a new angle setting tool

[Ken S]

I believe the TTS-100 Turning Tool Setter and the SVD-186 make sharpening and maintaining turning jouges the most advanced function of the Tormek. The combination offers both great versatility and efficient repeatability. For some reason, Tormek has not chosen to expand this very effective method to sharpening other tools, such as knives and chisels.

The WM-200 AngleMaster is a well designed tool. I would not be without one. It is, however, a tool I hope to use as little as possible. I should explain.

The bevel angle of grinding is determined by the angles of a right triangle. By definition, the angle from the grinding wheel to the universal support is ninety degrees, a right angle. The angles determined by the distance between the grinding wheel to the universal support and the projection distance of the edge of the tool from the universal support are the other two angles. By definition, the sum of these two angles must equal ninety degrees. With the Turning Tool setter, the distance between the grinding wheel and the universal support is determined by inserting the TTS-100 into the universal support. The two holes, A and B automatically set thirty and forty five degree angles. Inserting the gouge into one of the three distance slots automatically sets the projection distance. The TTS-100 even adjusts automatically for wear of the grinding wheel. The system is simple, every effective and offers repeatable accuracy with no other measuring.

By comparison, the usual methods of setting bevel angles with other tools, including the AngleMaster and using a black marker, seem primitive and slow.

I designed the kenjig (formerly known as the KS-150) to avoid the necessity of redundant measuring. Setting the kenjig on the adjustable stop of any of the Tormek knife jigs and adjusting the length of the jig with the knife attached to the pencil line (139mm) provided a consistent projection distance. Placing the universal support in the notch of the jig and adjusting the distance to the point where the jig touched the grinding wheel provided a consistent distance between the universal support and the grinding wheel. No precise measuring was required.

The jig length and position of the notch were determined using Dutchman's trig tables posted on this forum. They work very well. I also believe that using the tables may be intimidating to those of us whose math skills are rusty and or limited.

I designed the angle setting tool as a stand in for a knife blade. (Thanks, Steve, for suggesting the term "stand in".) This tool is very simple and easily home made. I used a piece of "welding steel" found at the same display in the hardware store as the aluminum bar stock for those of you have made one of Herman's HK-50 jigs. This particular piece was a length from a three foot length of 1" x 1/8" (25mm x 3 mm)  steel. I chose steel because aluminum can be "gummy" when ground. Aluminum or hardboard would also work, and the dimensions are not critical.

An acute bevel is ground on one edge. The tool resembles a small simple plane blade, although the bevel is left unsharp. The bevel should be less than the most acute bevel you plan to use. (Generally anything less than fifteen degrees.)

The tool is placed in any of the Tormek knife jigs and the jig adjusted to the 139mm line of the kenjig. The knife jig is set on the universal support, just as in sharpening a knife. The AngleMaster can be used to set the distance between the universal support and the grinding wheel to the desired bevel angle. The "stand in" tool provides a long, wide flat plane, like the back of a chisel, to facilitate easy and accurate use of the AngleMaster.

At this point, as long as the knife is set in the jig to the distance of the pencil line (139mm), the set up is ready to go. A much more efficient alternative is available. With the distance (universal support to grinding wheel) set, use a combination square set from the distance above the universal support to flat on the grinding wheel. Mark this distance on a new kenjig. Cut the notch to this length. Make sure the 139mm (or whatever length you desire) is marked on one face of the kenjig.

With the kenjig, setting the knife in jig length to the line and the universal support to grinding wheel distance to the notch will produce accurate and repeatable grinding with no further measuring required. Be sure to label the kenjig with the angle. Kenjigs may be produced for whatever bevel angle is desired. This tool can be used for more tools than knives.

I encountered one minor problem with the steel. I used the end of the piece. The length had been cut in the factory with a large punch, which rounded off the edge. This rounded edge, like the rounded edge of a carelessly back sharpened chisel, should be ground off.

I welcome comments and suggestions. See the included photos.






Ken

Many thanks, Jimmy.

[Jimmy R Jørgensen]

Need help with the pictures ?

[Ken S]

Thanks, Jimmy!!!!

Please check your email. I just sent the photos to you.

Ken

[Jan]

Thank you for your new interesting post, Ken. 

I will need some more time to digest your new approach, to see its strong side and efficiency/accuracy.

In the second picture, the Angle master is set to some 18^o, I am wondering why? In my understanding the standard Kenjig uses the following parameters: 139 mm for jig and knife length, 80 mm for stone-support distance and 30 ^o(2 * 15^o) for edge angle. Assuming a new grindstone.

Jan

[Ken S]

Excellent observation, Jan. Yes, the angle master is set for eighteen degrees. The kenjig was designed for one angle. With the new tool, any angle within a reasonable range is usable. Eighteen degrees is the standard first bevel Steve uses. I must have been asleep when I made the photos.......

Ken

[Jan]

Thank you, Ken, for your prompt explanation. 

So, if I understand you correctly, your new approach preserves the length of 139 mm for knife jig with knife, while the stone-support distance is set using the angle master for the desired angle. Your new tool provides enough place for the angle setter, ensuring very good  angle setting precision. The stone-support distance is then graphically transferred to a new kenjig.

In the case of the original kenjig, designed for 30^o edge angle, you experimentally estimated the length 139 mm and determined the corresponding 80 mm stone-support distance from the Dutchman's tables.

So I understand it, I hope rightly so.

Jan

[Jimmy R Jørgensen]

Danm i'm trying here. but i fail to get the hole point of this thread.. can someone erhh explaine it to me (as a 6 year old).. Thanks in advance.

[Ken S]

Jan,

There is nothing sacred about the 139mm projection length. I measured my paring, slicing and chef's knives in the Tormek knife jigs and noted the range of each knife from the minimum to the maximum lengths of the preferred knife jigs. I noted the range and picked 139mm, which gave me some "wiggle room" ("tolerance" or "adjustment room" would be better non English centric terms). i used the Tormek small knife tool for the paring knife to keep the range more consistent, although it could be done with the standard knife jig.

My original suggested measurements just happen to work for me. I would suggest others make their own measurements. It is a good part of the learning process.

Jimmy,

Think of a right triangle with the distance from the universal support to the grinding wheel being one leg. Imagine the point where the first side intersects the grinding wheel and the point where the knife edge intersects the grinding wheel as forming the second leg of a right triangle. The point where the knife jig intersects the universal support and where the knife edge intersects the grinding wheel form the hypotenuse of the triangle. As long as the angles of this triangle remain constant, the bevel angle will remain constant.

The kenjig allows us to return to a consistent edge projection and distance between the universal support and the grinding wheel. The original kenjig was designed to use Dutchman's trig tables to determine these dimensions.

The new metal angle setting tool works as a stand in for the knife blade, and provides a large flat measuring surface. This allows the AngleMaster to work more effectively. My plan is to use the tool with the AngleMaster only once, to set up the wooden kenjig. If a different bevel angle is desired, the setup can be used to set up another wooden kenjig

This is much more easily demonstrated with a video than in print. However, as you well know, my digital sharing skills are limited. My digital camera is capable of making good videos; I am not so capable (yet). I have many new digital skills to learn before attempting video. I am working on it! I recently switched to a Macbook Pro for my photo work with Adobe Lightroom CC. That's a lot for an old film guy to learn.

Don't hesitate to keep asking questions. That's how we all learn.

Ken

[Jimmy R Jørgensen]

Thanks Ken for taking the time to explain.


If you ever need help with the video part, of computer (altho i'm not a mac man) i might be able to help you out .

[Ken S]

Thanks, Jimmy. I think this will work for me, although I still have to modify the size. This image is approximately 25mm of my chef's knife edge.

I found the crop/resize button and resized this down to 400 x 267, a much more usable size. I will delete the larger image in a few days. Perhaps the old dog can learn new tricks after all.

Ken

[Ken S]

I almost started a new topic, "moderating the moderator". In my last post, I inadvertently posted an oversized photo. My intention was to leave it up for only a few days to show how easily oversized photos can be added.

Within a few minutes, the photo was resized. Either the "Overmoderator" in Sweden was at his post, or, more likely, the program automatically made the change. Either way, it was a good call.

Ken

[Jan]

Jan,

There is nothing sacred about the 139mm projection length. I measured my paring, slicing and chef's knives in the Tormek knife jigs and noted the range of each knife from the minimum to the maximum lengths of the preferred knife jigs. I noted the range and picked 139mm, which gave me some "wiggle room" ("tolerance" or "adjustment room" would be better non English centric terms). i used the Tormek small knife tool for the paring knife to keep the range more consistent, although it could be done with the standard knife jig.

My original suggested measurements just happen to work for me. I would suggest others make their own measurements. It is a good part of the learning process.

Thank you Ken, for pointing out how you determined the length of 139 mm. I remember that it was the result of a series of tests.

I want to assure you, that I do not have any problem with your length 139 mm. Conversely, you might remember that I adopted this length for my Knife Tip Setting Template.



for details see http://forum.tormek.com/index.php?topic=2562.30

So, I am glad that your new approach preserves the projection length of 139 mm! This protects my investment in designing the template.

Your new tool is a clever approach that is available to all, even those who do not have the Dutchman's tables by hand. Thanks for sharing it with us. 

Jan

[Ken S]

Jan,

You can easily find Dutchman's tables on the forum. Do a member search under"D" (just the search function doesn't bring him up. He only posted a few times. His post at the bottom of the page includes the link to his booklet and tables.

Ken

[Elden]

http://forum.tormek.com/index.php?topic=1849.msg9521#msg9521

[Jan]

Ken asked me to modify my knife jig positioning drawing into a form which can farther clarify his concept of a new angle setting tool. So my sketch is here. 



Jan

P.S.:The wheel-support distance can also be calculated with an Excel spreadsheet which is available for download at the following address:
https://www.dropbox.com/s/ypbtaxgycgoyls0/KENJIG_wheel_support_distance_1.xlsb?dl=1