Help shrinking tucks!

[Foamcar]

I made a tucking tool out of some bolt cutters by welding 2 rods on one side and one rod between the 2 on the other side. I am trying to make a part that has a slight arc to it and a double flange. After putting the first flange in, and tucking this flange I can get the desired arc. But, I am not able to properly shrink the tucks. I have tried at room temp and also heating the tucks red hot, but the arc just flattens back out, which I assume means I am not shrinking at all. Looked at Bill Gibson's great video I see he clamps on both sides of the tuck. Is this necessary in order to get the shrink. I am hammering on free metal. This is a 20 ga. partch where the rear quarter meets the door lock pillar, so there is a slight vertical arc on the outer surface. If I need to clamp, then I assume I just do one tuck, shrink, another tuck, shrink, etc. Could have had this thing cut and welded by now, but am trying to learn to do it the "right" way. Thanks

[larry mullen]

Foam car , Try putting more of a peak in each tuck . If you can get some arc in your angle , you could clamp to flat stock to help the shrinking process. Just takes some practice .
Larry mullen

[oldgoaly]

Just a little more "V" in the tuck, your real close! just don't hit it too hard!

[Bill Gibson]

Clamping isn't Neccessary.. but you need to get the sides of the tucks steeper than you have them. The object is to drive the metal back into itself. So the closer you can get the sides to straight up, without folding them over the better. That way when you hammer down on the top of the tuck the parts that are vertical, (or in other words standing on edge) will get shorter and thicker.
Clamping the sheet just makes the process faster and more consistant.
also if you are using a steel hammer and backingit up with steel it is easy to hit too hard as Terry said. If you do that you will stretch any shrink that you put in it. Try using a wodden mallet. Then after you get that down, you can try a steel hammer....

[Foamcar]

Thanks for the great tips. After my original post I went back out to the shop and tried clamping the metal down and that did not help much. I think(hope) the deeper tuck will do the trick. I did see those in Bill's video. The reason I did not go deeper is that I already had the correct arc on the part. Guess I will have to over arc it, then do some stretching after shrinking the tuck. Or, make a new tucking tool with smaller diameter rods. Done for today, so will try tomorrow and report back. I don't have any wooden hammers, but think I can go easy with my steel one.

[worntorn]

I made a leather slapper for this similar to the one I same in Ron Fournier's video. Works like magic.

It's just a piece of thick leather wrapped around some maple hardwood. I'll take a photo of it and post it. Took about 15 minutes to make.

Glen

[Foamcar]

Finally found the great discussion on tucking that my previous searches did not pull up:
http://www.metalmeet.com/forum/showt...t=tucking+tool

Wray says you need 70 degree tuck wall. Also, my tool made from a bolt cutter does not make a cone shaped tuck, it makes a semi cylindrical shape. Will this be a problem? I may be able to rework the shape with a file, if so.

[Dawai]

Wray would know.

http://www.youtube.com/watch?v=HyTl10E_tSs
I love to play with "things". Looking for the magic bullet to solve a issue. My shoulders are wore out so I hate hammering and taking pain meds.. so.. I tried to invent a new method.. Still working on it.

I've still not found the Holy grail of tuck shrinking.
For that part you got making there, a lancaster type shrinker would do it in a few minutes.. The teeth mark it up pretty bad tho..

[jlrussell4]

The reason I did not go deeper is that I already had the correct arc on the part. Guess I will have to over arc it, then do some stretching after shrinking the tuck

You will have to over arc it. When you planish the shrunk area you will stretch it. You will probably have to shrink and planish several times get the proper arc. Planishing will also relieve the tension you put in shrinking with the tucks making the next round of shrinking easy again.

[worntorn]

Just realized that you are working with steel, Im doing tucks in annealed 3003 al.

IM a novice too, but the tucks have been easy enough to deal with in al. with the leather and wood tool.
For steel you may be better off with a ball peen hammer, seems from reading the old threads the experienced fellows are using a ball peen in some form for flattening the tucks.

Wouldnt want to send you down the wrong path with my teeny bit of newfound metalshaping knowledge!


Glen