Hidden Tang Construction: Plugged

Hidden Tang Construction: Plugged

As with the pinned and through tang construction, the hidden plug method is solid, yet allows a little visual creativity if you like. The idea is to bolt the handle to the tang, then plug the hole where the nut is. This is the basic construction outline.

As with other construction methods it's extremely important that the tang is tapered in both dimensions. It is also very important that the shoulders are square and lined up. This is to ensure a good fit at the bolster.

Squaring the shoulder sharp means a clean fit to the bolster.

Fitting the Bolster

Marking out the bolster.
Punch and drill a series of small holes. As I normally make thinner blades I drilled these to 3/32".
Using a needle file I remove the material between the holes and make a slot.
This slot needs to be carefully made so as not to make it too wide. This would leave a gap between the bolster and the blade when assembled. This is the hardest part of the procedure.
We want the slot to be about 10 thousandth smaller than the shoulder.
Some simple hardwood "jaws" hold the blade when test fitting the bolster. You can slip a piece of pipe over the tang and gently tap the two together with hammer.
As the bolster nears the shoulders the gap should ideally disappear.

A tang screw needs to be fashioned to set into the hole/slot at the rear of the tang. I use stainless steel screws, usually 10-32, 10-24 or 8-32 and shape the head into a puck shape that fits into the tang and does not rotate.

Making the Nut

I found that the diameter of a regular hex nut is quite large and I'd like something smaller to fit in a smaller hole and have a smaller plug. I have some 1/4" brass round that I drilled out the center of.

The hole diameter will depend on your tang screw. For example 9/64" for an 8-32 tang screw.

Carefully tap the hole. I use some cutting fluid and tap by hand. One tapped, clean the threads and run a screw through it.

In one end of the "nut" cut a slot with a band saw or hack saw. This will allow you to tighten it on the tang screw with a regular screw driver.
In the rear of the block I use a Forstner bit to make a 3/8" hole. Forstner bits have the benefit of making flat bottom holes.

Here I am test fitting the tang screw and nut. At this point you can determine if you need to cut the tang screw shorted to fit correctly. If the tang screw is too long you won't be able to get your screwdriver properly on the nut to tighten.

Making the Plug

I made a screw to hold the plug material for turning. A wood screw with the head cut off works fine. The material needs to be at least 1/2" longer than the plug you want to make. Drill a small hole about 1/2" deep and thread the screw in.

Now you can chuck the material and make it round on the belt sander. The drill spins the material as it's shaped. Taper the plug and test it in the hole. It should fit snug and go into the handle block at least 1/4".
Here's the back end parts. I used a washer to help the fit inside the hole.
These are the handle components in order, less the bolster as it's on the knife already. Mix about a tablespoon of quality epoxy and coat the pieces as you slide them on the tang. Apply plenty of epoxy inside the block. Slip the washer and nut and tighten with a screwdriver. It's one big epoxy mess at this point.
Goop some epoxy in the hole and around the plug. A couple of gentle taps with a mallet will set the plug in place.
Once the epoxy is set you can trim or grind the plug flush to the end the handle. You can go about shaping your hand as usual.
When finishing the handle it's important to know how much you can take off the back. If you go too far you will expose the end of the plug or possible the nut.
You can see how the plug adds a little contrast and visual interest to the rear of the handle. I make plug from stabilized wood scraps, micarta and brass if additional weight is needed at the back end for improving balance.

Best wishes,


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