The Shop > Tools
Granite surface plate problem
PekkaNF:
Yesh. I have seen some of those videos and gained a whole lot better understanding what it really takes....way over my skills and tools.
You probably mean this one:
I did some reading on and something along with Repeat-O-Meter and Planikator could be a start, but buying new surface plate would be more cost effective and faster way. Maybe, if I had most of that stuff ready
http://www.starrett.com/metrology/metrology-products/precision-granite/standard-products/repeat-reading-gage
http://www.starrett.com/metrology/metrology-products/precision-granite/standard-products/planekator
http://www.benchtest.com/w-doall2.html
Pekka
BillTodd:
Interesting to see that the Starrett repeat o meter gauge has a Mahr indicator :-)
sparky961:
Get two more pieces of granite from your stone guy that are roughly the same size. Also pick up some silicon carbide powder or better yet diamond paste. In a pinch you can use a silicon carbide grinding wheel and pulverize it a bit.... but the former would be easier.
Start rubbing.
The 3-plate method of originating a flat surface (three, actually) is well documented elsewhere so I won't go into it here. I had a thread a while back where I was doing this with granite/marble countertop scrap. I can tell you it's boring, messy, and extremely time consuming. BUT IT REALLY DOES WORK.
Maybe you can find two more surface plates that are in similar disrepair, lap them all together, and sell the ones you don't need when you're done. It sounds like you can do a pretty good job of verifying your work, so you can feel good about a hefty markup for resale.
PekkaNF:
--- Quote from: sparky961 on January 16, 2017, 04:48:43 PM ---Get two more pieces of granite from your stone guy that are roughly the same size. Also pick up some silicon carbide powder or better yet diamond paste. In a pinch you can use a silicon carbide grinding wheel and pulverize it a bit.... but the former would be easier.
Start rubbing.
The 3-plate method of originating a flat surface (three, actually) is well documented elsewhere so I won't go into it here. I had a thread a while back where I was doing this with granite/marble countertop scrap. I can tell you it's boring, messy, and extremely time consuming. BUT IT REALLY DOES WORK.
Maybe you can find two more surface plates that are in similar disrepair, lap them all together, and sell the ones you don't need when you're done. It sounds like you can do a pretty good job of verifying your work, so you can feel good about a hefty markup for resale.
--- End quote ---
Have you ever tried this?
I did try to make a straight edge by scraping three this way least 18 years ago and I can tell that I'm not using it :lol:
It is not easy and it is not very automatic. Huge time (and effort saving) is available when you have known straight level to check. And it is another long trench war before you get from narrow straight edge to a surface level. Adds a whole new dimension. :bang:
And scraping will produce predictable results. Lapping will just even out minor very local surface faults. Lapping on those videos looks easy, but they don't show how the lap was straightened.
I'm still looking to have the Mahr plate reconditioned, but if that is not possible, I'm trying to buy one cheap/half decent and cross my fingers.
Pekka
sparky961:
Yes, I've done this. I used Silicon Carbide from a green grinding wheel. I presume diamond will cut faster and break down slower (if at all).
I haven't tried this with metal, but I expect that would take a lot longer by hand.
If the plate you have is in such horrible shape, is there any harm in trying? Mess it up and you still have plenty of material for professional resurfacing later on.
Navigation
[0] Message Index
[#] Next page
[*] Previous page
Go to full version