Make Tenons Using a Bump-cut

Bump-Cut CutAs my article on building the Southern Gent’s Mirror Stand – in the August 2013 Popular Woodworking Magazine (issue #205) – passed through design and begin routing (being passed from editor to editor for each to read and mark corrections), my terminology was called into question.

“What are bump-cut tenons,” I was asked. As I explained that it’s a cut made at your table saw in which you slide the workpiece back and forth as you also move the workpiece over the blade being guided by a miter gauge, eyebrows were raised. The reply was that I used another “Huey-ism” in my article.

I’ll bet there is another term for this process, but I have been unable to find it, outside of it being a referred to as a “quick-cut” tenon. Below is a short video to show exactly what I am doing. If you can name that method, and can back it up with a reference, please do so. If you want to have some fun and try to develop a name for this process that catches on, that would be fine. But please let us know you made it up.

If after you watch the video you don’t think this method for you, we have a couple of inexpensive downloads of other table saw tenon jigs you can download. One is from me. It’s a jig I”ve used in my shop from the beginning. The second is Robert W. Lang’s jig that we use in the PWM shop.

— Glen D. Huey

10 thoughts on “Make Tenons Using a Bump-cut

  1. kevinrf

    As a old “Normite” I can definitely say that he did a version of this back in the 1980′s. The main difference between you and him is that you use this for the entire process whereas Norm, following a quick series of saw blade passes on a tenon (not using a dado blade set up), would use the technique to clean off the in between pieces from the cuts and smooth off the tenon surface. It was nice to see this technique used for the entire tenon though.

  2. CyberBiker

    Glen,

    I learned a similar technique when I first bought my Shopsmith some 33 years ago. They actually have you nibble out the bulk of the waste then use the “bump” technique to smooth off the tenon. Back then, I had no idea that a shoulder plane existed, let alone owned one. Over the years, I have used the method off & on when I only had a couple of tenons to make. It also works for small dados if you set your stop blocks properly. A TV show put on by another magazine seems use this method fairly often.

    My safety rules have been to make sure that the Miter Gauge is solid and supports the work close to the blade, the fence is properly set and the workpiece is small enough to handle with one hand.

    A question for your consideration:

    On wider pieces (say about 3″ or more) that might be more risky to move in & out over the blade, would a sanding block or Gripper make it better for moving the work piece back & forth when working on the flat sides? – Just a thought that popped into my head as I was writing this.

    Dave

  3. BillT

    BTW, if you’re concerned that your miter gauge isn’t long enough for shorter pieces, you can build a fixture or add an extension to your miter gauge.

  4. BillT

    I’ve been doing that for years, after seeing Normie do something essentially similar on NYWS. I’ve never thought of it as a “bump” cut, but I did learn over the years of doing it that sliding the piece laterally across the blade like that while moving it back and forth helps make a smooth, flat side to the tenon, whereas just making a bunch of parallel cuts leaves a ridges surface that you then need to fine-tune with a shoulder plane or something. With the technique shown above, if you take your time and are sufficiently careful, you can pretty much end up with a tenon ready to be fit and glued.

  5. SteveL44

    I first observed this techniques13 years ago while taking a course by Chris Becksvoort taught at the Center for Furniture Craftsmanship in Maine. It was not actually part of the Shaker furniture design course but rather a technique I observed while watching Chris make presents (dovetail marking guides) for class participants. I have no idea whether there is an official name for the process but Chris referred to it as making “speed tenons.” That name made sense to me since one usually cuts tenon shoulders on the table saw and this process certainly “speeds” up creating tenons that are ready for clean up and fitting with a shoulder plane.

    At first I was very concerned about the safety of the process but quickly learned a couple of simple steps that largely allayed those fears. First and foremost – make sure that the miter gauge securely supports the work piece from behind. Second, complete the majority if not all of the waste removal with nibbling. That way the “speed tenon” is doing nothing more than smooting out high spots. Finally, and this is largely a repeat of the first warning, don’t use speed tenoning on short work pieces. There simply will not be enough support from the miter gauge. As with all wood working, it’s generally a good idea to use your head for more than a place to hold a hat and a pair of safety glasses. If you aren’t comfortable with the technique, don’t do it.

  6. Moontoad

    Oh, no! Tell me I heard wrong. My favorite woodworking video instructor using that “word” that drives me crazy, “heigth”. Please tell be this was an aberration and not a new “Hueyism.”

    1. Robert W. Lang

      I’d suggest taking a careful look at both videos. Most of what got me fired up 2-1/2 years ago was the lack of confidence and experience in the presentation. I still think that if a major magazine has to ask “is this safe enough to print?”, and posts the question online because they don’t have an answer internally, the answer should be no.

      The other problem I had was with the positioning of the hands throughout the operation in the “other” video, and the amount of material taken with each pass. There is a lot of shaky “death grip” action going on that looks to me like an accident waiting to happen. He doesn’t have good control over the work and his hands are close to the blade. There is also the suggestion that this is a best practice for all tenon cutting. If you have more than a couple of tenons to make, you quickly cross the line where a different set up would take less time overall.

      While I don’t cut tenons this way, I don’t have a problem with what I see in Glen’s video. He makes it clear that this is an acceptable method if you only have one or two tenons to make. He has more support behind the work with the bar on the miter gauge closer to the blade. He also has his hands in a much safer position, and he has more control over the workpiece with where and how he is holding it, and in the way he is moving the work into the blade. Lastly, he is nibbling off reasonable amounts with each pass, not the big bites taken in the other video. What you see in Glen’s video is an experienced, confident operator, in control of what he is doing and taking into account all the variables of the material, the machine and the operation. When I watch this video, the red flags don’t go up.

      Any operation involving sharp tools involves risks, and it is up to every individual to assess their own risks, taking into account their experience, tools and confidence level. Developing judgment is a fundamental skill in woodworking. If you’re trying to learn from an online video, look closely before trying something yourself, and think about who you’re watching. It isn’t that hard to discern who has experience and who hasn’t.

      In closing, here is what I said in my post back then, and what goes through my mind before I turn the machinery on:

      With an understanding of how the tools work and the material behaves, there isn’t any reason that you can’t work efficiently and safely at the same time. If you have to ask “Is this safe?” you should stop, look at the process and don’t go any farther until you can say, “This is safe.”

      Bob Lang

      1. gumpbelly

        I didnt watch all of the extra video, just looked at the provided pics on Bob`s link. Seems to me the biggest differences between what Glen showed versus what Bob showed was how the cut was backed up. Glen has full length support behind his stock, Bob`s doesn`t seem to. During the sliding (bumping) portion this full support is what allows a person to hold the stock in a controlled manner. That and the fact it isn`t a through cut make it completely do-able. Adding the caveat that it could be a quick step IF you just had one or two pieces to do, versus getting out the dado blade is what worries me, and I imagine it may be what will set off most readers who take exception to this cut. “If you can`t do it every time, it`s an unsafe shortcut, never to be done” I`m in agreement with Glen, you will get quicker cuts using a dado blade, or a router bit, but for just a few this is perfectly acceptable, and if you didn`t have a dado blade, is just another way to skin this particular cat.

        Have no doubt though that people have been doing this bump cut since table saw`s have been around, and in terms of no nos it isn`t even on the major radar screens. This cut differs little from using a router table with a straight cut bit to nibble off stock in this very manner, and no one raises an eyebrow. For my money both the TS and router use will require the good back up of the stock, just as Glen showed in his video.

        All that said, YOU the person standing behind the saw need to make your mind up on every cut, or procedure what you are comfortable with, and if you feel uncomfortable, then by all means break out the dado blade, router table, or hand saws and get crackin.

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