Granite Surface Plate 12" x 18" x 3" A Grade
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In the thousands of a Starrett, you do not have to worry about tens and hundred thousandths. If you spend your time in tens and hundred thousandths or in microns, then you need to spend the thousands. In my case, there is no high spot. A thousand eight". I am able to use it just fine. I can measure it to be flat and to be plus or minus A thousand one.
When it comes to "measurement" questions, I almost hate them. Several tenths of microns and several feet are what I measure. If this stone is measured with a machinists square, it is I use a stone that has been certified by national standards when I want accuracy. It's easy to throw and use this stone to get within a quarter inch of a flat surface. Subsidies would be requested if I demanded them If this flat surface was accurate to a micron, it would be just like
A certificate detailing deviations from absolute flatness comes with the plate, but I cannot recall the numbers. Plates with these tolerances are extremely suitable for the use to which they are
Support should be placed at three points on a surface plate, ideally located 20% of the plate's length in from the edges. The two support brackets and one center support should be centered on the long sides, and they should be placed 20 percent of the width in from each long side.
Selected User Reviews For Granite Surface Plate 12" x 18" x 3" A Grade
This is either a granite-like stone or concrete that is a light gray, almost white, and that has been colored black except for the base. As you can see, this is not a cosmetic issue, it indicates that the material had to be hidden. It is because granite is dimensionally stable and resistant to wear that it is used for surface plates. However, what is this stuff? On the pictures I uploaded, you can see some of the stains that were prone to spreading upon the bottom surface after a rag was used to apply black stain. This picture of the grayish paper towel square demonstrates how acetone can be used to remove dyes from products, which isn't possible with a marble or granite surface.
In spite of the black appearance in the photo, granite is gray. In today's world, there is granite and there is granite. It is likely that red granites (pink granites, in fact) have a greater quartz content, making them harder surface-wise. However, black granites, even though with less quartz, are firmer than granites (and as such are not strictly granites at all). This means that the same accuracy can be achieved with Grey granites can be found somewhere along the ridge. Due to granite's hygroscopic properties, gauges left on the surface can rust if they are left sitting in water. The gray ones are dyed before they become black, so the black ones can start out This is all very interesting to me, but I don't consider it relevant to my small shop application The information about the product I buy is just for my benefit. With this plate, you will also find a calibration map or sheet The photo is shown below. There is no identification of the measured points Are you left with any? Is that right? According to the sheet, my plate has a zero and a There is a continuous band of 1 micron at the diagonal corners and a peak of 2 microns at the center. In the center, the diameter is 3 microns. Please see (2). There are 90 microns in 3 microns. This plate has a central peak of 6 microinches, so it has a central peak of The square footage is 9000906 'Flat to ' is the Amazon page's description. The number 00005. In terms of microinches, if we read that as 50 microinches, then that means this guy does indeed measure within As other reviewers have pointed out, there is no indication as to where exactly the plate's support points should be located. The knowledge of its thickness is probably not vital for a plate this thick, but all the same it would be nice to know. My calculations suggest that, under its own weight, this plate would sag about 30 microinches in the middle if held at the 12" edge. The middle of it is high, so it will tend to be flatter due to that sag.
Kenobi tells you to keep looking as this is not the droid you've been searching I wish I had better testimony to state that it's great, but this surface plate is not up to the task of testing precision surfaces. In order to check Sykes for high spots and also to check for straightness, I used this to hold my indicator on it while I slid end to end. I can see the comparison of my level on my bed and the granite, and they are far apart. There must be a reason for this, since it's only finished on one side. But what good is it if you want to set it on a level table and it's Honestly, I'm a bit disappointed and I would have returned it if I'd checked earlier, but I had kept it safely crated until I was ready to take it out. suppose it would be fine for woodworkers, but it will be of no use to machiners. My recommendation is not to do what I did and go searching for the cheapest one so then you can compare against another cheaper one that is more accurate. As a result. Do yourself a favor, young jedi, and look for precision that is guaranteed on all sides. The fact that I own it now and am paying to have it precision squared on all sides may lead me to send it out at this time. Due to the fact that the bottom has not been sealed, keep your hands clean when handling oil or dirty items.
This is a great price for the quality of the plate. In the advertising, there is a glitch. This is the According to the web site, flatness of 000050" is appropriate for AA grade. Grade A is listed as being the grade of the plate. The number "000100". In the case of this plate, it rated It is right at the specification for Grade A at 5 microns. I just want to point out that this plate is flat to start with. There is no "000100" to be found. This is "000050".
Unlike the cardboard box it came in, the wood box it came in is a bit weak, meant more for shipping than long-term However, if you reinforce the corners, you have a great way to protect your surface plate when it isn't being used. I had to add a couple of small handles to my box so that I could pull it towards me when using it, and then push it back out of the way afterward. Moreover, I removed the front side of the box in order to be able to hang larger items from it without having to remove it from the box entirely. I may go back and fix the front before the lid is enclosed so that when not in use, the lid is completely closed.
Since I've been researching the many different ways I can sharpen my irons, chisels, and other cutting tools, I have been looking for ways to do it. In my research I have examined both the million dollar grinders and the inexpensive Woodworking is not something I know anyone who is good at. Whenever I watched my Grandfather sharpen his tools, I thought it was so cool. The old school route was what I decided to take. A granite piece as large and solid as this is a heavy Those interested in hand sharpening their tools and irons will find this to be very useful.
I received the item in a wooden box inside of a regular box and it came in a sealed bag with a questionable "flatness report. " As a result of its made in China and missing information on some of the bottom areas, I would say it's questionable. Despite the fact that the report may have been made up of random numbers, the actual product appears and feels authentic. Next to that, my Starrett straight edge was the most accurate I had, and it did not give me any indication that the stone was not perfectly My sample has a flatness of 2 and I received one of those. There are 7 micrometers in it. There are 106 microinches in this measurement. Based on what I think, since this is an nonstandard-sized plate and I had to use the flatness formula, the tolerance for flatness on the plate must be There is a 7 microinches difference. Having said that, you would be looking at around It has a tolerance of 76 micrometers. There are two numbers on my certificate. It is a Class 00 component that is 7 micrometers in diameter, but it could be truncated to allow for truncation, I couldn't tell for sure whether my plate was within the tolerance limit since it would be 799,999 micrometers in diameter. I use it for woodworking but, since I am not using it to do lab work, or anything more precise than that, it's not perfect but it's good enough For my purposes, I need to have it on.
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