Chris Schwarz's Blog

3/4″ Up-cut Spiral Router Bit

In my blog earlier this week on drilling holes for bench dogs and holdfasts I mentioned a 3/4”-diameter up-cut spiral bit we use in a plunge router to make perfect holes.

Several readers have asked where to get this magic router bit.

The bit is made by Onsrud, has a 1/2” shank and can be purchased a couple places. Woodcraft, carries it, although the bit (#03K53) is sometimes back-ordered in our experience.

It’s also available at Lee Valley Tools. The bit (86J01.42) is always in stock and goes out the next day.

Hope this helps. Happy routing! (I’ve never written that sentence before.)

— Christopher Schwarz

12 thoughts on “3/4″ Up-cut Spiral Router Bit

  1. blindleader

    I’ve always used Amana Tool router bits. I might have been sad when I paid for them, but are never sad when I use them. Amana has an astounding selection of bits, including 16 different spirals. And if you really want extra weight in your tool box, and holes in your wallet, some are solid carbide.

    I started my dog holes with a plunge router clamped (a necessity IMO) to the bench and finished with a hand held drill.

  2. blindleader

    I’ve always used Amana Tool router bits. I might have been sad when I paid for them, but are never sad when I use them. Amana has an astounding selection of bits, including 16 different spirals. And if you really want extra weight in your tool box, and holes in your wallet, some are solid carbide.

    I started my dog holes with a plunge router clamped (a necessity) to the bench and finished with a hand held drill.

  3. John Cashman

    I’ve used end mills and many work fine. The problem is that some of them have, for lack of a better term, a “dead” spot in the middle. If you try to plunge with them they won’t go, because the very center of the bit isn’t cutting — they were meant to enter the work from the side, as with a milling machine. The package won’t say whether they will “plunge,” since they were made for machine tools. But they can be a good bargain if you get the right one.

    1. macmarty15221

      Yes, the term is “center cutting”, some end mills are designed that way and some are not. This is usually given as part of the item description. (Certainly so on McMaster.com)

      1. John Cashman

        Thanks. I had no idea what the proper term was. I would assume that the bits made for woodworking would be center cutting, but maybe not all are.

  4. Frank F

    We have tried this technique with varying degrees of success, and mishaps. The problem is plunge routing a straight hole through the workbench, wihtout catching the edges of the router bit. If you somehow jig a fixture to hold the router in place, it works pretty good. If you try to rout by hand, we have had minor kickbacks, gouged tops and overall problems. Our workbenches are 3 inches thick. Even a very tiny move of the router causes the bit to grab. In addition, you must have a router that can plunge 3 inches (plus). It is fast, but sometimes fast is not the only solution. My bench is drilled using a spade bit and a right angle fixture ( made by General) that looks like a portable drill press ( costs about $30)that keeps the bit perpendicular. I screwed the jig down to a piece of plywood, clampled the ply in place, and drilled away. As fast, lower risk. A bit rougher hole sides, but it works.

  5. macmarty15221

    That is one hunka hunka burning steel! (OK, let’s not think about the “burning” part.) Not cheap either. I wonder what the functional difference is between this router bit ($44 at Lee Valley) versus an end mill with comparable size and geometry available for $22 at McMaster-Carr? (Item 3051A23) I’m sure that a tooling designer could wax philosophic on the differences, but would us mere mortals experience a difference?

    1. rwyoung

      How big is the collet in your router? The bit you specified from McMaster-Carr has a straight shank so good luck fitting that into your 1/2″ collet.

      2-flute mills work fine in routers so long as you have either a stepped shank (not terribly common) or a straight 1/2″ or 1/4″ shank. Doubled ended bits aren’t a good idea in a router. The collets aren’t deep enough to properly grip the bit. 3 and 4 flute bits don’t provide sufficient clearance for evacuating wood chips from the cut.

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