Bore Depth, Tip Prep and Why a Ferrule Sits High

The symptom is simple to describe: there is a visible gap between the bottom of the ferrule and the top of the hosel, usually a millimetre or two, sometimes more. Occasionally the ferrule spins freely when you touch it.

The cause is never the ferrule itself. Here are the four possibilities, roughly in order of how often we find them.

Cause One: The Shaft Was Never Fully Seated

By far the most common. During assembly the shaft was pushed into the hosel but did not reach the bottom of the bore, either because epoxy had already begun to thicken or because the installer did not twist and press hard enough to expel the air.

The ferrule was then positioned against the hosel and everything looked correct on the day. Over the following months, impact forces gradually drive the shaft the remaining distance down into the bore. The ferrule stays put. A gap opens.

How you identify it: measure how far the shaft protrudes and compare it against the known bore depth of that head model. If the numbers do not add up, the shaft is short in the hosel.

Cause Two: Inadequate Tip Preparation

Graphite and steel shafts both need the bonding surface abraded before epoxy goes on. On graphite this means removing the painted or clear-coated outer layer down to bare material for the full insertion depth. On steel it means scuffing off the chrome plating so the epoxy has something mechanical to key into.

Skip it and the bond forms against paint rather than against the shaft. Paint peels. The joint develops a small amount of movement, and that movement works the ferrule loose from below over time.

How you identify it: the ferrule spins or slides with light finger pressure, and if you pull the shaft the epoxy comes out as a clean tube with the shaft's paint still stuck to the inside of it.

Cause Three: The Hosel Was Not Cleaned

Replacement heads and pulled heads both arrive with old epoxy inside the bore. It has to be drilled or reamed out completely. Old epoxy left in the bottom of a hosel effectively raises the floor, so the shaft bottoms out early and sits proud.

This one produces a slightly different signature: the shaft is genuinely seated as far as it can go, but the club measures long and the ferrule sits high because the bore was shortened by the debris in it.

How you identify it: measured length is longer than the build sheet says it should be, by roughly the same amount as the ferrule gap.

Cause Four: The Ferrule Was Simply Pushed On Too Far

The benign one. The ferrule was seated correctly against the hosel at assembly, everything below it is fine, and it has crept a fraction up the shaft because it was a loose fit on that particular shaft diameter.

This is a cosmetic repair. Heat, reposition, re-seat, re-turn, done in ten minutes. It is also the least common of the four, which is why we never assume it without checking the other three first.

Telling Them Apart

1. Measure the club's playing length and compare it to spec. Long by roughly the gap size points at a dirty bore.
2. Try to rotate the ferrule with finger pressure. Free movement points at a bonding failure.
3. Check for any rotational play in the head itself. Any movement at all means the club comes out of play immediately.
4. If length is correct and nothing moves, the ferrule alone has crept and it is a simple fix.

The Rule We Work To

If there is any doubt about the bond, the club gets pulled and rebuilt rather than cosmetically repaired. Pulling a head takes fifteen minutes and costs a ferrule. A head separating from a shaft mid-swing is a genuine safety problem, not an inconvenience, and it happens to somebody every season.

We would rather rebuild ten joints that turned out to be fine than leave one that was not.

Prevention, Which Is All Bench Discipline

• Abrade the full insertion depth, every shaft, no exceptions.
• Ream every hosel on a replacement or pulled head before dry-fitting.
• Dry-fit and mark the insertion depth before any epoxy is mixed.
• Mix epoxy by weight and work within its open time rather than pushing it.
• Twist and press on insertion to expel trapped air and distribute adhesive.
• Let it cure overnight, undisturbed, before turning the ferrule or gauging the club.

None of that is difficult. All of it is skippable when a shop is trying to get a club out the door the same afternoon, which is exactly why we do not promise same-afternoon builds.

Written by Emory Castellano Bench notes · Naples, FL About 5 minutes