Does anyone on here have experience with pressing Shimano spindles into or out of the drive side crank arm? Specifically looking for insight on fixturing the crank arm. It appears the spindle can only be pressed one direction due to a lip on the end of the splines, shown in the pic below.
What makes this tricky is that the outer face of the crank arm doesn't have a good flat surface to support it with.
The only example I can find of someone doing this before is this MTBR thread where the spindle was pressed out on the way to fitting an Ochain to Saint cranks. Unfortunately the author just mentions that they machined a jig to hold the cranks, but they don't include any pictures of it. I would love to figure out a way to hold the crank that doesn't involve any machining. I'm debating getting a metal tube that's just big enough for the spindle to fit through, then just using an angle grinder to put a little angle on one side of it that roughly matches the profile of the crank in the above photo.
Can you 3d print things? It's big enough that a 3d printed jig might not just crush with some of the fancier filaments?
The AIs can now do photogrammatry 3d cad modeling, so you don't necessarily need to spend forever or use a 3d scanner (and forever) to model up a pretty well fitting jig.
I wonder whether you couldn't cast some suitably high strength resin* around it in the orientation you need for the press
*No idea what that might be
Maybe put a tube over the spindle and pull it out using the threads which normally house the preload adjuster.
Those threads are tiny, I doubt they could take the torque considering the preload is meant to be 1.5nM, I doubt they could take the 40+ it would be necessary to remove a press fit part.
Find a friend with a fractal vise?
A soft jaw vice that you place in a wedge could work, the crank couldn't shift down because of the wedge, then fit a slide hammer to get the spindle out?
Maybe. Or maybe it’s only 1.5Nm because it’s only preloading the bearings, and the preload cap is often plastic.
On the spindle side it’s M20x1.0 in steel, so IF the threads are deep enough it might be enough. Tightening the LH crank around the threaded part might improve the grip.
I feel like I know someone who did this to make a narrow, aero Dura Ace bottom bracket - unfortunately I can’t remember who.
You might be on to something with the slide hammer idea though. If the spindles being sacrificed, you could drill through the spindle, put a solid rod through the hole, and hit the rod.
Stupid question - does it actually need pressing if we use heat? If you pop the crank arm in the oven on max and the spindle in the freezer, is there enough relative thermal expansion it'll just drop in? I managed to replace pressed in headset shells just by heating the headset - the aluminium outer expanded more than the steel bearing and the bearing fell out. If that doesn't work, I'd follow your proposed approach of getting a bit of tube ground to about the right size then again use a bit of heat on the crank and tube with hot melt glue to take up the gaps so you don't mark the crank and hold everything in place while you either use a press or some threaded bar and some nuts. Then just melt it off at the end.
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