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 (not my pic).
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
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.
By my quick calculations, even a well designed 3D print with a strong material couldn't comfortably withstand the pressing force. Maybe in a perfect world, but I wouldn't be optimistic personally. Definitely a good idea though
I really like where you're going with that, but it seems like any decent epoxy/resin in the quantity I need is fairly expensive. I should've mentioned from the start that I'm trying to keep this on a fairly tight budget. I'll definitely keep this idea in the back of my mind though...
I'm totally with you on this one, and I bet it would work a charm for getting the spindle into the crank arm, but my main concern is getting the spindle out. Frankly I'm not too worried at all about getting it back into the crank arm. As far as getting it out goes, I could try using a torch on the crank arm or maybe popping the crank/spindle in the oven. Not sure how effective that would be though, and I still need a good way to support the crank arm while the spindle gets pressed out.
Fill the spindle with water, put it in the freezer, make Popsicle, torch the aluminum... steel is a shitty conductor ... 🤞 don't overheat the aluminum... 🤞 pull/press/hammer it out.. 🤞? Washers, vice, slide hammer kind of thing? IDK if Popsicle technology like that would actually work though, just a stupid idea.
I guess it depends on how concerned you are with potential damage. Even the cord guy who made it sound like he made a pretty nice jig said it was helpful to have a sacrifice available.
Yeah I'm not sure about the 3d print thing either, I was mostly just thinking that if it's a minimum amount of effort (take photos and tell robot to do it) that it could be worth trying. Definitely skeptical. 10000% would not spend a couple+ of hours scanning and modeling for that.
I don't know for sure if this would work either, but I think you're on to something. And I'll certainly use the term "popsicle technology" in the future. 😁
ewebster, you may be able to tap the spindle out from the non-drive side using the hot/cold method. If you can secure the crank arm in a vise using soft vise jaws, you should be able to tap out the spindle from above.
Ohhhhhh, the picture of the loose spindle isn't yours! I'd certainly start with the oven as differential thermal expansion plus softening any "stuff" in there should help. Can't use hot melt glue as a jig though... I'd probably actually cut and sand some softwood to the right shape as it's heatproof, won't mark the crank and will deform a bit to fit the crank as it gets pressed into it (plus it's cheap if you change your mind). As I like a bodge, I'd probably just put the crank on the shaped wood on the floor, get a friend to hold it in place with an oven glove, hold some wood against the top of the spindle to protect it and hit it hard with a hammer, to save mucking about with threaded bar on something hot.
What's the goal of getting it out?
Bit of a long story, but I'm trying to swap the spindles between two sets of cranks that I've got
73 --> 83?
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