MIMF

When I make braces I like to use my table saw for making the top braces. I have a slick jig for cutting in the top radius. The first thing I do is to size the stock. I do this by ripping the spruce on the band saw then using a thickness sander, You can rip your stock out any way that gets you good results. When ripping on a table saw THINK SAFETY. Use feather boards and press sticks. Here is a pic of my set up

Once ripped and sized I will but the side angle using the same holding mechanisms. after the sides are rough shaped I cut the radius . I like to use a 28 foot radius and use this jig on my table saw.

End shaping can be done many ways. Here is my favorite

The final step is notching for the X lap joint. I figure the thickness of the saw kerf and make a stop block to work with my rib fence. This way I get a nice consistent fit. I use the miter gauge of the saw.

Nice photo essay John, thanks. Not sure I understand the second post where you say "Once ripped and sized I will but the side angle using the same holding mechanisms."

fat typers thumb

Once ripped and sized I put the angle on the sides of the braces using the same holding mechanism as in ripping. This roughs the shape to later final shaping.
Feel free to correct the post Charles .
thanks

Hi John, nice to see you back at MIMF. So, the jig for cutting the radius on the braces has stops or hold downs or something, that allows you to bend the brace at your desired curvature and hold it in that position while it is cut, and after it is released from the jig, it springs back, with a nice curve along one edge. Is that it? I believe I've seen a commercially available jig that works on the same principle. Do you glue the braces straight off the saw, or do you touch up the glue surface at all (plane / abrasive / other)?

The way I made this was to set 2 stops ( those are the dowels) Then I set up the clamping point with the toggle pad at the point of the X brace intersection. I then tweaked at this until I hit the curvature I was looking for , in this case 28 feet. I found this to be very repeatable. I use a Forrest brand blade and it cuts nice so I can glue right off the jig. After I set the curve I set a screw in for the upper stop. Now I have a set of braces that will match.
It took a while to dial in this jig but it was worth the effort. I have seen others that are commercially available. Use what works best for you.

John I'm not sure what you are doing in Photo 1 and 4, why is the brace clamped to the fence ?

that isn't a brace it is a hold down feather board to hold the braces to the top for sawing

John, is there a picture missing somewhere ?

I can certainly visualise how one could cut a 28' radius on a brace on the tablesaw (although personally I would do it on the router table) but all I see in these pics is the workpiece tight up against the fence, which isn't going to give a radiused cut.

What am I missing ...

router tables will work but the jig uses the flex in the wood. Look close at the stops on the jig. the spring on the radius relaxes and the arc is 28 foot. These jigs are actually common.
There are 2 dowels that spring the blank, the screw toggle is set to the X joint. There is a screw that is the stop for the upper bout section of the brace. This works very well.

Springing a straight stick of wood wil not give a uniform radius: the curve will be tighter in the middle than at the ends. It works OK to do this if the curve is not too great, but if you glue the braces up in a radius dish you'll be springing them a bit between the center and the edge. I know one local maker who does his braces this way, but he made his own dish by springing a piece of Masonite, or some such, with a screw in the center and the edge supported. This seems to give the same sort of curve, but you have to watch where you put the rim down when you fit it so that the high point comes out in the right place. All in all, I find a uniform radius easier to get my head around, and not much harder to make.

Alan Carruth / Luthierr

I assume that this is how the jig works - the straight brace is placed in the jig, then flexed against the dowels and up under the slot and held there with the screw. It's run through the saw, and when removed, springs back with a convex radius. This was not very clear to me from the photos.

Once a brace is glued to a plate it becomes a hydrometer and is constant flux with Rh. It is always best to true the radius to match a disk if you have one

I use a hydrometer to measure the sugar content, thus alcohol potential, of my homebrew, but I use a hygrometer to measure relative humidity....

Agree with Al. I've tried cutting a radius in braces by springing them(Dana Bourgeois showed us this technique some 15 years ago), but found it less than ideal, and also found that each brace differed depending on how stiff the bracewood is. As simple and quick as it is to radius a brace with a hand plane, why bother? See short video....

http://youtu.be/C2Qeh9vjrck

Mario Proulx wrote:I use a hydrometer to measure the sugar content, thus alcohol potential, of my homebrew, but I use a hygrometer to measure relative humidity....

Agree with Al. I've tried cutting a radius in braces by springing them(Dana Bourgeois showed us this technique some 15 years ago), but found it less than ideal, and also found that each brace differed depending on how stiff the bracewood is. As simple and quick as it is to radius a brace with a hand plane, why bother? See short video....

http://youtu.be/C2Qeh9vjrck

Did you just use an emoticon.... Don't poke a sleeping bear right oh sorry <BG>

OK, On track. John, nice to see you back at the MIMF. Thanks for posting your method.

Did you just use an emoticon...

Only when they're called for.

I'm assuming that a simple "<g>" will be lost on all the unwashed that will now flock to the new forum.....

; )

Love this place!!