opens automatically after threading via stopper and cam disengagement	Boosts cycle repeatability and operator efficiency
⚙️ Fine Threading at High Speed	Operates efficiently from 100–600 RPM with minimal deviation	Delivers high-speed threading with superior accuracy
🛡️ Stable Cutting Dynamics	Rigid build and precision-ground components reduce vibration	Enhances thread quality and tool longevity
🔧 Quick Chaser Replacement	Cover plate with four screws allows fast chaser change	Minimizes downtime and simplifies maintenance
🧪 Material Versatility	Optimized for MS, CI, low carbon steel, aluminum, copper, and steel	Ensures reliable threading across common industrial metals

🔑 Key Advantages:

v  Universal Machine Fit: Universal Machine Compatibility Designed for maximum adaptability; SDH die-heads are compatible with horizontal lathes for unlimited threading lengths, as well as vertical drilling,  milling machines and radial drilling machines with rotating, reversing spindles - when equipped with a special MT shank for short-length threading. They are also suitable for CNC, VMC and HMC machines in short-threading applications, provided that each threading cycle allows for manual door-opening to enable die-head locking. This versatility makes them a dependable choice for both traditional and automated machining setups.

v  Threading Flexibility: Supports both right-hand and left-hand threads with dedicated chasers for each.

v  No Spindle Reversal Required: Once threading is complete, the SDH model automatically opens using a stopper mechanism - eliminating the need to reverse the machine spindle.

v  Chaser Compatibility: Accepts all standard Coventry HSS chase sets, only the proper chaser size is required.

v  Material Suitability: Optimized for ductile metals like MS, CI Casting, Low Carbon Steel, Aluminium and Copper, and also suitable for Steel.

v  Cost-Efficient Threading: Achieve precise, high-speed threading across multiple sizes using a single die-head - minimizing tooling costs and maximizing productivity. Ideal for high-volume production environments where accuracy and efficiency are critical.

v  User Requirement: For best performance, operation by a skilled machinist & semi-skilled machinist is recommended.

v  High-Speed Output: Enables threading faster than SD Model and suited for rapid multi-size threading at low cost.

⚡️Quick & Easy Installation – Model SDH:

High-Precision, Self-Opening Die-Heads for Efficient Thread Cutting

Model SDH Die-Heads are engineered for high-speed, precision thread cutting - ideal for mass production and heavy-duty applications. Suitable for mounting on centre lathes, capstans, turret lathes, and semi-automatic machines, they streamline threading operations with accuracy and ease.

Mounting & Setup:

v  The die-head is typically inserted into the tailstock of a lathe, while the workpiece is secured in a chuck.

v  Threading is performed using four chasers, numbered 1 through 4, arranged clockwise in dedicated recesses and held in place by a cover plate.

Chaser Replacement & Head Closing:

v  To replace chasers, loosen the four screws securing the cover plate and rotate it counterclockwise to remove.

v  To close the die-head, rotate the front handles counterclockwise until the locking pin engages its seat.

v  The cam ring locks into position at an angle of 25° during this operation.

Thread Diameter Adjustment:

v  A tangential adjusting screw with a knurled counter-nut enables precise regulation of thread diameter.

v  A rear handle (not present on SDH-1) allows for two-cut operations without adjusting the screw:

Ø  First Cut (Roughing): Set handle to the ‘Minus’ (–) position (toward the adjusting screw).

Ø  Second Cut (Finishing): Set handle to the ‘Plus’ (+) position (away from the adjusting screw).

v  Never leave the handle in an intermediate position during operation.

v  Avoid switching between positions while the head is closed, unless pressure on the opening spring is released, to prevent excessive wear on the locking mechanism.

Setting Thread Size:

v  For accurate diameter control:

Ø  Set the handle to ‘Plus’ position.

Ø  Adjust the knurled screw until the engraved zero lines on the head and scale align (centered between ‘+’ and ‘–’).

Ø  Verify with a trial cut before full production.

Cutting Guidelines:

v  For thread sizes over 3/8”, use a two-step cutting approach:

Ø  Rough Cut: Handle on the (–) scale side

Ø  Finish Cut: Handle on the (+) scale side

v  Start at a low RPM, increasing gradually to find the optimal speed based on material and chaser condition.

v  Apply gentle pressure until the chasers engage - never force them, as this may damage the cutting edges.

v  Maintain consistent pressure as the die-head moves, allowing for any drag from turret or saddle weight.

v  Ensure the workpiece diameter is correct or slightly oversized (max 0.001” / 0.02 mm).

Self-Opening Mechanism:

v  The threading length is controlled using a fixed stop or manual stop.

v  When the stop engages, the die-head continues to advance 3–4 mm, allowing the chasers to feed forward.

v  This action disengages the cam from the locking pin, triggering the die-head to open automatically.

🎯 High-Precision Features:

v  Consistent Thread Accuracy: Delivers uniform, high-quality threading across large production volumes, ensuring minimal deviation and superior fit.

v  Self-Opening Mechanism: Built-in snap-action system opens the die-head automatically at the pre-set thread length for precision control and cycle repeatability.

v  Fine Thread Diameter Adjustment: Equipped with knurled adjusting screws and engraved calibration lines for micrometric regulation of thread size.

v  Precision-Ground Components: All critical parts are manufactured to close tolerances, enabling seamless assembly, smooth performance, and reliable interchangeability.

v  Stable Cutting Performance: Rigid construction and optimized cutting dynamics reduce vibration, enhance surface finish, and extend tool life.

v  Speed-Optimized Operation: Performs efficiently within a wide RPM range (100–600), with excellent results even on materials with hardness up to 20 HRC.

v  Two-Cut Functionality: Roughing and finishing thread cuts achieved without tool change - just a simple handle adjustment.

v  Precision Engineering: Designed for high-speed, accurate thread cutting, suitable for low-volume production and heavy-duty jobs alike.

📐 Technical Operating Range:

v  Threading Speed: Recommended threading speed: 100–600 RPM, depending on material hardness, thread size/pitch, and chaser condition. (Always use coolant for finish-grade threads and longer tap life.)

v  Material Hardness: 0–20 HRC

v  Maximum Threading Length: Offers unlimited threading lengths on horizontal lathes, while supporting short-length threading applications on vertical drilling machines, milling machines, CNC, and VMC setups.

v  Mounting Shank Dimensions (MT Shank GP Dia):

Taper	Dia (inch)	Dia (mm)
MT1	0.475”	12.0650
MT2	0.700”	17.7800
MT3	0.938”	23.8252
MT4	1.231”	31.2674
MT5	1.748”	44.3992

🛠️ Maintenance Note:

To extend the life of this tapping attachment or any die head, die holder, or tap chuck avoid constant use at upper or lower limit capacities. Consider rotating between two or three units for heavy-duty applications.

🔩 Chaser Thread Standards

Thread	Full Form	Description
NPT	National Pipe Taper	Tapered thread used in U.S. pipe fittings. Creates a seal via thread interference.
BSP	British Standard Pipe	Common in Europe and Asia. Includes BSPT (tapered) and BSPP (parallel) threads.
BSW	British Standard Whitworth	Coarse thread with rounded crests and roots. Used in older British machinery.
UNF	Unified National Fine	Fine-pitch thread used in precision applications. Part of the Unified Thread Standard.
UNC	Unified National Coarse	Coarse-pitch thread for general fastening. Also part of the Unified Thread Standard.
Metric	ISO Metric Thread	International standard. Uses millimeter-based pitch and diameter.

🧰 Where They're Commonly Used

v  NPT: Plumbing, gas lines, hydraulic systems (mostly in North America)

v  BSP: Water and fluid systems (Europe, Asia, Australia)

v  BSW: Restoration, vintage British equipment

v  UNF/UNC: Automotive, aerospace, general engineering (U.S. and Canada)

v  Metric: Global standard for bolts, screws, and fasteners

🏭 Chaser Material -  Performance Comparison

Feature	M2	M2 + Coating	M35	M35 + Coating
Base Material	HSS (no cobalt)	Same + surface coating	HSS + 5% cobalt	Same + surface coating
Heat Resistance	Moderate	Improved	High	Excellent
Wear Resistance	Good	Better	Very Good	Superior
Tool Life	Standard	Longer	Long	Longest
Thread Finish	Acceptable	Smoother	Clean	Best-in-class
Cost	Low	Slightly higher	Higher	Highest
Ideal Use	Mild steel, alloys	Medium-duty runs	Stainless, tool steel	High-speed, tough jobs

⚙️ Estimated Production Ratios (Relative Tool Life)

Chaser Type	Relative Tool Life	Typical Usage Ratio*
M2	1× (baseline)	40–50%
M2 + Coating	~1.5×	20–25%
M35	~2×	15–20%
M35 + Coating	~2.5–3×	10–15%

*These ratios reflect how often each type might be used in a mixed production setup, assuming cost and performance are balanced.

🔍 Production Insights

v  M2 is suitable for short-run jobs or general-purpose threading where cost is a priority.

v  M2 with coating offers better performance in medium-duty production, especially with coolant-assisted threading.

v  M35 is built for demanding materials like stainless steel and excels in automated setups.

v  M35 with coating is the top-tier choice for continuous, high-speed production with minimal downtime.

💡 Decision Tip

If your production involves frequent threading of hard materials or long cycle times, investing in M35 with coating can reduce tool changes and improve consistency. But for cost-sensitive, low-to-medium complexity jobs, M2 or M2 with coating may be more economical.

📐 Recommended Cutting Angles (Material-Wise)

Material	Rake Angle	Clearance Angle	Notes
Mild Steel	0°–5°	6°–8°	Neutral rake prevents edge wear.
Alloy/Tool Steel	0°	8°–10°	Harder steels require minimal rake for strength.
Cast Iron	0°	6°–8°	Brittle material; avoid positive rake.
Brass/Bronze	10°–15°	6°–8°	Softer, free-cutting; higher rake reduces cutting force.
Aluminum	15°–20°	6°–8°	High rake angle improves chip flow.
Stainless Steel	0°–5°	8°–10°	Tough material; rake kept low to avoid edge chipping.

 

🎯 "Intelligent Quick-Analysis Tool Designed For Discerning Business Customers." 🎯

 

🛠️ SDH Model Self-Opening Die-Heads – Dimensional Range Smart Overview

Model	Model Size / Chaser Set	Capacity (mm)	Capacity (inch) [BSW, UNF, UNC]	Short Cutting (Dia x Length)	Pipe Capacity (inch)  [BSP, NPT]	Shank Options	SDH - Approx Weight (Kg.)
SDH-1	5/16"	2–8 mm	3/32" – 5/16"	11 mm × 12 mm	—	5/8” or 20 mm	0.800 Kg. / 0.900 Kg.
SDH-2	1/2"	4–14 mm	3/16" – 9/16"	16 mm × 24 mm	1/8" – 1/4"	1” or 30 mm	1.900 Kg. / 2.000 Kg.
SDH-3	3/4"	6–18 mm	1/4" – 3/4"	22 mm × 35 mm	1/8" – 1/2"	1-1/2” or 40 mm	4.200 Kg. / 4.300 Kg.
SDH-4	1"	10–24 mm	3/8" – 1"	30 mm × 40 mm	1/8" – 3/4"	1-1/2” or 40 mm	5.500 Kg. / 5.600 Kg.
SDH-5	1-1/4"	12–30 mm	1/2" – 1-1/4"	35 mm × 45 mm	1/4" – 1"	2-1/8” or 60 mm	8.800 Kg. / 9.300 Kg.

 

🔩 SDH Model Stationary Self-Opening Die Head – Quick Smart Summary

Engineered for high-speed, high-precision external threading, the SDH model offers automatic die-head opening, universal machine compatibility, and micrometric thread control—ideal for mass production and heavy-duty applications.

🔑 Key Features

v  🔓 Auto-Opening Mechanism: Built-in cam disengages the locking pin at preset thread length—no spindle reversal required.

v  🎯 Precision Thread Diameter Control: Knurled screw with engraved calibration lines enables micrometric size adjustments.

v  🔄 Two-Cut Threading Mode: Rear handle toggles between roughing (–) and finishing (+) cuts without tool change.

v  🧰 Universal Compatibility: Mounts on center lathes, turret lathes, drilling, milling, CNC, VMC, and HMC machines.

v  🔁 Thread Direction Flexibility: Supports both right-hand and left-hand threads with dedicated chasers.

v  🧪 Material Versatility: Optimized for MS, CI, low carbon steel, aluminum, copper, and steel.

⚙️ Operating Highlights

v  Threading Speed Range: Operates efficiently between 100–600 RPM depending on material and chaser condition.

v  Unlimited Thread Length: On horizontal lathes; supports short-length threading on vertical and CNC machines.

v  Chaser Replacement: Quick-change system with four screws and cover plate for fast maintenance.

v  Mounting Options: Supplied with straight shank; Morse taper (MT) shanks available on request.

📌 Safety & Performance Tips

v  Use Coolant: Always apply cutting fluid for better finish and tool life.

v  Avoid Overload: Do not operate at extreme capacity limits; rotate between units for heavy-duty use.

v  Correct Setup: Ensure proper chaser seating and handle positioning before operation.

v  Trial Cut First: Always verify thread size with a trial cut before full production.

 

🔩 SDH Model Stationary Self-Opening Die Head – Quick Smart Analysis

Aspect	Details
🔧 Type	Stationary Self-Opening Die Head – designed for automatic external threading
⚙️ Function	Enables external threading with auto-release at preset thread length
🔄 Mechanism	Cam-based disengagement system opens die head smoothly after threading
📐 Thread Range	Supports various metric and imperial thread sizes via interchangeable chasers
🛠️ Applications	Ideal for mass production external threading on lathes, CNCs, and milling machines
✅ Advantages	Increases threading speed – Ensures consistent thread length – Reduces operator fatigue
🏭 Use Case	Center lathes, turret lathes, CNC, VMC, HMC, and vertical machines

v  Overview: Stationary Self-Opening Die Heads (SDH) are designed for high-speed, precision threading without spindle reversal. They feature:

Ø  Self-opening mechanism for smooth operation

Ø  Compatibility with right- and left-hand threads

Ø  Adjustable thread diameter via calibrated knurled screw

Ø  Two-cut threading (roughing + finishing) without tool change

Ø  Precision-ground components for vibration-free performance

v  Tap Monitoring Integration: When paired with automated tap monitoring, SDH systems gain:

Ø  Real-time detection of torque spikes, misalignment, and dull taps

Ø  Evaluation of tap engagement and clutch response

Ø  Alerts for thread profile inconsistencies and feed mismatches

v  Benefits:

Ø  Minimizes downtime through early issue detection

Ø  Enhances thread quality and tool longevity

Ø  Enables predictive maintenance and operator feedback

v  Ideal For: High-volume or precision tapping environments where consistency, speed, and tool protection are critical.

TOOLS AND APPLIANCES CORPORATION

BLOCK NO.: 135/2, BILESHWARPURA, P.O. CHHATRAL - 382729,

TA. KALOL ( N.G.), DIST. GANDHINAGAR.

MO. 6355213404, 6355251586,

Email :- taco@imitoolsindia.com, salestaco@imitoolsindia.com.