Ordered a Foam Knife 1 tip for my Oscar and couldn't get it to thread on to my steam wand. They even sent me a replacement to try and it's the same. AFAIK the wand is indeed original to the machine (wand and tip match shape/appearance of stock) but I've read multiple reviews on the product that mention use on an Oscar. Espresso Parts staff even confirmed it should fit my wand, so I'm curious if I should be ordering an Oscar or LM and to swap with mine to make this work.

both the vortex and the foam knife will fit on to oscar wand
thread pitch and gauge 1/8 G for the stock Oscar wand
which I believe to = 1/8 BSPP
while a 10 mm x 1 fits for 2 threads it must be forced to engage further

took a new wand and threaded a vortex on , unnerving resistance at the 3 rd thread
but threaded on easily after

your wand may have had a non stock tip on at some time in the past ....
thread cleaning or new wand , and at least new washers...

Sounds like we're on the same page, I meet some pretty stern resistance almost immediately after it catching threads and I simply wasn't comfortable continuing to force it in and perhaps damage the threads of either the wand or the tip. I gave it he wand threads a quick cleaning and they appear to be straight, damage free, and have no debris or buildup. Should I just give this a shot and try to muscle it past this point of resistance? Or just bite the bullet and order another wand hoping it's a bit easier to thread?

tough call , it's your high dollar steam tip
early oscar wands have threads up to the shoulder , later wands are undercut

on the foam knife , my oldest and most used , all three taps threaded easily , on the vortex , newest and least used , only the starter tap would thread into the tip , mid and bottoming taps would not start

sorry to be so little help
g'luck

I had previously been trying this by hand without any tools. Gave it a try this morning with a wrench and it went on a lot easier. Now that it's done, I just need to get used to how different it is - thanks for the feedback plindy.