Derby Extra Double Edged Blades

I was really looking forward to trying a derby blade as they're what my dad uses daily and has done for many years. He loves that he can get 100 of them for £6.73 on eBay (a figure he quotes every time we talk about shaving) and that he gets a week out of each blade. Using his figures, that works out at a phenomenal 6.7p per blade and less than 1p per shave. Ideal! You know how much I love a bargain and that's the sort of price I can get behind. Along with my trusty Palmolive stick, I could be shaving as much as I like for £3.50 per year!

A Derby Extra (before the bloodshed)

So It was with delight that I unwrapped the fresh Derby blade and inserted it into my R89, all the while inspecting the odd markings. It has some Turkish writing and each face and edge is numbered. Is this usual? Have I been missing something up until now? I can kind of understand both edges of the Double Edged blade being numbered, but each face too? Are you expected to flip this bugger over halfway through the week and keep going with the other side? If that's what you do then please let me know in the comments. The fit in the razor was great mind you. The blade centred easily and the short edges overhung by a little more than I was used to but not too far by any means.

All that proved to be academic once I started my shave. The tugging, pulling, and overall roughness of this first pass completely shocked me. I persevered and carried out pass two and three which were slightly better. I nicked myself twice on my right cheek in the process though and could feel stinging when rinsing my face with water between passes. It was awful. This was confirmed when I passed my alum block over my face and felt like I had been slapped with 1000 pins and dowsed in chilli powder. Not very nice. Over the course of the next few hours in noticed a huge patch of razor burn just below my chin, worse than I ever had even with the dullest of cartridge razors. It was truly a woeful shave, and had I not had plenty of successful, smooth shaves with the Muhle blades previously, I would have thrown my whole kit in the cupboard and gone back to carts.
Given the nod of approval from my dad for these blades I thought I should give them the benefit of the doubt and have another go. Maybe that was just a dud. Maybe my Derby had come from a bad batch or had been dropped in the factory or something. My next shave was two days later and I nervously opened a fresh Derby blade and started my first pass with great trepidation. It was exactly the same. Draggy, tuggy, rough, miserable. The only blades in my cabinet at this point were more bloody Derby efforts so I grudgingly finished my shave and made a note to order some different blades. Any blades. Except Derby ones. Because no amount of pain is worth saving a few pence each week.

So there you go. One man's meat is another man's poison. The blades my old man has sworn by for years and years managed to maul my face to bits with minimal effort. I couldn't quite believe the difference between the Muhle blades I'd learnt with and these ones. The skeptic in me had always believed that "all blades must be the same, they're just sharp bits of steel" while the engineer in me thought about material properties and machining tolerances affecting performance. Just shows you, you must always, and without question, trust the engineer.

• Blade: Derby Extra Super Stainless Double Edge Safety Blade
• Cost per blade: 6p
• Cost per shave: <1p
• Place of manufacture: Turkey
• Material: Stainless Steel
• Average Shaves/Blade: 0
• Aggressiveness: Not aggressive, just uncomfortable for me. 

• Safety Razor Used: Muhle R89 Closed Comb
• Soap Used: Palmolive Classic Shave Stick. 

Chris