Proto “Anti-Slip Design Combo Wrenches – Review


Proto “Anti-Slip Design Combo Wrenches

Proto ASD set

Of the dozens of types of wrenches, combination wrenches are by far the most common. First introduced in 1933 by the Plomb Tool Company (Plomb became Proto in 1948), the combination wrench quickly gained prominence due to the versatility of having open and box ends on the same wrench.

1933 Plomb Tool ad:

Pic 1-Combo Wrench Ad (1933)

We won’t speculate as to whether Plomb was referring to “Skinned Knuckles” or taking a jab at The SK Hand Tool company

Today combination wrenches are an essential part of any tool collection and while the overall design hasn’t changed much over the years, they have seen some improvements. In 1994 Proto introduced their TorquePlus box end design which they claim reduces the risk of fastener rounding and allows up to 15% more torque to be applied. The most noticeable change came in 2001 with the introduction of their “Anti-Slip

Design” (ASD) open end.

So what is “Anti-Slip Design”? It’s essentially a set of barely noticeable notches on the inside of the wrench jaws as seen here:

Pic 2 ASD open end

Proto claims these notches, in conjunction with an arched jaw, prevent slipping and fastener damage by increasing the contact area by up to 400% through “off-corner engagement”. The big question is does it work, or is it all just a gimmick?

Proto ASD (Torqueplus)

To find out, I tested various sizes on my 1962 Cub Cadet project. It’s 51 years old and sat outside for 3 years before I acquired it, so it should provide a fine platform for our test. The wrenches feel nice and balanced in your hand and are available in full-polish, satin, and black industrial, finishes. I opted for the satin due to it’s textured grip when oily or greasy and it’s scratch resistance because nothing ruins your day like marring up a new set of wrenches. These wrenches come in a “long pattern” as a standard length which while not always ideal in tight spaces, allows for greater leverage and torque. In addition to the ASD open end, these wrenches also incorporate the TorquePlus system on the box end which, for some reason, makes me feel better about my investment.

Proto ASD (misc)
During the testing process I figured out that 51 years of crud and rust made for stubborn bolts and an excellent slippage test. While mostly smaller sizes like 3?8″, 1?2″, and 9/16″, I did run into the occasional 11/16″, 3?4″, and even a 15/16″. In each case the ASD’s broke the bolts loose without any slips whatsoever.This video shows the fastener gripping abilities of the ASD wrenches compared to an older smooth jawed Proto combo.
I honestly believe I could have pulled it completely off the jack stands if I?d wanted to. As for fastener gripping, I’m calling them a successAs for fastener damage, while I can honestly say I made it through the teardown process without stripping a single bolt, these were Grade 5 fasteners with a sort of “they don’t make ’em like that anymore” about them. But for what it?s worth, not a single corner was rounded.

All in all these wrenches are pretty nice. They perform as advertised, the overall quality is excellent, and they are backed by Proto’s Lifetime Warranty. They provide excellent fastener gripping while not damaging the fastener like some competing designs which makes them perfect as an everyday set. I feel they were worth the price I paid and while I consider them very affordable for the level of quality and performance they deliver, they may still be a little much for the some DIY’ers to justify. Proto also incorporates the ASD feature in their crows foot wrenches as well as their new ratcheting combos. It?s also notable that the ASD feature does not apply on wrenches 11/32” and smaller or 1-5/16” and larger in SAE sizes, nor does it apply to metric wrenches 9mm or smaller. Be sure to shop around for them as prices tend to vary considerably. Nothing brings out curse words faster than busting a knuckle and while I can’t say these wrenches will eliminate them forever, but they’re a big step in the right direction.  Check out




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