Longerons

I am getting ready to start the longerons and purchased the dies. I cannot seem to find a video on how they work. Does anyone know where there might be one.

I bought some regular angle aluminum to practice on before I take the plunge. Any advice will be considered.


Thanks

Don
Tail done
Renewing this week

My experiences

dsm8 said:

I am getting ready to start the longerons and purchased the dies. I cannot seem to find a video on how they work. Does anyone know where there might be one.

I bought some regular angle aluminum to practice on before I take the plunge. Any advice will be considered.


Thanks

Don
Tail done
Renewing this week

Click to expand...

I'm not aware of any video on the use of the dies.
My recollections:

1) Use a large (5 to 6") vise. I used a 4" vise, and found it wasn't quite tough enough--you really have to do some serious tighening of the vise
2) Move the dies about two inches between squeezes.
3) It takes multple passes along the length of the longeron to get the curve to match that of the sheet metal you are matching the curve to.
3) I used a bit of lubricant on the dies to ease romoval--the horizontal side of the longeron is being shrunk by the dies, so it gets progressively tighter.
4) I still had a difficult time getting enough bend with the dies, and ended up putting a layer or two of tape on the dies to effectively increase the radius of the bend.
5) I sold my dies to another builder, who found that his aluminum angle was a slightly thicker gauge, and the dies would not work without some re-machining. Hopefully your dies are large enough for the angle.
6. After getting the bend done properly, you need to open up the angle on the forward ends. Using the vise to squeeze things open was futile. Using the remaining length of angle on top of the longeron to minimize damage, an anvil, and about a three-pound equalizer (sledge) seemed to do the trick.
6. The first longeron took me a few hours to massage into shape. The second one was completed in about 20 minutes--must of learned something that I've now forgotten along the way

Did mine with the dies and a HF 6" vise about a month ago and all went well. PM me if you would like to talk specifics. I would be happy to talk with you on the phone.

I did pretty much ditto what Rob and Jerry said ? except for Rob?s step six. Based on a suggestion from Joe in Michigan, to open up the end of the longeron I used a pipe coupler placed between the angle and the vice (think it was a coupler for 1"pipe). It opened the angle quite nicely ? just make sure you feather out the relaxing of the angle as you move aft so you end up with a nice transition.

Happy Building,

See http://www.vansairforce.com/community/showthread.php?t=69024
Didn't use the dies but info about the angle.

ditto Rob's suggestions - especially about the 4" vice not doing a good enough job.

I made my marks at 1 inch a spacing. I wasn't smart enough to get something to practice on so I ended up ordering more longerons (it can't hurt anyway).

I might think about using an arbor for the spreading (greater than 90 degree angle), since I have one now. You'll find the arbor works well when putting the brass inserts into the brake lines down the road...

I ended up using a pipe inside of the bend of the angle and squeezing it in the vice to open it up. It still wasn't easy. It was easier than my first try with a hammer...

I used painters tape on the angle to keep it from getting marked up during the process.

My third and fourth longeron went much quicker

Bob

Longeron

Thanks for all the advice. Will start tomorrow

I agree with all of the above recommendations. One additional nugget I found helpful was to ensure a consistent bend radius for each pass. I did this by turning the vice handle to the same position every time I set the bend, say 3 o'clock. I would check the bend against the template. If I needed more bend, I would tighten to 5 or 6 o'clock for each position on the next pass. If I remember correctly, the first longeron took 7 or so passes. After the learning curve the second one was much quicker.

Brian