WEN 10423 3 x 2 x 1-Inch Steel-Hardened Precision 123 Blocks, Two Pack

Bought two sets, so four total.Cleaned them off with mineral spirits and some denaturated alcohol and measured all dimensions, and each end, with Mitutoyo calipers (precision to 0.0005"). They all landed on the 0 but depended on the pressure applied, meaning they are probably somewhere in their stated 0.0002" tolerance. The middles all dipped to X.9995" with the same pressure applied to the edges, but stayed at 0 with lighter pressure, so each of the blocks has a very mild dip in the middle, but that's ok.I also used a DIN 875/00 knife-edge reference square to check for square. They're good enough for wood working and some rough machining setups. Some corners were so good there was zero light leak. Others were off a bit. Definitely not ultra-precise blocks, but more than good enough for most needs, especially at this price point.Blocks like these make EXCELLENT clamping and square blocks for building boxes or other things where traditional full size woodworking clamping squares won't fit. They also won't flex or bend, so you can apply significant clamping pressure to use these to force tight joints into square.

I've found more uses for these blocks than I thought I would. Size is accurate, machining is high-quality. Quick set-ups for 1" / 2" / 3" increments, check square on both sides of a table saw blade at once, bolt them together to make a 90-degree corner block, hold-down for small light-weight glue-ups, etc.

I love how simple these are. I don’t know how I survive these past years without them. I have one on every one of my drill presses now in the shop. These are a great value and great quality. Highly recommend recommended.

These blocks are dead accurate and solid. Great for squaring up jigs, tool setup, or clamping small parts. Threaded holes are clean and consistent. Feels like a machinist tool at a woodworker's price.

I ordered these for general use, such as level the gantry on my 3D printer. I used my micrometers and these 123 blocks are only accurate to about 10 or 15 thousandths, depending where you measure. That is good enough for most people, but these are not blocks that a true machinist is going to want to use for precision work that needs to be within a few thousandths. There is ample oil on these blocks and they are flat enough they will ring together on most surfaces. Overall I think for the price they are a good set of blocks you can use for odd purposes without feeling guilty of damaging them.

I purchase several things on Amazon and was giving pretty in-depth reviews. From this point on, here's the new agenda…. if it works as advertised, is well made, meets or exceeds the description, is a value, and arrives in a fair amount of time, it will get a "star rating" equal to what my expectations were/are. If it doesn't meet these criteria, then I will most definitely and descriptively tell the short comings of the products and you as a consumer will not have to go through the trouble of buying the product without some background knowledge. If the sell pulls that item and relists under another description, I will put the exact same review on the seller's feedback page. Sellers have done this a couple of times in the past, and I was true to my word then as well as now. DR

These blocks are great. I checked their accuracy with micrometer, spot on! And you get 2 of them - Bonus!

Couldn’t ask for a better product. Great price too.