Point Contact Transistor Apply Spring Tension Seat Point
# Apply Spring Tension and Seat the Point Assembly: Where Two Separately Built Objects Finally Touch
Everything from Step 1 through Step 10 built and verified one object, the germanium body. Everything from Step 11 through Step 12 built and verified a second, independent object, the point-and-spring assembly. Step 13 is where those two tracks stop running in parallel and actually meet: the spring is loaded, and the formed point is pressed against the conditioned face for the first time in this sequence. Every verification performed so far checked one object or the other in isolation. This step is the first to test both at once, together, under load — and it is entirely possible for a body that passed every earlier check and a point assembly that passed every earlier check to still fail the moment they are finally brought into contact.
Spring tension is bounded from both sides, the same way nearly every other quantity in this sequence has been. Too little force and the point makes an inconsistent, high-resistance contact with the germanium — the surface Step 9 conditioned and Step 10 protected is still there, but a point barely touching it cannot deliver a reliable electrical path across that surface into the bulk. Too much force risks cracking the germanium body outright, especially given how thin Step 2 may have left it once the spreading-resistance tradeoff from that step is taken into account, or it risks mechanically disturbing the conditioned surface layer itself, undoing Step 9's work by brute force rather than by chemistry. The correct tension sits in a narrow band between a contact too weak to trust and a load strong enough to damage the very thing it is supposed to touch.
Seating is a distinct requirement from tension, and satisfying one does not guarantee the other. Applying the correct spring force is a question of magnitude; seating is a question of stability — whether the point, once loaded, settles into one fixed position rather than chattering, creeping, or shifting under the sustained load it will carry for the rest of the device's working life. A point contact can receive exactly the right tension and still fail to seat properly if the geometry underneath it, however precisely built by Step 12, allows any residual freedom of movement once force is applied. Because this sequence has protected point-contact spacing down to a tolerance measured in thousandths of an inch since Step 1, any unseated motion at this stage — even motion too small to see without instrumentation — can be large enough to matter at that scale, in exactly the way Step 12 already warned a small attachment error could be magnified into a large positioning error at the tip.
This step is also the first point in the sequence where Step 12's leverage risk and Step 1's spacing requirement are tested together rather than separately. Step 12 raised the possibility that a small misalignment at the spring's attachment point could be magnified by the arm's length into a tip position error. That risk was real but unmeasured at the time, because the point had never actually been loaded against the germanium it was built to touch. Seating it here, under real tension, for the first time, is the first opportunity to discover whether that risk materialized — and if it did, this step is where it becomes visible, not the step where it was actually created.
| Step | Process operation | Input | Output | Specification | Constraint |
|---|---|---|---|---|---|
| 13.1 | Determine the target spring tension range from the device's contact-resistance and germanium-integrity requirements | Verified germanium body from Step 10, verified point-and-spring assembly from Step 12 | Target tension range | Lower bound set by acceptable contact resistance; upper bound set by germanium fracture risk and surface-disturbance risk | A single target value without both bounds risks optimizing one failure mode while ignoring the other |
| 13.2 | Bring the point assembly into initial contact with the conditioned face at low tension | Target tension range from 12.1 | Point in light contact with germanium | Contact established without exceeding the lower edge of the target tension range | Applying full tension before confirming position risks damaging the germanium before alignment is even checked |
| 13.3 | Verify tip position against the point spacing established in Step 1 and Step 3, while still at light contact | Point in light contact from 12.2 | Position-verified light contact | Measured tip position within the spacing tolerance, before full tension is applied | Discovering a position error only after full tension is applied makes correction far more disruptive |
| 13.4 | Increase spring tension to the full target range and confirm the point seats into a stable position | Position-verified light contact from 12.3 | Seated point assembly, under full tension | No detectable creep, chatter, or drift once full tension is applied and held | A point that reaches target tension but continues to move has not actually seated, regardless of the force reading |
| 13.5 | Verify germanium integrity and surface condition were not disturbed by the seating process | Seated assembly from 12.4 | Integrity-verified seated assembly | No new cracking, and surface condition still within Step 9's target range after seating | Seating that damages the very surface it depends on can pass a tension check while failing the device's actual requirement |
| 13.6 | Record applied tension, seating verification, and position measurement against both the germanium body's and the point assembly's provenance | Verified seated assembly from 12.5 | Documented seated assembly | Tension, seating result, and position recorded against both records from Step 2.6 and Step 11.6 | Without records tied to both objects, a later failure cannot be attributed to the germanium side, the point-and-spring side, or this step's own seating process |
Step 13 does not build anything new; it is the first step whose entire purpose is to find out whether everything built separately before it actually works together. Nine steps verified the germanium in isolation. Two steps verified the point-and-spring assembly in isolation. This step brings them into contact under real, sustained load for the first time, and only now does it become possible to discover a combination failure that no single-object check could have revealed — a spacing error from Step 12's leverage risk, a surface disturbance from too much tension, or a contact too light to trust. Everything after this step depends on this one having actually worked, which is exactly why it is specified against both objects' requirements at once rather than against either one alone.