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In the Shop => General Tormek Questions => Topic started by: Garrett47 on December 17, 2024, 10:58:10 PM

Title: Serrated knife sharpening wheel
Post by: Garrett47 on December 17, 2024, 10:58:10 PM
I saw an announcement earlier today about new Tormek wheels for sharpening serrated knives. Where can I get more info? I looked at the website and did a search but couldn't find anything. Any guidance appreciated.
Title: Re: Serrated knife sharpening wheel
Post by: tgbto on December 18, 2024, 09:16:54 AM
Wow, a triangular wheel ? With a dual-MB102 "spaceship" contraption for truing it ? Or with a diamond-coated apex ?
Title: Re: Serrated knife sharpening wheel
Post by: Ken S on December 18, 2024, 11:50:29 AM
Garrett,

I saw what I believe is the same wheel for sharpening serrated wheels on facebook. It is actually a Slipakniven product, not Tormek. I don't know anything about it, although I have had success with the few peoducts I have ordered from ẞlipakniven.com.

Ken
Title: Re: Serrated knife sharpening wheel
Post by: tgbto on December 19, 2024, 08:20:55 AM
So this is actually a thing (https://slipakniven.com/product/grinding-wheel-set-for-serrations/), even though not a Tormek thing...

Still, there are two fundamental issues with such wheels :
- If the wheel is noticeably wider than the serrations of the knife (as seems to be the case in the pictures on their website), then the result will be rounded out teeth and untouched "valleys". If the wheel is noticeably narrower than the serrations, it will be fragile *and* will cut aggressively.
- How do you restore them when they wear down ? I guess one could use diamond plates and aim for a triangular shape, but it will be fidgety.

IMO, a thin triangular or cylindrical rod used either freehand or on an edgepro-like system will make for a much more controlled process and repeatable results. Along with a flat benchstone for the backside.
Title: Re: Serrated knife sharpening wheel
Post by: sharpening_weasel on January 11, 2025, 04:48:08 PM
Is that a tormek subsidiary? How is that site and manufacturer up and running? Don't get me wrong it looks like they sell great tools, but it seems a little more officially making use of tormek intellectual property than, say, the late and great Wootz/Knife grinders AU.
Title: Re: Serrated knife sharpening wheel
Post by: Thread Killer on January 12, 2025, 04:14:07 AM
It is out of stock (too popular?)........ Waiting for an email. It beats using the edge of the wheel, I would think. BTW It is slipakniven,com not blip.
https://slipakniven.com/product/grinding-wheel-set-for-serrations/
Title: Re: Serrated knife sharpening wheel
Post by: 3D Anvil on February 26, 2025, 02:40:08 PM
Interesting product!  I think these would also be quite useful for sharpening recurve knives.
Title: Re: Serrated knife sharpening wheel
Post by: tgbto on February 26, 2025, 03:24:29 PM
I hope I got that kind of basic math right, but I'll wager "R7" means a diameter of 14mm.

So for all knives with serrations spaced less than 14mm apart (which incidentally means all of my bread and frozen food knives), this wheel will grind the apex of the teeth and not the space in between the teeth.
Title: Re: Serrated knife sharpening wheel
Post by: 3D Anvil on February 26, 2025, 06:30:53 PM
Quote from: tgbto on February 26, 2025, 03:24:29 PMI hope I got that kind of basic math right, but I'll wager "R7" means a diameter of 14mm.

So for all knives with serrations spaced less than 14mm apart (which incidentally means all of my bread and frozen food knives), this wheel will grind the apex of the teeth and not the space in between the teeth.

14mm is .55", which seems about right for most bread knives.  I know that Cliff Curry sells a 6" by .5" CBN wheel for bench grinders that he recommends for bread knives.  Of course that's going to be more for cutting in new serrations as opposed to touching up existing ones.

Anyway, I'm going to order a pair of the SlipaKniven wheels when they come back in stock and will report back.
Title: Re: Serrated knife sharpening wheel
Post by: tgbto on February 27, 2025, 03:34:36 PM
Quote from: 3D Anvil on February 26, 2025, 06:30:53 PM14mm is .55", which seems about right for most bread knives

Well my typical bread knife is akin to this one.  (https://www.amazon.com/Victorinox-6-8631-21B-Bread-Knife-Stainless/dp/B0888WVGCB)

It has 35 serrations in less than 8.25", which is at most a .24" pitch.

On this other one (https://www.amazon.com/Cuisinart-C77TR-8BD-Triple-Rivet-Collection/dp/B01AVNZ7QM), it looks like a .25" pitch at best (31 serrations in less than 8").

For both, the wheel will ride on the teeth.

Wolfgang demonstrates using the edge of the wheel with what looks like a 3-ish mm corner radius, which seems more like it. Typical triangular ceramic rods have an even higher curvature.
Title: Re: Serrated knife sharpening wheel
Post by: RichColvin on February 28, 2025, 01:36:22 AM
I recently got a grinder used to sharpen a chainsaw's saw chains.  The grinding wheels used to sharpen the cutters are thin and rounded on the edge.

(https://www.sharpeningsupplies.com/cdn/shop/files/3700684-z_2043x1330.jpg?v=1714071205)

The two sizes most typically used are 1/8" and 3/16" wide.  They are only 5" in diameter, so I don't think they would work on the Tormek, but possibly they would work on a different style grinder and grind them by hand.

These are available as traditional grindstones (many types), CBN, & diamond.
Title: Re: Serrated knife sharpening wheel
Post by: 3D Anvil on February 28, 2025, 06:04:12 AM
Quote from: tgbto on February 27, 2025, 03:34:36 PM
Quote from: 3D Anvil on February 26, 2025, 06:30:53 PM14mm is .55", which seems about right for most bread knives

Well my typical bread knife is akin to this one.  (https://www.amazon.com/Victorinox-6-8631-21B-Bread-Knife-Stainless/dp/B0888WVGCB)

It has 35 serrations in less than 8.25", which is at most a .24" pitch.

On this other one (https://www.amazon.com/Cuisinart-C77TR-8BD-Triple-Rivet-Collection/dp/B01AVNZ7QM), it looks like a .25" pitch at best (31 serrations in less than 8").

For both, the wheel will ride on the teeth.

Wolfgang demonstrates using the edge of the wheel with what looks like a 3-ish mm corner radius, which seems more like it. Typical triangular ceramic rods have an even higher curvature.

Yeah, those are smaller serrations than the ones on the Mercer bread knife I'm using.  I looked at a couple others we have and they are smaller.  I guess you'd need at least two sizes to cover all the bases.
Title: Re: Serrated knife sharpening wheel
Post by: tgbto on February 28, 2025, 08:20:02 AM
Plus I realized afterwards that a serration is not a half-circle, but rather a portion of it, so the diameter can be wider than the pitch.

I measured my ceramic rod that just barely fits inside the serrations of a Wüsthof bread knife. It is 8mm in diameter.
Title: Re: Serrated knife sharpening wheel
Post by: RickKrung on February 28, 2025, 02:57:41 PM
Quote from: tgbto on February 28, 2025, 08:20:02 AMPlus I realized afterwards that a serration is not a half-circle, but rather a portion of it, so the diameter can be wider than the pitch.
...snip...

A radius gauge set, like below, is the right tool to measure the serrations. Match the curvature of the gauge to any portion of a internal or external radius and read the measurement from the stamped markings. 
Title: Re: Serrated knife sharpening wheel
Post by: Ken S on February 28, 2025, 04:21:01 PM
I have problems seeing the practicality of a specially shaped wheel for serrated knives.

With chisels and plane irons, the same grinding wheel can be used to sharpen the entire range of these. This is not the case with serrated knives. Even with bread knives, where  a given knife will have uniform size and shape of the serrations, I know of no standards for bread knives. This is even more problematic with more tactical knives which may have more than one  size serration on the single blade.

How many grinding wheels would be necessary to "cover the waterfront? Unless these wheels were diamond or CBN, each wheel would require its own dressing tool. How much total cost would be involved? How many serrated edge knives would be a realistic expected volume? What would be a realistic surcharge for serrated knives?

I have a Henckels bread knife which I have sharpened. My tapered DMT round diamond file can sharpen it, although my results have been very uneven. I only used it once for that purpose. My best results have been with using a wooden dowel wrapped in wet and dry abrasive paper. I have used both self adhesive and regular abrasive paper held in place with Scotch tape. Both seem to work equally well.

With the knife resting against a table, sharpening knives one serration time does not require much time and the "tooling cost" will be minimal. if an in between diameter dowel size is needed, a little sanding is all that is necessary for a custom size.

Ken

Title: Re: Serrated knife sharpening wheel
Post by: 3D Anvil on February 28, 2025, 08:01:49 PM
Quote from: RickKrung on February 28, 2025, 02:57:41 PM
Quote from: tgbto on February 28, 2025, 08:20:02 AMPlus I realized afterwards that a serration is not a half-circle, but rather a portion of it, so the diameter can be wider than the pitch.
...snip...

A radius gauge set, like below is the right tool to measure the serrations. Match the curvature of the gauge to any portion of a internal or external radius and read the measurement from the stamped markings. 
Thanks!
Title: Re: Serrated knife sharpening wheel
Post by: 3D Anvil on March 01, 2025, 06:41:20 PM
So until now I've been getting by on bread knife sharpening by ... not really sharpening, but by using the SchleifJunkies' "leather wheel for serrations" and the edge of a belt to strop serrations.  I was using 1 micron diamond on the wheel and PA-70 on the belt.  Worked okay, but not really satisfactory for a dull knife.

This morning I leveled it up, using 20 micron diamond on the wheel, and I'm pretty happy with the result!  I was sharpening a Mercer bread knife with roughly 1/4" serrations.  Before sharpening, it measured at around 300 BESS.

I did 3-4 passes on the bevel side at the measured edge angle (25°) and then stropped on the edge of a leather belt with PA-70.  That got my BESS reading down to 110-125g, which to me is more than acceptable for a bread knife.

Now, I don't know how it would work with a really dull knife, and it's obviously not going to restore a knife with rounded points, but that's a topic for another day.

https://schleifjunkies.de/en/product/leather-wheel-for-serrated-edge/
Title: Re: Serrated knife sharpening wheel
Post by: Columbo on May 03, 2025, 07:17:53 PM
Quote from: Ken S on December 18, 2024, 11:50:29 AMGarrett,

I saw what I believe is the same wheel for sharpening serrated wheels on facebook. It is actually a Slipakniven product, not Tormek. I don't know anything about it, although I have had success with the few peoducts I have ordered from ẞlipakniven.com.

Yes, I saw that but he's out of stock. So is Curry's Custom Cutlery Cliff the owner his are out of stock as well. He's out of Hawaii. He has quarter inch, half inch, and 1 inch diamond wheels that are 6 inches in diameter can be run on a Buck tool 1750rpm machine.

Ken
Title: Re: Serrated knife sharpening wheel
Post by: Columbo on May 03, 2025, 07:37:46 PM
Quote from: 3D Anvil on March 01, 2025, 06:41:20 PMSo until now I've been getting by on bread knife sharpening by ... not really sharpening, but by using the SchleifJunkies' "leather wheel for serrations" and the edge of a belt to strop serrations.  I was using 1 micron diamond on the wheel and PA-70 on the belt.  Worked okay, but not really satisfactory for a dull knife.

This morning I leveled it up, using 20 micron diamond on the wheel, and I'm pretty happy with the result!  I was sharpening a Mercer bread knife with roughly 1/4" serrations.  Before sharpening, it measured at around 300 BESS.

I did 3-4 passes on the bevel side at the measured edge angle (25°) and then stropped on the edge of a leather belt with PA-70.  That got my BESS reading down to 110-125g, which to me is more than acceptable for a bread knife.

Now, I don't know how it would work with a really dull knife, and it's obviously not going to restore a knife with rounded points, but that's a topic for another day.

https://schleifjunkies.de/en/product/leather-wheel-for-serrated-edge/

What do you mean by the belt?
Title: Re: Serrated knife sharpening wheel
Post by: Columbo on May 03, 2025, 08:04:15 PM
Quote from: RichColvin on February 28, 2025, 01:36:22 AMI recently got a grinder used to sharpen a chainsaw's saw chains.  The grinding wheels used to sharpen the cutters are thin and rounded on the edge.

(https://www.sharpeningsupplies.com/cdn/shop/files/3700684-z_2043x1330.jpg?v=1714071205)

The two sizes most typically used are 1/8" and 3/16" wide.  They are only 5" in diameter, so I don't think they would work on the Tormek, but possibly they would work on a different style grinder and grind them by hand.

These are available as traditional grindstones (many types), CBN, & diamond.

So to understand more clearly, please, are you using these wheels that are more so meant for chainsaws, and that can be used on let's say a Buck-tool 1750 RPM machine, to sharpen serrated knives?
And if so, naturally, one would have to get two sizes to accommodate the different widths of the scallops. Correct?
Thank you in advance, sir
Title: Re: Serrated knife sharpening wheel
Post by: Ken S on May 03, 2025, 11:36:51 PM
I have two questions for those of us wanting to sharpen serrated knives with a Tormek.

First question: How many serrated knives do you realistically plan to sharpen, both in number and in frequency? Related to this is how much revenue is projected?

In my own case, I only occasionally sharpen my Henckels bread knife. A wooden dowel wrapped with wet and dry abrasive paper does a very adequate job at low cost. Time is not excessive.

My second question is really a concern for the basic Tormek philosophy of sharpening. Are these six inch CBN wheels going to be used with anticorrosion solution and only remove minimum metal? For me, "the burden of proof" is on the wheels and their use.

Ken