Knife tip grinding - To Pivot or Not To Pivot

[cbwx34]

Well, finally got some time to finish this small collar idea tonight...... And gotta say it's much nicer than just the straight cut off version.
Turned a little nub on the end of some acrylic blank I had laying around here...but if i were too do it all over again, this could all be done with the stock collar piece chucked up in the lathe...I just felt I cut the first one a bit short anyway
Still no laser line, but i think i did better keeping to the LOC

Operation feels very very smooth. Setup was the same as mentioned previously with my template. Pivot point seems to remain on the side of the shaft (on the side towards the tip), not in the center of the jig shaft

As I hope you can see in the attached pic, the bevel width looks pretty good.
Bevel angle isn't perfect, but it's close all along the length (sorry, i don't have any fancy accurate measuring tools for that).
With the exception of a couple extremes (user error), the bevel width is 1 to 1.4mm. Again, without any serious measuring tools, i think this seems about right for the difference in blade thickness at the heel, belly, and tip


At this point I think i can do pretty well with this collar and setting up something to mark the LOC, with just a bit of practice.
Definitely finding it MUCH easier to keep smooth/even transitions and bevels than the wide stock collar was, so for this part I think I'm now satisfied 

(apologies for the crap pictures, don't have any good options for resizing here in my phone too meet the attachment size limits while still keeping good detail)

P.S.
Also don't be thrown off by the crazy wide marker on the blade. I wanted to be sure to cover all the old grind experiments, so I just went with a really fat marker right up over the bevels and onto the face

Looks good! (Stylish too.)   

With a stop collar, a "laser LOC" isn't as necessary.  You can setup the knife in the jig, then set your sharpening angle with the AngleMaster (or however you do it), then just draw a line on the stone (or a reference point next to it), and with the power off, just check and see how the knife moves in relationship to the line, and adjust it in the jig, if needed.  Experience tells me that after a few knives, you'll be able to set the knife in the jig, pretty much where it needs to be... especially now that your two pivot points are much closer together.  The laser becomes more important when there's really nothing else to keep the same point on the stone (freehand or collar free). 

I like it.  Bevel looks good too.   

[Kavik]

Thanks man 
I know the laser line isn't THAT important, but thought it might help still during the training and building muscle memory stage.
Depending on the profile of the curve to the tip, even with the collar it's still possible to end up well above or below the line

If i don't end up working all weekend, maybe I'll just pull one of the laser diodes off my drill press.... I never use it on there anyway, and can always reinstall it when I'm done needing "training wheels" here



Out of curiosity: I know someone said the newer knife jigs don't use the stop screw anymore...I'm guessing a new collar would have no way of working on an old jig, with no o-ring to hold it in place, but would an old collar still thread onto a newer jig?

[cbwx34]

Thanks man 
I know the laser line isn't THAT important, but thought it might help still during the training and building muscle memory stage.
Depending on the profile of the curve to the tip, even with the collar it's still possible to end up well above or below the line

If i don't end up working all weekend, maybe I'll just pull one of the laser diodes off my drill press.... I never use it on there anyway, and can always reinstall it when I'm done needing "training wheels" here

Out of curiosity: I know someone said the newer knife jigs don't use the stop screw anymore...I'm guessing a new collar would have no way of working on an old jig, with no o-ring to hold it in place, but would an old collar still thread onto a newer jig?

With a stop collar, I don't think you'll see a real benefit to the laser, (but no harm trying... well, unless you stare at it...  ).

Yes an old collar will work on a newer jig.  (A bit of a sidebar, I've found that on the new collar, the stop can turn if you're not careful.  Definitely not as secure as the old version, but a bit easier to work with).  The collars actually look the same, (there's even an indicator on the new collar of the "spot" for the locking screw), but interestingly enough, the interior diameter of the new collar must be slightly bigger... I had to remove the O-ring to get the old collar on.  Once on though, it works no problem.

[Kavik]

Interesting............thanks 
(check your pm  )

[Ken S]

You guys are liable to end up like me..........with a box of spare Tormek jigs and parts in various stages of repair. 

Ken

[Kavik]

Lol there are worse things to waste money on
But I think I'm happy with just this one mod for the time being, I suggest giving it a try
(still planning to eventually make a platform, but no desire to modify any of the other actual jigs at the moment)

If you've got a lathe and a spare collar, it only takes a few minutes to do

I cut down a second one last night that I'm sending out to cbwx to get a second opinion on it. 
I mention this only to show,  in the attachment, how easily it can be cut out of the original collar without needing to add an additional piece like i did in the first attempt.

[cbwx34]

You guys are liable to end up like me..........with a box of spare Tormek jigs and parts in various stages of repair. 

Ken

I'm sure I'll give you a run for your money...

For me, modifying a sharpener, is 1/2 the fun.  I don't expect Tormek, (or anyone else for that matter), to duplicate the setup I made in the other thread (adding a 2nd USB, sharpening parallel, etc).... just a modification I've enjoyed playing around with, to see what comes out.  If something develops that benefits someone else... so much the better.  No different than modifying a car for one's individual taste... (although cheaper I'm sure).   

I cut down a second one last night that I'm sending out to cbwx to get a second opinion on it. 
I mention this only to show,  in the attachment, how easily it can be cut out of the original collar without needing to add an additional piece like i did in the first attempt.

Thanks!  Looks good... looking forward to giving it a go. 

[RobinW]

I gave up a couple of years ago trying to sharpen our kitchen knives on the Tormek as I was unhappy with the results. I was wrestling with my thoughts on Lift and Pivot, coupled with trying to work out the effects due to the width of the knife jig collar. (We have since used a proprietary knife sharpener in the kitchen and it is more than sufficient for our needs.) I subsequently threw out all the spare knifes on which I had been practising.

Today my son asked me if I could rescue one of his Global knives - the edge is best described as torn to shreds! He doesn't know how, and his propriety sharpener isn't improving matters, and it is only the one knife which has a problem.

So I have just ploughed through all of this Topic, its associated links, printed off the diagrams, got my head round all the various trials and outcomes, and will in the near future have another go at knife sharpening.

With regard to the above comments that it may be of no interest to others (only the two, three main protagonists), if you asked me a week ago I would agree, but now I have a situation to resolve, it is all suddenly very interesting! Some good work has been undertaken and posted. Thank you.

[cbwx34]

I gave up a couple of years ago trying to sharpen our kitchen knives on the Tormek as I was unhappy with the results. I was wrestling with my thoughts on Lift and Pivot, coupled with trying to work out the effects due to the width of the knife jig collar. (We have since used a proprietary knife sharpener in the kitchen and it is more than sufficient for our needs.) I subsequently threw out all the spare knifes on which I had been practising.

Today my son asked me if I could rescue one of his Global knives - the edge is best described as torn to shreds! He doesn't know how, and his propriety sharpener isn't improving matters, and it is only the one knife which has a problem.

So I have just ploughed through all of this Topic, its associated links, printed off the diagrams, got my head round all the various trials and outcomes, and will in the near future have another go at knife sharpening.

With regard to the above comments that it may be of no interest to others (only the two, three main protagonists), if you asked me a week ago I would agree, but now I have a situation to resolve, it is all suddenly very interesting! Some good work has been undertaken and posted. Thank you.

Glad to hear... hope it works out.  Be interested to know what, if any problems you might encounter... would probably help lead to even a better solution.

If nothing else, you can always fix the damage on the Tormek, then switch to your regular "proprietary" sharpener.  (Be curious to know what that is... probably best shared in a private message, if you care to).

Thanks... glad to see there's an interest... hope it helps! 

[RobinW]

As I'm due to be away for a while, I managed to have a couple of hours this afternoon sharpening knives.

First was a 4" paring knife. This brought back to mind another reason why I stopped sharpening knives on the Tormek. A couple of times, whilst grinding towards the edge, it caught and managed to lift the jig off the usb, spun the jig and knife under the usb, whereupon it tried to give me a major Tormek tattoo in the midriff!

So tried sharpening away, and managed to get bevelled surfaces which were pretty rough despite having pre-graded the stone surface with to fine. The edge was not particularly sharp as barely catching my thumbnail and not readily cutting paper. Persevering with free hand honing I managed to polish a lot of the striations out and get a sharp edge.

I then tried an 8" chef's knife. This brought back to mind a previous issue - large knives get obstructed by the honing wheel when sharpening away. However the 8" was accommodated without too many issues. Again the bevelled surfaces were pretty rough, but the situation was again rescued by free hand honing. I always find that free hand honing is liable to round over the edge. I would prefer a jig in the expectation of achieving better results. 

So I took the bull by the horns and had a go at the Global knife. Despite getting equal sized bevels on both sides, again with poor surface quality. The edge looked and felt as though there was a burr, but it was not sharp. It didn't want to 'saw' through a piece of paper. After several attempts between honing and re-grinding I eventually got a satisfactory result. I did find when grinding this knife, it did not feel as comfortable on the stone as the previous 8" knife; it was susceptible to wander off line.

Having absorbed the information in the previous posts by others above, I tried to keep the section of the blade being ground, in line with my LOC on the wheel, lifting and pivoting as necessary to maintain this, without being concerned whether it was lift or pivot but what felt comfortable. I did find that towards the heel end of the Global blade it swung above the LOC, whereas the other 8" knife didn't. Overall the bevel thickness was pretty even along the length of the blade, so quite satisfied.

Anyway, for the short time I had, without practice, I have got three sharp knives. More through beginner's luck rather than being in full control of the situation. Certainly not as confident for repeat purposes as I would be when doing chisels and plane blades. Mind you, it took me many attempts (months!) to master the SE76 square edge jig.

[cbwx34]

As I'm due to be away for a while, I managed to have a couple of hours this afternoon sharpening knives.

First was a 4" paring knife. This brought back to mind another reason why I stopped sharpening knives on the Tormek. A couple of times, whilst grinding towards the edge, it caught and managed to lift the jig off the usb, spun the jig and knife under the usb, whereupon it tried to give me a major Tormek tattoo in the midriff!

So tried sharpening away, and managed to get bevelled surfaces which were pretty rough despite having pre-graded the stone surface with to fine. The edge was not particularly sharp as barely catching my thumbnail and not readily cutting paper. Persevering with free hand honing I managed to polish a lot of the striations out and get a sharp edge.

I then tried an 8" chef's knife. This brought back to mind a previous issue - large knives get obstructed by the honing wheel when sharpening away. However the 8" was accommodated without too many issues. Again the bevelled surfaces were pretty rough, but the situation was again rescued by free hand honing. I always find that free hand honing is liable to round over the edge. I would prefer a jig in the expectation of achieving better results. 

So I took the bull by the horns and had a go at the Global knife. Despite getting equal sized bevels on both sides, again with poor surface quality. The edge looked and felt as though there was a burr, but it was not sharp. It didn't want to 'saw' through a piece of paper. After several attempts between honing and re-grinding I eventually got a satisfactory result. I did find when grinding this knife, it did not feel as comfortable on the stone as the previous 8" knife; it was susceptible to wander off line.

Having absorbed the information in the previous posts by others above, I tried to keep the section of the blade being ground, in line with my LOC on the wheel, lifting and pivoting as necessary to maintain this, without being concerned whether it was lift or pivot but what felt comfortable. I did find that towards the heel end of the Global blade it swung above the LOC, whereas the other 8" knife didn't. Overall the bevel thickness was pretty even along the length of the blade, so quite satisfied.

Anyway, for the short time I had, without practice, I have got three sharp knives. More through beginner's luck rather than being in full control of the situation. Certainly not as confident for repeat purposes as I would be when doing chisels and plane blades. Mind you, it took me many attempts (months!) to master the SE76 square edge jig.

Glad you were able to make a go of it... bummer it didn't come out quite right.  It looks like you've been a Tormek user for a while, so you're familiar with the system.  The only thing I can think of, in reading your post, is maybe a bit too much pressure?  Knives benefit from a light touch... especially the last few passes, I have found.  That and marking the edge with a Sharpie or marker, and make sure your hitting the very edge... sometimes when knives are sharpened with another type of sharpener, "matching" another method can take a bit more than expected... especially right at the very edge and if the other sharpener sharpened or honed at a higher angle... it will look like you're there, but there might be a very small section that still needs to be reached, so the knife won't cut well.  As for the finish being "rough"... not sure why.  Are you basing that on how it looked, or how it cut?  I know others have commented that it takes a bit to grade the stone "fine"... that, and once again sharpening pressure can affect the result.

Any other thoughts on the pivoting?  Think a smaller collar would make a difference (good or bad)?

But at least you got 'em sharp!   

[Ken S]

Robin,

This must be particularly frustrating for you with your trained and experienced engineer's mind. Looking at what you wrote, what struck me was what you did not write. Did you begin by using the TT-50 truing tool? (Please note that I did not write "a truing tool". Of all the redesigned Tormek jigs and accessories, I consider the TT-50 to be the most essential, "must have" tool, along with a microadjust support bar.)

An untrue grinding wheel, and its accompanying gremlins can sneak up on you. It has happened to me several times, including, embarrassingly, while I was demonstrating the Tormek at a woodworking show. Now, whenever my sharpening is off, I use the truing tool. I prefer to make several light passes. Often my first removes only air. I usually advance by half numbers. The second pass will only touch the highest spots. This is the pass that tells the tale. I make my passes slowly, following the recommended handbook time of ninety seconds. Each succeeding pass is advanced half a number, paying attention to the sound and cutting pattern. When I reach a pass when the entire surface, both circumference and width, is lightly cut, I am done.

I am a devout believer in frequent, light truing. In special cases, I have made quicker passes to give a coarser grit. I have also made deep (half a turn) passes when frustrated with a glazed blackstone. My preference is light, slow passes. When I am on my best behavior (not always), I will true my wheel at the end of my sharpening session. This should be a habit, like checking fuel and oil levels in your car.

I don't mean to sound pious or preachy. I have come to this belief through multiple missteps.

I usually sharpen in the trailing grind direction (away from the knife). My eight inch chef's knife and slicer are my two longest knives. A high production sharpening session may consist of three or four knives. I like to be "plumb with the universe" when I sharpen and not rushed. A freshly trued wheel helps keep my head clear. I prefer light grinding passes. I think rounding with the honing wheel is often caused by not being focused on the work. I am as guilty of that as anyone. Jan proposed having the kenjig double ended, to allow setting Distance with the leather honing wheel. I like that idea for those with agile minds. My preference would be a clearly marked kenjig set for the nonchanging leather honing wheel diameter.

I started the trick and tips (not my title choice) topic. I still believe in learning with a chisel,regardless of what you normally sharpen. That topic needs a follow up knife topic. Ideally, Tormek needs to produce an indepth knife sharpening video in its new video production facility.

I suspect most of us have not really mastered the SE-76 Square Edge Jig, and certainly the newer SE-77 jig. We are penny wise and pound foolish. We will willingly purchase a blackstone or Japanese wheel, but not want to spend the small amount of money for several Irwin 3/4" Blue Chip chisels and spend a very few quiet hours really mastering the Tormek. Like most of us, I procrastinated in using the TT-50 Truing Tool, foolishly not wanting to wear out my precious grinding wheel, and doing mediocre sharpening. I made the same foolish mistake with the stone grader.

Redouble your efforts with a quiet, organized mind, and do not become discouraged.

Ken

ps I think good thoughts about you whenever I make metric measurements.

[wootz]

This is how we do a curved tip:
- Mark the tip radius perpendicular to the edge.
- Clamp in the middle of the straight segment.
- Start at the bolster end, and grind the straight segment as usual, sliding across the stone with the knife jig perpendicular to the Universal Support till you reach the marked radius line.
- At this point fix the jig position at the US, not sliding laterally further.
Do the tip radius by pivoting the jig and raising the handle, till the radius line comes perpendicular to the US (i.e parallel to the wheel margin) - not any farther.

Step 1 - straight segment


Step 2 - curved tip

[Ken S]

It would be interesting to do slow motion videos of a dozen expert Tormek knife sharpeners.

Ken

[Jan]

Wootz, thanks for sharing your procedure, appreciated! 

I applaud your emphasis to maintain the normal to the edge perpendicular to the USB.

Jan