Another Elevator Brake Question

[JoeG]

I'm off to Lowes in a few minutes to pick up the material for my 2x8 elevator skin bending brake. I plan to build it and use it today.

I'm trying to figue out if I need any spacing between the two boards when I hinge them together, Or do I just stack the boards and attach the hinges at one side?

I have read that some folks use a 1/8 inch dowel. Others have positioned the trailing edge of the skin against the hinges before the fold. Seems like there must be some space between the hinge edge of the boards to allow this to happen.

I'm sure, that like many parts of this project, this will take less time to actually do than I have put into contemplating doing it. I guess that's what they call the "learning curve". I'm already fretting about the trime tab folds...

Thanks in advance for your comments and pictures.

 

[hevansrv7a]

Yes you need a spacer

I borrowed mine, but I do remember it. You need a spacer or some spacers to keep the vertex of the aluminum out of the vertex of the hinged angle. If not, you'd make the radius of the bend too sharp. Given that there is a spacer in place, you need to ensure that the metal will not slip away from the vertex as pressure is increased. A few side clamps outside the width of the brake will do it. Good luck.

 

[rickmellor]

Didn't use a spacer

I just set the boards on top of each other and screwed the hinges on. I controlled the angle of the bend by varying the distance from the hinges to the trailing edge. It worked well and the bend radius is spot on.

-Rick

 

[RV8N]

Just use your hand seamer

I built and used the wooden bending brake on my first couple of control surfaces but wasn't happy with the bends. The brake also didn't fold the skins enough. I had to figure out a way to finish the bends. I took my hand seamer and opened it up until it would barely compress the skins. Start at one end of the bend and work your way to the other end, overlapping your compressions as you go. When you finish, tighten the screw a little and do it again. Repeat until you have the skin bent to exactly the right amount.

I much prefer this method and have not used the wooden brake since discovering it. I have always had perfect bends.

Karl

 

[osxuser]

I assume you have a vise grip hand seamer from your description? Mines just a pair of plyers, and i'm getting to this point soon (as soon as I start construction back up...

 

[RV8N]

I assume you have a vise grip hand seamer from your description? Mines just a pair of plyers, and i'm getting to this point soon (as soon as I start construction back up...

Yep, Avery's vise grip hand seamer.

Karl

 

[JoeG]

Success!

Here's a shot of the finished bend...

http://img183.imageshack.us/img183/662/dsc0502wo2.jpg

The whole bend process took about 10 seconds once everything was set up. Kinda anti-climatic... but in a good way! I'm curious if you experienced builders think the bend looks adequate. Everything came out straight, but I want to make sure I have the proper radius.

Here's a tip. I was concerned about the skin sliding out of the brake once under pressure. I actually bought some double-sided tape in anticipation of this happening. But when it came time to make the bend, I realized that the tape was not necessary. I didn't use any clamps either. The friction of the blue film against the lumber held everything in place. Yet another reason for leaving the film on the skin as long as possible.

Once again another "difficult" task accomplished without incident. Good judgment on my part I'm sure . Of course, what is it they say, good judgment comes from experience.... which comes from bad judgment!

The best judgement in this case was reading these awesome forums and checking out some of the various builder sites ahead of time. It made this task a triviality.

 

[AltonD]

When I bent my first elevator, I agonized over this. I didn?t want to over bend them. I put the skin ~1/2 way in the brake and pressed, removed, cleco?d up the elevator, then fussed over it for two days. Un-cleco, repeat, with the skin a little further back in the brake. Cleco back up and fuss some more. Finally, I took it back apart, stuck it in the brake, all the way to butt up against the hinge, made a quick downward movement till the stiffners bottomed out, Perfect. It looks just like yours. The second one was much easier: Stick it in the brake, bottom it out, done.