Bowie Knife

[dusmif]

What we are saying is that if you now flip the knife jig and run the other side of the blade on the stone, the grind line will be higher; the grinds be of different height on the sides of the blade. Thick blades (i.e. where the blade centerline is above the jig centerline) get a higher bevel on the base side.

Thank you wootz. I apoligies for my lack of expertise, this is something new to me.
I am getting the bevel higher in the front/point of the knife, as you can see from my photo, should I not get the bevel at the bottom of the knife and not 5mm higher up.
Now as you clearly explained I will get a differnce bevel on the other side, which that is insult to injury.
This is a disapointment for me after I spend € 800 and I can't get my Bowie Knife sharpened.
To tell you the truth I bought it to sharpen my working tools, but at least I was hoping I could do even my Bowie. 
I am sure that a more experience person can do it, so it seems I can't do do it to lack of my ability.
So, the Tormek it seems is restricted to paricular knives only, others with a knife like mine had to modiefy the jig, which I  do not know how.
Anyway, thank you for your help and to all those who took the time to post their advice, at least I didn't ruined my Bowie with the help of the forum members.

Regards
Alf.

[Jan]

This spring my countryman shared his unique simple way for sharpening thick knives. He designed eccentric cam for the SVM-45, which should enable to mount also thick knives symmetrically. 
https://forum.tormek.com/index.php?topic=3918.msg26586#msg26586

Recently I have received a sample of this cam printed on a 3D printer. I plan to test it soon.

Jan

[dusmif]

This spring my countryman shared his unique simple way for sharpening thick knives. He designed eccentric cam for the SVM-45, which should enable to mount also thick knives symmetrically. 
https://forum.tormek.com/index.php?topic=3918.msg26586#msg26586

Recently I have received a sample of this cam printed on a 3D printer. I plan to test it soon.

Jan

Thank you Jan, It seems promising,  but I hope that you or someone will make a video how to use it, because I am still not able to understand how to use it. Again thank you.
Alf.

[RichColvin]

I made two, one with more offset than the other.  Works well.

[wootz]

Alf, we've all been there with thicker knives. The fact is that no slow wet grinder, Tormek or else, has a self-centering knife jig.
Any local machining shop at your place should be able to mill the 0.5 mm and 1 mm recess for you, using an end-mill. Bring the 2 knife jigs to them disassembled, give them only the lower static part, and draw a line in front of the pins with a permanent marker to show them where to mill. It is a 5 min job for the machinist/turner.
Show them a photo from my website to illustrate what is be done: http://knifegrinders.com.au/05Equipment_jigs.htm

For the bevel not to widen towards the tip, clamp the knife not in the center of the blade, but closer to the tip - this is explained in the Tormek manual.

[dusmif]

Alf, we've all been there with thicker knives. The fact is that no slow wet grinder, Tormek or else, has a self-centering knife jig.
Any local machining shop at your place should be able to mill the 0.5 mm and 1 mm recess for you, using an end-mill. Bring the 2 knife jigs to them disassembled, give them only the lower static part, and draw a line in front of the pins with a permanent marker to show them where to mill. It is a 5 min job for the machinist/turner.
Show them a photo from my website to illustrate what is be done: http://knifegrinders.com.au/05Equipment_jigs.htm

For the bevel not to widen towards the tip, clamp the knife not in the center of the blade, but closer to the tip - this is explained in the Tormek manual.

Thank you wootz,for your time to post this advice and explanation. I will study your photos and I can do the milling myself, ( I have to buy another jig, just in case I make a mistake    ) because I have a milling machine along with a lath too. Regarding the clamping of the knife, it is a very good advice, I will try it too. I have not read the manual because mine is in German, since I bought the T8 fom Germany; no agent here in Malta for the Tormek.   But I try and download it and print it.

Thank You.
Alf.

[jeffs55]

Dusmif,
I recently sharpened a Filipino bolo knife about the same thickness as your Bowie. The bevels will be way off as in several degrees.

This is my pet peeve, biggest complaint with the Tormek. There is no way around this issue using Tormek supplied jigs.

[dusmif]

Dusmif,
I recently sharpened a Filipino bolo knife about the same thickness as your Bowie. The bevels will be way off as in several degrees.

This is my pet peeve, biggest complaint with the Tormek. There is no way around this issue using Tormek supplied jigs.

That is really very disapointment, as you said. I would except Tormek should solve this problem, knowing this issue.
Alf.

[RickKrung]

...snip...
Any local machining shop at your place should be able to mill the 0.5 mm and 1 mm recess for you, using an end-mill. Bring the 2 knife jigs to them disassembled, give them only the lower static part, and draw a line in front of the pins with a permanent marker to show them where to mill. It is a 5 min job for the machinist/turner.
Show them a photo from my website to illustrate what is be done: http://knifegrinders.com.au/05Equipment_jigs.htm
...snip...

It is a very easy operation.  I clamped the fixed jaw (static in Wootz' terminology) directly to the mill table, using precision parallels to lift it off the table to clear the "Tormek" logo raised lettering.  I used other precision parallels in the mill table slots to align the front edge and clamped it using standard mill table clamps.  This placed the upper/inner surface of the jig parallel to the table top and locating pins parallel with the longitudinal axis.  If you don't use the parallels under the jig, the locating surface of the inner jig jaw will not turn out parallel and the knife will mount canted. 

I used a 1/2" carbide end mill and made a couple passes, shifting to ensure full coverage.  To start, I brought the end mill down to just touch the jig surface and then using the knee of the mill, raised the table the desired amounts of stock removal.  I did use the DRO readout to know how much to raise the table, but using the knee screw, the DRO is not necessary at all.  If using a mill that does not have a knee, bring the quill down to just touch and use a spacer in the quill stop to set the depth.  Check your work as you progress to be sure to not over-shoot the desired depth/stock removal. 

Didn't take any photos of it, but I could set it up again and take some, it is that easy. 

Rick

[dusmif]

Thank you Rick.
When I decided to buy the Tormek, I thoght, well my worried days are over for sharpening my tools, first week I was a bit confused, now after trying to read as many as threads as possible on this subject: Now I am lost  That what old age dd to you. 

[Jan]

Alf, J.W.Goethe said: 'All theory is gray, but the tree of life, my friend, is green.' 

I thing that after successful sharpening of first couple of knives you discover the wonderful world of sharpening and forget the initial stumbling.

What concerns your Bowie knife, the Tormek knife jig is not suitable for such a thick knife. When you mill away 1 mm from the static clamp (as mentioned by Wootz and Rick), you will get a jig for a 4.5 mm thick knife. For your Bowie knife it would be necessary to mill away 2 mm, but this is not possible because the static clamp has not enough material.

Recently I have built a self-centering knife jig for Tormek which was inspired by the Lansky knife clamp.
https://forum.tormek.com/index.php?topic=3834.msg25694#msg25694

This simple jig guaranties the same bevel angle for both sides of thick knives. It is an easy afternoon task if you have a shop with drill press and a belt sander. 

Jan

[dusmif]

Alf, J.W.Goethe said: 'All theory is gray, but the tree of life, my friend, is green.' 

I thing that after successful sharpening of first couple of knives you discover the wonderful world of sharpening and forget the initial stumbling.

What concerns your Bowie knife, the Tormek knife jig is not suitable for such a thick knife. When you mill away 1 mm from the static clamp (as mentioned by Wootz and Rick), you will get a jig for a 4.5 mm thick knife. For your Bowie knife it would be necessary to mill away 2 mm, but this is not possible because the static clamp has not enough material.

Recently I have built a self-centering knife jig for Tormek which was inspired by the Lansky knife clamp.
https://forum.tormek.com/index.php?topic=3834.msg25694#msg25694

This simple jig guaranties the same bevel angle for both sides of thick knives. It is an easy afternoon task if you have a shop with drill press and a belt sander. 

Jan

Hi Jan,
You are a lifesaver, I was worried sick thinking about how to modify the Tormek jig, knowing that 50% if not 75% I would destroy it.
With your idea I am more at ease doing this jig, knowing that if I am not satisfied with the result I just try another, time is no problem for me.
I assume that to find the bevel with your jig is the same as one do with the Tormek knife jig?
I never thought that to sharpen a knife involves so much calculations, and special jigs.
Thanks mate.
Alf.

[Jan]

Alf, you are welcome! 

Yes, the bevel angle setting process for the self-centering jig is the same as for the Tormek knife jig. It is descried in the hand book.

Knife sharpening is a specialised know-how, but do not be worried about many calculations. Later you will see that sharpening a knife with standard thickness (2-3 mm) is a routine task.

In the attached picture you can see how typical sharpening process works geometricaly.

Jan

[dusmif]

Hi Jan, Thank you.
It is good to know that there is always online help for any future problems, thanks to members of this forum.
I tried several chisels  and in that regard I am very happy with the results, they are the easiest to do, I think, now I will try some of my plane blades, I assume these will be no problem too.
The knives are the tricky ones, it seems, but in time I am sure I will find a way how to do them, I am in no hurry and willing to learn.
I will start with some old knives ( not important ones ) I have and leave the bowie until I get some experience and finish your jig 

Thanks.
Alf.

[Ken S]

Alf,

If your initial attempt  to modify the knife jig does not go well, here is a link to the part replacement:

https://advanced-machinery.myshopify.com/pages/replacement-parts-for-svm-45-svm-100-and-svm-140-knife-jigs

https://advanced-machinery.myshopify.com/pages/replacement-parts-for-svm-45-svm-100-and-svm-140-knife-jigs

Also, be sure to register your Tormek online (www.tormek.com). Once you log on, you can download the latest version of the handbook in multiple languages at no charge.

Ken