Hock Blade in a Lie-Nielsen Plane?

The Cut-Away View -- the blue thing is the breaker

The Cut-Away View — the blue thing is the breaker

We are often asked if our blades will fit in a Lie-Nielsen plane. The answer is… usually. Hock blades will drop in to many Lie-Nielsen bench planes but there can be a problem with the breaker fit. And, no, Hock breakers don’t fit Lie-Nielsen bench planes so the solution is a bit more complicated than that.

Breakers are part of the plane while blades are temporary visitors. A blade will move a couple inches through the plane over the course of its life while a breaker will move back and forth a mere fraction of an inch while adjusting the depth-of-cut. Therefore, the distance from the sharp end of the breaker to the small rectangular slot is critical. And the Lie-Nielsen breakers’ hole pattern does not match the Stanley’s that Hock breakers are designed to replace.

So, what’s the problem? Hock blades are 3/32″ (.094″)  thick while Lie-Nielsen’s are 1/8″ (.125″), 9/64″ (.140″), or 11/64″ (.170″). When you install a Hock blade into a Lie-Nielsen plane the thinner blade moves the breaker down lower onto the adjuster lever (the yellow thing in the cut-away photo). That lever is tapered so it’s not uncommon for the breaker to jam partway onto it, making it inoperative.

However, and this is the “a bit more complicated” part, many times there is no problem and the Hock blade will simply drop in and require no modification. A frog adjustment may be needed as the thinner blade will make for a wider mouth and you may wish to close it a bit by moving the frog forward. But, it the breaker jams down onto the adjuster lever, read on.

Okay, what to do? There is still considerable demand for O1 blades, which Lie-Nielsen no longer offers. (O1 still outsells A2 here at Hock Tools, BTW.) If you want a Hock Tools O1 blade for your Lie-Nielsen plane, and encounter the fitment problem described above, you could file the adjuster lever to allow the breaker to seat properly, or you could file the little rectangular slot just a little to achieve the same effect. I strongly recommend the latter course of action because if you ever wanted to return your plane to “stock” condition, you’d only have to replace the breaker (and maybe not even that) to do so. Your LN plane will hold its value forever and if you (or your estate) ever wanted to sell it that value will be higher if the adjuster lever is unmodified.

File the slot at an angle to open it up to receive the adjuster lever

File the slot at an angle to open it up to receive the adjuster lever

Use a file small enough to get into that little slot and file it at an angle so that it tapers up from the underside to allow it to fit over the adjuster lever. You shouldn’t have to remove much metal. File slowly and carefully and check the fit often.

Linda and I have become good friends with the Lie-Nielsen gang over the years. They often recommend us to their customers who ask for O1 blades. And I had Deneb vet this post in case he had anything to add. We all want our customers to have the best tools possible and are happy to work together to that end.

About Ron Hock

Owner of HOCK TOOLS (.com) and author of "The Perfect Edge, the Ultimate Guide to Sharpening for Woodworkers"
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4 Responses to Hock Blade in a Lie-Nielsen Plane?

  1. Thanx for still making O1 and explaining how I can fit them to my LN planes.

  2. bpholcombe says:

    Ron, I just received one of your blades and made this change. My LN plane is a relatively newish vintage (maybe 2012~) and I had to involve a bit more in this process than depicted here. First, the LN chip breaker is hardened steel, momentarily forgetting that I did-in one of my Corradi files on this advice, so it may be worth amending that to save people from making the ‘Doh!’ moment as I did.

    After adjusting the fit between breaker and frog to accommodate the thinner blade I also had to attend to the length of the cap screw, which was now too long. On my bronze version of the plane the cap screw is near bottomed out in the hole in a stock setting, so I needed to remove some material from that screw to accommodate the thinner blade.

    Thank you for making such wonderful blades, sharpening and using O1 rekindled my relationship with this plane.

    • Ron Hock says:

      I just contacted Deneb at LN. He says the breakers are not hardened but are laser-cut which surface hardens the area that was cut. So I suppose one could heat the slot to not-quite red hot and let it cool very slowly. Then try to file it. Or grind it with a small stone in a Dremel.

      I had Deneb vet this entry before I posted it but the laser-hardening slipped his mind. I’m sorry about your file.

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