HOW TO DRILL OUT STAKES

HOW TO DRILL OUT STAKES

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  • On 15th August 2015

DON’T FORGET TO DRILL OUT THE STAKES when replacing the bearings in your wheels’ hubs.

Because if you did, you would 1) have a captivating story to tell and 2) you would end up with an unusable hub that you would spend some time convincing yourself is perfectly safe to use when, in fact, it isn’t.  There is a lot in a “stake” because of what is at stake.  Your life.

A “stake” means many things. of course, but with regard to fastening, “staking” is a technique of preventing a threaded connection from becoming loose by deforming a part of the “bolt” or “nut” or both.  This will become a little clearer in a moment.

Replacing the bearings in a HONDA CB550 hub requires removing a bearing retainer whose purpose, as its name implies, is to keep the bearing in place.  Many people have struggled with removing the bearing retainer and doing some irreparable damage because they were unaware that the bearing retainer is “staked”.  “Staked” means that after screwing the retainer in place, the aluminum flange/nut the bearing retainer screws into is distorted in order to prevent the bearing retainer from coming out.  This is done using a punch placed in the space between the retainer and the hub and hitting it with a hammer.  The indentation made by the punch tool deforms the flange and causes a radial expansion of the metal into and over the threads.

Here is a photo of an original stake in a HONDA CB550 rear hub.

Original "stake" in a HONDA CB550 rear hub

Original “stake” in a HONDA CB550 rear hub

Note the radial expansion to the right.

It is virtually impossible to remove the bearing retainer without “drilling out the stakes”.  Many have reported that they have managed to get the retainer to turn a few turns and then it got stuck.  By that point, the threads in the hub are destroyed and the retainer is “welded” in place.  Repair is almost impossible.  Turning the retainer back until the stakes are visible again and then drilling them out might be the only reasonable course of action.

Drilling the stakes out is relatively easy.  I use a 5/32” drill bit and drill about 1/16” deep.  The idea is to drill out the stakes (to avoid confusion and misunderstanding, “drilling out” means removing the deformed material) until a clear line/space can be seen between the retainer’s threads and the hub’s threads. Here is a photo of what needs to be accomplished.

Drilled out stake

Drilled out stake

Even when the stakes are properly drilled out, it might still be very difficult to unscrew the bearing retainer.  It is left threaded (it tightens when screwed counter clockwise) and there is an arrow on it showing the direction in which it is screwed back in, not the direction in which it should be unscrewed.

Bearing retainer

Bearing retainer

The arrow is the faint curved line at the top.  It points to the left.

Since the retainer sits on the left side of the hub (the same side that the sprocket is on), the tightening direction is the same as the direction in which the wheel turns.  So, as the wheel spins counter clockwise when viewed from the left side of the bike, i.e. when you are looking directly at the sprocket, the bearing retainer will spin in a direction that will tend to keep it tightened.  I assume this is what the designers and engineers intended when deciding to have the retainer left-threaded.

If a reasonable amount of leverage does not move the retainer, it should be heated “super-hot” and then it will be easier to remove it.  The retainer appears to be stainless steel (it is only mildly magnetic) so rust is unlikely the reason why it is difficult to remove. Only resort to hammering the bearing retainer using a punch or some other tool, if all else fails.  Stainless steel is relatively soft and the force needed in order to get the bearing retainer to move will likely deform the retainer.  You will then have to either buy a new one (luckily, they are available) or very carefully file out all deformations especially at the bottom to ensure that it will screw back in and sit flat against the hub’s flange.

Once the retainer has moved a quarter turn out, it should be very easy to remove it by hand.  If it does not unscrew easily, spray WD-40 and try again.  If still very difficult, the stakes may not have been properly drilled out.  Go back and drill another 1/32” down or so.  DO NOT DRILL TOO DEEP.

Note the beveled edge (the bright curved line) in the hub at the bottom of the stake in the photo below.

DRILLED OUT STAKE SIDE VIEW

Chances that the original stake is deeper than the bottom of the beveled edge are very slim, so, this is as far as you would need to drill.  Drilling further down and going into the threads is, in my mind, unnecessary and could damage the threads.

For information on how to remove the bearings themselves, click here.  Prior to hammering out your bearings, carefully inspect the old bearings and note that the smaller of the two bearings sits flush with the hub’s flange.  This bearing is a “floating” bearing meaning that there is no hard stop for it and it is possible to drive it in further than intended when you are installing the new one.

I hope this helps.

QUESTIONS?