Messages

[Version 3.00 has been released]

Version 3.00 has been released (NOT available as Public version)

Introduction video is at https://youtu.be/EWMpvw2No0Y

Main news:

• File format change
  File format was changed from *.xlsx to *.xlsm, which supports Macros and VBA programming language. Without this step, it would have been impossible to overcome the existing limitations and continue the development.
  
  
• 
  Data import feature
  Ability to import data from previous versions of TC, from 2.63 onwards. Import is supported from both Full and Public versions.
  
  
• 
  Backup feature
  Possibility to back up the current TormekCalc status and option to backup/export the file to the original *.xlsx format. Such file will behave as TormekCalc 2.xx series.
  

Note: All users of the full version should have received the new version, if not, please send me a private message or email. Some messages are being returned to me as undeliverable, probably due to more aggressive anti-spam filters.

jvh

... My main use for this would be using it to get a more precise angle when I'm honing along with the honing calculator that Vadim used in one of his video.  The extra sharpness he got out of the knife after using the FVB was pretty impressive.

Hello,

The claim that extra sharpness can be achieved using FVB makes no sense from a technical point of view, whether you use a calculator or not.
As long as the same honing wheel is used, the same angle setting, the same procedure (guidance, pressure and number of passes) and of course the same knife in the jig, it doesn't matter what position the sharpening is done in.

OK, we can talk about ergonomics where FVB IMHO slightly leads, also there is no risk of the above mentioned jig collisions with Tormek nuts, it helps sharpen specific knives etc. On the other side, on a horizontal USB you can better see the apex and the process of forming of the grinding paste on it while honing.

I admit that ergonomics can affect the result, but a significantly different result has no technical justification, especially when both methods of honing allow comfortable work.

The causes of such a result can only that:
1. Different angle was set on FVB and horizontal USB (my guess).
2. A different honing procedure has been used, which means different pressure and guidance of the jig.
3. You want to get the results you expect / confirmation bias.
4. Marketing interests prevail (whatever that sounds like).
5. I'm completely wrong and arguments will come up to prove it. Until then, I'll take the claims of extra sharpness from FVB as myths, of which there have been many and they go round and round.

I'm sorry if that sounded harsh, but I see no reason not to speak out against things that don't make sense from a technical standpoint.

I am working to put together an offering for this & a few other items like Rick's pin pivot jig.  As I look at the prices for various metals, aluminum is significantly less expensive than stainless steel, so I will be able to offer a FVB in aluminum for much less than stainless steel.  Also, if the two rods are threaded, that adds a lot to the cost.

So what I am looking at as options are:

   
• Stainless steel block with stainless steel threaded rods or
• Aluminum block with straight, unthreaded rods (like the original universal support bars)

The stainless steel will probably be 2x the cost of the aluminum one.  Which would be preferred?

Rich

Aluminum block (cheaper, lighter), definitely with straight bars (no thread), with stops and grooves for quick adjustment - reasons and inspiration here https://forum.tormek.com/index.php?topic=4129.0

jvh

On the (amazing) Tormek Calc2 spreadsheet, what is cell 13 (Frontal vertical base offset F [mm]) measuring? Is it what I show in the attached picture?

The note references marks on the rod, I don't see any marks on the setup I have.

Hello Martin,

yes the measurement position is correct, but it also depends on the type of FVB and its dimensions (constants), namely FVB body thickness,  constant VF (and constant VH).

What type of FVB do you use (manufacturer)?

Reference marks on the rod are on my version of FVB - see https://forum.tormek.com/index.php?topic=4129.0. They are used to quickly adjust the position of the FVB


jvh

Hello Mike,

I have no problem with this. I understand what is the problem and therefore I mentioned "sharper angle grinding" option in my previous post. All deviations caused by hollow grind are calculable and if you take them in account you can eliminate their impact, eg. you can grind microbevel on the flat stone or directly on the Tormek.

A brittle edge indicates a problem with the bevel angle being too sharp. But it's not the fault of grinding - there you can set what angle you want to grind - this is due to the rather inappropriate use on too hard material/wood...

Why should I grind / hone over the complete height of the chisel bevel if I know that resulting angle will be wrong?

jvh

[thicker]

My main point was that between what you call the apex and the edge heel, the soft iron layer will be thinner...  that's all...   And if you have experience with Japanese blades (especially high quality ones, not the junk that is generally sold through the western tool dealers...) you would know that the wrought iron layer is integral to the support of the thin blue or white steel layer...  and the risk of tapping out a Japanese kanna blade is high enough without thinning out the layer...  (and if you never tapped out a blade, you aren't using the plane very much, or have one of the junk blades that has a huge flat on the edge of the ura...)  You don't tap out a blade at the edge heel, you tap it in the middle, between the apex and the edge heel...  where it would be thinned out...

I'm not saying that you -can't- grind a Japanese blade on a Tormek...  just that I wouldn't (and neither would any of the guys that I know that use high quality Japanese tools...) ever grind a $600 hand made blade, and wouldn't see any reason to grind a cheap one either...  a hollow grind would structurally change the blade, and not for the better...

JH

Hello,

I must repeat that the soft iron layer will be thicker after hollow grinding (for the same apex angle). And for a thin layer of blue or white steel the rounding of the hollow grind is negligible, even if you grind a sharper angle as shown in Example 2 in my previous post. Other possible problems are described here too.

Please look at the enclosed picture what is difference between flat and hollow grind in higher zoom.

Can you explain how a hollow grind would structurally change the blade?

My post is not meant to be offensive, I'm just trying to verify if the information makes sense and if it's not another myth about grinding...

jvh

[more material at the edge heel due to hollow grind]

You really don't want a hollow grind on a Japanese kanna blade (or Japanese chisel blades either...)  The blades of Japanese tools are made from two different types of steels...  there is a very hard steel that is brittle (the cutting edge...) laminated to a much thicker and softer iron...  the thicker iron keeps the more brittle cutting edge supported, and if you use a Tormek to hollow grind the bevel, you will be significantly reducing the thickness of the supporting iron...  mostly because of the thickness of the overall blade, and the length of the bevel...  (most of my kanna blades are around 25 deg. or so, and almost a half inch of bevel...)  Same goes for Japanese chisels...

On western blades, the whole blade is the same type of steel, so hollow grinding isn't a problem...  but I would think that if and when you go to tap out the blade (which you will have to do at some point...) it's stressful enough to do it with the full support of the softer iron, but I would think that the possibility of cracking the hard steel would go up many times with a hollow grind...

Also, the main advantages of a hollow grind being to keep a narrower bevel "stable" when honing and not needing to hone as much steel on each sharpening pretty much go away with Japanese blades...  I've found that the wide bevel makes it very easy to keep the blade flat on the stones, and the softer iron hones so easily that they are much easier to sharpen on stones than western blades...

I use my Tormek all the time for western blades and knives...  but wouldn't touch one of my good kanna blades on it...

Also, no micro bevels or ruler trick bevels on the back on Japanese blades... 

Hope this helps...

JH

Hello,

no, that's not true. If you will have 25° at the apex you will have more material at the edge heel due to hollow grind. You can see what's happening during flat and hollow grinding in this video.

In example below are calculations for chisel with edge heel thickness 5 mm, chisel (single bevel) grind, angle 25°, wheel diameter 240 mm. Hollow grind depth is in that case 0,122 mm, but there is no reducing the thickness of the supporting iron.

The problem with the hollow grind is that the apex angle is 25°, but the angle between the apex and the edge heel is 27,579°. Compared to flat grinding there is "unground" material on the edge heel (due to the rounding of the wheel), which does not allow the blade to be tilted below 27,579°, because it would not cut as the apex does not touch the material. This makes the cut more aggressive because the edge is directed more into the material. This also affects the subsequent re-sharpening on a flat stone, where the minimum angle 27,579° is also ground (if the apex and the edge heel are touching the stone).

If you count with this you can start grinding with a sharper angle to get the angle between the apex and the edge heel equal to 25°. Second picture shows that you have to set initial grinding angle to 22,17° (= apex angle) and this slighly reduce thickness thickness of the supporting iron - hollow grind depth will be 0,146 mm. Is it too much?
But this is not the end, now you can continue on the flat stone - when the apex and the edge heel are touching the stone you will grind 25° angle + you will reduce also hollow grind depth while grinding. Other possibility is to grind 25° microbevel on Tormek too. 

Personally, I see no reason why Japanese chisels could not be sharpened on the Tormek. It will only be better to use advanced grinding techniques...

jvh

[TormekCalc2]

I have a question about knife sharpening apps. It is not my intention to compare apps or discuss their value. I have watched a number of well done videos about using these apps. These videos all seem to focus on sharpening one knife. I understand that this simplifies the learning process; it is an effective teaching technique.

What I have not seen is a video showing a typical sharpener situation with ten to twenty (or more) knives to sharpen in a morning. In a hypothetical ten knife batch, how many would receive the computer "treatment"? I realize there is no simple stock answer. I am just curious, not critical.

Ken

Hello Ken,

as I know, there is no such app except TormekCalc2 / BatchCalc module. Sharpening of up to 6 knives / tools in one go is supported at current version, but that can be easily increased. The main reason why there are only 6 positions is that you need the same amount of jigs for batch grinding.

Another unique feature of this module is that the height difference between the individual steps is converted to the required turns of the Tormek Micro adjust nut. I can say, from my own experience, that this method of setting up is fast and very, very accurate.

Unfortunately, the BatchCalc module is not freely available for several reasons, the main one is that the implementation of such functionality is not trivial at all and there is a lot of work and know-how behind it.

Video how it works is here: https://youtu.be/9qtyTKqQb1g

jvh

@ Rick & Mike:
Thank you for your posts. 

@ Alf:
Please look at help in cell comments, functions should be well documented here. I will try to add more instructional videos to my YT channel in the future, unfortunately I have a lot of other work at this moment.
If necessary, you can also send me a private message and I will try to answer specific questions directly.

jvh

Jvh, but will by looking only, one can check the sharpness?
Alf

Alf,

it depends. Sharpness for what? For the lowest BESS or for real use?

Sharpness is only one part of the problem. You have to consider also the real use, edge toughness, edge retention, corrosion resistance. You have to remove burr completely.

BESS shows you the sharpness in one point of the edge at a given time. When you repeat the measurement the next day you will get a value ca +20 g higher due to the oxidation of the edge. The BESS value will increase significantly after a few cuts etc.

With a good microscope... what do you think, is it sharp? (And you can still use cigarette paper, hair etc.)
https://youtu.be/QG_z9ynBht8?t=122
https://youtu.be/NXz7WB_qhqk?t=92
https://youtu.be/8LS17P0k4hw

jvh

Hello,

why do you need to measure BESS value? I'd rather invest in a good microscope - you'll see what's going on on the whole edge, not at single/few points...

jvh

Hello,

something like this? (Not my ideas, taken from CZ forum.)

jvh

JVH,

Thanks for the screen shots.  They are helpful.  I tried replicating your examples, but don't get the same results, at least with some of the jig parameters that my version of the spreadsheet had as defaults. 

I looking for what other parameters are different,  I see that some of the jig dimension parameters differ for the SE-77 in BevelCalc, but these are values I can't alter on this tab. I've tried changing values in the Jig tab, and while that does change the displayed values, I still don't get the same Bevel Angle as you.  The differences are very minor and immaterial, I think.  Probably some other parameter differing in decimals. 

What would be the reason for the different jig parameters?  I am curious how you measured those jig parameters as they require some careful alignments and could make a difference in results.

I believe I get your point and can use BevelCalc. 

Rick

Hello Rick,

sorry, I used my version of TC2 while I experimented with another support with different diameter, so calculated results was for USB dia 15,3 mm.
I changed the pictures in the previous post, you should get the same results if you use the same machine constants.

jvh

Hello CB,

thank you, I couldn't be here for a few days...

Thanks, CB.  I guess that helps.  It took me a while to figure out the number of significant digits makes some difference and how to set it to display correctly (T USB).  It appears VUSB is a required input in BevelCalc for the Bevel Angle to calculate correctly.  I took that value from TormekCalc, but if I have to measure it as well as T USB, I don't want to bother.  That is one reason I am using T USB, so I don't have to measure VUSB. 

Hello Rick,

VUSB is not required input, you can enter T USB dimension (Top of USB to wheel surface T [mm]) in BevelCalc too. But if you enter T USB only, you get angles in all Bevel angle Δ [°] cells, because this dimension is the same for all USB types and it is not clear which one you are calculating.
You can also enter T USB and VUSB together (or HUSB / FUSB) dimension, then VUSB dimension has higher priority and it will override calculated angle for VUSB. Take a look at the attached pictures for a better idea.

jvh

Great 😊 I'll give it a shot, dusting off the old excel skills. Great tip btw. I'm guessing it will be possible to save the offset angle for honing for specific knives/steels.

Hello,

You can save the offset angle to Notes for knives/tools and Sharpening notes for materials.

I do not plan to load these values automatically, because I consider this concept to be problematic. As you may have noticed, I don't automatically follow the suggested procedures, instead I try to verify them and find out what they really are. My experiences suggest that the correct grinding technique and more precise settings between the individual steps have a significant effect on the formation of burrs, which can be eliminated during grinding and subsequent honing at a higher angles is not necessary.

jvh

Wow just found this and it's a game changer!

Is it possible to add data for felt wheels and recommended honing angles like knifegrinders recommend? Understand if this is only for Tormek specific products^^
Would you be interested in adding Swedish language to the Excel file? I might be able to provide this if so. Cheers!

Hello LarK,

yes, you can add data for any wheel or machine. There are 3 slots for custom wheels in hidden columns, but you can also change unused wheels data specification to something else. For honing at higher angles is designed "Grinding angle shift ±Δ [°]" function, see picture.

Any translation is welcome, if you do it you will become a contributor. Please use the "Language5" column on the Languages sheet, send me a PM for help if necessary, as there are formulas in some cells.

jvh