ITI/NCVT Tool & Die Maker (AITT Theory) case studies
ITI/NCVT Tool & Die Maker (AITT Theory) · Put your knowledge to work in context.
The ITI/NCVT Tool & Die Maker (AITT Theory) is the theory paper of the All India Trade Test sat by trainees who have completed the Tool & Die Maker trade under the Craftsman Training Scheme. It is a trade-theory assessment, not a design portfolio review: it tests whether you can reason about materials, machines, tooling geometry and press-tool practice the way a shop-floor toolmaker must. The ITI/NCVT Tool & Die Maker (AITT Theory) case studies are 5 cases and about 3,252 words.
1Jammed slug, bridged interlock and a taped light curtain on a 150-tonne press
At a press shop running a 150-tonne mechanical press on fan-motor laminations, the operator clears a jammed slug by sliding the fixed front guard aside and reaching under the ram while a helper keeps both hands on the two-hand control. Tool changes on this press are done without lockout; the flywheel is simply allowed to run down.
679 words, about 3 min2Cracked D2 punch after a one-shot harden and single temper
An HCHCr (AISI D2-type) punch, 40 mm diameter with a 0.5 mm fillet at the shank-to-body junction, is hardened in the tool room. The trainee loads it cold into an open gas-fired furnace set at 980 °C, holds for 15 minutes, quenches in still oil at 30 °C, and tempers once at 180 °C for one hour.
659 words, about 3 min3The 25H7 batch that failed on a micrometer but passed the plug gauge
An inspector checks 40 bores specified as 25H7 (25.000/+0.021) using a 25-50 mm inside micrometer graduated at 0.01 mm. Readings scatter from 25.030 to 25.036 mm, so the whole batch is marked for rework.
646 words, about 3 min4Pocket 0.06 mm over on one wall and under on the other after G41 finishing
On a vertical machining centre, a rectangular pocket 60 x 40 x 12 mm deep in mild steel is roughed with a 12 mm four-flute HSS end mill, then finished with a climb-milling pass using G41 D01. The pocket measures 0.06 mm oversize on the +X wall and 0.06 mm undersize on the -X wall, but is correct in Y.
664 words, about 3 min5Chipped washer die with 0.05 mm clearance on 1.6 mm CRCA
A progressive die blanks washers from 1.6 mm cold-rolled mild steel, outside diameter 50 mm, hole 20 mm. Clearance was ground at 0.05 mm per side on both punch and die.
604 words, about 3 min