After reading several negative reviews, I almost didn't get these, but I'm glad I did. I use pipe clamps to glue together table tops, amongst other applications. Some have been over 6 feet wide, involving 7 planks and 5 pipe clamps. I have had the threads tear out on a pipe clamp on multiple occasions. This is not the kind of thing you want to have happening while your glue is drying, and you are stuck with digging the thread end out and frantically re-threading your pipe! So the Irwins--yes, they just slip right on the end, no threading needed. Even if the pipe is threaded, they will still grip it firmly. I am at a bit of a loss to understand some of the complaints about spinning. To avoid spinning, you simply hold the clamp body with one hand while cranking with the other. I even had to do this with my threaded pipe clamps, because if you don't hold the body while turning, your clamp may not spin on the pipe, but it can flop right off your workpiece. I never thought about using these as spreader clamps until I read a review that said that they could not be used as spreader clamps--which made me think, maybe they could be. And in fact, they can be. I had the horrible job of repairing a table, where someone had hammered on the round base with 5 4" nails, which needed to be removed. I tried a mallet, which wouldn't budge it. Then I got to looking at this clamp. If you look at the illustration, imagine cutting a piece of support wood to fit into the area you would normally clamp. Do that. Now, as you turn the clamp to squeeze the support piece, it will cause the back side of the clamp ends to spread out. Okay--it's not so convenient, as you have to cut a support piece to length to fit each spreading application. You can only use them at the edge of a piece (not in the middle), so you might have to counter with another spreading clamp at the other side, and it's clumsy handling the wood cut AND the clamp--but it can be done, and when you get it right, it's a VERY powerful spreader. It eased the base right off, 5 fat, long nails screeching against the friction. My clamps came properly assembled, but I have to admit that the first time I used them, I put the non-crank end on backwards; it almost looks right but it's not and of course it won't tighten. As for the horrible plastic packaging--yes, it must be made of kryptonite! But I was able to get it off without any tools by tightening the clamp (the handle sticks out of the plastic case) until the plastic ruptured. The final thing I want to say is, these are best used with black steel pipe--not galvanized pipe. Black steel pipe is a hardened steel and costs a little bit more (I paid about $17 for 20 feet of it). But the black steel somehow fits the clamps better (as in, the clutch never slips), and flexes less under tension. Worth the extra money. Now--think about the economy of pipe clamps. They are, by far, less expensive than any clamp that can exert that much pressure. They are versatile--just cut a piece of inexpensive pipe to the correct length, and you have a new clamp. I have 5 Bessey clamps, and they are fine, but frankly, for most applications, I find myself reaching for my Irwins, which exert more pressure and quickly change out to any length. And pipe clamps last forever. Two of my Besseys cracked after several years of use. I've never ruined a pipe clamp. In sum--for me at least, a non-threaded pipe clamp offers several advantages: no stripped threads, easy dissassembly, quick pipe changeovers. These clamps also sit high enough so that you can put them anywhere on the workbench and have room to rotate the screw end, so they don't have to hang over the end of the bench. Nice fit and finish, well-aligned pipe holes, snug screwing mechanism--no complaints.