Problem with the SE76

[banewf]

Yesterday I tuned up 2 hand plane blades from a couple of old planes I picked up. All appeared to have gone well until I checked with a square to see if I was successful in slightly rounding the outside corners. To my dismay I discovered the entire cutting edge, while nice & sharp, was tapered. i.e. it had the shape of a skew chisel (obviously not that extreme but it was on a taper).

I rechecked that I had the two tightening screws tight - they were. What I discovered was that the plane blade could actually be pushed out of square with the SE76 - it was only by a couple of degrees but enough to mess up the squareness. I took the blade out of the jig, checked there was nothing on the side of the blade or inside the jig that might have prevented the blade from seating against the edge of the jig. There was nothing. I retightened everything, put the jig on the support, allowed the blade to sit on the wheel, & tried pushing sideways (parallel to the support arm) on the back end of the blade. I was again able to move the blade by a few degrees.

To make certain it wasn't something peculiar to the plane blade I went through the whole process with the other one ... same thing.

Has anyone ever experienced this? I've cranked the tightening screws but it doesn't seem to help.

For Jeff ... could the SE 76 be the culprit? Have there ever been any instances where the SE76 was machined poorly?

Appreciate any insights you might have.

[Jeff Farris]

The very first thing to do is to confirm that the Universal Support is parallel to the grindstone. Bring the Universal Support down to the grindstone and inspect the gap. If it is not parallel, true the wheel and try grinding again.

That said, there are a myriad of things that will affect the grind while you're working. Keep that square handy while you're grinding. If you find it out of square, just concentrate a bit more pressure on the long point until it is square.

[banewf]

Thanks for the tips. FYI ... when I did discover the "skew" shape on the blade the first thing I did was re true the stone. I was able to resolve most of the problem by insuring I pushed the back end of the blade towards the honing wheel to insure the long point was being ground more. Not something I was really thrilled to have to do - I expected the jig being designed to "square the tool to be sharpened to the stone" would do what it was designed to do.

Do you have any comment regarding the fact that the SE76 does not hold the blade square? Why would there be movement? I can buy your comment regarding there being many things that can happen while you are sharpening (i.e. uneven pressure, etc) - but I can't accept that the jig allows this much movement.

Your comments ...   

[banewf]

I just found and read the earlier posts by RobinW and KenS on getting a square edge on chisels and plane blades. Seems I'm not alone. Their comments were very detailed and provided some clear insights as to why this problem exists and offers suggestions to rectify it.

Rightly or wrongly it appears I expected far too much from the SE76.

[Ken S]

It seems to me this squareness issue is caused by either defective equipment or operator error/inexperience.

I can think of one good way to resolve the issue.  Jeff, would you please run a chisel through the sharpening process with your SE-76 and describe how square the edge is?

Jeff is arguably one of the most knowledgeable and experienced Tormek users in the world.  If his off the shelf equipment can get a square edge, then we need to work on our technique.

Jeff, will you help us out?

Ken

[Jeff Farris]

Ken, et. al

The SE-76 is like any other piece of gear. If you expect miracles without putting in some effort on your own part, you're bound for disappointment. Here's a list of all the little things that can go wrong.

1) Universal Support not parallel with the grindstone.
2) Tool out of square to begin with.
3) Sides of tool not parallel (register to one side and check from the other).
4) Clamp not applied evenly (always check that the clamping bar is parallel to the jig frame).
5) Stone glazed on one half and free cutting on the other.
6) Tool squirms away from the register when clamped (very, very common).
7) Flaw in the steel (uneven tempering).
Dominant hand pressure heavier than other.
9) One side of tool allowed more time off the grindstone than the other.

And, there's probably another dozen or so that I'm not thinking about right now.

What I do is keep a 4" Starrett adjustable square next to my Tormek. If squareness of edge is critical to the tool's use, then I check it frequently and adjust my pressure and the stone condition as needed to deliver a square edge. The wider the tool, the more difficult it is to keep square, and so the more often I check.

[Ken S]

Thanks, Jeff, for a thorough and honest post. 

It's easy to think that an expensive piece of equipment like the Tormek should be able to be accurate without much tweaking.  In industry, even top quality tools like Starrett are reqularly calibrated.  How many squares or levels, even new expensive tools are truly square or level?  If they were, why would we check levels at the store?

I think Jeff's post indicates the necessity of being diligent and continually checking.  Another interesting thought is:  "If squareness of edge is critical to the tool's use,"  How much squareness do we really need?  I'm not advocating sloppy work. Dovetails have traditionally been chopped with hand sharpened chisels.  I doubt the early craftsmen kept a Starrett square next to the oil stone.  Like Jeff, I keep a Starrett square very nearby.  However, I do believe that for most work, anything resembling square is probably very adequate.  My most often sharpened chisels are my old ever faithful Stanleys which have seen numerous nasty excavations in less than pristine conditions over the years.  Certainly squareness is not a requirement for them.

I do believe there is room for improvement.  I like Mike's idea about establishing a more accurate front reference surface.  Some roughing up should improve the gripping surfaces of the jig. 

It is regrettable that the Tormek, like most tools, is sold without a good training session with an expert who can verify that the machine is properly tuned and the operator has mastered some of the basic use skills.

I have posted, both on this forum and directly with Tormek, that more thorough video training aids would be beneficial.  Jeff's training films, especially the turning packet are excellent, as are the you tubes done by Alan Holtham.  However, there is room for more training films on basics such as establishing squareness and proper touch.  Good training aids would speed up this learning process, and probably prevent premature discouraged selling off of new machines.

Let's keep using this forum to make our sharpening better.  We need to keep dealing with the frustrations head on.

Ken

[banewf]

Thanks Jeff and Ken. I'm the first to admit that as a newbie I'm on a steep learning curve. I'll keep at it. I am happy we have this forum to draw upon - there's definitely a great deal of collective knowledge out there and I appreciate the fact people take the time to not only read the questions but also share their experience.

While I still believe the SE76 should hold the tool square, now that I know it doesn't I can figure out ways to work around it.

The journey continues ....

[Jeff Farris]

Thanks Jeff and Ken. I'm the first to admit that as a newbie I'm on a steep learning curve. I'll keep at it. I am happy we have this forum to draw upon - there's definitely a great deal of collective knowledge out there and I appreciate the fact people take the time to not only read the questions but also share their experience.

While I still believe the SE76 should hold the tool square, now that I know it doesn't I can figure out ways to work around it.

The journey continues ....

I don't want to argue or split hairs, but...the SE-76 does hold the tool square to a very high degree of accuracy. The limitations are in the grindstone shape, the cutting condition of the grindstone and how pressure is applied to the tool.

[Dakotapix]

On this same subject, I picked up a 1/2" Stanley 750 chisel off eBay recently and put it into the SE-76 jig and after tightening down noticed that the chisel was definitely canted toward the left end of the jig, making it impossible to do a grind the would be true. I suspect I tightened the left screw too much but wonder if shimming the left side of the jig with a piece of wood on these narrow tools would help. Or is it enough to tighten just enough to keep the jaws of the jig parallel?

I'll be trying this today and will probably answer the question myself. Just wondering what Jeff and others may do.

[Jeff Farris]

It is not necessary or advisable to put the same amount of torque on the left clamp that you put on the right.  Consider the leverage that the space gives the left clamp. It will, without question, roll the tool to the left if you apply equal torque. Tighten the right clamp first, then tighten the left clamp until the clamping bar is parallel with the jig frame, plus about 1/4 turn more. More than that will start rolling the tool.

[Dakotapix]

Yup, I just confirmed what you said in reply to my question. No shim, just eyeballing the jaws to make certain they were parallel after first tightening the right hand knob. The Stanley chisel sharpened up nicely with a mild hollow grind. I finished up with a micro bevel on a 10,000 grit waterstone by hand.

[ironduke]

Good thoughts for all.  I think the best summary is from KSMIKE on an adjacent forum.  Look here:"Topic: SE-76 - random thoughts on grinding a square edge, and a slight modification."  I would like to suggest the following although I have not yet tried it.

1st, before mounting your blade use a little sharpie ink or machinist's layout fluid to coat the flat side of the blade in question (the non-bevel side).

2nd, using the long edge of the blade that will mount on the right side of the SE-76 and a good square that you have already checked, scribe a line across the blade.  This line should be square to the "reference edge" of the blade in question.  You may find that the original blade edge was further off a square line than you thought.

3rd, mount the blade into the SE-76 as described in an earlier comment.  Tighten the right-hand screw slightly and then tighten the left-hand screw sufficiently to get the top plate of the ST 76 in contact with the blade across the full width of the blade.

4th, work slowly on the coarse stone setting and then on the fine stone setting as needed.  As you do this, keep checking on the position of the blade edge with respect to the line in the marking fluid.  This will advise you on progress toward a square edge as you go, and you can adjust your approach to the grindstone accordingly.

I have not tested how the above recommendation works on a wet grinding stone.  I have used it on dry grinding stones to good advantage in the past.  It may be a month or so before I get a chance to do this for real on a Tormek machine.