Messages

[TormekCalc2]

Hello everyone,

new public and non-public version of TormekCalc² is available (v2.67).

Main News:

• 
  CompCalc [New non-public module]
  
  Allows calculation of the grinding angle compensation if wheels with different diameters are used for grinding.
  It is a problem which, as far as I know, was first described by Gilles in this post and calculated using the Polishing angle calc, which is still available there. CompCalc is based on Polishing angle calc, all credit belongs to Gilles.
  
  Although this phenomenon may not be visible on wheels with a similar diameter and small blade thicknesses, it can cause problems with thicker blades (eg. chisels) and when switching from a smaller wheel to a larger one (eg. 200 mm coarse wheel on T-4  and 250 mm fine wheel on T-8).
  
  You can find more about this phenomenon in this video: https://www.youtube.com/watch?v=h_qRUvSvcLQ
  
  
  


• 
  BatchCalc [Non-public module]
  
  The whole module for batch sharpening has been significantly redesigned so that new functions can be built into it.
  The step generation procedure has been completely reworked. Now the grit of the wheels is also taken into account, proceeding from the coarsest to the finest. If grit is not specified (or is not a number), it is assumed to be the honing wheel that is placed at the end. 
  
  New unique functionality for grinding on wheels with different diameters has been added. It is a compensation layer that automatically calculates grinding angle corrections when moving from a smaller wheel to a larger one. There are two types of compensation, and using this feature brings unexpected grinding benefits...
  
  You can find more information in the same video: https://www.youtube.com/watch?v=h_qRUvSvcLQ
  
  Using and capabilities of BatchCalc module can be found in this video: https://www.youtube.com/watch?v=9qtyTKqQb1g
  
  Attention: For several different reasons, I have decided that these modules will be freely available only to contributors and donors. There is a lot of work, time and know-how behind the development. If in doubt, please compare what the public version of TormekCalc² (even the oldest) offers compared to commercially available applications. If you have further questions, you can send me a private message or e-mail message (see FAQ sheet in TormekCalc²).
  
  
  


• 
  Materials
  
  Added Hitachi GIN-3 and GIN-5 steels to the material table.
  
  

Ideas for improvement are welcome as well as feedback. Please feel free to contact me if you need any further information.

Hint: If you have data in Knives or Tools sheet just select all uses rows between column C to AD (included), copy them to clipboard (Ctrl+C) and paste them as VALUES to new version of TormekCalc2.

Enjoy!

jvh



Attention!

Due file size and forum restrictions (maximum individual size is 256 KB) is TormekCalc2 version 2.1+ available only on external web storage.

Download HERE (WebShare.cz, click Download File and then Download slowly).

Current version 2.67
(TormekCalc2_Public_v267.zip, packed size 2 026 804 bytes, TormekCalc_Public_v267.xlsx, unpacked size 2 186 094 bytes + sample pictures in the Knives and Tools folders.)

That is my problem, because my manual is in German. 

Hello dusmif,

see links.

Manual: Instruction SVH-320 EN

Tormek's video: Tormek Planer Blade Attachment SVH-320
Highland Woodworking review: Tormek Planer Knife Jig SVH-320

jvh

Hello,

I would like to thank Wolfgang, Sébastien and Victor for next part of the Live Sharpening Class, it was excellent again.

Perhaps you are thinking, I do not have the diamond wheels which can grind flat bevels with the MBS-100 Multibase. Why should I bother to watch this video?

Good question. Here is a good answer. As an example, one of the frequently asked questions is about the dreaded "hollow grind". Near the beginning of this video is one of the best explanations of the amount of hollow grind left by a Tormek wheel I have ever seen. Using a 250mm diameter grinding wheel set to a 20º bevel and a 2mm thick blade, the deepest part of the hollow is .03mm, or roughly .001". That is roughly one third of the thickness of a single sheet of copy paper. That is small enough that I do not worry about it for my chisels, plane blades and kitchen knives.

Most of the online classes have parts like this which apply to several areas. Don't sell yourself short by watching only those classes which you think only apply to you.

Ken

Hello Ken,

0.03 mm is really small, but it's only one part of a more complex problem. It is indicated in the video (ca. 4:45), but it is not explained exactly.

Wolfgang said: "Force, of cource, is a little bit aggresive, it will dig in little bit faster..."
This is because in the example shown, the apex angle is 20°, but the angle between the apex and the edge heel is 21.26°. 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 21.26°, 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, and this is IMHO the main thing that should be taken into account.
This also affects the subsequent re-sharpening on a flat stone, where the minimum angle 21.26° is also ground (if the apex and the edge heel are touching the stone).

This problem increases with blade thickness, sharper angle and smaller wheel diameter. It is usually negligible for knives, but may not be the case for tools...

jvh

P.S." The picture shows a thickness of 4 mm, but this is because the calculation is performed for symmetrical blades. The example shows a chisel grind, from which you get a "symmetrical" by multiplying the thickness by two.

Hello,

most have already been answered, just another point of view...

I only have one machine and in this case it is best to have more jigs + water troughs (I don't like particles from coarse wheel on fine wheels).
Diamond/CBN wheel were already mentioned, unfortunately there is no equivalent for SJ-250, so USB height change will be still necessary. Good software for batch grinding is an advantage. 

I don't see the time needed to change a wheel as a big problem, because it always takes me the most time to center the knife in the jig. If you have more machines, you need to change the USB height on each of them instead when changing the angle or protrusion length (or move the adjusted USB if machines are the same).

Another question is, what "stellar edge" do you need to have and for what kind of knives? Because this has a huge impact on time consuming.

Personally, I consider BESS to be more of a marketing tool. Yes, it can really help in personal growth, but:
- Cutting speed and acceleration change the resulting value.
- Media tension changes the resulting value.
- The axial force during test changes the resulting value.
- You get information from one point (or a few points).
- You sharpen the knife and measure the BESS. When you repeat the measurement the next day you will get a value ca +20 g higher due to the oxidation of the edge.
- After a few cuts, the BESS will increase significantly.

I mean, it's easy to forget the real use. You can prepare the knife for the test (sharper angle is better), you get a nice value, but what does it say about edge retention, edge toughness? How to compare values with others when the result depends on individual techniques?

jvh

Hello Pavel,

I have an older Fiskars 1500 Pro (type 12180 or 122190). It has the original bevel angle 30° and I have never had a problem with it.

Whether is bevel angle narrow or not depends on the use, your needs, used material, heat treatment etc., there is no one-size-fits-all advice. And Rich's Sharpening handbook is really great resource.

Personally, I would keep the current angle, in case of problems it can be increased at any time.

jvh

If I can copy/paste the knives table, the upgrade is going to be fairly quick as I will just have to change the wheel diameters on the TormekCalc tab, along with the values for the KG FVB which do not match the default values. I don't know if there would be a real interest in having the most commonly used FVBs available from a drop-down list with a Custom choice, same as the wheels. But all in all it's only a matter of filling less than ten cells.

Hello again,

could be, can you send me these default values? (But at first I will probably add some info table with values for different FVB types.)

Last, for the material, the only steel I have which I cannot find in the list is Hitachi GIN-3 http://zknives.com/knives/steels/ginsanko.shtml, semis stainless 59-62RC which I have in my Korin Ginsanko Deba.

I have added Hitachi GIN-3 and GIN-5 steels to the material table. Thanks for noticing.

jvh

[TormekCalc]

Hey jvh,

A quick question on upgrading from one version of TormekCalc to the next... Do you keep some kind of crude backward compatibility, so I can copy/paste the diameters and knife dimensions / angles / protocols ?

Cheers,

Nick.

Hello tgbto,

good question. See below, I basically try not to change the structure of the tables, but sometimes it's not possible.

TormekCalc
- possible for green cells D10:D13 and shadow cells D16:D22 (since v.2.01)
- not possible in Wheel table (Real diameter, Machine, Grinding angle shift) as I have added new wheels in v.2.63

BatchCalc
- new module in v.2.63, no previous data

Knives + Tools
- possible for both databases since v. 2.01. Just select data between column C to AD (included), copy them to clipboard (Ctrl+C) and paste them as VALUES to the new version of TC2.

BevelCalc
- possible for green cells D7:D20 since v.2.40 ("Angle jig" calculation was added)

EdgeCalc
- possible for green cells D9:D11 since v.2.01

Materials
- not needed if no changes were made to Material table, otherwise insert rows, and copy/paste data

Jigs
- possible to copy/paste data, but it can corrupt translation in ,,Notes" column.

Settings
- not possible in Default values table as structure was changed
- possible for green cell in Machine table since v.2.01 - copy and paste data as VALUES into the appropriate cells in the new version of TC2

It is important that the databases can be copied without any problems, the other modules do not have much data and the upgrade should take about 10-15 minutes.
If it is not possible to copy the data at once, due to a change in structure, it is possible to copy and paste it in parts to the appropriate place in the new version.

jvh

[This is related to the clamping / feeding method]

Actually, I think you two are talking about 2 different things.

Dutchman is correct that a thick blade sitting on the stone is at a different angle than a sharpened blade.  But, the calculator gives the "sharpened angle", which is what we want.  So, if I sharpen the thick blade correctly, working both sides and never sharpen past the center line, I will end up with the desired angle.

jvh is correct that if I take that same blade and sharpen past the center line, (think of the extreme where I sharpen one side all the way to the other side, then flip it over), I will shorten the Projection Distance, which will change the resulting angle.

In either event, thickness does not matter in a blade that is correctly sharpened. 

Hello again,

yes, in this example the angle changes and I pointed this problem two times in my video, but it has nothing to do with the thickness of the blade. This is related to the clamping / feeding method (and axis and protrusion length).

When a thick blade is sitting on the stone it means that there is some ungrinded material and you are above the blade axis and not at the point where you should be. The same situation is when you are under the blade axis.

A simple example - let's imagine that we mount the SVD-110 in the opposite way than usual and try to grind the chisels. We will grind chisels with different thicknesses, feeding method is shown by the arrows. As you can see the apex angle always remains the same regardless of the thickness, so how the thickness affects sharpening angle?

jvh

As I don't have jvh's machinery skills, I am more thinking of drilling through the jig handle close and parallel to the axis and setting a blind nut which would allow me to correct by adding just enough offset on the long side to make sure the knife sits on the laser line on both sides. It is probably not perfect but it is the only doable thing I can think of with my skills, the excentric bushing and the like being out of my league.

Hello tgbto,

all you need to make an eccentric bushing is a drill, drill bits and a piece of aluminum rod. I made first pieces this way.

I hope I understand what you mean... but if the knife sits on the laser line on both sides, it does not guarantee that it is well centered, it only means that the protrusion is the same. I check the symmetrical clamping with AngleMaster as described in Reply #61.

jvh

[the grinding angle will rise as the jig protrusion length will shorten]

... [snip]
I released a new video where you can find an answer to the question of whether the blade thickness affects the resulting grinding angle.
... [snip]
jvh

I do not agree that the sharpening angle is not affected by the thickness of the blade when the blade is clamped in the jig resting on the USB.
During the sharpening process, the tip of the blade will lower towards the stone, while the resting point of the jig remains on the USB. This will cause the jig to tilt towards the stone, changing the angle.
I described that in my publication "More math for the Tormek grinder" after CBWX34 reported that problem to me. See https://forum.tormek.com/index.php?topic=1849

Hello Dutchman,

no, this is something else. It is caused by excessive grinding. If you grind over the axis^*) the grinding angle will rise as the jig protrusion length will shorten. It is also mentioned and showed in my video HERE. But it has nothing to do with the thickness of the blade.

jvh

*) Meaning the axis of the blade in this case, as the calculations in TormekCalc2 are performed for symmetrical grinds by default.

Nice job (as always).

Probably worth pointing out (or correct me if I'm wrong), 😑 that these are scale drawings that validate the formulas, not just drawings made with numbers inserted.

Hello cbwx34,

you are right, the dimensions are "live", they are from parametric CAD, not static images. I drew 3D models of my T-8 and some jigs and use them to verify the calculated results.

jvh

[https://www.youtube.com/watch?v=vG_MmPIUPss]

Hello,

I released a new video where you can find an answer to the question of whether the blade thickness affects the resulting grinding angle. It also briefly introduces EdgeCalc - next module in the TormekCalc2 - its using and capabilities.
The bonus part focuses on verifying the results using a goniometer (laser protractor).

Link: https://www.youtube.com/watch?v=vG_MmPIUPss

jvh

Hi JVH
I found shims very fiddley and sensitive to tiny movements, especially when the blade also tapered towards the tip. I could make them work but it took so much time to set it up. Have you a source for tapered shims, that would make like very much easier? Instead, I considering making different angle rebates in a couple of my SVM-45s but without a machine shop, this was likely to be a little uneven. I thought about using a homemade jig to hold the bottom jaw against my belt sander...

Hello Merx27,

Yes, that's right - fiddly, time consuming...
I haven't any source of tapered shims. I am using a piece of cable tie as shim + double side tape if I need it.

I like the look of the adjustable jig - did you make that? My fear, when considering something similar, was that the pivot between the shaft and the jaws might not be strong enough with a large knife but you have inspired me to reconsider. I'm not sure how the different protrusion lengths help but it may be that I haven't got my head fully around how you use it.

Yes, one of the prototypes. It is robust enough for such a task, but the precise setting can also be time consuming.
I made several designs and there are different ways how to make the adjustable version. In the end, when I compared the price, versatility and speed and accuracy of the settings, I ended up again with an eccentric bushing. But I don't give up, I have some more ideas how to made a perfect jig...

jvh

Thanks again JVH, you are helping me to get my head around all of this  . I relooked at the eccentric bushing idea and see now that it is a good way forward so I will resin-cast a 12mm tube against the inside of another larger tube (18mm) and then experiment with a scale to aid set-up.

I still cannot see how shims work unless they are used to rotate the blade in the jig, please see my attachment.

It is likely that the Tormek manual method has a small effect but for me, all it does is change how much I lift the handle of the blade. I will stick with the guideline approach (laser or otherwise) as this suits me and gets excellent results

Thanks again for your help

Hello Merx27,

a shim can help, but must be placed at the end of the jaw only (or have a triangle profile). An eccentric bushing is also very helpful here because the correction with shim is very rough and the bushing allows fine adjustment.

Other way is special jig. Although it looks weird, the blade is well centered. There is different angle on each side but also different protrusion length, so you get an even grind when you flip it.

See the photos for a better idea...

jvh

[one side of the jig is raised and the other is lowered. The axis of the top of the jig moves and this centers the blade.]

Hi JVH,
This is just the shot of my front page of the spreadsheet inspired by yours. To calculate the different USB height needed for the inverted jig: I use an angle finder to get 'Total angle between primary bevels' and then take that angle off the 'delta k' for the and then recalculate to give me desired bevel angle with new USB height. I then divide the difference in USB heights by 0.3 to give me the number of numerals to raise.

The eccentric cam can be similarly calculated but it is still prone to human error so I am currently focusing on a jig that holds Vee section blades in alignment as this removes the need to remember to do anything between sides but not yet settled on a solution. I do not see how the shimming methods can work as they still maintain the error in angle orientation and shifting the blade parallel to the jig makes no difference at all (IMHO)

Tonight, I experimented trying to get an even bevel width around the curve of a blade and when  I moved the jig towards or away from the tip of the blade, as suggested in the Tormek manual (P53 of v. 10.5) it made NO difference to the bevel width! So, I then used a laser guide-line across the stone while using the SVM45 and successfully kept an even bevel around the curve of the blade by keeping it on the laser line. This removed the black magic of how much to lift and rotate the blade.

Hello Merx27,

by turning the eccentric sleeve, one side of the jig is raised and the other is lowered. The axis of the top of the jig moves and this centers the blade. The aim is to obtain a symmetrical clamping before grinding and no further adjustment is required during grinding. The method I use is described below.

Shims method works the same way but from other side. Keep in mind that the work axis does not have to pass through the tool axis all the way, as this is not necessary - for correct adjustment the axis must pass through the axis of the blade and through the jig center in the point where it rests on the support.

I can confirm that the method described in the Tormek manual (P53 version 10.5) has a visible effect, at least on knives from a length of approx. 15 cm.

jvh