Multi-function Metal Machines

[Chris In Marshfield]

Hi all,

About to cut out and bend the ribs for my Bearhawk wings in the next week or so, and I know I'll have to, at some point shortly afterward, cut out the rib stiffeners and attach angles (90-degree strips riveted to the side of each rib). Just perusing one of my fellow builders' logs, and he had 370 of those little monsters made up at the time he created them. Since my building partner and I are building two of these aircraft, that'll make 740 of them, and wondered if a tool like this one would pay for itself in time saved for such an event:

http://www.grizzly.com/products/12-S...Machine/T21320
Of course, it'll be handy for plenty of other metal operations on the plane as well, and maybe its big brother, too:

http://www.grizzly.com/products/Shee...hine-30-/G4011

Any opinions on these devices?

~Chris

[corsair82pilot]

If it is just for two aircraft, it might be less expensive to get it done by a shop. Or if you have a local vocational school, they might do the bending and cutting for you.

[Tom Downey]

Hi all,

About to cut out and bend the ribs for my Bearhawk wings in the next week or so, and I know I'll have to, at some point shortly afterward, cut out the rib stiffeners and attach angles (90-degree strips riveted to the side of each rib). Just perusing one of my fellow builders' logs, and he had 370 of those little monsters made up at the time he created them. Since my building partner and I are building two of these aircraft, that'll make 740 of them, and wondered if a tool like this one would pay for itself in time saved for such an event:
http://www.grizzly.com/products/12-S...Machine/T21320

Of course, it'll be handy for plenty of other metal operations on the plane as well, and maybe its big brother, too:

http://www.grizzly.com/products/Shee...hine-30-/G4011

Any opinions on these devices?

~Chris

I have one of those Grizzly 3 way machines it is very handy, and will do most all light duty work of building aircraft.
3 things you need to do to one before you press any aluminum. polish the dies both the upper and lower they are pretty rough and scratch the aluminum. set the sheer clearance to cut soft material, it comes too loose and merely bends the sheet. and finally, adjust the rollers to give a true cylinder bend, it will produce a cone other wise.

I use mine a lot and it works well, but the local air-conditioning and ducting company will do the job cheaper than the cost of a 3 way sheet metal machine.

[DaveH]

Try your local EAA chapters, the two I have been to in my area(SE Michigan) have workshops and equipment for members to use.

[Chris In Marshfield]

Try your local EAA chapters, the two I have been to in my area(SE Michigan) have workshops and equipment for members to use.

Unfortunately, there aren't any in my chapter, and the next closest chapter is an hour away (although I haven't checked with anyone there). But being only a couple of hours away from Oshkosh, I'm not too far away from equipment if I need anything specialized.

I do plan to check with the maintenance shop at our FBO, though. They do have a couple of smaller metalworking machines. And there's no shortage of machine shops where I live, either, so I can go that route if I need to.

Appreciate the input :-)

~Chris

[messydeer]

I'm 95% through with scratch building my Sonex. As far as I understand it, the wings are similarly made, aluminum skin with one-piece ribs fore and aft of the main spar. Twice as many ribs as the Sonex, though. I made form blocks out of MDF, cut the blanks with snips, then took 4 or 5 at a time and used a router to cut the edges and lightening holes. Used dies to smash the flanges of the lightening holes. Made the rib flanges by hammering the edges against the form blocks.

I spent about 2 minutes going through several pages of Eric Newton's website, http://mybearhawk.com/ in the wing section and didn't see a slip roll or shear mentioned. What are other builders using? A long brake is definitely needed, but they are way expensive to just use it for a day or two. I'd guess that besides those few long bends for the spar you'd get by with a much smaller brake.

For me, making the ribs with the form blocks, dies, and router was fun. Deburring all the edges was the tedious part.

Dan

[Chris In Marshfield]

That's exactly how I'm planning to build mine: trace ribs, hand-cut with snips, route out the final shape and lightening holes, shape flanges around the forms. The use of the machine would be for cutting/bending straight pieces, such as the stiffening angles that each rib has, as well as any other accessory brackets, etc. that might come along later. I was looking for something that might cut down on the time required to do some of the ultra-repetitive tasks, like those stiffening angles. I get the feeling that I won't gain much.

I agree that a long brake is needed. The spars require an 8-foot brake. But I have access to one of those without having to buy one (pretty dang expensive, anyway).

Appreciate your input, Dan :-)

~Chris