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What's Wrong with this Picture??? MSC 2-1/2" Expanding Arbor

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Here's a little item I laid out 45 bucks for  :wack: :wack: :wack::

MSC Expanding Machinable Lathe Arbor, 2-1/2" Face Diameter x 4" Length

What's wrong with this picture?


--- Quote from: vtsteam on April 10, 2022, 10:23:29 PM ---Here's a little item I laid out 45 bucks for  :wack: :wack: :wack::

MSC Expanding Machinable Lathe Arbor, 2-1/2" Face Diameter x 4" Length

What's wrong with this picture?

--- End quote ---

Dunno, could be many things. One problem might be thin wall on stub, that expanding screw looks relatively thick.
A tiny screwed taper trying to move large chunks of steel. The centre hole and taper should be much larger.

I'm not sure that the screw looks long enough to engage the unslotted part of the arbor.


Seadog has it. Everything else in the ad description is truthful. It WAS 2-1/2" in diameter. It WAS a mandrel. It DOES fit in a lathe, and it IS machinable.

It just doesn't expand. 

Well, I take that back. If you take the 8mm Allen wrench supplied and cut with a grinder to a straight length and then weld that into 1/4" pipe, then make a 4" Tee handle for it, and try to expand it with that wrench and find it still doesn't expand perceptibly, so you slip a 8" pipe cheater over the new wrench handle and apply force until the expansion screw stops in a tight jam almost impossible to undo even though you greased everything with high pressure grease, you will get a measured .005" of expansion. Only at the very tip of the far end.

Who in their right mind thought that a small screw would perceptibly deflect six 3" long pieces of 1" thick tool steel enough to grip a part in a lathe? A part, which, to slip onto the 4" long arbor, needs at least .005 inches of clearance in the first place?  And the available .005" expansion only achievable with an oversized dumb-donkey wrench and cheater bar?

How can MSC ship these things out with a straight face? Have they ever tried one? Was it an April Fool's Day special, and I didn't notice?

Ya know it's not unusual for me to buy "cheap" tooling (this wasn't cheap btw) since it's what I can afford, and then have to correct something, or find a way to live with some small issue, or for it to have limited life, or a rough finish, etc. But this is a first..... where the simple purpose of a tool is so completely and obviously missing. An expansion arbor that doesn't expand. What were they thinking? That no one would notice?

I mean it seems obvious in hindsight, and embarrassing, not comprehending for several hours, so sure that it must work, that I went to the trouble of making a bigger wrench for it, somehow still believing that those 1" thick jaws would move. Of course they can't! Just look at the damn thing, Steve!  :hammer:

And ya know, I had a bad feeling buying it in the first place. It was a stretch, 45 bucks for something fairly simple, that I have made myself in the past (much smaller, however). But I thought, Steve, just buy it, that will let you get on with this engine build, without taking on yet another tooling project. Grow up, you don't have to make everything. The engine is the important thing. Get this thing and be done with it.

And the cool thing was, it was machinable, so it would fit the 2.400" bore I needed to hold. So naturally I did machine it before finding it wouldn't grip the part. I got a nice tight sliding fit. Both loose, and unfortunately with the mandrel "expanded"! So the return option wasn't available.

Anyway, what to do......

Well, notice the following ad, also found on Ebay. See any difference? And these are smaller -- 1-1/2" 1-3/4" and 2"...


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