Beginner's questions

[Lukas M]

Hello fellow knife sharpeners!

I am trying to teach myself how to sharpen knifes, as a freshly baked chef this should be rather useful and with the T-4 model i am getting very pleasing results but i am facing one problem where i just don't seem to be able to find a solution on youtube. The goitre on my knifes (i hope i am using the correct english word for that, the thick part at the end of the blade, most german knifes unfortunatly have that) kind of blocks me. If i don't reduce it somehow then there will always be a gap between the cutting board and my knifes which makes cutting chive for example hard to do.

Now i want to know from you experts how you do it? Do you just grind it away at a steep angle on your T-4? If yes, doesn't the stone get uneven? Or are there any more elegant solutions which i am just too stupid to see? I don't want to damage my knifes by overheating the steel or anything of that sort and i already have a knife at home which i tried working on, when i was still an apprentice, with a belt grinder and that poor thing now looks just too damaged to use in front of any fellow chef.

Thanks in advance for any replies!

[Ken S]

Welcome to the forum, Lucas.

The English word most commonly used for the thick part of German style knives is "bolster". As the knife is sharpened, if the bolster is not reduced or thinned, the bolster will prevent the part of the blade near it from making contact with the cutting board. This is sometimes called "the green onion effect" referring to the green onions which are not properly cut because of a protruding bolster.

The way to correct a protruding bolster is to thin it, removing the protruding area by grinding it away using a rolling motion. Unfortunately, Tormek has not made a video showing how to do this. Here is a link to a youtube showing how to thin a bolster. The sharpener is using a belt grinder, however, the rolling motion would be the same with a Tormek.

https://m.youtube.com/watch?v=oRWjeDiLw_c

It is good to practice this. Use the "edge trailing" side of your Tormek (the grinding wheel moving away from your knife). Work slowly with light grinding pressure and the grinding wheel graded fine. With practice you will be able to work faster eventually. Do not be in a hurry.

Be patient; you will soon become proficient with thinning bolsters.

Do not be hesitant to ask questions. You are among friends who all had to learn these skills.

Ken

[kwakster]

Try using the side of your Tormek stone for getting the bolster back in line with the cutting edge.
That's how i do it anyway.
Use a light touch and check often using good lighting.
I also have a piece of cutting board which i hold up to the edge during the process to check if any light peeps through underneath.
With the last couple of passes i also take off the entire old apex, and only then create a new one.
This removes the old and possibly damaged metal (mostly from steeling way too hard) and makes sure that the new apex is made up entirely from fresh & undamaged steel.
If you do this you will most likely notice an improved edge holding of your knives.

[Lukas M]

Thank you both, Ken and kwakster for your quick replies!

Ammusingly when i first wanted to try removing the bolster with my Tormek i thought of using the side of the stone but quickly abandoned the idea out of fear of damaging the stone. Your tips will be of enourmous help, i am sure and i can always practise with the knife i ruined so long ago 

[kwakster]

One thing i forgot is that i do most bolster grinding and old apex removal lengthwise.
With my left hand i hold the pommel of the knife, and with my right hand i pinch grip the back of the blade.
Then i let the protruding bolster touch the side of the stone, like putting the needle on a record if that means anything.
Doing it this way allows me much more control over the process, and thus a much better end result.

[cbwx34]

Nothing wrong with the above, if that's the route you decide to take... but personally, I'd take another look at using the belt sander you have... I think that's the better tool for the job.  Steve Bottorff, a member here who does most of his sharpening on the Tormek, uses the belt sander to reduce bolsters.  Here's a video of him briefly showing his technique...

https://youtu.be/1Gt_J9PXa-U?t=49s

If I have to do it on a Tormek... I use the face of the wheel.  For the majority of the work, I hold it essentially 90° to the wheel and move it back and forth, so the wear is even across the wheel.  I can also thin the sides a bit in a similar fashion.  If there's a recurve in the heel area of the blade, I will repair it (after reducing the bolster) by setting the knife in the knife jig at a very high angle... this works to repair the recurve without making it worse.  (You still have to work the entire blade to keep everything consistent.  Once the recurve is gone, lower the angle and sharpen as normal.  (On a belt sander, you can put the blade 90° to the belt, if you have the room, to recreate the blade shape).

I personally, am leery of using the side of the wheel, if you put a groove in it, I think it's there permanently, and am not sure if it would eventually affect it.  So, I would just add, make sure you don't hold the knife in one spot.  Plus, I think the face of the wheel would work faster (although I've never tested this).

I think the biggest mistake I made in learning to make repairs, was trying to repair and sharpen at the same time, which for me, made things worse... I'd end up chasing my tail, and grinding too much off the knife.  Make the repair first, get the knife in the shape you want it, then sharpen, worked better for me.

[Fernando]

I think that this image can be useful for future references of knives, including the Germany knives.

[Grizz]

good post Fernando !

[WolfY]

Can't agree more with what cbwx wrote.
The Tormek is not made for steel removal/ grinding. For that you need dedicated tools. Either bench grinder or belt grinder (my pref.).
I'm working often on location and need to do some steel removal like straightening the edge, even giving the first grind to the primary edge before sharpening, or grinding the bolster and take with me a regular belt sander for woodworking purposes. It doe's the work perfectly. Using the 80/120 grit belts.
It is also very good for round pizza knives

[Ken S]

I hope Tormek will produce a training video concentrating on more advanced knife sharpening. Things like bolsters and low spots in the curve of blades are real life situations which hinder knife use. What good is a Tormek sharp knife if the edge is prevented from meeting the cutting board by a high bolster or a low spot in the blade?

I reduced a bolster using the T2, a machine not specifically designed for such work. Normally, I might have used my belt grinder, however, the knife was in my hand and I was standing at the T2. The T2 did the job well and efficiently. If I had a number of problem bolsters to correct, I would have turned to my belt grinder, because I happen to have one. I would not purchase a belt grinder just for the possibility of an occasional bolster.

I would like the Tormek video to include having bolster thinning as part of routine sharpening. There is an English idiom, "A stitch in time saves nine". A regular pass or two on a bolster prevents larger problems.

Ken

[WolfY]

Can't agree more with what cbwx wrote.
The Tormek is not made for steel removal/ grinding. For that you need dedicated tools. Either bench grinder or belt grinder (my pref.).
I'm working often on location and need to do some steel removal like straightening the edge, even giving the first grind to the primary edge before sharpening, or grinding the bolster and take with me a regular belt sander for woodworking purposes. It doe's the work perfectly. Using the 80/120 grit belts.
It is also very good for round pizza knives

An Angle grinder that is more common to have can do the job too. But you have to know how to handle it safely and secure the knife on a bench or bench wise.

[Ken S]

My preferred tool for lowering a bolster or correcting a blade shape is my belt grinder. It does the job well and quickly. The Tormek can also handle these jobs, just not as quickly. Time can be an important factor for a busy farmer's market sharpener. For most of us, myself included, who are low volume sharpeners, the occasional knife bolster correction might not justify the expense of purchasing a second machine. My Viel belt grinder is a useful complement to my Tormek. I converted it to variable speed and added a reversing switch. It is a nice tool, but cost me almost the cost of snother Tormek.

Before considering any other tool for bolster work, I would first learn how to correct the bolster with the Tormek. Incidentally, a coarse diamond or CBN wheel can remove a lot of metal quickly with a Tormek.

Ken

[bisonbladesharpening]

WolfY, if you don't mind sharing, what process do you use for pizza knives
on the belt sander. I have a viel which I use for bolster repair and reshaping
blades.  I'm also looking for a better way to do robot coupe type curved food processor blades.
I use lansky's for them now but it is time consuming.  Appreciate any and all feedback.
Best Wishes, Tim

[Fernando]

good post Fernando !

thanks a lot.

[andrew08]

WolfY, if you don't mind sharing, what process do you use for pizza knives
on the belt sander. I have a viel which I use for bolster repair and reshaping
blades.  I'm also looking for a better way to do robot coupe type curved food processor blades.
I use lansky's for them now but it is time consuming.  Appreciate any and all feedback.
Best Wishes, Tim

Hi Tim,

Waring food processor with LiquiLock seal system comes with a total of 5 different blades and discs cover all of processing needs easily. The feed chute on its lid is large enough to push large ingredients with the help of a food pusher without cutting them.

A 5 year warranty covers for any damage to the motor and a 2 year warranty is there for its parts and labor. The simple on/off and pulse settings make it exceptionally easy to operate even for workers at a commercial setup with no prior knowledge.