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My revised thinking about the SVM and KJ knife jigs.

Started by Ken S, November 29, 2023, 06:03:28 AM

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Ken S

Part of the Tormek philosophy is not abandoning  support for older, out of production models. Part of this program includes maintaining only the latest parts in inventory when they are compatible with older models. An example of this was the disappearance of the stainless steel straight main shaft when the EZYlock shaft became available. Tormek quite logically concluded that, as the EZYlock was fully backward compatible, there was no need for the expense of maintaining the straight shaft in spare parts inventory. 

As newer, improved versions of jigs and accessories are introduced, older versions are no longer listed in the product line and are discontinued. I suspect this will happen with the SVM jigs, if it has not already happened.

I now think of the SVM and KJ jigs as two different tools. The KJ is self centering and can do convexing. The SVM, while not self centering, offers adjustability of the end stop. while this may not be necessary for many users, for high volume knife sharpeners it is highly desirable. Therefore, I think it is prudent for a knife sharpener who is seriously contemplating starting a knife sharpening service to acquire an SVM-45. The SVM and KJ jigs complement each other. The KJ is the jig of choice for thicker knives. In my opinion, the SVM is the correct choice for rapid switching of knives of typical thickness. I believe a well equipped sharpener should have both. I do not believe duplicating the long jigs is as critical.

At this time, finding SVM jigs among dealers' stock or used should not be difficult. I would not wait.

Ken




Dutchman

I would like to recall the message below. The Adjustable Stop could be added to a self-centering Jig
"It isn't rocket science surely?"
Quote from: Sir Amwell on December 01, 2022, 12:26:16 AMI appreciate previous comments but there is a glaringly obvious issue here. And we should not be afraid to call it out. The new KJ 45 jig is really good for centring most everyday knives be they thin or thick on the blade stock. But it is really compromised for its lack of adjustment on the jig protrusion. The old svm jigs were great for adjusting jig protrusion and no good for centring thin or thick knives. And they are knife jigs. Remember that.
So why not the best of both? Let's challenge Tormek to do the right thing and produce a self centring jig with the ability to adjust the stop. It isn't rocket science surely?

HaioPaio

Quote from: Dutchman on November 29, 2023, 12:14:45 PMThe Adjustable Stop could be added to a self-centering Jig
"It isn't rocket science surely?"
I agree. I would not mind loosing the theoretical capability for "grinding convex edges".

Ken S

I agree with both replies.I believe most of those who purchase the KJ-45 to provide self centering to their present knife jigs would also purchase an improved jig which combined self centering with adjustability. I would keep the KJ-45 for the occasional convex grind. Adjustability would be useful with every knife.

Ken

Thy Will Be Done

I do professional sharpening and having both is a must, there's been plenty of knives coming my way that don't fit within the constraints of the KJ-45.  Chopping knives are thick and when they are full flat grind it is not compatible, which IMO is one of the biggest reasons to own a grinder like this in a home environment is reworking heavy/thick tools that would be a major work on stones.

Ken S

You present a good actual experience based case for a professional sharpener to have both jigs.

Ken

3D Anvil

The SVM jig is much better if you want to pivot a knife with a big belly, assuming you have some kind of after market pivot add-on.  This could be addressed in an updated KJ-45 with an adjustable stop, which I would really love to see.

Thy Will Be Done

Quote from: 3D Anvil on December 13, 2023, 03:08:57 PMThe SVM jig is much better if you want to pivot a knife with a big belly, assuming you have some kind of after market pivot add-on.  This could be addressed in an updated KJ-45 with an adjustable stop, which I would really love to see.

What is this pivot you speak of? 

I generally get around having to pivot blades just by clamping the jig further towards the handle or right at the handle and also angling the jig to match the curvature.  This way I generally get nice even bevel width just about all the way to tip in almost all cases.  Some really heavy bellies on short 4" under blades can be a real challenge though to get it clamped the ideal way.

cbwx34

Quote from: Thy Will Be Done on December 14, 2023, 06:53:45 PM
Quote from: 3D Anvil on December 13, 2023, 03:08:57 PMThe SVM jig is much better if you want to pivot a knife with a big belly, assuming you have some kind of after market pivot add-on.  This could be addressed in an updated KJ-45 with an adjustable stop, which I would really love to see.

What is this pivot you speak of? 

I generally get around having to pivot blades just by clamping the jig further towards the handle or right at the handle and also angling the jig to match the curvature.  This way I generally get nice even bevel width just about all the way to tip in almost all cases.  Some really heavy bellies on short 4" under blades can be a real challenge though to get it clamped the ideal way.

Rich has documented the various versions of pivot jigs here:

https://sharpeninghandbook.info/indexJigs.html#PinPivotCollar

(There are several versions.)

It would probably solve your challenge.   :)
Knife Sharpening Angle Calculator:
Calcapp Calculator-works on any platform.
(or Click HERE to see other calculators available)

Sir Amwell

I don't think I'm going off topic here. I have been quoted from a previous post. I stick by those comments. I sense many may be in agreement with me, whether professional sharpeners or home sharpeners. I return to my original post. How can we as a user community put positive pressure on Tormek to do the right thing with this issue?
As a professional sharpener I would gladly invest in 6-8 new jigs that catered for self centering AND adjustable stop.
I currently use 8 of the old svm jigs ( 2 milled for thicker blades) and 1 kj45(which I rarely use).
I batch sharpen.
Imagine how much more efficient it would be with a hybrid jig?
So again, how can we get Tormek to do this?

tgbto

I'm not sure we can do much, aside from laying down facts on why this is desirable, and more generally constructive criticism.

When faced with such comments, Tormek seems to follow the usual stages of (commercial) grief, beginning with denial, and sometimes ending up accepting the issue and doing something about it (The AngleMaster for knives and the FVB/MB-102 being two excellent examples of this).

Now to be realistic, we have to admit that :
- It takes a lot of money to develop a new (high quality) jig, that can be reliably produced at a reasonable price.
- The number of people that this is a problem for are probably a few dozens and will never buy enough jigs to make such a redesign economically viable
- Knife sharpening is an afterthought for Tormek, but the market size is big enough that they have been putting a lot of effort to adress it better

So all in all, I think the KJ has been developed with the objective of adressing the assymetrical bevel issue, at a time when Tormek was still asserting that the best way to set a predefined angle was the AngleMaster. So they wouldn't bother with including a way to set a projection distance, because as they put it in a video at the time "in the end it doesn't matter", and they -understandably - wanted to keep the KJ cost as low as possible. Denial stage, remember ?

Therefore however loudly we protest, it won't change much in the near future, when the non-recurring costs for developing the KJ have to be covered tenfold before they dare think of redesigning a jig.

I might even go as far as saying that they consider angle calculators some kind of a threat, and they dismiss their interest in patent filings, writing : "There may be errors in computation-based solutions". As if that was not true of just any human action, be it through software or hardware. So it is quite convenient for them to produce a new jig that will de facto negate the interest of calculators.

My best guess is there will be a market for third-party jigs that allow to adjust projection distance on a larger scale than the SVM, with a more reliable way to prevent this distance from changing during sharpening, and with a way to guarantee symetrical clamping. At a much higher price.

AFAIC, I've stocked on SVMs and I deal with assymetry for wide knives by sharpening one side, then the other, fiddling with the USB height and a controlled number of turns one way and the other. I don't sharpen enough of these that it is worth losing time to reset USB height for each knife.


Ken S

Sir Amwell and Tgbto,

I believe the most effective way to reach Tormek on this matter is via individual emails sent to (support@tormek.se) attn: design committee. These emails should be constructive, polite, and focused. The sender should be clearly identified, including that he is a dedicated Tormek knife sharpener.

What you are asking Tormek to do runs contrary to customary for a  for profit business practice. That does not mean that Tormek will not listen or respond. I have found in my personal dealings with Tormek that they do listen. Tormek produced a limited production run of the US-400 due to user requests. When this run sold out, I emailed Tormek suggesting longer legs would make the US-400 more useful. The result was the more versatile US-430.

The email to support should include what you want in the jig as well as what is not as important to you. you should also include how many jigs you would like to purchase and how much you would be willing to pay per jig. You should also calculate, but not include in the email, how much you would be willing to pay a local machinist to design and machine a jig for you.

If you are in no hurry, a jig from Tormek is probably a good choice, although it may well take a couple years to come to market. A local machinist will probably be much quicker. I would expect either to be expensive.

If Tormek receives emails from a hundred users wanting to purchase several hundred jigs, they might take up the project.
emails from fifteen users wanting a total of thirty jigs probably won't generate much interest.

The design committee must hear from you.

Ken

RichColvin

Quote from: 3D Anvil on December 13, 2023, 03:08:57 PMThe SVM jig is much better if you want to pivot a knife with a big belly, assuming you have some kind of after market pivot add-on.  This could be addressed in an updated KJ-45 with an adjustable stop, which I would really love to see.
As Ken notes, the SVM and the KJ jigs really need to be viewed separately.  

With the SVM jigs, the SVM's stop is adjusted so that, when affixed to the knife's blade, the projection stays at 139mm (or is it 129mm?  Can't remember as I use a jig for this too.)  And the USB's height is fixed for a given angle.  The height of the USB can be set easily using the HanJig (https://sharpeninghandbook.info/indexJigs.html#HanJig) or very accurately using one of the calculators like CB's or TormekCalc. 

With the KJ jigs, the projection changes based on the blade's width, and the sharpener needs to adjust the height of the USB.  The Knife Angle Setter from Perra (https://sharpeninghandbook.info/indexJigs.html#KnifeAngleSetter) makes this quite easy.  

Neither is harder or easier than the other, just different. 
---------------------------
Rich Colvin
www.SharpeningHandbook.info - a reference guide for sharpening

You are born weak & frail, and you die weak & frail.  What you do between those is up to you.

Ken S

I think we must establish our individual priorities. In my case, Ihave only one knife noticably thicker than the acceptable range of the SVM, a Mora Garberg at 3.2 mm, and acouple thin paring knives.I could do work arounds, although the KJ is inexpensive enough to warrant purchasing. I feel no need to convex edges, and I have a US-430 tohandle my cleaver. I have several SVM jigs, including a set of milled jigs and feeler gages to handle thicker knives as recommended by Wootz. Among my SVM jigs are three pre 1992 jigs purchased used which allow me to standardize on 139mm projection, even with paring knives.

I believe knife jigs will continue to evolve. For those in a hurry,I recommend working with a local machinist and being prepared to pay very small production prices.

Ken

tgbto

Quote from: Ken S on December 17, 2023, 11:24:10 AMAmong my SVM jigs are three pre 1992 jigs purchased used which allow me to standardize on 139mm projection, even with paring knives.

It's a shame those shafts have gotten shorter. A drill collar or milled pin-pivot-style or 3D-printed handle is quite helpful to standardize projection distance as well.