Evidence grade: B2 — Practitioner rule of thumb Effort: Intermediate–Advanced · 1–3 hours · welder or bushing stock, drill and reamer, welding PPE
Weld the hole shut and redrill it true — or weld in a bushing sized to your pin. Those are the lasting fixes. Epoxy fill is defensible only for zero-load holes, and even there a bushing is better.
Why the hole got oval
Holes wallow out because the bolt or pin moves inside them — usually because the pin was the wrong size to begin with. As one farm mechanic puts it: "It's wrong size pin that starts the oblong wear" (source 1). The fix has to restore a round hole that fits the pin snugly, or the wear starts again immediately. Whatever method you choose, finish with the correct pin diameter — a repair that reuses the sloppy pin is a repair that fails twice.
The three methods, ranked
1. Weld-fill and redrill — the standard fix. Weld the elongated hole shut ("weld up the egg"), grind flat, and drill back to the pin size (source 1). The pro trick for keeping the original center: put a carbon or copper rod of the pin's diameter in the hole as a placeholder and weld around it — the weld won't stick to carbon or copper — then knock the rod out (sources 1, 2). One caution from the trade: if too much carbon gets into the weld, the fill can become too hard to drill with HSS bits (source 1). For a through-hole, a copper plate behind the hole as a backstop works the same way (source 2 — opened 2026-09-30).
2. Bore oversize and weld in a bushing — best when alignment matters. Cut, grind, or machine the wallowed hole round, fit a steel bushing (or a section of tube with the right ID and OD), and weld it in (source 1). This is the preferred method where the hole location must stay exact, and it has a bonus: next time the hole wears, you replace a bushing instead of re-welding the part. Thick weld washers around the bushing add bearing area where there's room (source 1).
3. Epoxy fill — zero-load holes only. Packing a wallowed hole with epoxy and redrilling it is a hack, not a repair. It can hold a bolt that only positions a cover or a guard — but it has no verified strength in shear or under vibration, and it will not survive a pin that hammers. If you're reaching for epoxy, ask first whether a bushing (method 2) would fit — it almost always would, and it actually lasts.
⚠️ Stop rules
- Steering, suspension, brakes, lifting points — STOP. A wallowed hole in anything whose failure means loss of control or a dropped load is professional repair or part replacement. No exceptions for "it'll probably hold."
- No welding skill — don't weld. Pick the bushing route with a press fit and have a welder do the welding, or hand the whole job to a shop. A bad weld in a hole is worse than the wallowed hole — it looks fixed and isn't.
- Cast iron housings — special rules. Cast iron doesn't weld-fill like mild steel; the trade practice is brazing with brass after careful tinning (source 2 — opened 2026-09-30), or a bushing. When in doubt, see Repair Lab A4.
PPE and handling
- Full welding PPE for methods 1 and 2: auto-darkening helmet, welding gloves, flame-resistant jacket, boots. No skin exposed — arc flash burns what it touches.
- Ventilation is mandatory when welding — fumes from the arc, from coatings on the steel, and from galvanized parts (zinc fume) are all hazardous. Grind coatings off the weld zone first, outdoors or with extraction.
- Eye protection for all drilling and grinding. Deburr every edge — a fresh-drilled hole is a razor.
Honest limits
- Weld-fill changes the metal around the hole: heat-affected zones can harden, crack, or distort thin sections. On thin or critical parts, the bushing route disturbs less metal.
- The carbon-rod trick is practitioner wisdom, not a procedure with published parameters — rod size, heat input, and cleanup all affect the result (B2, honestly labeled).
- Epoxy fill has no published strength data for this use. "It held" stories exist; so do "it walked out" stories. Neither is data.
- Prevention beats all three methods: correct pin size, tight bolts, and periodic re-tightening. The hole only wallowed because something was allowed to move.
Sources
- TractorByNet — "fixing elongated holes in farm equipment??" — https://www.tractorbynet.com/forums/threads/fixing-elongated-holes-in-farm-equipment.174454/ — weld-in bushing (category 2/3 adapter bushings, fit and weld); weld shut and redrill ("weld up the egg and redrill to the size of your pin"); carbon-rod placeholder trick with the HSS-drilling caveat; drill oversize and use a bigger pin; tube with correct ID/OD TIG-welded in; thick weld washers; wrong-size pin as the root cause.
- Shop Floor Talk — "Oblong Hole" (archive) — https://www.shopfloortalk.com/forums/archive/index.php?t-20564.html (opened and read 2026-09-30). Copper plate behind the hole, fill with weld, grind, redrill ("will last another 50 years"); cast iron filled with brass after careful tinning.
Repair Lab · Release 1 · Evidence last checked September 30, 2026 · A project of AOJEL