buying steel

Two things.

Thing One
I'm still struggling with the design and materials for the hoist cart's outriggers.

• they need to extend far enough out that some kind of stowing means is necessary,
  otherwise, I'll be destroying my shins against them constantly

• from a mechanical strength view, a sliding/telescoping mechanism looks better than
   something that swings around on a pivot, and it occupies less space

• telescoping tubing is hard to come by, you usually end up fabricating at least one of
   the two pieces, and that is exactly what I intend to do.

obviously the parts aren't aligned or fixtured

• I have rectangular tube I'd like to use which is perfect for the outrigger arms, except I cannot buy a ready-made outer tube / shell / housing with the right ID

  I bought a lot of steel to weld up my own housings to fit the those two tubes I have on hand, but one dimension, which appears on two long pieces, is too small by about 1/16in.  I'm goingto try to fill it in with weld anyway.  Then comes the adventure of cleaning up the interior enough that the tubes will actually slide into it.  >_> 

 I've been planning on making the 'H' beam first, so it can be welded from inside.  If I decide I don't want to do that, I could also drill a series of holes or mill slots in the wide bit, and weld the center web from outside. Clearance is set with thin (.015

 Anyway, here's Wonderwall a lashup of my general idea:

But I paid for .125 thick, Hillman!

Thing Two
 Be careful when buying steel from hardware stores. They cheat you on dimensions like thickness.

 ie; you pay for 1/8in thick material, but it's really .114 or even worse.

the offending vendor (found at Ace Hardware)

How thick will this stick be?  How thick will that stick be?  Astonishingly, there is variation in a single short stick.  Yes, I checked my measurements several times.  The measurements at left were AVERAGE, not the smallest on the sticks.  The smallest was around .112 on both which is just ridiculous.

 When I buy steel from the surplus yard, and have to blast rust and mill scale off of it, it's right. on. dimension. Hot rolled, cold rolled, doesn't matter.

When I buy clean steel from McMaster, it is either right on dimension, or a few thou over.

 HOW IS THIS STUFF TOO THIN, THEN??  This stuff comes out of a rolling mill, for Ghu's sake.  What could someone possibly do to add variation in thickness?  It would seem impossible, but calipers don't lie, and neither does a dial indicator on my surface plate.

WTAF, Hillman?!?

 Parts of this assembly can see up to1,200 lb strain, and if it breaks, people could get badly hurt.
I guess I'd better re--figure the complex box beam calcs I already did once like half a year ago, to see whether I need to buy all new steel (and then throw this Chinesium garbage through Hillman's office windows - the one in Boulder).  Grump.

 Hillman would try to throw their "overseas partner" (China) under the bus, to which I would respond, "Don't you perform incoming QC? Don't try to tell us this is a one-off."

 I've seen this at two different Ace Hardwares, but oddly, I can't find anyone else whinging about it on Reddit or YouTube.  Obviously it's a secret conspiracy against me, then. =^_^=