Horizontal Drilling on the Lathe: A Jig for Accurate Dowel Holes
A wood lathe is usually associated with turning bowls and spindles, but it's capable of more than shaping round workpieces. With the right jig, you can also use it to drill accurate, repeatable holes in the ends of boards.
I like using dowel joinery for some of my woodworking projects. But when a recent project called for drilling a lot of dowel holes in similar workpieces, I wanted a faster way to get consistent results.
That's what led me to build this horizontal drilling jig for my wood lathe.
The jig holds each workpiece in position while a drill bit mounted in the lathe does the drilling. Once everything is set up, it's easy to repeat the same hole locations across multiple parts.
A Shop-Made Jig for Drilling Dowel Holes
The biggest advantage of this setup is repeatability.
When drilling dowel holes in the ends of boards, it's important that the holes are positioned accurately so the mating parts fit together during assembly.
Rather than measuring and laying out every hole individually, this jig establishes a consistent position for the workpiece.
The workpiece rests on an adjustable platform, while a fence controls its position relative to the drill bit.
That makes the setup especially useful for projects with multiple identical parts.
An Adjustable Platform Fits Different Workpieces
The jig attaches directly to the bed of the lathe using a pair of knobs and washers.
One of its most useful features is the height-adjustable top.
By raising or lowering the platform, you can position boards of different thicknesses so the drill bit enters at the desired height.
To make the adjustment easier, I added short strips of adhesive measuring tape to both sides of the jig.
These scales help me set each end of the platform to the same height, keeping the top level and helping the holes run square to the ends of the workpieces.
Once the height is set, knobs at each end lock the platform in place.
Use an Adjustable Fence for Repeatable Hole Locations
The top of the jig includes a length of recessed T-track that holds an adjustable fence.
The fence makes it easy to position each workpiece for drilling the first hole.
Once the fence is set, I can place one board after another against it and drill holes in the same location without repeating the layout.
Use a Spacer Block for Additional Holes
When a workpiece needs more than one dowel hole, a simple spacer block makes the job easier.
After drilling the first hole, place the spacer between the fence and the workpiece to shift the board a consistent distance.
This establishes the location for the next hole without having to reposition the fence or measure each board.
It's a straightforward technique that saves time when making multiple matching parts.
Drilling Holes with the Lathe
To use the jig, mount a suitable drill bit in a chuck on the lathe's headstock spindle and secure the jig to the lathe bed.
Adjust the platform height and fence position to align the workpiece with the bit.
With the workpiece securely clamped to the jig, the rotating bit can drill into the end of the board as the workpiece is advanced along the jig.
For deeper holes, withdraw the workpiece periodically to clear chips and reduce heat buildup.
Safety note: This is a specialized lathe setup. The workpiece must be positively secured and guided so it cannot rotate, lift, or catch on the bit. Keep hands away from the rotating drill and use a suitable drilling speed. Confirm that your lathe, chuck, and jig are appropriate for the operation before attempting it.
Adapt the Jig to Your Lathe
The drawings show how the jig is constructed, but you may need to modify the dimensions or mounting arrangement to fit your particular lathe.
The important features are the adjustable platform, secure bed mounting, and movable fence.
Together, they provide a way to position workpieces consistently and drill matching holes without repeated measuring and layout.
A Time-Saving Addition to Your Wood Lathe
If you use dowel joinery regularly, this horizontal drilling jig can be a worthwhile shop project.
It's especially helpful when drilling holes in the ends of multiple similar boards, where accuracy and repeatability make a big difference.
And it's another example of how a simple shop-made accessory can expand the capabilities of a tool you already own.
Once the jig is built and adjusted to your lathe, you'll have a convenient way to tackle repetitive end-grain drilling jobs.
I like to use dowel joinery on some of my projects. But recently, I had a project that required drilling a lot of dowel holes in similar workpieces. Since all the holes were located in the same place on the workpieces, I came up with the jig you see here. It allows me to accurately position my workpieces so that I can quickly drill the holes with a bit chucked in my lathe.
The jig attaches to the bed of my lathe with a couple of knobs and washers. And the top can be raised or lowered to account for workpieces of different thicknesses. I added short strips of adhesive measuring tape to both sides of the jig to help ensure the top is level and the holes are drilled square to the end of workpieces. Knobs on each end of the jig secure the top in place.
An adjustable fence locks into T-track that’s recessed into the top of the jig. The fence allows me to position each workpiece to drill the first hole. I use a spacer block between the fence and workpiece for additional holes. The drawings here give all the details on how to build it. You may need to make some modifications to fit your lathe, though. Once the jig is built, it really is a significant time-saver.
