Tweet
Hi, people, it’s been a long time since I was able to spend much time doing woodworking. My job became much busier when I was invited to join a different faculty at the university, and I also began spending more time doing serious photography (one of my earliest loves). As a result, I had less concentrated time to do ww'ing, and fell into doing just little fixit jobs around the house, and couldn't spend the time on the forums as before. That much hasn't really changed, but there are a number of projects I’ve got lined up for this next year, and I’m hoping to spend a bit more time checking back in here, at least on a ROM basis. I still love the BT3000, and am impressed that US tablesaws have finally come around to requiring riving knives--something we BT3000 users have appreciated since long ago.
Anyway, for my first new contribution, I’ll talk about a new (for me) tenon jig. To be honest, I’m amazed by the wide variety of tenon jig designs now available on the net (hey, the 'net has increased about 100x in volume the past decade!), so in advance I’ll tell you this isn’t at all fancy, just a basic jig that happens to be an improvement on the one I used to use.
About nine years ago, I cut my first mortises and tenons when I built (Kanon’s Cabinet and the Boot bench. To cut the tenons, I used the simplest and probably most common tablesaw tenon jig found on the web (very much like the one described HERE, which I believe was designed for the BT3000). As anyone who has tried one of these knows, they work pretty well on short, light workpieces like the slats on my boot bench or the spindles of a Morris chair, but they become quite a bit more unwieldy and even potentially dangerous when trying to cut deep through-tenons on a settee’s four-foot-long stretchers (I can’t even imagine what it would be like trying to cut them for a six-foot couch). An additional problem with my first tenon jig was the clamp used to hold the workpiece in place. Nine years ago I couldn’t find proper toggle clamps here in Japan and made do with the table-top clamp shown in the photos. It worked okay—but it was difficult to keep in proper tension due to the insufficient length of the threads.
Anyway, based on the experience I had cutting the tenons on a similar project this summer (an Arts and Crafts loveseat, more about which I’ll write later), I made the following pretty elementary conclusions about this type of fence-riding jig:
1. Sideways motion when cutting tenons on long, vertically standing workpieces is primarily a result of the lack of sufficient width in the base of the jig, insufficient jig height to stabilize the board, and insufficiently tight tolerances in the pieces gripping the rip fence.
2. Front-back rocking motion may occur when trying to cut a deep tenon on a large vertically standing workpiece, and that rocking is primarily a result of the lack of sufficient jig length and weight.
In a word, it’s better to build the jig bigger in every dimension. That really sums it up, and so end of story, except for the part about tolerances around the rip fence. That’s where I got a bit inventive (I hope).
I don’t do this kind of cutting often enough to make me feel the need for one of the amazing dial-in-the-value mechanical jigs like Steve Maskery’s “Ultimate Tenon Jig”, but I did want something more stable than the little one I currently had. As a result, using the basic same design principles as the earlier one, but adding additional size and a movable spring-forced pressure fence, I produced a new jig that is much better than my old one. Yes, it’s still a simple manual type that requires movement of the rip fence to adjust, but the difference in stability is worlds apart, which for me is the most crucial element.
Material: baltic birch plywood, oak, Philippine mahogany, pine, ebony
The new and old tenon jigs:
Side by side
The difference in width and height is evident at a glance; the old jig has an effective width of 8 cm and height of 23.5 cm, while the new one is 16.5 cm wide and 30 cm high. It is this width and height that provide lateral stability and resistance to sideways swaying when cutting long boards.
Maximum base width of old jig was only eight centimeters:
Maximum base width of new jig: 16.5 cm
This photo also shows the movable pressure fence being forced against the right side of the rip fence, thus keeping the jig in perfect alignment with the fence.
I also had trouble with front/back rocking when the saw tended to bog down cutting deep tenons on long boards. That’s a function of the length of the jig; the old one was only fourteen centimeters long:
Length of the old jig’s top plate: 14 cm
In contrast, the new one has a top plate forty-one centimeters long.
Length of new jig’s top plate: 41 cm
This shot of the underside shows the fixed fence at right, the movable spring-held pressure fence in the middle, and the outrigger with its wide ebony foot on the left. The ebony is slick and produces less resistance to sliding on the table surface. I probably should have placed a strip on the bottom of the main fixed fence as well.
For the spring shafts, I used 8 mm threaded rod with epoxied nuts embedded on the side of the movable fence, with standard wingnuts on the outside; the threaded rod is additionally fixed to the nuts with loctite to prevent unthreading them as I turn the wingnuts. I was initially worried that I would have to search around the many shops at Tokyo’s Akihabara in order to find springs of the proper dimensions and tension, but I was knocked over when by chance I found the perfect springs at Tokyu Hands in Shibuya. I should note that when the springs are released, the friction is enough to create quite a bit of resistance to pushing the jig—it can be done, but I’ve found it’s better to tighten the wingnuts half a turn or so to ease the pressure off just a bit; that makes the jig slide easier while maintaining good tension against the sides of the rip fence.
Anyway, for my first new contribution, I’ll talk about a new (for me) tenon jig. To be honest, I’m amazed by the wide variety of tenon jig designs now available on the net (hey, the 'net has increased about 100x in volume the past decade!), so in advance I’ll tell you this isn’t at all fancy, just a basic jig that happens to be an improvement on the one I used to use.
About nine years ago, I cut my first mortises and tenons when I built (Kanon’s Cabinet and the Boot bench. To cut the tenons, I used the simplest and probably most common tablesaw tenon jig found on the web (very much like the one described HERE, which I believe was designed for the BT3000). As anyone who has tried one of these knows, they work pretty well on short, light workpieces like the slats on my boot bench or the spindles of a Morris chair, but they become quite a bit more unwieldy and even potentially dangerous when trying to cut deep through-tenons on a settee’s four-foot-long stretchers (I can’t even imagine what it would be like trying to cut them for a six-foot couch). An additional problem with my first tenon jig was the clamp used to hold the workpiece in place. Nine years ago I couldn’t find proper toggle clamps here in Japan and made do with the table-top clamp shown in the photos. It worked okay—but it was difficult to keep in proper tension due to the insufficient length of the threads.
Anyway, based on the experience I had cutting the tenons on a similar project this summer (an Arts and Crafts loveseat, more about which I’ll write later), I made the following pretty elementary conclusions about this type of fence-riding jig:
1. Sideways motion when cutting tenons on long, vertically standing workpieces is primarily a result of the lack of sufficient width in the base of the jig, insufficient jig height to stabilize the board, and insufficiently tight tolerances in the pieces gripping the rip fence.
2. Front-back rocking motion may occur when trying to cut a deep tenon on a large vertically standing workpiece, and that rocking is primarily a result of the lack of sufficient jig length and weight.
In a word, it’s better to build the jig bigger in every dimension. That really sums it up, and so end of story, except for the part about tolerances around the rip fence. That’s where I got a bit inventive (I hope).
I don’t do this kind of cutting often enough to make me feel the need for one of the amazing dial-in-the-value mechanical jigs like Steve Maskery’s “Ultimate Tenon Jig”, but I did want something more stable than the little one I currently had. As a result, using the basic same design principles as the earlier one, but adding additional size and a movable spring-forced pressure fence, I produced a new jig that is much better than my old one. Yes, it’s still a simple manual type that requires movement of the rip fence to adjust, but the difference in stability is worlds apart, which for me is the most crucial element.
Material: baltic birch plywood, oak, Philippine mahogany, pine, ebony
The new and old tenon jigs:
Side by side
The difference in width and height is evident at a glance; the old jig has an effective width of 8 cm and height of 23.5 cm, while the new one is 16.5 cm wide and 30 cm high. It is this width and height that provide lateral stability and resistance to sideways swaying when cutting long boards.
Maximum base width of old jig was only eight centimeters:
Maximum base width of new jig: 16.5 cm
This photo also shows the movable pressure fence being forced against the right side of the rip fence, thus keeping the jig in perfect alignment with the fence.
I also had trouble with front/back rocking when the saw tended to bog down cutting deep tenons on long boards. That’s a function of the length of the jig; the old one was only fourteen centimeters long:
Length of the old jig’s top plate: 14 cm
In contrast, the new one has a top plate forty-one centimeters long.
Length of new jig’s top plate: 41 cm
This shot of the underside shows the fixed fence at right, the movable spring-held pressure fence in the middle, and the outrigger with its wide ebony foot on the left. The ebony is slick and produces less resistance to sliding on the table surface. I probably should have placed a strip on the bottom of the main fixed fence as well.
For the spring shafts, I used 8 mm threaded rod with epoxied nuts embedded on the side of the movable fence, with standard wingnuts on the outside; the threaded rod is additionally fixed to the nuts with loctite to prevent unthreading them as I turn the wingnuts. I was initially worried that I would have to search around the many shops at Tokyo’s Akihabara in order to find springs of the proper dimensions and tension, but I was knocked over when by chance I found the perfect springs at Tokyu Hands in Shibuya. I should note that when the springs are released, the friction is enough to create quite a bit of resistance to pushing the jig—it can be done, but I’ve found it’s better to tighten the wingnuts half a turn or so to ease the pressure off just a bit; that makes the jig slide easier while maintaining good tension against the sides of the rip fence.
Loring in Katy, TX USA
).
Comment