Scissor Jack

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Dan Erlewine demos the Scissor Jack, to simplify tricky repairs inside acoustic guitar bodies.

Video Transcription

[on-screen text reads: Stewart-MacDonald - Dan Erlewine]

Using the Scissor Jack

Dan Erlewine: I'm trying to glue a brace in here with one of these little prop sticks inside and press the brace shot when the glue's in there. And if they fall over during the work, it's bad and sometimes, you got to get five or six of them in there.

With this guitar cut in half, I can show you what I'm trying to do here. I'm trying to prop these braces tight using these little stick jacks for the pressure and you're working blind and then that's what happens.

Gluing braces

Here's the Scissor Jack. It makes those stick jacks obsolete, and with it, I can probably glue two braces at once even with a caul and sort of clamp in the center and get pressure on both ends.

The Scissor Jack comes with magnets. Now, if you screw one to each end, you can do this. You put a magnet on a little brace caul and you bring that in through the soundhole and come in from the outside with another magnet or, in this case, I've got two little magnets stacked up, and it'll hang right there waiting for you. So you can be very accurate and gentle with the pressure.

Jacking up the X-brace through the soundhole

The Scissor Jack comes with two magnets and brass mounting screws and a flexible extension. With the flexible extension, I can reach way back here. Right now, I'm on the main X-brace, jacking it up, and I'm not reaching through the soundhole, so my arm isn't in the way. I'm not fumbling, and I can see what I'm doing.

Routing a saddle slot

Here, I'm going through the soundhole with the extension to push the bridge back to where it was under string tension. I measured it with this dial indicator before I took off the strings, and now, I can push it back to zero and get ready to route a saddle slot for a transducer pickup.

Fingerboard extension support for fret work

Also, through the soundhole, I can use the jack to support the fingerboard extension when I'm fretting, make it solid.

Those are just a few of the ways that I use the scissor jack.



Dan Erlewine

Guitar Repairman and Builder