Review Title: Trash Engineering, Fabricated Design Theories, & Denial. Ex-Toolmaker Exposes the Reality.
Verified Purchase: Ordered 10/05/2026 | Delivered 10/10/2026 | Direct Case Ref: Interaction with Parts & Service (Rob) Do not let the premium brand name fool you. This Dual Grind kit is a masterclass in lazy engineering, horrific machining tolerances, and defensive customer service. As an ex-tool-and-die maker, I know how to read a caliper and a micrometer, and the measurements on these parts straight out of the box are a flat-out joke. Here is exactly how bad LEM's quality control and engineering choices are: • The Auger Stud (#F): The drive square measures 12.15mm. A standard 12mm wrench will not fit it. The original stock stud that came with my grinder fits a 12mm wrench perfectly. When I called them out, Customer Service (Rob) claimed they intentionally bloated the square to 12.13mm–12.15mm as an engineering feature to "restrict the use of a standard blade." This is a complete lie. I measured the internal square of my stock standard blade (12.26mm) and the new dual blade (12.44mm)—both slide onto this accessory stud perfectly. It restricts absolutely nothing. They simply invented a fake engineering theory to cover up sloppy factory machining that locks out standard tools. • The Splined Sleeve Tool (#G): The flats are machined to an awkward 25.95mm. This locks out a standard American 1" wrench (measuring 25.68mm) and leaves a 27mm wrench with massive, unusable play. When I asked why they didn’t machine it to a globally recognized 27mm standard, Rob dodged the question entirely, told me to use a sloppy adjustable wrench, and then lost his temper in all-caps: "USE WHAT EVER TOOL YOU DEEM FIT TO ATTEMPT THE REMOVAL." A premium company telling customers to use an unsafe, edge-stripping crescent wrench is embarrassing. • The DualGrind Knife (#D): Due to garbage bulk packaging, the cutting edges arrived with visible micro-dents, rolled metal, and uneven surface grinding paths across the faces. When I sent crisp, high-resolution photos of these defects, Rob and his "product team" flatly denied it, claiming the blade was in "very good shape as if it was new." If you run a blade with uneven grinding paths and dented edges, it will smear and mash meat instead of shearing it cleanly. The Reality: I am doing this by hand in my apartment. Because LEM’s engineers don't know how a tolerance stack stack-up works, and their customer service refuses to acknowledge factory flaws, I now have to spend my free time with a precision file and diamond plates manually remanufacturing their product. I will be draw-filing the stud down to a true 12.0mm so my standard wrench works, and lapping the factory blade faces flat myself. If you buy this kit, expect a headache. You will either have to buy a rare 26mm wrench, use a dangerous adjustable wrench that will round off your parts, or manually fix the kit on your own time because the factory couldn't get the math right. Completely unacceptable. UPDATE (10/20/2026) — MY REBUTTAL TO LEM's CORPORATE RESPONSE: LEM’s corporate office responded to this complaint on other consumer platforms by attempting to reframe their mathematical tolerance failures as my "personal preference" for different tool sizes. Let’s look at the hard, unassailable numbers: 1. Wrench Lockout is a Fact: Machining an accessory drive square to 12.15mm means a standard 12.0mm tool physically cannot slide onto it. Locking a customer out of standard, safe tools is not an intentional "design decision"—it is a sloppy factory machining error. 2. Fabricated Engineering Theories: Their Parts & Service department explicitly claimed this bloated shaft was a safety feature meant to "restrict the use of a standard blade." I measured the internal square of the stock standard blade (12.26mm) and the new dual blade (12.44mm)—both slide onto this 12.15mm accessory stud perfectly. It restricts absolutely nothing. They simply invented a fake theory to cover up a machining mistake. 3. Severe Quality Defects: Their product team flatly denied seeing any defects on the knife. High-resolution inspection shows a 0.1mm to 0.3mm radius right on the shearing edges, meaning the blade is completely dull straight out of the box. Combined with the uneven, non-uniform factory grinding paths across the faces, this blade will smash and macerate meat through friction rather than cutting it cleanly. I have already taken the parts to my apartment workbench, draw-filed the stud to a true, functional 12.0mm, and hand-lapped the blade face flat myself to eliminate that radius. I shouldn't have to act as the final quality control inspector just to make a premium kit work with standard tools. Potential buyers should know that if their parts don't fit, LEM will blame your "preferences" instead of fixing their steel.
By Yervand G.