4.4.3 STD vs. VACU

4.4.3   concept 

 Finger inserts seat in one of two ways — STD (Standard) or VACU (Vacuum) . The insert type you record on the sheet (see 4.4.2) tells Spectre Cloud how the hole is drilled. This page explains the difference. For the OD-sizing concept, see 4.1.6 . 
 📐 STD (Standard) 
 Standard inserts are press-fit : the hole is drilled to the insert's OD, at full depth, and the insert is pressed in and held by friction against the ball's coverstock. 
 
 ✅ Drill bit size equals the insert's published OD — a direct, one-to-one match, full depth. 
 ✅ A correct STD fit presses in with firm hand pressure or a seating tool — it shouldn't drop in freely or need excessive force. 
 ❌ Never undersize an STD hole — a too-tight press-fit risks cracking the ball surface. 
 
 📐 VACU (Vacuum) 
 VACU inserts are drilled in two diameters so the insert has room to expand: 
 
 Drill the top portion at the size shown on the spec sheet. 
 Drill that top portion 1" deep . 
 Continue to the insert's actual OD for the rest of the depth. 
 
 The oversized top forms a pocket — a void where the insert doesn't touch the surrounding ball wall — giving the insert room to expand. 
 
 ✅ The spec-sheet OD for a VACU insert is the top-portion (pocket) size , not the insert's body OD. 
 ✅ The deeper portion is drilled to the insert's actual OD, exactly like a STD hole. 
 ❌ Drilling the whole hole at one size removes the pocket entirely and defeats the VACU fit. 
 
 📊 STD vs. VACU 
 STD (Standard) VACU (Vacuum) Drilling Single diameter at the insert OD, full depth Oversized pocket ~1" deep, then actual OD to depth Spec-sheet OD means Drill size for the whole hole Top-portion (pocket) size Why Friction press-fit Void lets the insert expand 

 Related Sections 
 
 4.4.2 — Finger inserts (recording type, size, OD) 
 4.1.6 — Insert OD concept: STD vs. VACU, insert size vs. OD 
 2.6.6 — Autofill Insert OD 
 
 Tip: The most common VACU error is drilling the whole hole at one size. Remember it's two cuts — the spec-sheet size for the first inch to form the pocket, then the insert's actual OD to depth.