Tag Archives: tenons

Bump-cut Band Saw Tenons

IMG_1439Because I had to make the columns on my tall clocks longer than needed so I could form the reeds with my scratch stock, each column needed to be cut to length. (The blue tape held together a fracture at the end of the column – I use this same technique when turning, if need be.) Once at length, each end of the columns needed to be reduced in diameter to fit into the brass capitals. Then ends of the individual reeds are then shaped further.

My first thought was to load a column at my lathe and turn the tenon before I cut the pieces to length. I want a snug fit through the capital, and there would be no way to check the fit while on the lathe – there was about 2″ to remove off each end of the columns, so I couldn’t simply slide on the capital. IMG_1440If I cut the lengths first, I lost the center markings and, for me, that makes loading the piece on the lathe too much of a hassle (I’ve not had success remarking the center whether using a center-marking gauge or not).

What I decided to do was to cut the columns to length, then use my band saw to form the tenons – it’s a similar operation as making a bump-cut tenon using a table saw. (You can see a short video of this technique here.) In the photo above right, you see the end of the columns after its been cut to length. (You can also see that there is more work to do on the reeds.) And below you can see my setup at the band saw.

IMG_1443

I used a bench hook to guide the stock, and used a spacer (set between the hook and band saw table) to locate the hook fence just beyond the blade. This setup is somewhat critical. If you’re too far beyond the blade, you will remove too much material. (If you’re in front of the blade, your tenon would be too fat.) I say that setup is somewhat critical because you do have a little adjustment. IMG_1445That comes from moving the band saw blade forward or back using the guide bearings on the saw. A simple tweak can push the blade forward to allow you to dial in the best cut. I went for a tenon that was just too snug to fit my capital so I could lightly sand the tenon to fit. The photo shows a closer view of the setup. (Click on the photo to see it even larger.)

I positioned the column tight to the second block – that piece has a 1/2″ notch which is the tenon length, and I’ve clamped it tight against the bench hook to make sure the two are aligned. With the column set against the second block, I spun the stock to cut the tenon shoulder. I then nibbled away the waste in one area of the tenon – it takes a bit of wiggle and movement. Once that area is flat and clean, I began the bump-cut technique. IMG_1446Back and forth into the second block while rotating the column; it’s like rubbing your head as  you pat your stomach.

When a full rotation is finished the tenon is formed. Two clocks, four columns per clock and two ends per column left me with 16 tenons to form. Taking the time to set up this method saved me time in the long run. And I didn’t waste a column that needed to be replaced with another – that would have burnt at least an hour of shop time.

Build Something Great,

Glen

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Filed under Jigs, Power Tools, Shop Tips, Tall Clock

Two of My Top Ten Gripes

Woodworking is a great way to make a living. There are, however, problems with even this career. This week I’m posting two of my current top ten gripes.

Bump-cutNumber one on my list – this specific gripe stays at number one or number two throughout most of the year – is the safety police. If this is you, please know that it is not your job to constantly point out things that you consider too dangerous. The fact that I don’t have on safety glasses and ear protection as I work at my table saw or run a router is not the end of the world. These particular violations have been pointed out so often that we all know the rules. If you feel you need to wear glasses every time you step into your shop, then do so.

Number two this week are those that hear someone state a woodworking rule, but do not hear or understand the exact meaning of that stated rule. Case in point: Don’t use your table saw fence in conjunction with your miter gauge, and never glue cross grain.

This past week I posted on the Popular Woodworking Magazine (PWM) blog about bump-cut tenons. This technique has been used for years and years – someone commented that they had seen Norm Abram use this on New Yankee Workshop. The rule that should be followed is that you should not use your table saw fence in conjunction with your miter gauge IF YOU ARE MAKING A THROUGH CUT. That last portion of the sentence is the real message. If you’re not cutting through, use your fence and miter gauge as you see fit.

Another rule is that if you glue cross grain your board will split. I ran into this problem way back in another post on the PWM blog dealing with case sides in lowboys. It has also surfaced when working on the returns around slant-lid desk lids. Both can and often were glued fully.

IMG_1060Take a look at the this photo. What you see is a torn-apart bookcase side that I assembled in 1977 or 1978. (It was a bookcase for a high school sweetheart who broke up with me before I finished the top section.) These boards have been stored in a stone-walled basement of an old farmhouse, been moved from house to house in six moves and have been stored in my garage for the last 20 years. This week I went to re-purpose the wood to knock out a couple small drawers. I tried to knock off the blocks with my hammer, then tried to hook the claw of said hammer under a corner to split the pieces apart. No luck. Finally I drove a screwdriver between the two pieces and the split was made.

In the photo you can see that the regular yellow glue did not fail. What failed was the wood. While this glue-up was across only about 8″, I think it shows that it’s possible to glue in this manner and there are certain circumstances when it is OK to do so. You just need to know the rule – the exact rule – and when you can bend it. (I always glue the first 4″ to 6″ of moldings I use on my projects.)

Please don’t blindly follow what you hear or read.

Build Something Great!

Glen

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