Cutting Automotive Shock Pistons?

I used my 10" lathe for a couple last week. I just chucked up the body kind litely and hit it with a threading cutter (because that's what was in the toolpost). cut it right open, sprayed oil in a nice 360 pattern.

2nd one I stopped as soon as it broke through, turned the opening down into the chip pan. Then completed taking it off.

All is soft stuff except for the shaft itself. Bandsaw won't have any problem with anything except the hardened shaft surface.

It's messy, but I've cut them with a chopsaw, sparks and all, and nothing caught fire. My purpose is usually to salvage the shafts, so I don't mind trashing the rest of it.

How do you figure? I've cut a lot of shocks over the years. The pistons are made of cast aluminum, stamped mild steel, or powdered metal. There are shim springs in them that are hard, but the chances of hitting those is slim.

All I have is a mini-lathe. Unfortunately, these aren't mini-shocks. :)

I don't like the "except" above. I assume you mean it will just slow it down somewhat.

Hmm, didn't think of doing that. I've got one of those, and it isn't a mini-chopsaw, so I should be fine. Probably faster than waiting on that bandsaw, too.

Just out of curiosity, what do you salvage the shafts for?

--Donnie

The shaft is hard-chromed. I doubt a bandsaw will be able to bite into it. The hard part stops about an inch from the treaded part, typically. It's obvious by looking at it.

Absolutely. I try to cut them close to the base, as the inner cylinder is some nice tubing that is useful. I try to miss it.

They make great arbors. Both ends are threaded on a reduced shank. The shaft is very accurate If you need to mount a gear, just turn the shaft to the ID, slip the gear on, then use spacers and nut to hold it. After a couple uses the shafting becomes stock for miscellaneous projects. I've seen shock rods used as replacement shafts for a QC box. They are often just the right OD, and all they need is a keyway. Very nice low-friction shafts.

Nope, the strut rods are hardened chrome, and no cutting tool will cut that surface. The inside is also darn hard, but can be cut with difficulty by carbide cutters. The chromed surface, however, can only be cut by grinding wheels or abrasive saw blades. The inside of the shaft is still too hard to bandsaw with any blade I have.

Jon

: > All is soft stuff except for the shaft itself. Bandsaw won't have any : > problem with anything except the hardened shaft surface. : >

I haven't had any problem turning these once past the 'crust'. Doesn't turn very pretty, but it's machinable for my purposes. I don't think my HF bandsaw would have a problem cutting a de-chromed section. but I may have to try it now.

On 9 Nov 2005 14:28:33 GMT, with neither quill nor qualm, Donnie Barnes quickly quoth:

I've salvaged several strut rod shafts by cutting the housing open with a 4x1/16" cutoff blade in a die grinder. HF sells the disks in

10-packs for $5 on sale quite often.

Since they were old and worn out, they were already depressurized.

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Thanks. Looks like I'll be using the chop saw or a cutoff wheel.

Yeah, and that's obvious when that's the case. Mine aren't depressurized, but I'm cannibalizing them nonetheless.

In case anyone cares, it's common to do this on strut cars to replace the shocks with single adjustable race shocks. It's easier for them to manufacture an "insert" that goes in the original strut body than to manufacture complete replacment struts.

So you drill a small hole in the bottom of the strut to depressurize, then cut the top of the strut off and remove guts. Then drill a larger hole in the bottom, insert the new shock, and run bolt through bottom hole into new shock to hold it in place.

--Donnie

Err, while you might normally be on to something, you might note that Miatas are double wishbone cars and my original (and subsequent) posts have been about cutting *struts*, not shocks.

Besides, the Spec Miata shocks are Bilsteins that you can take apart without cutting. :-)

--Donnie

Only if you are willing to lose a blade. I can't vouch for ALL strut rods, but the one pair I have are pretty darn hard stuff, and it ate my bandsaw blade in one second. I had ground below the chrome first. I had to do all work by grinding or turning with carbide tools, and it was quite hard on the carbide, too. I made an extension punch for an air chisel, and use it as a "mini jackhammer" for blasting holes through concrete walls. It does an amazing job without any attempt to harden it, even. I do have to resharpen the point on the thing a dozen times while making the hole, though.

Jon

Gee, and to think I didn't think I'd have any use for those shafts when done. :-)

--Donnie