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KM-1 Kerfmaker

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KM-1 Kerfmaker

Item Number: 6000101

Availability: In Stock

Quick Overview

Anybody who has been working wood for any length of time understands the pain of sizing grooves with today's off-size sheet goods. If you have ever tried to "dial in" a dado head with paper shims or fussed with a wobble head dado set, you know this hassle intimately.

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Product Description

The KM-1 Kerfmaker is an ingenious little tool that makes sizing grooves and dado cuts painlessly easy. It is unbelievably fast and accurate.  (The video below shows the tool in action) We can't imagine how you can get anything other than dead perfect results. Precision milled from aluminum, this tool is sure to be one of your most cherished shop aids.

Whether you own a table saw, chop saw, radial arm saw, the Jointmaker Pro, router table or any other tool that makes a clean kerf, you can use the KM-1 to expand that kerf to suit your needs. It is an amazing little tool that has earned our coveted "Bacon Saver" status. This means you will get gallery quality results every time you use the KM-1 Kerfmaker. The KM-1 is perfect for: Frame work, box makers, shoji screens, torsion boxes, carcase work, drawer making and the list goes on. It is a tool that once used, you will never want to lose.

The concept is simple: the KM-1 is first "calibrated" to the particular cutting tool’s exact kerf. (See video demonstration). This is a one-time step. You then simply gauge the thickness of your stock with the KM-1, lock and you now can use the KM-1 as a flip stop to create a groove the exact width of your stock! It is fast, and potently accurate. One KM-1 will work for every tool you own. (If your router table fence floats, you will need two KM-1’s to accurately size grooves). 

The KM-1 is so handy you may want to consider a dedicated unit for each of your cutting tools.

Please visit our <a href="">Kerfmaker forum</a> to learn more about this amazing tool!

Machined anodized aluminum approximately 3 1/8” x 1 ¼” x 1/2”
Can I use a Kerfmaker as a Tenonmaker as well? I'd like to use one tool for both dado cuts and tenons?

No. The Kerfmaker and the Tenonmaker have opposite functions.


The Kerfmaker subtracts one kerf width to create a cut that exactly matches the thickness of the stock, as gaged by the Kerfmaker, to be inserted into the dado or groove created by using the Kerfmaker as a flip stop.


The Tenonmaker adds one kerf width to an existing mortise or groove, as gaged by the Tenonmaker, to create a tenon that fits the exact width of the mortise or slot created by using the Tenonmaker as a flip stop.


Why can I not get the correct width of the cut?

Prior to starting, close the Kerfmaker jaws and make sure they close all the way. Next, the orange jaw needs to be calibrated to the exact kerf . Prior to calibration the tool needs to be closed and locked. The two cuts create a small block and when placed back into the corner of the parent stock, the offsets are the EXACT thickness of your saws kerf. Make sure the orange lock wheel is locked tight. The gauge jaws are completely closed. Once this “one time” calibration is done, the tool is ready for use. You will never have to adjust it again unless you change the blade on your saw.

Next, loosen the gray lock wheel and gauge the the thickness of the stock you want created, a groove or dado. Keep in mind, if you want a slip fit, make sure the KM-1 mimics the slip fit. If you want a tight fit, make sure the KM-1 does not fall off when turned upside down. This tool will mimic EXACTLY the fit you choose.

Here’s how the KM-1 works, the calibration process is actually subtracting one kerf from your gauged material. When used as a flip stop, you can’t get anything but perfect results.

Visit the Bridge City YouTube page and look at the KM-1 videos. Here’s one we produced:

Customer Reviews

10 Item(s) Show per page
  1. Doesn't match Review by Gonz

    Did not read specs when ordered. Tool color should have matched previous tools. Other then that tool is fine (Posted on 7/24/17)

  2. Outstanding - a class changing tool Review by woodPixel

    The kerfmaker is a game-changing tool for all woodworkers that need to cut an accurate kerf.

    I bought 5. One for myself and 4 for woodworking friends. As a professional who makes a living out of rapid accurate work for customised/bespoke projects, the KM1 has boosted accuracy, cut speed and confidence dramatically.

    Dados and kerfs are such a tiny part of any project, but get it wrong and you'll curse for the rest of the job.... so instead of futzing around with setups and tap-tap-tap... the KM1 makes it a quick no-fuss process.

    The KM1 takes a little time to "get your head around" (it's dead simple, but seems like witchcraft) but once used a few times you will NEVER go back to your old methods.

    woodPixel - Australia.
    (Posted on 7/11/16)

  3. Consistency at last Review by rwebb

    This was a bit tricky to get the hang of at first, but then you realize how wonderful it is to use. The video was sufficient to get you started. I made quick reference blocks for my different table saw blades of different thicknesses, and now I'm set. I still start with a test joint, (which is usually right on) and then go to work for repeated reliable lap-joints for any project. I use it mostly with my table saw sled. Wouldn't be without it now. Stays set when you tighten it down. Great design. (Posted on 2/13/16)

  4. Good but hard to execute Review by Tom

    I had to fiddle with this quite a bit to get it to work, more because of the vagaries of getting the kerf set correctly than the design of the tool. It did not work well for me in making multiple cuts, i.e. box joints, but then they don't claim it works well for that either. (Posted on 9/14/15)

  5. Good but hard to execute Review by Tom

    I had to fiddle with this a lot to get it to work, more because the vagaries of setting the kerf correctly than the design of the tool. Once set it works as performed. But not so good for multiples, e.g. box joints - at least for me. (Posted on 9/14/15)

  6. A tiny gem Review by Steven

    A small tool yet it packs a powerful punch especially when you're trying to set up your tools for flawless, gap-free joints. There's a terrific video by HalfInchShy outlining it's many uses on YouTube, check it out: (Posted on 1/2/14)


    Incredible tool; I got a perfect kerf on my first try. Recommend all woodworkers get one. Sure you might get along without it---there *are* ways to do the same thing for zero cost. However, this is just so much faster and it's such a cool tool. Live a little---just get one. (Posted on 12/5/11)

  8. Exceptional product Review by William

    KM-1 Kerfmaker works as advertised! (Posted on 11/2/11)

  9. This thing id NEAT! Review by Chucko

    I had some reservations about spending so much money for this tool but it turns out to work exactly as advertised first try! I used the no measure calibration technique illustrated on the product information video and ended up shimming the measurement by one paper thickeness. I have used it to make a jig for routing small mortises and found it to be incredibly accurate. This device is worth the money spent as it cuts down certian cerf measurement and cuts to seconds. I am looking forward to finding how many different ways I can put this device to work. (Posted on 11/2/11)

  10. Awesome Review by Dee Bee

    I live in Australia - I am really impressed with Bridge City Tool Works. I have just bought tools of them and I will be 'back for one of these VERY soon. It seems to make woodworking so easy!!! (Posted on 5/23/11)

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