Thread Cutting Apparatus for Schaublin 70

Based in part on a 1950s threading device, I developed my own design suitable for the new spindle with a 7206 angular-contact ball bearing. I acquired a 70-30.000 spindle and took precise measurements.

I wanted the tool to be as versatile as possible. Today, the Schaublin 70 is mainly used for prototype work. It is very important to be able to quickly and easily reconfigure the apparatus for a new operation or disengage it entirely to perform other tasks on the lathe without removing the thread cutting device. Naturally, the fewer the components between the spindle and the longitudinal carriage lead screw, the smaller the error. A compromise was necessary.

The complete design took me about two months to develop.

The base is made of cast iron; I could not find a foundry.

The crown of the driving gear is wider than the gears themselves. Two intermediate wheels, as well as the driven wheel on the pivot, are also wider and rotate more stably.

The apparatus contains about 150 parts, roughly 50 of which—like bearings or bolts—I purchased, though most required further machining. Manufactured parts are mainly made from C45 steel, which I hardened, tempered, ground, filed, sandblasted, or polished. Chamfers were made by hand or corrected on the lathe. The design allows production entirely with my own capabilities.

The pivot handle is knurled, hardened, tempered, and blackened.

The apparatus contains seven bearings, yet is robust and easy to operate.

The thread cutting apparatus is essentially a gearbox that allows the cross-slide carriage to move a set distance while the spindle rotates. The kit includes 17 change gears, enabling the most common threads, both metric and imperial. Mounting them on a triple lyre expands the capabilities. Using these combinations, I calculated a compact set of gears.

Through the built-in pivot, both right- and left-hand threads can be cut. A disengaging device with an adjustable stop allows the apparatus to be engaged or disengaged automatically or manually.

The thread cutting apparatus can also serve as an automatic drive for the cross-slide carriage.

Sales

Six thread cutting apparatuses have been sold: to Japan, two to the USA, two to Germany, and one to Kuwait.

Capabilities:

• Cut threads with a cutting tool or mill using the vertical slide;
• Grind threads after hardening;
• Select the appropriate cutting tool depending on whether standard or special-shaped threads are required;
• Achieve perfectly shaped thread turns;
• Control the diameter of internal and external threads, and if necessary, adjust for missing or excess dimensions, which is practically impossible with a tap.

General:

• Thread cutting attachment with drive via a universal joint shaft for internal and external threads.
• Designed for use on open or closed spindles.
• Lead screw pitch: 1 mm

Working Range:

• Maximum thread length: 52 mm

Gear Set:

• 30-33-35-38-39-40-45-46-50-60-70-75-80-85-100-120-127 (17 gears)

Thread Pitch:

• Metric threads with pitches: 0.075–0.08–0.10–0.125–0.15–0.175–0.20–0.225–0.25–0.30–0.35–0.40–0.45–0.50–0.55–0.60–0.70–0.75–0.80–0.90–1.0–1.25–1.50–1.75–2.0–2.25–2.50–3.0–3.50–4.0 mm
• Imperial threads with 90-80-72-68-64-60-56-52-50-48-46-44-42-40.64-40-38-36-34-32-30-28-26-24-22-20-18-16-14-12 threads per inch

Standard Equipment and Accessories:

• Driving gear with 40 teeth for spindle mounting;
• Telescopic universal shaft with interchangeable 120 mm extension;
• Mounting device for the cross-slide with disengaging mechanism;
• Adjustable stop for engaging and disengaging the device;
• Interchangeable extension, 190 mm length;
• Interchangeable extension, 250 mm length;

Attention! Any listing on Kalaido is definitely a fake. The police have been informed. You can purchase the THREAD CUTTING APPARATUS only from Alexander Babel!