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How to make chisel edges square

Started by Sir Amwell, November 06, 2022, 10:02:50 PM

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Sir Amwell

Hi everyone. I am new to chisel sharpening though I have good experience sharpening knives on a Tormek t8.
I have chisels to sharpen which are not square at the edge. I suspect due to incorrect previous sharpenings. How can I correct this before actually sharpening?
I have diamond wheels, SE77 jig and MB100.
I tried to attach a photo from my library but it says the file is too big which I don't understand.
Help with theses issues would be much appreciated. Thanks.

RickKrung

Ken is our resident chisel expert ;D, maybe he will chime in. 

I am not sure that you can or want to correct the out-of-squareness before you proceed with sharpening on the Tormek.  I think that is all part of doing it on the Tormek. 

Do you have the manual for the SE-77 and have you studied it?  There are two knobs that need to be maniputated in a coordinated manner to adjust squareness and it my not be intuitive.  Takes practice and careful attention.  One primary purpose of those knobs is to allow for creation of camber to the bevel.  I did this most recently with one plane blade.  That is the devil of it, though as if they are not adjusted properly the can cause out of squareness.  I found it took a LOT of black marker and checking frequently, making small adjustments, particularly when I was going for a square bevel on a different plane blade. 

Rick
Quality is like buying oats.  If you want nice, clean, fresh oats, you must pay a fair price. However, if you can be satisfied with oats that have already been through the horse, that comes at a lower price.

Sir Amwell

Thanks Rick.
So are you saying that as long as the chisel is correctly aligned in the SE77 then the sharpening process will correct the non squareness?

RickKrung

#3
Yes and No.  Yes, that once you get the blade correctly aligned it should proceed fine.  GETTING it aligned properly is the trick.  With the old jig (SE-76), which was not adjustable, the blade had to be shifted in the jig or more pressure applied to one side or the other.  With the new jig (SE-77), it can take quite a bit of fiddling to get the blade set so it is grinding square.  A very small, fairly accurate square is most handy, one that is small enough to place along the bevel while it is in the jig.  One that is adjustable is really handy.  There have been a couple threads on this forum about all this.  Take some time and do some searches, for more in depth discussion of the how-to but also to see what sorts of small squares folks have found useful.  Here is one about getting it square.

When using the square, normally it is held along the side of the blade (chisel or plane), so you must make sure the sides are parallel, not angled, otherwise, you will misled in what is square on the bevel. 

BTW, you didn't answer the question about whether you have the manual and have studied it. 

Rick
Quality is like buying oats.  If you want nice, clean, fresh oats, you must pay a fair price. However, if you can be satisfied with oats that have already been through the horse, that comes at a lower price.

Sir Amwell

Yes I have the manual and studied it. Can't find anything I find relevant to squaring the edge. Stuff about the 2 micro adjusts for cambered edges.....

RickKrung

#5
Quote from: Sir Amwell on November 07, 2022, 12:15:08 AM
Yes I have the manual and studied it. Can't find anything I find relevant to squaring the edge. Stuff about the 2 micro adjusts for cambered edges.....

Those are exactly what you must adjust to get it set to square.  When used for cambering, the knobs are backed off and the jig can rotate left and right which is what produces the camber.  For grinding square, the knobs must be set tight so the jig does not move, but because there is no "exact" square setting, you must "discover" it for yourself.  There is a raised line on the two parts that indicate "about" center, but it is not exact and cannot be relied upon. 

There is information in the manual that touches on all this, it just doesn't go into a lot of detail.

Page 121 (in the PDF file manual I have).  It even refers the reader to the next one.


Page 125.  This refers to applying pressure to one side or the other.  I find this less than effective.


Page 126.  All three figures here speak to the issue.  The middle one referring to the indicator line is only somewhat close, as I said, you cannot rely on it, you'll have to make fine adjustments to get it truly square.


Rick
Quality is like buying oats.  If you want nice, clean, fresh oats, you must pay a fair price. However, if you can be satisfied with oats that have already been through the horse, that comes at a lower price.

Ken S

Ken chiming in......

A black marker and a small square are both very useful (essential) in grinding square chisels and plane blades.

Check the chisel you are sharpening. Be sure to check it from both sides. Mark the bevel with your black marker.

Take one light pass across your chisel. Hold the square next to your chisel edge. If the edge is not square, the initial light pass should be square with the blade of your square. The goal is to have each pass gradually make the edge more square. The most common mistake is plowing ahead before you are grinding square.

Proceed slowly with your first chisels. You will soon pick up speed as you gain proficiency. Do not move on until you are happy with your first chisel. Midwidth chisels are the easiest to sharpen. Start with something in the 1/2" to 3/4" width.

Keep us posted.

Ken

Ken S

I find the coverage of the adjustment knobs in the handbook unfortunate. The emphasis should be on cambering planes, not on aligning chisels. The SE-77 is a major advance for cambering plane blades. Being able to control camber with bench planes is one of the things which distinguishes a cabinetmaker from a woodworker. The amount of camber sets the cut depth of a planes which varies according to the function of the plane.

Ken

RickKrung

#8
While the design may be a major advancement for cambering, it does serve dual purposes and by virtue of its adjustability to accomplish cambering, I think it is incumbent on Tormek to adequately explain how to set it up so that squareness can be achieved. 

Rick
Quality is like buying oats.  If you want nice, clean, fresh oats, you must pay a fair price. However, if you can be satisfied with oats that have already been through the horse, that comes at a lower price.

Ken S


Sir Amwell

Thanks both. I posted initially because I found the manual lacking here. Yes it does state what the adjustment knobs do but does not instruct how this would work in practice.
My ( probably faulty) thought process is as follows.
Align chisel in jig.
Somehow imagine using the truing jig in reverse.
The chisel become the wheel, the wheel becomes the the truing tool.
Gradually, starting at the highest point of the chisel edge, lower the usb with each pass......
This is where it falls down because each adjustment of the usb alters the angle.
I will try Ken's advice and see how it goes.

tgbto

I am not an expert in chisels, but I thought I might comment on the "angle" part : the USB height will change the grinding angle, not the squareness of the edge wrt the sides of the chisel. I'd advise sharpening at the desired angle, not higher, so you don't end up with a dual angle edge. Then you grind it (on the SG, graded coarse) until your edge is back to square, knowing that it will in any case grind more on the side that needs to be shortened.

In other terms, don't fiddle with the USB height during the grinding process; your analogy with the truing does not really apply because the truing jig is self-supported by the fork that clamps on the USB rod. So adjusting the height adjusts the depth of cut. With the chisel jig, adjusting the height will change the grinding angle, as it will always be such that the point furthest away from the usb contacts the stone.

Just for what it's worth : it is recommended to always end by raising the USB, not lowering it to avoid hysteresis. To put it another way: always rotate the microadjust nut a bit past where you'd want it then rotate it back to where you actually want it... should you want to adjust the height.




WimSpi

Quote from: Ken S on November 07, 2022, 03:39:23 AM
I find the coverage of the adjustment knobs in the handbook unfortunate. The emphasis should be on cambering planes, not on aligning chisels. The SE-77 is a major advance for cambering plane blades. Being able to control camber with bench planes is one of the things which distinguishes a cabinetmaker from a woodworker. The amount of camber sets the cut depth of a planes which varies according to the function of the plane.

Ken

Here, as a woodworker, I agree 100%.
Wim