Thread: Sundry Items
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Old 09-17-2011, 08:26 AM
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Default Re: Sundry Items

Quote:
Originally Posted by MichaelKellough View Post
I always wondered how you can get accurate surfacing with something that breaks down as it's used.
That is a valid question. I can tell you from experience with my particular machine as applied to slabs of mild steel seen on my planes that unless I pay attention and dress the wheel constantly the wheel will start at say a depth of 4 thou but by the time it reaches the full width of the work piece it is cutting at somewhere between 3 and 4 thou-so I never just take one pass and always swap the work piece end for end on the same face and take another cut to cancel out that effect, and always cut with the same leading edge ie the one nearest to me.
The other thing is if you watch the wheel face you can see that the part doing the work is right next to the leading edge -there is a narrow ring of red- as the wheel wears this red ring moves towards the trailing edge and it is then time to dress the wheel again when that red line is right at the trailing edge.If you just continue grinding without dressing the surface pattern quality deteriorates at that point in addition to a loss of accuracy.
The above is assuming that one uses the correct wheel for the job-generally along the lines of hard steel requiring a soft wheel and soft steel etc requiring a hard wheel. If you get neurotic about it you can end up spending more too much time changing wheels for different applications so the idea is to find the happy medium . If you bear in mind that a plane maker will be grinding mild steel, annealed tool steels, hardened tool steels and brass (at times the brass and mild steel require to be ground at the same time ) then you get the picture. I use the wheel grade you see there as recommended by the supplier, but have tried those blue SG (seeded grit) and prefer the white ones. Pink stones are very nice for hardened steels. And on it goes.....
It would be nice to have a massive machine with a wheel width of 11/2 inches or more so that some of these problems are not so acute but these machines are super expensive. Now you begin to know why Uncle Karl needs to recover some expenses when he churns out his planes- and you are so lucky to get planes from me at such marvelous prices
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