Good day all! I started grinding my first 8 inch newt today using a kit from William Bell. I started with the 60 grit as instructed and have put four hrs into the project. Instead of using the supplied glass tool I opted for a two inch pipe cap tool. Can anyone suggest when I should change grit to the 80 stuff? Should I wait to change after I have my full curve ground or should I change to 80 grit at some point before I reach the desired saggita? How can I tell when to go to the next grit?? :S (F/L approx 1700mm so I calculate saggita approx 1.5mm. Any advise would be greatly appreciated.
8 inch newt
Started by Philip2, 06/13/2004 07:28PM
Posted 06/13/2004 07:28PM
Opening Post
Posted 06/13/2004 10:17PM
| Edited 06/13/2004 10:19PM
#1
What kind of tool are you going to use once you get the sagitta close?
If you are going to make a tool from dental stone and unglazed tiles, then you need to curve to go all the way to the edge so you can use the mirror as a mold for the tool. Don't even think about using the pipe cap throughout the entire grinding process!!
With a full size dental stone/tile tool, you switch to the 80 grit as soon as you make the tool. After that, just make sure you check closely for pits before continuing on. At least 6 to 8 wets on each grade at 5 or 7 minutes per wet should get you through fine. Spend a little more time on the wets at the 12 and 5 micron level, maybe 12 to 15 minutes each, but you only need 3 or 4 wets each.
Keep us posted.
Walt
If you are going to make a tool from dental stone and unglazed tiles, then you need to curve to go all the way to the edge so you can use the mirror as a mold for the tool. Don't even think about using the pipe cap throughout the entire grinding process!!
With a full size dental stone/tile tool, you switch to the 80 grit as soon as you make the tool. After that, just make sure you check closely for pits before continuing on. At least 6 to 8 wets on each grade at 5 or 7 minutes per wet should get you through fine. Spend a little more time on the wets at the 12 and 5 micron level, maybe 12 to 15 minutes each, but you only need 3 or 4 wets each.
Keep us posted.
Walt
Funding Member
