HFS(R) Ultra Precision 1-2-3" Blocks，Machinist Block Set 2pcs/Pair, 0.0001" with Screw in Plastic Case

Accurate at least to 0.0005” - Perfect for a Hobbyist As an amateur machinist, I don’t need any more accuracy than these blocks provide which is at least 0.0005” according to my Mitutoyo Digimatic Caliper (of the same resolution). Both bock measured the same on all parallel sides. Though I did not specifically measure for parallelism, given that measurements taken on a few different areas all returned within 0.0005” it’s safe to say both blocks are parallel to within that degree. Pros: -Reasonably precise pair of blocks, 0.0005” on all dimensions. -Quality blow mold case. -Hardware and Allen wrench included for use in setup. -Ships with oiled rust prevention paper coating. -Price point. -Inexpensive enough where there’s no need to be precious with them. Cons: -None really. -Protective oil is thick and gummy, requires little effort to remove. -One of the bolts loosened during shipping was rattling around in the case. Hard to beat the value for dollar here. Precision is not lab grade, but good enough for the shop/garage—adjust expectations accordingly.

Precise and good quality. Fast shipping.

Like All cheap 123 blocks the non-threaded holes are too small and the included bolts do not pass through them and go into a threaded hole on the other block. The alternative is to spend hundreds of dollars. I do like have the case to keep them safe but it too has an issue that there isn't a good cut out for my fingers to get the blocks out of the case it without spilling the screws. Over all a good value for the price.

If you know what these are for, you need to buy it because I've notice they sell out of stock pretty fast. Precision quality in a sturdy plastic case. A must for every woodworker or maker. The price was quite reasonable considering the quality. I am considering buying another set. A great find.

I have had more expensive 1 2 3 blocks prior and used the crap out of them but left them in a garage and they ended up with too much rust to salvage. I bought these as a cheaper replacement and they are of equal quality to my previous ones (which had cost me twice as much) and came in a case with bolts and an allen key to attach them together to make a bigger block if needed. Each block was greased up and carefully wrapped in industrial VCI paper which keeps it from rusting during transport and storage which was a reat touch. I am keeping mine inside so I cleaned them off and wiped them in isopropyl alcohol, then put a thin coat of oil on them instead. Just be prepared to clean them prior to first use. I will defiantly be buying another set or 2 down the road for sure.

I bought these to use for fit ups and fabrication. They work perfectly for me. I did check with my (cheaper) dial calipers, they are within .001. I definitely don't work with those tolerances so it's not a big deal to me. You might as well throw the case away, it's made of cheap plastic and doesn't even latch closed. I haven't used the hardware as I only set them up on top of a fab table, and don't bolt them down to a mill or anything like that. Would buy again if I had to.

Price is right, quality of the blocks is good, and the case is a nice touch over some other inexpensive brands. Bolts are the weak spot, though they do work. More importantly, the tool and gauge guy at the factory checked them on his AA surface plate with proper indicators. In each plane they are parallel and square to within 0.0001" - total deviation. Absolutely nothing to sneeze at from any manufacturer. They are wrapped in plastic, paper, and heavily coated in oil. Keep them cleaned and lightly oiled, and they should last long enough to pass them to the grandkids.

The surface plate showed a maximum flatness deviation of 0.0001” when swept from multiple locations across the entire surface. The 3×2 faces of the 123 block were parallel within 0.0001” total. Squareness of the 3×2 face to the 2×1 face came out at 0.0008” total deviation. Since the opposing faces are verified parallel, that error splits evenly, putting each 3×2 face square to the 2×1 face within 0.0004” per 3” or 0.00013” per inch. Minus one star because the description states “0.0001 squareness accuracy” whatever that means. It’s 0.0001” PER inch.