Thursday, June 9, 2011

Bridge City KM-1 Kerfmaker User's Guide

In many of my podcasts, I've used the Bridge City Toolworks KM-1 Kerfmaker to create exactly sized grooves and dados.  It can be shrouded in mystery if you are just looking at the catalog.  Come to think of it, it can be shrouded in mystery when you are reading the "user's manual".

In this video, I'll give you a tour of the KM-1, show how to effectively set the kerf using the actual cutters, and show how to use it in many situations on the tablesaw, router, mitersaw, bandsaw, and even the Bridge City JMP Jointmaker Pro.  There'll be a number of demonstrations with close-ups to unveil the shroud!

The KM-1 is part of Bridge City's "Essentials".  While many commemorative tools are made only once never to be made again, the KM-1 is generally always available.

If there's one thing I could say to convince you of its utility, it would be this:
I've only used my dado stack in two sizes: 1/4" and 1/2"; the shims are still shrink-wrapped
(I've always wanted to use the word 'shrouded' in a blog posting; hurrah!)

EDIT: at the time I posted this, Bridge City was regrettably out of the KM-1s.  I just got confirmation from Bridge City that they will be back in stock in 6-8 weeks.  That puts them as available around the last week of July 2011/early August.  Put yourself on the list to get one when they are available.  Worth the wait.  I waited much longer as I got in on the first run!


  • Marilyn said...

    Yeah! Thanks for doing this. This is really, really helpful. Love all the little helpers too. I've been looking to purchase this little gizmo and this will be most helpful when I go to use it.

    Did I hear doves in the background?

  • HalfInchShy said...

    Glad it will be useful, Marilyn... once you use it, you'll wonder why I made a video on it as it becomes second nature to use. Coincidentally the day I started recording this, someone asked me a bunch of questions on placement of the TM-1 (KM-1's cousin), which is very similar to placement of the KM-1.

  • Anonymous said...

    Great video! I would have never
    thought of using it with the router.
    Thanks again for answering all my questions last week, too! Using my TM-1 is truly second nature now.

  • Steve said...

    Thanks for that, Paul I have one of those, and have used it sparingly, having had to look at the instructions each time. I really appreciated seeing you use it with the router.

  • JimE said...


    Found your site a couple of weeks ago and love it. The videos are just my style. Kind of in the "Woodworking for Dummies" theme.

    I've been looking at the KM-1 since it came out and just never had the drive to order it until I watched your video. Now you've cost me $75+. Maybe.

    I just went the to website to order it and there is a message: "Our Of Stock -We will make this product available for Pre-Orders when and if we receive enough interest. Click the sign up statement above to join the list."

    Now look what you've done!

    Anyone have one for sale?

    Kodak, TN.

  • HalfInchShy said...

    D'oh! Yes, I checked their site before posting and saw it was in preorder again. They had a lot in stock fairly recently, but John E sells a bunch of them when he does woodworking shows and I believe he just did 2.

    I know they don't intend for those to go out of stock for long so put yourself on the preorder list. You can also write them and ask when they think they will be ready. Since they just changed their website completely 2-3 weeks ago, I don't know how they are recording wish items to know to produce them.

    The address you want is (hi, Natasha!) During the summer, they work a compressed workweek so you may not get a reply on a Friday.

    Worth the wait :)

  • Vic Hubbard said...

    Now I get it. I've gotta go see how much for this. Very cool tool. Really great job, Paul-Marcel!

  • David Harms said...

    I was admittedly confused on how one of these would be useful in the shop and now I know, nice tutorial Paul.

  • Vic Hubbard said...

    Damn!! Out of Stock! I put my name on an alert list. MUST HAVE THIS TOOL!

  • Don said...

    Hi Paul
    Saddlestrum (Don) here in B.C. Great explanation of the Kerfmaker. Have been on the waiting list for about 3 months so hoping John has these in production and they see daylight shortly.
    Keep up the great videos.

  • HalfInchShy said...

    Thanks, Don! Per the updated schedule on their site, they start shipping Monday. If you haven't ordered one yet, I'd guess you could now or Monday. Also, if you are going to WIA, I believe they will be selling them there.

  • pmelchman said...


    you are using the 1400 with two guide rods and the guide rail....what is the black handle that rides on the rail? I am having a hard time finding the handle



  • HalfInchShy said...

    Hi Patrick,

    The pads on the guide rail are the "guide stops" for the Of-1400. If you mean the collar I slipped on the guide rods to act as a stop fence, that's the micro-adjuster for the MFK-700. You can order one separately off EKAT (Festool parts system); in fact, you could order just the collar and screw. As I mentioned in the video, though, you could just use a depth collar you use with drill bits of an appropriate size. Those are really cheap and will lock securely.

  • Lane said...

    i understand how to calibrate the saw blade to the kerfmaster but what procedure do you use to calibrate to a router bit?

  • HalfInchShy said...

    Hi Lane,

    You could always make a setup block like I showed for router bits... really easy after you just chucked up the bit, but when I've used bits, I usually pinch the bit between a board and the grey slider of the KM-1 then turn the bit gently counter-clockwise so the teeth will push out the slider, but not try cutting into it. Works well. I do most of my dado with one of two spiral bits I have. I made a setup block for one; I'll make one for the other next time I use it (use the spin method that time, but after I'm done, cut a board to make a setup block for next time).

  • nickT said...

    I finally got my KM-1 and it works great for getting the proper width dado (groove). However, I don't see how it will help me make edge grooves that need to be centered. For those I've always done the cut-flip-cut procedure using scraps until I get the right width.

  • Amitch13 said...


    Great video, now I won’t one! Unfortunately there out of stock so I have ordered the TM-1 so I have a new toy to play with while I wait for them to make some more, any chance you can do a guide for the TM-1 as well?

    Keep up the good work

  • HalfInchShy said...

    Thanks, Amitch!

    Sadly, you missed the last KM-1 by 2 weeks. I hope you clicked the waiting-list link; I believe you get an email when they are in production again, but they go fast. Kinda wish they'd make a bigger order; isn't like they take a lot of room to stock! Other option is to write them an email and ask to be on a waiting list.

    I don't yet have a video on the TM-1. Keep meaning to do one, but haven't gotten to it. I have an outline of advanced uses for both the TM-1 and KM-1 I'll do someday; once you understand the math formula each solves, you can use the in a lot more places!

  • Unknown said...


    I just ordered both the KM-1 and the TM-1 so I am VERY eager to see any updates on the KM-1 or your planned video on the TM-1. Frankly, your videos do an awesome job of clearly explaining how to use these tools as otherwise just reading the manual seems VERY confusing. As always, thanks for all your great help.


  • HalfInchShy said...

    Thanks, Tim... you'll like the KM-1; super useful gauge in a lot of ways.

    I don't have a newer KM-1 how-to video, but the KM-1 label to the right of the main text on the blog will show currently 6 entries related to the KM-1. The No Comment #2 build video will only have it as a cameo, but the video on making the tapered octagon for that build does use it in a not-so-common way.

    I don't have a TM-1 video yet; since I use a Domino for mortises, I don't need to make perfectly fitted tenons often, but once you understand the formulas the KM-1/TM-1 solve, you can use them for other things. I have an outline somewhere for other methods I've used. Need to find it and decipher my writing to put something together... but not until Angle Madness is built! Don't want to get distracted off that build again :)

  • Amitch13 said...

    Hi Paul, I'm expecting my km-1 tomorrow!!!

    I watched the video on the tapered octagon but did not see where you used the km-1. Am I being an idiot?

  • HalfInchShy said...

    From 12:00 to 14:00 in the tapered octagon video, I mentioned using the KM-1 to cut out the part of the octagon where the table top would go. This was before I changed the design to flip the top part upside-down. However, I did use the KM-1 there to get the part removed to exactly match the tabletop thickness so a Domino pushed in from the top cap would correctly line up with the rest of the Domino mortise in the lower part (assuming a hole in the table top for the Domino to pierce).

    -bleck- don't like how I edited that video at all... hopefully that means the edits are getting better!

  • Anonymous said...

    I just received my KM-1, thanks to your video. What a cool tool. I see they received a patent on the apparatus and method last summer:,746,116.PN.%2526OS%3DPN%2F8,746,116%2526RS%3DPN%2F8,746,116&PageNum=&Rtype=&SectionNum=&idkey=NONE&Input=View+first+page

    If that link doesn't work, search for U.S. Patent Number 8,746,116. It has useful drawings and a description -- but not better than your video!


  • HalfInchShy said...

    Thanks, Billy... very cool that they got the patent. He has a lot of patents, I believe, on different mechanisms he comes up with for planes, the Jointmaker Pro, etc. He's a super interesting guy to speak with if you ever get a chance.