There’s Something Strange About These Rolling Knife Sharpeners..

Tumbler Rolling Knife Sharpener — Review Summary

Main Features

• Two-sided rolling sharpener with an advertised 800-grit diamond disc and a stainless-steel honing surface.
• Costs about $100.
• The reviewer says it can establish an initial bevel on knives of a suitable size.

Pros and User Experience

The sharpener worked well at first, and the reviewer initially liked the rolling-sharpener concept. The diamond surface cuts aggressively when new. According to the reviewer, loose abrasive particles wear away during a normal break-in period, after which sharpening takes much longer.

The sharpener can technically sharpen a knife, but the reviewer argues that this alone does not make it good value.

Cons and Test Findings

• Too slow for many casual users: After sharpening several knives, the reviewer found that performance had dropped off, making the process frustrating and time-consuming.
• Too fine for dull knives: The reviewer considers 800 grit too fine for quickly restoring many dull kitchen knives and would prefer a coarser diamond surface of around 320–400 grit.
• Poor burr removal: In the reviewer’s tests, the stainless honing side did not remove the burr. A burr remained after about 15 minutes of sharpening; a leather strop with abrasive eventually removed it.
• Soft honing surface: The reviewer measured the stainless surface at roughly 6 HRC and argues that it is too soft to remove steel effectively from the knife. They checked their Rockwell test against a calibration plate and say the calibration was accurate.
• May not fit every knife: The reviewer encountered a size issue while testing.
• Requires basic sharpening knowledge: A beginner tester struggled and eventually asked for help. The reviewer emphasizes that rolling sharpeners do not eliminate the need to understand how to create an apex, raise and remove a burr, and finish an edge.

Comparisons and Design Context

The reviewer could not verify who invented the rolling-sharpener design. They found repeated claims that the Horl company in Germany created the original in 1993, but did not receive clarification from the company before publishing. They also questioned claims that the design came from a U.S. patent that expired in 1966, saying the patent they examined did not appear to describe this type of rolling sharpener.

The reviewer suspects the Tumbler may be a copy or knockoff but says they have no proof.

Compared with the Tumbler’s advertised 800-grit diamond side, the Horl is said to use 46-micron abrasive (about 320 grit) and a fine ceramic side. The reviewer believes these differences would address the Tumbler’s main shortcomings and considers the Horl more expensive but a better value by comparison.

After seeing a video of someone sharpening a butter knife with a Horl, the reviewer tried the same with the Tumbler. That attempt took a long time. The reviewer then demonstrated a different butter knife becoming shaving-sharp in about two minutes using a brick, to illustrate that “it sharpens” is not, by itself, a measure of quality.

Verdict

The reviewer does not recommend the Tumbler at $100. It can form an initial bevel, but in their testing it was too slow and ineffective at removing burrs. The reviewer suggests that people willing to spend substantial time sharpening may be better off learning to use ordinary stones.

Someone who already owns the Tumbler and is satisfied with it need not change their approach, but the reviewer would not buy this version.

Speaker Perspectives

The reviewer provides the product tests, technical analysis, and verdict. The reviewer’s brother, described as a novice, found the process frustrating and gave up before completing the sharpening. No numerical rating or score is given.