Jointing Mandolin and Archtop wedges

[Duct Tape]

I've been reading many of the posts on the "Builders" thread, now on page 309 and came across this one about jointing

https://www.mandolincafe.com/forum/s...-jointer/page2

My question, which I perhaps missed in the first 308 pages is, how do you joint, either by hand plane or jointer, two plates which are already wedge shaped? Some type of spacer b/w them, which would require some trial and error for each set of plates to get the edges to 90?

Thx

Jon

[Bill McCall]

Presumably one surface of the wedge is flat, and has the grain perpendicular to it. Pretty straight ahead, unless I'm missing .

But if the wood was split, and you don't have a flat surface, you'll have to face one surface to get there.

[sunburst]

I'm not sure I fully understand what you are asking, but there are lots of ways to establish a 90 degree angle.
If using a jointer, I determine my book match and establish one flat surface on each piece accordingly (as Bill suggests), then register that surface against the jointer fence. A well set-up jointer, used properly, will then produce edges 90 degrees to those two flat surfaces.
Using a hand plane it's about the same procedure. Establish a flat surface on each piece then plane an edge 90 degrees to that surface. I do that either by "shooting" or by simply planing the edge and checking with a machinists square.

[Mike Conner]

Jon,

There is an older school way of jointing plates with a hand plane:

First, I remove the extra material of the wedge by ripping on the tablesaw, leaving about a 3/4" thickess.

Then, clamp the two plates together with the face side out. In the case of wedges, I put the resawn surface in and the wedge surface out (these are archtop guitar plates):



I plane the edge with a Stanley #6 set for a very light cut. It takes a little practice to have a nice even stroke and follow through to keep the joint true. The reason this works well is that even if you are a little off of 90 degrees to the face, the errors cancel when the plates are met. You check the joint in the usual way - "candle" by holding together in front of a light and look for gaps.

Once satisfied, I have a simple platform made from framing lumber to support for clamping:


I do the back plates the same way. I have done this for many years building furniture and it works really well for me. I really like the shooting board concept, and if I was working wth thin resawn flattop instrument plates I would definately construct one.

The Stanley #6 plane was inherited from my Grandpa and definately in "user" condition. Gives me a smile every time I use it.

[edit] just looked at Jon's link in the original post. Descriptions of the same process I show above. I feel even better about it now
//mike

[Duct Tape]

Thanks for the helpful replies. I am referring to wedges but seems like I can find a 90 on my jointer as John notes, as long as I don't take too much off since wedges aren't too oversized. Once there I'll likely hand plane to final if I don't get there just on the jointer.

Best to all.

[sunburst]

That what I usually do; square them up on the jointer and refine the joint with a plane (#7).