It was fitting I listed to the "This American Life" episode on fiascos yesterday before trying to saw the stuck stem off the fork tube on my early 00's steel framed Hardrock. I did make some headway, and have read enough posts regarding sawing the stuck stem through to remove it to know it's going to be destroyed in the process, but thought that using a grinder to remove the stuck stem would be easier than using a hacksaw. I haven't seen any posts on that and doubt I've thought of something new here, is this a good choice? Or should I just suck it up and keep using the hacksaw?

Have you tried soaking the stem area in WD-40, or some other penetrant? Sometimes a good soaking and working it will get the rust to break free and then you can use a wrench or other things to get it to start turning, then soak it more, etc. I had to go that on an old BMX bike once and it took a couple of days, but it worked.

then you need to get out the fused parts with no leverage to twist them with relative to each other..

You own a drill press? one that takes a 7/8" drill bit?

I've tried the penetrating oil (pb blaster) but this is an aluminum stem stuck on a steel fork tube that's going to require more than that.

+1 on PB Blaster or even better, Kano Kroil.

No drill press, but I do own a drill. Thanks for the idea.

The big drill bit can be chucked up in a Lathe , too , then the fork gets clamped where the cutting tools go ..

trick is to move the 2 parts together strictly aligned with each other..

not a hand held winging it project, best to do right. or just throw it in the bin in the 1st place

The stem was adjustable, and has a gap in the front where the 2 halves of the stem are squeezed together. Drilling down through the gap may give me enough room to insert of pry bar and get the 2 halves to separate again.

Ah so not the usual quill stem & galvanic corrosion. secret detail.

Yep, sorry I should have included those details shouldn't I?

I've noticed , here, Its all to common to assume that the unknown is known

on both sides of the screen . so it goes..

If you can do it safely, sometimes you can use a propane torch and heat the area then beat on it with a soft mallet to help break the corrosion loose. Lots of old motorcycle tricks I'm trying to think of, but a motorcycle can be beat on a little bit more. Only thing I'm worried about with cutting off and trying to drill out is that if the drill isn't perfectly centered you may ruin the part.

Have you tried locking the stem in a bench vise and using / turning the frame to get maximum leverage? I have seen this work on Al seat posts that have galvanically seized to CrMo frames.

You could also try plugging up one end of the steerer and fill with ice water for about 30 min. or better yet put it in the freezer for at least an hour and then quickly heat the steel part with a torch and immediately try to twist or hammer the stem loose. Sometimes this can break free the parts but go easy on the heat. It doesn't need to be much hotter than too hot to touch.

Grinders don’t work particularly well to remove aluminum alloys. Aluminum simply loads up the the wheel. I’ve had to remove stuck seat posts by cutting them out.

Cut the stem / seatpost off leaving a fair amount of space above the frame. Then cut a slot along the length of the remaining cyclinder still inside the frame. You don’t want to try to cut all the way through; you’ll probably cut into the frame if you do. You will create a slot with a slight dome in the middle, thinner at the ends. Take a cold chisel along the length of the slot to create a crack in the remaining web. Cut a second slot nearby using the same technique. Somewhere around 1 cm is appropriate. Now you can use some sort of punch (including the chisel you have in your hand) to pry the section back. Now you can take a pair of channel locks or visegrips to squeeze the remaining post away from the frame. You may have to repeat several times.

I’ve used hacksaw blades which was an all day job, but it became manageable when I used a sawzall type electric hacksaw. Less than an hour to remove the seat post the last time, probably 30 years ago.

Thanks for all the advice, I ended up using the hacksaw and everything is apart. I'm at the "we're going to have to order those parts" of this project now.

then, NB, it flings the bits back out at a high velocity back at you ..
so not a safe practice..