Review : Mousetrap steel from Razor Edge


Specifications

The Mousetrap by Razor Edge Systems [img ref] uses two counterweighted rods stainless steel rods to allowing burnishing or steeling the edge of a knife under consistent force (two preset levels) at specific angles and unlike traditional steels, both sides of the edges are burnished at the same time creating a sharper and stronger edge. The angle of contact is about ~35 degrees per side for the first stage steeling, and ~27 degrees per side for the heavy setting.

Compared to a normal smooth steel

The Mouse Trap was compared to a Raz-R steel also from Razor Edge Systems by honing Olfa heavy duty standard blades (0.5 mm) which had been blunted by cutting 3/8" hemp rope. More rope was then cut to check the edge retention properties of the edges, and the the steeling repeated twice more to check extended use properties, 126 cuts of hemp rope each round. Three blades were tested for each smooth steel, in total, 24 rounds of 126 cuts.

In short, using standard sharpness checks on thread and poly, no significant difference was noted in the initial sharpness of either type of steeled edge, nor in the edge retention. As an extended usage trail, both steels were used on various utility and kitchen knives on a daily basis over a period of several weeks to check the performance in less controled conditions - again no no significance difference in performance was seen.

Second stage honing

When steeling using the counterweights stops being effect The Mousetrap has a second setting which is used to apply more force. The blade is pressed all the way down and drawn through the rods at high force which thins the edge and aligns it under higher pressure.

This can also be done on a regular smooth steel, however the edge so produced (by either steel) is highly deformed and under great stress. It is therefore very weak and the edge retention rather low. Much more optimal edges could be produced with a slight abrasive hone either using a butcher steel or a diamond or ceramic rod.

Pass around

On friends who didn't sharpen knives at all, the Mouse Trap was very well recieved. The instructions are dead simple and there is no setup and honing takes a few seconds and require little to no skill. Kitchen knives can stay pretty at near 100% sharpness for months with frequent steeling. However with those people that frequently used regular smooth steel none of them preferred the Mouse Trap. It is bulkier, not nearly as portable, and can't be used on knives which are ~3/16" or thicker, and as well is useless on knives with edges that are more obtuse than its preset angle.

To steel or not to steel

When a knife blunts, the loss in cutting ability is often attributed to metal wear however blunting is frequently mainly edge deformation, a combination of impaction and metal bending or rolling to the side. A hone can be used to grind a fresh edge however the deformed metal can just be straighted. Steeling aligns the edge, restoring it to a crisp and even line [ref].

Besides saving metal, using an abrasive is in general much longer than a simple steeling. Steeling only takes a few seconds and doesn't deposit significant grit on the blade or on the hone so there is no cleanup. It also takes a lot less skill than freehand honing. Steels are also usually cheaper, more durable and are easier to maintain than hones. However with recent ceramic and diamond honing rod abrasives, a lot of these reasons are simply not true anymore.

For example a fine ceramic or diamond rod offers the same speed and simplicity of honing as a steel, and has none of the usual drawbacks of sharpening stones such as needing to be lapped or having to use oil/water. These rods do remove some metal, however it takes 100 - 1000 sharpenings to remove one mm of metal from the edge of the knife depending on the edge angle and the grit of the ceramic or diamond hone, ie. years of constant use. In general, the lifetime of most knives tends to be dominated by the occasional accidental damages that force heavy honing.

Finally, abrasive rod honing produces a stronger edge than steeling which gives much improved edge retention. While a steeled edge can get very sharp, within a few percent of optimal is possible, it is less durable than when it was freshly honed and thus it will blunt faster, and in fact will relax back into a blunted condition even without use. E

A side note on blunting and the effect of steeling

In the above several reference are made to steeling restoring the cutting ability within a few percent of optimal (95%+). Even though some wear is present on blunted edges, in general it is mostly deformation, and steeling can also compensate for wear by "smearing" out the edge due to pressure and adhesive friction which thins the edge angle and raises the polish. Thus a knife can usually be made sharper after abrasive honing by using a smooth steel. This does lower the edge durability though as the steeled edge will relax slightly and thus lose some sharpness.

Other viewpoints

John Machtinger was one of the individuals who used the Moustrap for an extended period of time, some comments :

It's worked great for me so far. I have used it on two knives, a chef's knife and a vegetable/utility knife. The chef's knife is a $29 Dexter / Russell Sani-Safe marked "S145-8 High Carbon Steel," but it is definitely a stainless steel. I used it for a few years until it got dull. Then I tried it as the first knife I sharpened with my EdgePro Apex. I sharpened it to 100 grit. The edge feels slightly toothy and not very polished. I have been satisfied but not happy with its sharpness. I haven't had time yet to work with the EdgePro more to refine my sharpening skills.

The vegetable knife is a $17 Japanese utility knife with a high carbon steel inner bonded to a stainless exterior. I bought it from Lee Valley Tools ref I've never sharpened this knife. The web page for this knife says to use a 1000 grit waterstone on it.

For both knives, before each use I swipe the knife through the Mousetrap twice, so that the "ears" are parallel to the floor on each pass. Like you, I've noticed that the blade is not perfectly pinned into the "V" made by the smooth rods, rather it floats around a bit. But the smooth rods float with the knife as well, compensating somewhat for this movement. I can imagine that the edge winds up very slightly "wavy," in that the edge is realigned at each point on the knife, but that such alignment may very slightly along the length of the knife. But in use I have never noticed this.

The result is that over the past seven months, I have not sharpened either knife and their performance has degraded very gradually over time. It took six months before I got to the point where I would like to sharpen both knives, but the knives have performed well during this time. The use that my knifes have seen is light lunch and dinner prep for two people. Figure 3 lunches and 4 dinners per week.

So I would say that it works great, especially for someone who hasn't learned how to use a manual smooth steel to a high degree of accuracy. I don't have to think or work to use the Mousetrap. I prefer this method.

The Mousetrip is noisy. Each knife use results in two "ka-CHUNK" noises as the "ears" fall back onto the rubber-ringed stops. But it's still well worth it for me to keep using it.

Feedback

Comments can be sent by email to : cliffstamp[REMOVE]@cutleryscience.com or by posting in the following thread on Bladeforums :

More information can be seen on the Razor Edge website. As for sharpening in general, I highly recommended reading Steve Bottorff's : http://www.sharpeningmadeeasy.com/

Last updated : Fri Oct 10 14:02:32 NDT 2003
Originally written : 08/32/2002

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