Sharpening knives with full bolsters

[wanderingwhittler]

I recently completed my first reprofiling and sharpening of a knife with full bolsters, a Wüsthof Classic 9 cm paring knife. As I approached the full bolster, the wheel started to cut into it. At first I thought I might try to bring the new edge all the way back to the edge of the bolster, but then thought better of it and backed off once the grinding sound changed. Here is what I ended up with:



It looks like the blade gets thicker as it blends into the bolster and the bevel moved up as a result, which isn't particularly aesthetically pleasing.

My question is how an expert would handle this type of knife on the Tormek? And, related, what is considered the professional standard for sharpening this sort of knife? If possible, I'd appreciate pictures that can act as a reference which I can strive to match as I continue to gain experience.

By the way, I searched the forum and found plenty of references to reducing bolsters, but have not yet been successful in finding any that address technique for handling this situation. It's quite possible that it's been covered before and I just didn't find it, though. Any pointers to existing threads would be appreciated.

Thanks,
Greg

[RickKrung]

My question is how an expert would handle this type of knife on the Tormek? And, related, what is considered the professional standard for sharpening this sort of knife? If possible, I'd appreciate pictures that can act as a reference which I can strive to match as I continue to gain experience.

By the way, I searched the forum and found plenty of references to reducing bolsters, but have not yet been successful in finding any that address technique for handling this situation. It's quite possible that it's been covered before and I just didn't find it, though. Any pointers to existing threads would be appreciated.

Thanks,
Greg

Good question and observation.  I've had a few to deal with lately and have not done as pretty a job as I'd like, so I'm trying to avoid reducing the bolsters now.  I too would like some guidance on how it is done.  I seem to recall somewhere it being done on a belt sander.  Was that SteveB? 

Rick

[cbwx34]

Good question and observation.  I've had a few to deal with lately and have not done as pretty a job as I'd like, so I'm trying to avoid reducing the bolsters now.  I too would like some guidance on how it is done.  I seem to recall somewhere it being done on a belt sander.  Was that SteveB? 

Rick

Yup

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

[Ken S]

I have reduced a bolster using a Tormek, actually a T2, not really designed for that work. The result was satisfactory, however, like Rick, I prefer to use a belt grinder, one of many things I have learned from Steve Bottorff. Steve´s website is sharpeningmadeesy.com. It is a good site to bookmark. his Sharpening School DVD is outstanding.

Ken

[wanderingwhittler]

Thanks for the pointers on bolster reduction. It's an operation I wasn't even aware of before I started reading this forum. I'm hoping it will be a while before I have to try it myself.

Does anyone have any tips about how they handle the edge as it approaches the bolster? Do you let the bevel get wider like I did, or stop short and accept a dull area there, or something else?

[cbwx34]

...
Does anyone have any tips about how they handle the edge as it approaches the bolster? Do you let the bevel get wider like I did, or stop short and accept a dull area there, or something else?

There are a few options...

You can do what you did... just sharpen it and live with the change in bevel.  (Some have called it a "smile").  Nothing wrong with it other than how it looks, and practically, you end up with a slightly longer edge that is all sharp (no dull spot).

You can try and stop in sooner, and reduce it as part of the bolster as needed.

You can make an effort to try and sharpen it at a higher angle so it matches the rest of the bevel... (bit of a pain in the arse).  Work it as a separate section.

You can cut a "sharpening notch"... a little cutout you can make with a file or dremel tool (carefully).  Don't usually see these on kitchen knives though... more common on pocket/edc knives, hunting/camping knives, etc.

No really right or wrong way... doing what you did is fine, just doesn't look "normal".  I've done it for others and told them why, usually on less expensive knives... didn't seem to matter to them.

[Ken S]

Greg,

One of the things I like about Steve Bottorff's Sharpening School DVD is that he doesn't dodge the difficult issues. Steve discusses fixes for things like bolster problems; low spots in knife blade curves; broken tips; etc. Jeff Farris worked for Tormek when he did his Tormek videos. The Farris videos are in general the closest that Tormek has come to doing videos geared to existing customers working in the field instead of marketing.

Dealing with issues like bolsters is a real world problem. These problems are not unique to Tormek, however, the sharpener with a Tormek must know how to deal with them. I feel existing Tormek users deserve better video support.

Ken

[wanderingwhittler]

There are a few options...

You can do what you did... just sharpen it and live with the change in bevel.  (Some have called it a "smile").  Nothing wrong with it other than how it looks, and practically, you end up with a slightly longer edge that is all sharp (no dull spot).

You can try and stop in sooner, and reduce it as part of the bolster as needed.

You can make an effort to try and sharpen it at a higher angle so it matches the rest of the bevel... (bit of a pain in the arse).  Work it as a separate section.

You can cut a "sharpening notch"... a little cutout you can make with a file or dremel tool (carefully).  Don't usually see these on kitchen knives though... more common on pocket/edc knives, hunting/camping knives, etc.

No really right or wrong way... doing what you did is fine, just doesn't look "normal".  I've done it for others and told them why, usually on less expensive knives... didn't seem to matter to them.

Thanks CB, that's all very helpful.

It's funny: I routinely put sharpening notches into pocketknife blades that I sharpen to around 20-22 degrees inclusive for whittling, but it didn't even cross my mind to do that with a kitchen knife. I think I might find it odd looking.

For now I'll be satisfied with what I did. If I'm feeling ambitious next time I may try one of the other options you mentioned.

Greg,

One of the things I like about Steve Bottorff's Sharpening School DVD is that he doesn't dodge the difficult issues. Steve discusses fixes for things like bolster problems; low spots in knife blade curves; broken tips; etc. Jeff Farris worked for Tormek when he did his Tormek videos. The Farris videos are in general the closest that Tormek has come to doing videos geared to existing customers working in the field instead of marketing.

Dealing with issues like bolsters is a real world problem. These problems are not unique to Tormek, however, the sharpener with a Tormek must know how to deal with them. I feel existing Tormek users deserve better video support.

Ken

Thanks for the reply, Ken. I know some things I'm wondering about are not unique to the Tormek, but it's not always clear to me (1) what the best outcome is regardless of sharpening equipment and (2) how to get as close to that outcome as possible on the Tormek.  Having videos from Tormek that address at least point (2) for a variety of real-world issues would be very welcome.

Regarding the Sharpening School DVD, based on what you said, I'm assuming it addresses (1). Does it offer any guidance for (2)?

By the way, I've only been able to find seven Jeff Farris Tormek videos, all found here. Is that the entire collection, or are there others that I have not yet been able to track down?

Thanks,
Greg

[Elvis]

what was the ultimate outcome from your inquiries? I find myself dealing with the same issues.

regards

Elvis

[3D Anvil]

I think reducing the bolsters is the way to go.  I've done it on a belt grinder (Ken Onion) and also on the Tormek, using the side of CBN wheels.  Of course it could also be done on the SG wheel.  It's quicker than you might think.

[Thy Will Be Done]

Are you breaking the hard corners of the stone with the stone grader before sharpening?  Looks like corner dug in there, you can knock that edge down quite alot to keep the stone from digging in.

[John_B]

I would discuss what you intend to do with a customer beforehand. Some may be concerned with looks over performance.

[Sir Amwell]

It seems like bolsters on kitchen knives are a design fault which discourages repeat sharpening. Even on bench stones hand sharpening it causes problems. Either not full sharpening in the area near the bolster or 'smiles' bellyward of that. 3 choices I can think of.
Reduce the bolster.
Put a choil just in front of bolster ( doesn't look good on a kitchen knife).
Stay away from it by a few mm and leave that unsharpened bit of steel in front of the bolster.
I usually opt for option 3 and explain it to the customer.
Not keen on kitchen knives with bolster for the above reasons....

[BeSharp]

It seems like bolsters on kitchen knives are a design fault which discourages repeat sharpening.

It's a safety feature to prevent the fingers from touching the blade. Probably invented by the Germans? (HYenckels, Wusthof...)