It's common with people who think they should weld the nut onto the axle's stud (as with a nutted spindle) but don't have access to a welder (thankfully:)) Andy.

This sucker was bad, Both sizes must have had the dreaded steel-aluminum galvanic corrosion. The threads stripped out of the arms on on both sides too. No help from the torch. I pulled out my sawzall to finish them off. On the drive side, even cutting the slots didn't help. I had to cut the chain rings. When I got thru the middle gear, the tension released and it popped off,

https://cimg1.ibsrv.net/gimg/bikefor...b810a10715.jpg

But I found out later that an automotive pickle fork would have worked. These look like tuning forks with tapered tings that you slip under a tie rod end, Then you tap with a hammer and it spreads the pieces apart,
https://cimg4.ibsrv.net/gimg/bikefor...8daddd1574.jpg

Common problem when using a Puller instead of a Yanker.

Those balljoint splitters aren't great, they might work on a NDS crank but access is difficult to impossible on a DS crank, especially if you can't remove the rings.

ummmm... dependent on the Bottom Bracket style and materials, those pickle forks can also ruin the frame's BB threads......

"tap with a hammer" is not correct... try "Beating the living daylights out of the Pickle Fork."
i've tried the pickle fork a couple of times, when dealing with cranksets that refused to budge using the correct puller..
i ended up cutting/splitting them... i just recently did that to an arm with the puller threads ruined by previous attempts to remove the arm...

i deal with old rusty bikes fairly often... too often... you did well cutting/splitting the crankset.
i get 2 slots cut, then use a shallow taper chisel and 3 lb. rock drilling hammer to finish cracking the arm.
and, once the slots are cut about 2/3 of the way, you can, sometimes, get the final cracking by hitting the crank arm out by the pedal threads...

This thread is somewhat useless without the word of Brandt:

":> My cranks get loose, quite quickly too; over about 10 miles or so from being solid to flopping about in the breeze. Any suggestions?

Your cranks are ruined! Once ridden in the "floppy" mode, the square taper in the crank can no longer be secured on the spindle. Get some new cranks and properly tighten them after lubricating the tapers. Proper tightness can be guaranteed only by torque wrench or a skilled mechanic. The second of these is less expensive and you might be able to get a demonstration of what is tight enough.

The admonition to not lubricate the tapers of the crank spindle seems to find life only on bicycle cranks, of all the machines I have seen. I have pursued the "dry assembly" instruction by talking to crank manufacturers and discovered that they apparently had warranty claims from customers who split their cranks open. It is easy to prove that cranks cannot split by over-tightening simply by attempting to do so. It is not possible to split a major brand crank this way, the bolt will fail first.

Crank failure from "over-tightening" is caused by the re-tightening of previously properly installed cranks. Once installed, a crank always squirms on its taper, and because the retaining bolt prevents it from coming off, it elbows itself away from the bolt and up the taper ever so slightly. This can be detected by the looseness of the retaining bolt after the bicycle has been ridden hard.

Grease in this interface does not affect performance, because only the press fit, not friction, transmits load from crank to spindle. As any bicycle mechanic can tell you, crank bolts are often appreciably looser after use, the left one more so than the right. This occurs because the left crank transmits torque and bending simultaneously
while the right crank transmits these forces one at a time. The right crank puts no significant torque into the spindle. Either way, the looseness occurs because loads make the crank squirm on the spindle and the only direction it can move is up the taper, the retaining bolt blocking motion in the other direction.

Regardless, whether grease or no grease is used, in use the spindle and crank will make metal to metal contact and cause fretting corrosion for all but the lightest riders. The purpose of the lubricant is to give a predictable press fit for a known torque. If the spindle is completely dry this cannot be said, and even with marginal lubrication, some galling may occur on installation. Lubrication is only used to guarantee a proper press because the lubricant is displaced from the interface in use. Taper faces of spindles show erosion and rouge after substantial use, evidence that the lubricant was displaced.

"Dust caps" aren't just dust caps but retention for loose bolts. It is not that the bolt unscrews but that the crank moves up the taper. However, once the screw is unloaded it can subsequently unscrew and fall out if there is no cap.

Because cranks squirm farther up the taper when stressed highly, the unwitting mechanic believes the screw got loose, rather than that the crank got tighter. By pursuing the crank with its every move up the spindle, ultimately the crank will split. It is this splitting that has been incorrectly diagnosed as being caused by lubrication. I have
never seen a warning against re-tightening cranks after having been installed with a proper press fit. It is here where the warning belongs, not with lubrication.

For the press fit to work properly, the pressure must be great enough to prevent elastic separation between the crank and spindle under torque, bending, and shear loads. This means that no gap between crank and spindle should open when pedaling forcefully. Friction has no effect on the transmission of torque because the crank creeps into a position of equilibrium on the spindle in a few hard strokes.

Failure of this interface occurs when the press fit is too loose allowing a gap open between spindle and crank. Torque is transmitted by the entire face of the press fit, both the leading edge whose contact pressure increases and the trailing edge whose contact pressure decreases. If lift-off occurs, the entire force bears only on the leading edge and plastic failure ensues (loose crank syndrome). Tightening the retaining screw afterward cannot re-establish a square hole in the crank because the retaining screw will break before the spindle can exert sufficient stress to reshape the bore. Beyond that, the crank would split before any plastic deformation could occur even if the screw were sufficiently strong.

Because retaining screws could become entirely lose from squirming action, especially if the press is relatively light, "dust caps" should be used to prevent screws from subsequently unscrewing and causing crank bore failure. Besides, the loss of the screw won't be noticed until the crank comes off, long after the screw fell out.

The argument that the greased spindle will enlarge the hole of the crank and ultimately reduce chainwheel earance is also specious, because the crank does not operate in the plastic stress level. At the elastic limit it would break at the attachment knuckle in a short time from metal fatigue, that occurs rapidly at the yield stress. In fact, the depth of engagement (hole enlargement) can increase with an unlubricated fit faster than with a lubricated one, because installation friction is the only mechanism that reams the hole.

Jobst Brandt"

"Proper tightness can be guaranteed only by torque wrench or a skilled mechanic. The second of these is less expensive"

Not in this century

A 10 minute crank swap turns into a 2 day affair. Stripped threads results in brute force.

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