scratch builder question

[sonex 1614]

I am cutting some forms for bending various parts. What radius' did you use? so far I found 1/8, 1/4, 1/2".

[falvarez]

If you are talking about aluminum plate (i.e. 1/8" and 3/16"), I used the Arbor Press with a v-block and a small piece of 1" pipe. I think there is an EAA Hint For Homebuilders video showing the technique...if you can't find it let me know and I'll post a link.

In the case where the piece was too small for the v-block, I just put it in a vice (with aluminum protecting the jaws) and hit it with a rubber mallet.

With these two techniques, I was able to pretty much bend all the metal for the project to a fairly accurate degree.

If you were asking about the thin sheets being formed over wood blocks, I just barely rounded the wood block off (maybe 1/16" radius).

[sonex 1614]

There were some clips made of .060 aluminum that called for a 1/8 radius. And a few other thicker parts like you mentioned. I know some builders have made hardwood blocks to make the radius of the .060 and thicker material so they had a nice consistent bend to form the part. I am a new builder so it is all a learning experience for me. I greatly appreciate the help and advice!

[falvarez]

I agree that on the .060 that the blocks should help you achieve a good radius. I was able to bend the .060 on a small 24" brake so for that I used the technique where you add extra sheets of metal to the bend to give you the radius that you need. But a wood block would have worked just as well....and may have been easier.
You can never have too many tools and tricks at your disposal when building :D

Also, I am continued to be amazed at some of the things builders come up with...there a times when it just seems too difficult to form a part or mount something....then read through other builder sites and see some creative way that makes it simple...its also a great way to get a visual queue for whatever parts you are building before you actually attempt it. I think the Sonex Foundation guys have pulled together a pretty comprehensive list of these sites.

[Bryan Cotton]

A rule of thumb is the radius of the bend should be at least 4 times the thickness.
Bryan

[sonex 1614]

Thanks for the replies.All great info!

[sonex892]

I found this page on the Aircraft Spruce website which may help answer your question

http://www.aircraftspruce.com/catalog/p ... malloy.pdf

Steve
Sonex 892

[dcstrng]

I found this page on the Aircraft Spruce

Super table... thanks for posting...

[EricS]

A very useful tool to have around the shop is AC43.13 1b/2b. For those not familiar, it's basically the mechanic's bible for standard practices. If you've got questions about hardware, cables, sheet metal, fluid lines, etc, this will guide you in the right direction.

Aircraft Spruce has them available for $20. http://www.aircraftspruce.com/catalog/bvpages/ac4313act.php

[sonex 1614]

Thanks guys!