6 x 8 x 2 Grade B O Ledge Inspection Granite Surface Plate

So smooth, so flat, so heavy. This is a perfect size and a must have for the serious knife maker or small scale machinist. When flat matters, a surface plate is a must! This will outlast me if I take care of it. Great price.

As the title says, this was a fabulous purchase and is perfect for my leather work. The photo doesn't show it's thickness as I've countersunk it with just a small amount raised above the desk surface. I will start by saying it's HEAVY. I don't think I realized just how heavy this would be and even lowering it into the cutout compartment area was a huge feat. I will advise that if you intend to do leather stamp work on this it will require something to absorb the shock underneath. Mine is resting on a foam yoga mat like surface in a build in/converted keyboard tray slide out which we reinforced. This photo shows it with the dusty look it had upon receipt but after one quick cleaning it has not had that look any longer. It's very nicely smoothed. The edges are nice, there are no imperfections and this was just a fabulous purchase! Highly recommended.

Initially I was very skeptical of this surface plate, the low price coupled with mixed reviews on other sizes from the same manufacturer placed it solidly in the "too good to be true" zone but I figured I'd give it a shot and if it didn't meet the advertised tolerances I'd just return it. I'm glad I took the gamble because it ended up not only meeting but surpassing my expectations despite a major hiccup in delivery. I knew it was heavy so when I saw it was out for delivery and my dog started barking at the door I opened it to take it directly from the UPS guy so he didn't have to awkwardly set it down. As I opened the door he stumbled a bit coming up my front steps and dropped it from chest height onto my concrete front porch and it landed right on the corner. When I was unpacking it to inspect it for damage I initially wasn't very impressed. It came packaged in a cardboard box that contained a wooden box with the surface plate inside of it wrapped in a thin foam sheet, maybe 1/8" thick at most. I'd seen some reviews say it came in a wooden box and for some reason I had it in my mind that it would have a nice storage/protection box like gauge blocks do, this is not the case. The wooden box is made from the worst quality OSB you could imagine and sloppily put together, it is only there to protect the surface plate in transit and nothing more. I sliced my hand pretty good on some of the staples that had been holding the wooden box together before the drop as they were sticking out into the cardboard but I don't think that's entirely from the drop as they were sticking out similarly in other places so be careful when opening it. As unimpressed with the packaging as I was it did do its job, the OSB in the corner it landed on had basically disintegrated so there were a ton of splinters and chunks of OSB as well as a fair bit of granite chips, gravel, and grit which had me worried. After very careful examination though the surface plate came out undamaged, no chips, cracks, or any indication it had ever been dropped aside from the mess of a box it had came in so I have no clue why there was granite debris in the package with it. After inspecting it for damage and sending the UPS guy on his way I inspected the surface plate with both a Mitutoyo 543-793 digital indicator (0.0001"/1um resolution, +/- 0.0001" accuracy) and a Mitutoyo 513-409 dial test indicator (0.0002"/2um resolution, +/- 3um accuracy) mounted to a Starrett surface gauge and boy was I impressed. The listing for the "Grade A" plate I purchased claimed +/-0.0005" and the maximum deviation I was able to measure across the plate was ~4um or ~0.00016" with the majority of the plate being dead on flat not even a wiggle on the needle. On the plate I received two of the corners and one spot near the edge are high by 1-2um and a third corner is low by 2um. All of the high or low sections are very small, a single to a few square centimeters at most. For the price tag of $120 I went in with basically zero expectations and honestly would have been happy if it was within 0.001" and maybe I'm just a lucky winner of the cheap Chinese surface plate lottery but I'm extremely impressed. That said though, this is not a Grade A plate per ASME standards, even calling it Grade B in its current state is generous and the example I received is much better than advertised, I'm sure that won't be the case for everyone. I'm certain that if I put a little bit of work into cleaning up the high spots I could have it calibrated and certified as Grade B, anything beyond that would require equipment that I don't have. Overall, for the price, I'd say this plate is definitely worth it if you're just getting into machining as a hobby or looking for a small plate for inspection of smaller parts that don't require crazy tight tolerances. I think the biggest value, at least in the example I got, is how little work is needed to clean it up into a higher grade plate than it is out of the box.

very good plate, class B good price, will do for knife making.

Received in one day. Looks fine. Best deal I found without looking too hard. The one thing people should know (and the pictures clearly show this) is that all edges are beveled with some of the corners being deeper or a bit inconsistently done. On mine it's very slight. Most likely done so they don't have to worry about chips on the edges. For a sanding surface this will make no difference but for me, square edges woud be preferable. For the price it would be hard to do better if you don't need it for the straight edge. It's well packaged in all-natural wood, paper and cardboard. : ) I find no nicks scrapes or flaws of any kind. I have no way to test for flatness. I am satisfied with my purchase.

Would it pass muster in a real tool room? Most likely not. I might take it in to work and run a surface comparator over it for fun just to see what it’s really good for. But for the price and what I’ll use it for in my home shop. Well worth it to me. It’s like the import “disposable hammer” level of tooling for my metrology. But if your looking for accuracy levels to the tune of .001”. I’d be confident enough in it. Came in a wooden crate. Very well packaged given that it was free freight. My UPS lady was particularly annoyed with me for having an 80lb phone book size parcel. Sure, I’d MUCH rather own a large pink granite plate. But my wallet can’t complain given the accuracy vs price. Bottom line? Wouldn’t bet my career on it. But it’s got acceptable tolerances for my uses.

The product I received had a large chip on one corner, and a small chip on another corner. I am not sending it back, and without the chips, I might have given it five stars. VERY heavy/dense slab, seems to be very flat, and should work well for my purposes. But the chips are very disappointing, though they will not actually affect my use of this item.

It's a flat rock. It arrived in one piece, although a little dusty. There's no useful data on the "calibration certificate", but at least they fixed the spelling of "standards". I can swing a tenths indicator around on it and the needle moves by about 0.0001", although I am aware this doesn't really prove much. Overall, can't complain!