Benchmark Tools 4866 4 inch Precision Double Square Replacement Blade 4R Graduations (1/8, 1/16, 1/32 and 1/64) Hardened Stainless Steel (4" Replacemnt Blade)

Nice compact and reliable square

I took a chance on the four inch version and replaced my double square blade.And I loved it so much I bought 3 more and 4 of the six inch blades for spares.They read easy. Are bang on and they lock up real nice.Im going to give them 3 thousandths of error on the eighth and one and a half on the sixty fourth.The four and six inch blades both get 3 thousandths of error to my heighth checker. Which has one. And the table, which has one but it's just a little worn in, so I'll give it two.All added? There's your three.Bang on square blades as I said.They are for small squares.I could see some cheaper six inch multi squares having a tough time gripping it.If your screw bottoms out before it's tight?Shave a bit off of the back of the head of the screw and it will come down for ya.Mine fit fine but I prefer a double square and they're a little smaller by design.I would happily buy these again and actually I did already. And I have spares.Heck I about got a dozen of em.

Love this guy. I also bought the 6” metal ruler too which fits. I can use either ruler interchangeably which is awesome. Accuracy is perfect when measured against my machinist squares both for measuring and squareness at 4 and 6”.

My first check for squareness out of the box didn’t go very well - the lines made by flipping the tool along a straight edge and striking lines along the blade clearly showed the lines weren’t parallel. However, once I cleaned the gunk out of the stock piece where the blade slides through and rechecked for squareness, it seemed to be fine. The only issue I have with the tool is that the locking screw is difficult to turn after it is tightened.Beyond that, the tool is put together very solidly with no play between the stock and blade and is a very convenient size to carry with you for checking squareness, gaging depth, marking straight cut lines and making small measurements that would be difficult to do with larger measuring devices.

There's an easy fix. As other reviews have stated, the thumb wheel was unable to lock the sliding ruler in place. The reason is the casting where the rim of the thumbscrew bears is not flat; it's pretty ragged and unfinished straight from the casting process. I removed thumb wheel, spring, and locking pin, and used a narrow 1/2" file to flatten the casting (yellow line in attached pic) just enough to give the thumb wheel a place to spin against. After reassembling it works smoothly and locks the ruler in place very securely. The sad thing is this should already be done at the factory. I could've returned it for an exchange, but the chances of the replacement having the same issue are pretty good, based on other reviews. I'm happy with it now, but when it arrived it was completely unusable straight out of the package.

I purchased the 6" replacement blade for a replacement of a 6" Mitutoyo machinist combination master set, I did not expect the quality to be this good for the price, the blade has a non glare satin finish with excellent tolerance, with excellent rigidity for being used with machinist square and center heads. I will definately try more Benchmark tool products in the future, Amazon to the rescue again, thank you.

Great little square. I use it all the time but I have to be careful when setting it down. The knob does not tighten as much as I would like it to.

Perfect fit for 2 older I gauging squares that I couldn’t read anymore.Crisp clear lines.Perfectly packaged.