🧱 Blocks Precision-Hardened 0.0002-303-5500N Review

I have access to some really accurate grind gauges and this is what I see. 0001 to 0.0003 which I like because you can shake them off with a surface grinder and they still fit. If you're working where you need more accurate blocks, you shouldn't use 123 blocks. Excellent value for the size. The hardness was 62 HRC, higher than specified and the same hardness as heat treated D2 tool steel.

The holes in these blocks are precision drilled unlike the blocks sold here by other vendors. The box it comes in is also different, so it must be from one of the best Chinese suppliers. With this construction of blocks it is very important that the holes are accurately drilled and tapped in order to assemble them at right angles and in larger versions for installation. The others I ordered had to be returned because if you can't assemble them and hold them accurately, they just weigh paper…

They are surprisingly accurate in price. They are just as good as my (also Chinese, but not the cheapest) digital calipers. Arrived well oiled, wrapped in wax paper and in a plastic bag, but packaged in a fairly flimsy box that was nothing more than a padded envelope. . Both blocks fell out of the box inside the envelope. One of mine was slightly scratched in transit so one corner had to be adjusted a bit to remove the raised edge. Clean them with some acetone or brake cleaner and then hit them