03-27-2018, 10:50 AM
How much truer could something be Jan? Nothing new about this idea and that's for certain! You know Ken, as soon as I finished the post above, and particularly after I saw a picture of one of these modified for electric power, I thought "looks like a big ol' Tormek to me". I really like the idea of having absolute and immediate control over the speed of the wheel. That ability as well as the ability to introduce water to the process would be a good way to test some sharpening theories.
I think that I would like to recast a wheel regardless. While I have a great regard for how things used to be done I would still like to end up with a time effective sharpening device. I learned a little more after posting yesterday. Apparently these old grinding wheels were made up of some form of sandstone. The silica in the stone was the primary abrasive. Most used a drip can on the top side to wet the stone. At least one source said that a trough on the bottom was a bad idea because the silica slurry build-up would be washed away. I assume that grindstone material might change from geographic region to geographic region.
I mentioned in a post in another thread a few weeks ago that we had at one time constructed our own (albeit much smaller) grinding stones. The bonding matrix for those stones included fly ash, plasticizer, and a special grade of portland cement. One could add any grit or type of abrasive one's heart desired to this matrix and at concentrations (by volume) as high as 65% abrasive/35% matrix. The PSI of these stones could be adjusted from 5 - 11,000. At 11,000 PSI you're falling just a few thousand PSI short of some ceramics as I recall. The biggest drawback is that it takes about 30 days of cure time for these stones to reach 85% cure and, I think, 6 months for full cure. Curing must occur in a wet environment.
I think that some combination of the above is what I would like to make a grinding wheel out of. Mounting grinding belts is tempting for obvious and practical reasons but I don't want to offend Thomas by becoming too modern here. I don't want to offend myself either so I lean toward a 180-220 grit maybe SC or AO wheel. Add a good means of controlling sharpening angle and we might just be in business. I've already assigned a name to this endeavor - The Thomas Project.
Headed to the farm tomorrow and then Quincy, Illinois Saturday to attend number 5 grandchild's first birthday. Will try to take some pictures if I can find a likely candidate treadle grinding wheel for refurbishment. You know how that goes. You've been looking at something for ten years and it looks just fine from a distance...then you have a closer look.
I think that I would like to recast a wheel regardless. While I have a great regard for how things used to be done I would still like to end up with a time effective sharpening device. I learned a little more after posting yesterday. Apparently these old grinding wheels were made up of some form of sandstone. The silica in the stone was the primary abrasive. Most used a drip can on the top side to wet the stone. At least one source said that a trough on the bottom was a bad idea because the silica slurry build-up would be washed away. I assume that grindstone material might change from geographic region to geographic region.
I mentioned in a post in another thread a few weeks ago that we had at one time constructed our own (albeit much smaller) grinding stones. The bonding matrix for those stones included fly ash, plasticizer, and a special grade of portland cement. One could add any grit or type of abrasive one's heart desired to this matrix and at concentrations (by volume) as high as 65% abrasive/35% matrix. The PSI of these stones could be adjusted from 5 - 11,000. At 11,000 PSI you're falling just a few thousand PSI short of some ceramics as I recall. The biggest drawback is that it takes about 30 days of cure time for these stones to reach 85% cure and, I think, 6 months for full cure. Curing must occur in a wet environment.
I think that some combination of the above is what I would like to make a grinding wheel out of. Mounting grinding belts is tempting for obvious and practical reasons but I don't want to offend Thomas by becoming too modern here. I don't want to offend myself either so I lean toward a 180-220 grit maybe SC or AO wheel. Add a good means of controlling sharpening angle and we might just be in business. I've already assigned a name to this endeavor - The Thomas Project.
Headed to the farm tomorrow and then Quincy, Illinois Saturday to attend number 5 grandchild's first birthday. Will try to take some pictures if I can find a likely candidate treadle grinding wheel for refurbishment. You know how that goes. You've been looking at something for ten years and it looks just fine from a distance...then you have a closer look.