Grinding plane blades out of square

[Johnny danger]

I just recently purchased a used supergrind 2000. I have not bothered to read the id tag to even know how old it is or what model it is-figures. I am restoring a bunch of Stanley planes I have purchased over the years, and I am to the point where I want to sharpen blades for useable shape. I redressed the wheel and checked for tool rest bar perpendicular to wheel, all looks good, however, when I ground the first blade the top is now ground dramatically out of square. I've read through the manual to be sure I am on target with set up, but I do not see anything that addresses my issue. I have watched a couple of U-tube videos and do not see anything there in terms of my dressing the wheel or set up. Obviously I am doing something very basic wrong. I have never used a grinding device like this before, I always roughed my edge on a bench grinder and then worked the blade on waterstones to sharp-very time consuming. I was hoping to be able to achieve a sharp edge with this machine in a much quicker and friendlier approach. Advise please.

[Ken S]

Welcome to the forum, John. Good question.

The trick to getting square edges is to start with a black marker. Take a pass or two, and then check that you are grinding square by using a square.

If your initial passes are not square, you will need to adjust your plane iron. The typical mistake is to leave out the initial check and keep on grinding. Unfortunately, this just magnifies the problem.

Keep us posted.

Ken

[tgbto]

I've never ground plane blades, but wouldn't the square trick help as well ?

That is, tracing a line on the top of the wheel, perpendicular to the side, and check that the plane blade is on the line and stays on it when moving the jig ? As shown by Wolfgang in this video....

[rolsen]

wouldn't the square trick help as well

I'm pretty sure that is one good point to start, though I've never used it for hand plane irons.

I'm using the technique Ken S described, have been for years with good results.

[John Hancock Sr]

All good suggestions. Slightly out of square is annoying but not critical, but it is nice to get them perfectly square.

First question. Are you using the old SE-76 or the new SE-77.

If you are using the se-76 you need to slightly adjust the "tilt" of the blade in the jig to get it into square. It only has to be very slightly out for it to go out of square. I use a small double square to check it regularly until it is sharpening perfectly square.

If you are using the new 77 then I adjust the knobs for square, again checking regularly until it comes into square.

Also make sure that the iron is hard up against the square stop before tightening it down. It is easy to slip slightly as you tighten it.

[Herman Trivilino]

I redressed the wheel and checked for tool rest bar perpendicular to wheel, all looks good,

Not sure what's perpendicular to what? After truing, the cylindrical surface of the grindstone will be parallel to the horizontal portion of the universal support rod (USB).

however, when I ground the first blade the top is now ground dramatically out of square.

It's absolutely essential that the horizonal portion of the USB be parallel to the axis of rotation of the grindstone. They could have been knocked out of parallel if the USB was bent or if the two vertical portions of the USB are not parallel to each other. Or both! Less likely, but still possible, the frame is bent so that the main shaft no longer points in the same direction it used to. Perhaps before you ever acquired the machine it had fallen on the floor!