Another se77 out of square plane blade

[CraigS]

I'm coming in late to a moribund thread. But I too am fighting the SE77. I'm a seasoned Tormek user, and had no problems with the SE76. I foolishly sold that before I tried the SE77.

The problem is that with the datum marks aligned, a grind is noticeably out of true 90 degrees.

Now I've very recently fitted a new shaft, nylon bearings and grindstone to my T7, and have verified from the support bar that the stone is flat and true to better than 1.5 thou (40 microns) referred to the bar itself.

Checking with a plane iron that is true 90 degrees with a Moore&Wright square, with the edge painted with a sharpie, I can only transfer sharpie to the stone with the SE77 datum lines misaligned by 1.5mm.

That seems to be a very large error. Anyone else have that problem with an SE77?

Of course I'm kicking myself for selling by trusty SE76 *before* I tried out the SE77.

Craig

[micha]

Craig,
welcome to the forum!

That seems to be a pretty large deviation. Is your support bar itself at a right angle and do you somehow make sure the support bar and the stone surface are still parallel after height adjustment?
(I hardly dare asking, but it's easily overlooked.)

Mike

[CraigS]

Hi Mike

I'll do a check with calipers that the distance tracks with the support bar in the right position for grinding

Good suggestion!

Craig

[CraigS]

OK - 52.4 at one side of the stone and 52.6 at the other. Those measurements to a sharpie line on the stone drawn at right angles to the outer face of the stone (after checking that the face and edge were at 90 degrees).

So I think we can discount a lack of accuracy in the support bar at working distance referred to the stone.

Craig

[micha]

Ok, Craig,

guess we can sort out that one, it would not have that much of an effect.

You wrote about having checked the angle of the plane iron - is it still rectangular with the jig after having it clamped there. (I assume you align it with the jig's shoulder, right?)
Also be sure to clamp the iron evely and don't overtighten the screws. Keeping that clamping bar parallel or not can really make a diifference.

Mike

[CraigS]

It is fine with the two datum lines offset by about 1.5mm - nice 90 degrees; or hardly any gap between a square and the edge after a grind. Maybe I'll just have to put up with it. But it is not really satisfactory, and candidly is a retrograde step as compared with the SE76 that just did 90 degree grinds (if you used it right!) - which lets face it what 99% of what you want to do with chisels and plane blades, unless it purposely has a skew (like a LN 140 skew block plane; but that is 18 degrees, and I think is beyond the SE77)

I've twice tried to get a response from Tormek about this datum offset, but so far nothing.

Craig

[Ken S]

Craig,

I agree. Selling your SE-76 prematurely may not have been wise. While they sharpen the same tools, the SE76 and 77 have two different intended purposes. The SE-76 is intended only for square edges. It can handle some rough camber grinding; however, it does not do this very accurately.

Tormek misses the main advantage of the SE-77. The two adjustment knobs allow very controlled, accurate amounts of blade camber. This technique is primarily used by high end woodworkers like furniture makers. With a typical set of three bench planes (jack, jointer, and smoothing), each would have a different amount of camber to fit their functions.

I generally use the simpler SE-76 for chisels. I would suggest you look for a replacement SE-76. They are not rare.

Ken