Topic: Still having trouble w/ 6" jointer blades

[bnlsrv]

I retrued the wheel. Confirmed that the base jig will lay flat across the entire surface (had a thumbwheel difference of '4'). I wasn't willing to take off half a thumbwheel (Jeff's suggestion) because I've already taken these blades down pretty far with all of the problems I'm having. $54 for the set of 3. Put the blade on the jig, confirmed the setting with the paper across the stone. Turned the both wheels up 2 numbers - the stone will not grind off the edges, continue to get a smile in the blade. I've tried 'playing with the stops', nothing has helped. I've gone back and forth 10 minutes. After finishing the ten minutes the hone wheel side of the stone is lower by .010. I'm placing my hands evenly across the 6 inch blade - I've tried them on the black knobs, & below the black knobs. Far as I know I"m pressing evenly. I'm beginning to suspect a faulty stone that is wearing unevenly - .010 in ten minutes. Is that possible? With that kind of uneven wear (opposite side is not wearing like the hone wheel side) I can't see how I'm going to get the blades to be straight. Another couple of hours shot. I await further instructions. I'll try grinding them at the existing setting for another 10 minutes in case I'm not doing it long enough.

[Jeff Farris]

The uneven wear is troublesome, but on the other subject, I have another issue we should explore.

Are the stops set so that the left edge of the blade traverses all the way to the right side of the stone and the right edge of the blade traverses all teh way to the left side of the stone?  This will minimize the effect of an uneven stone.  I am going to invite Torgny Jansson to review this thread for his comments.

[bnlsrv]

I've been at it for another 20 minutes. These changes are helping.
1- I put myself at the front of the machine.
2- I adj the stops to within 1/2 inch opposite - but I'll adjust them even farther.
3- I'm frequently regrading the stone with the 220 side.
4- I'm going back and forth repeatedly. I still do not have an even line, though it's getting very close. One side is still too high, starting at the edge to about 3/4 inch in. Frankly I'm afraid to adjust the thumbwheels again.

[bnlsrv]

Started at 7Pm and finished (3) 6 in. jointer blades at 1 am in the morning. Still couldn't get a perfect line but it was definately better - except the last one. Too much being taken off on the far wheel side. Gave up.
What worked best:
1- Position myself in front of the machine
2- Stops set for middle of wheel both edges. Going past middle produced more problems.
3- Recheck frequently the wear of the stone, and reset jig for parallel jig placement.
4- Do not press hard! - too much leverage produced from the length of the jig.
5- continue going back and forth with very little pressure until there is very little sound heard. Still produced a wavy line.
I'm not pleased at how long this takes.

[bnlsrv]

Checked the wear on the stone this morning. Inner edge is more worn by .010, used machinist square and feeler gauge. Outside diameter of stone went from 245 mm to 243mm, can't really check the inside w/o taking the stone off. Ran the jig down without the blade on to check if I can make the jig parallel with the stone - not possible anymore. Too much worn on the inner edge. I'd take the stone off and turn it around to see if the problem follows to the other side but it looks like that's not possible with the indention of the stone.

If I retrue this stone again -
Where should the stops go?
How much pressure should I use?
I have the blade in the middle of the holder, where should I place my hands?

I'm running out of blade on this one, not sure I can go at this again. This was the first one I tried originally, when I had the trouble with the squareness of the jig.

[Jeff Farris]

Please call me during business hours Monday.

Jeff

[bnlsrv]

I'll call Monday morning. I think the problem may be how much pressure I"m putting on the jig when I grind, and perhaps a stone problem. Not sure about the stone because I might be the problem. On a positive note - the blades are absolutely razor sharp! I got most of the wave out - just one end is usually high, but again it might be how much pressure I'm putting on this at the beginning of the grind. I look forward to speaking with you about this and perhaps we can figure this out. I think that once I get the hang of this it is really going to save me time not taking my blades in for sharpening.   I'm working with free, construction oak - from lining tunnels, etc, so it's pretty  dirty and hard on the blades.