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  #1  
Old 08-31-2009, 06:35 PM
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jhnarial jhnarial is offline
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Default Who prefers tuck shrinking?

For those of you who know me, I decided that I preferred stump shrinking over tuck shrinking. Never the less I have practiced both methods.

Tonight when I got home, I thought hell I'm going to clean the shop (it's a mess ). Then I noticed my tucking forks were getting all rusty. So I sprayed it down and sanded the rust off. Then I noticed a piece of scrap metal,so I figured might as well get some practice in and tuck shrink the edge and snap a few photos. Really I was just trying to talk myself out of cleaning the shop

I don't tuck shrink very often and what I realized is, that it's because it's so much more work than stump shrinking.

I have to work the tucks inside out, I would prefer to work them from the outside but I just don't have a post dolly good enough for it.

quill holder 131.jpg

quill holder 132.jpg

quill holder 133.jpg

quill holder 139.jpg

quill holder 141.jpg

quill holder 142.jpg

That was one round of tuck shrinking. I could have cleaned it up but what's the point.

What I do when I tuck shrink is, I start from the rear and work my way forward. I take swift hits alternating sides to I reach the mouth of the tuck. I have tried it several different ways but this seems to work the best for me.

So what I am curious about is, who prefers tuck shrinking? Also how do you tuck shrink?
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Last edited by jhnarial; 08-31-2009 at 06:45 PM.
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Old 08-31-2009, 09:26 PM
fordguyfordman fordguyfordman is offline
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Myself, I preferr stump shrinking. I also started out tuck shrinking, even made a few forks for good friends.
Then I ended up making a stump, laminated hardwood. Wow was that a lot easier and faster.
One thing about the forks thou. They are a lot quieter than my stump.
Tom
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  #3  
Old 08-31-2009, 09:37 PM
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Kerry Pinkerton Kerry Pinkerton is offline
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I do both. When I want a shrink in a particular spot...especially a deep shrink, I'll do the tuck by hand.

I still have trouble shrinking as deep with the stump/tuck puck as I can get with the tucking forks.

That said, I don't use manual methods much any more. It's not that they don't work as well, or even sometimes easier, than the kick shrinkers or thumbnail machines but my arthritis talks to me if I swing a hammer too much. Getting old is a bitch!
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Old 08-31-2009, 10:08 PM
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I guess I still do both too.Even when I stump shrink,I don't like shrinking all the way to the end of an edge.When I do it just folds over,so on the end I put one or two tucks.

I'm hoping when I get my machine done I will retire my stump Kerry.

Kerry to shrink deep into a panels stump shrinking,I vision the area I want to shrink as if it were a pie shape.Then work that pie shape starting from the point working outward towards the mouth and it usually pops out a few tucks at the end.

You gave me the advice on the pie shape at the Aprils fool meet and I have been using it ever since.

It's the same with thumbnail shrinking right?
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Old 08-31-2009, 10:16 PM
Barry Barry is offline
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Both as well for me. Like Kerry I find tuck shrinking better when I need the shrink in a specific spot. I have the option of the thumbnails in the Nibbler, but sometimes it's a PITA to put them in for a small amount of shrink.

The tuck shrinking method I prefer is from the outside in, using the Captain Kirk style hammer. I find this to be very controlable and have less issues with the tuck escaping this way.
My personal nemesis with shrinking (both tuck and machine) is the bubble (or high) that I tend to have showing up inboard of the shrink. Getting this shrunk down or blended always seems to be an issue. I am sure it is something to do with technique but I can never seem to eliminate it - some days are just better than others. No amount of alternating short & long seems to help......
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Old 08-31-2009, 10:28 PM
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Barry

I work on the inboard areas first.I don't try to smash them out with one blow I try to work them toward the tuck.

I went to a class and Jim showed me how to do it but he made it look easy.His hammer control was really good.He nibbles at the tuck until he works out the tuck.You can actually feel heat in the tuck when he is done.He was able to get a lot of shrink with each tuck,Way more then I ever got.

His method was the same as Kirks same hammer and all.
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Old 08-31-2009, 10:52 PM
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Will give it a try & report back - thanks Johnny!
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Old 08-31-2009, 10:55 PM
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All I know about tuck shrinking I learned from Wray, Randy, Kerry and John Kelly. I use a bit of John Kelly's technique added to what I was taught. I usually use a body hammer to trap the open end of the tuck, by working it closed from outside in, then grab a bfh and smash it down.

The stump is a lot quicker, but there are times and places that the stump just doesn't quite do it.

I'm also in the same boat as Kerry. Not arthritis, but I have some issues with my right hand that make hand hammering an experience, to be sure. I shrink with machines most of the time, but I find it a good reminder not to lose touch with the manual techniques. I think it serves to remind you exactly what is happening to the metal.

Hey John, Jim who?

Tim D.
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Old 09-03-2009, 08:15 AM
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Kerry Pinkerton Kerry Pinkerton is offline
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OK, I'm confused Tim...I wrote:

Quote:
Originally Posted by Kerry Pinkerton View Post
I agree. Anytime you hit a panel, you're pushing the metal in the path of least resistance. If you're over a hole in a stump, the subsequent stretch is what causes the tuck to form, which can then be shrunk. Since most panels are made by both stretching and shrinking it works fine.
Then you said...(Pulled from a couple posts here)

Quote:
Originally Posted by tdoty View Post
...I disagree with that and have for a long time.
......

I still contend that stretching does NOT cause tucks or ruffles to form - drawing causes that. You mught get some stretch during the drawing, but the stretching doesn't cause the tucks to form.

Almost any form of shrinking will have some stretch to go along with it. Planishing out those shrinks will definitely have a bit of stretch to go with it.

Tim D.
Are we debating semantics here?

If I changed this phrase:
Quote:
the subsequent stretch is what causes the tuck to form
to this:
Quote:
the subsequent movement of the metal is what causes the tuck to form.
would you still disagree?

Or perhaps this:
Quote:
the subsequent increase in surface area in the impact zone is what causes the tuck to form
I'll agree that at a deeper 'physics' level, there is both stretching (thinnng) and drawing (pulling from surrounding metal) going on during the impact. Usually, I'll describe the process as 'stretching' to keep things simple and, at the end of the day, the result of a hammer blow over an unsupported area is a thinning of the metal and an increase in surface area which is generally called a 'stretch'. Right??
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Old 09-03-2009, 09:34 AM
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Quote:
Originally Posted by Kerry Pinkerton View Post
If I changed this phrase:

to this:
Quote:
the subsequent movement of the metal is what causes the tuck to form.
I'll agree that at a deeper 'physics' level, there is both stretching (thinnng) and drawing (pulling from surrounding metal) going on during the impact. Usually, I'll describe the process as 'stretching' to keep things simple and, at the end of the day, the result of a hammer blow over an unsupported area is a thinning of the metal and an increase in surface area which is generally called a 'stretch'. Right??
There we go! A lot of what is referred to as stretching involves very little stretch and a lot of drawing.

Marty's rubber die example where "the outer edges hold the material while the center stretches to the form of the die" is stretching. There is some drawing likely to occur to, since the rubber die can only hold the metal with so much resistance to movement - it will still slide.

A hammer with a high crown (small radius) will stretch more usually than a low crown (large radius) hammer. The higher psi = more movement at the point of impact and less movement of the surrounding metal.

What you have said, Kerry, more closely reflects my way of thinking. Tuck shrinking involves moving the metal to form the tuck. Forming the tuck moves the metal by drawing from other parts of the panel, though the surface area stays basically the same. The same thing can be done working in the hollow of a stump. Working the resulting tucks - formed by either method - changes the surface area and is indeed shrinking.

Does wheeling cause stretching? I would say yes, even though it is actually thinning the metal where the wheels meet and pushing the resulting excess metal out from the point of contact into the surrounding area. If you form a bowl purely by stretching in the wheel, how many sympathetic tucks or ruffles are formed along the edge? That is one example of why I say stretching does NOT cause tucks to form.

Another example would be to bolt a ring around a hollow (stump or whatever) to keep the metal from moving and push the center of the panel into the hoolow. Most of what is happening is stretching, though you will get some draw from below the surface. If you were to loosen the holding ring and perform the same operation, you would get a lot of drawing and not much shrinking.

I wish I could explain the rest of it. Everytime I try to put it into words without visual aids, it takes a few thousand words to explain what I could say in 3 or 4 pictures. Since I live in one place, do my sheetmetal work in another and my stump is currently in yet another place, it is surprisingly difficult to put everything together to do a photo session.

Maybe it is all semantics, but semantics are the road to universal understanding - or a universal misunderstanding It is not always the tools that you use, but the way that you use them that decides the results.

Tim D.
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