metal stretcher & shrinker
 

Hello all,

I just bought a set of tools consisting of a metal stretcher and a
shrinker. They work unbelievably well. The problem is they leave marks on
the metal due to serations on the jaws. I was wondering if anyone has a
stretcher/shrinker with smooth jaws, and how well it works. I could grind
off the serations and if I lost 3/4 of the ability to stretch/shrink, it
would still be acceptable since it works so great now. But if they don't
work at all with smooth jaws, I won't bother.

Thanks,

Bill Chernoff

Those marks are what does the work. Without them no shrinking or
stretching happen because the steel cannot be held solid enough to be
formed.

--
Steve W.


"Bill Chernoff" wrote in message
news:IjXve.1814988$6l.1322410@pd7tw2no...
Hello all,

I just bought a set of tools consisting of a metal stretcher and a
shrinker. They work unbelievably well. The problem is they leave
marks on
the metal due to serations on the jaws. I was wondering if anyone has
a
stretcher/shrinker with smooth jaws, and how well it works. I could
grind
off the serations and if I lost 3/4 of the ability to stretch/shrink,
it
would still be acceptable since it works so great now. But if they
don't
work at all with smooth jaws, I won't bother.

Thanks,

Bill Chernoff





----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==----
http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups
----= East and West-Coast Server Farms - Total Privacy via Encryption =----

Bill Chernoff wrote:
Hello all,

I just bought a set of tools consisting of a metal stretcher and a
shrinker. They work unbelievably well. The problem is they leave marks on
the metal due to serations on the jaws. I was wondering if anyone has a
stretcher/shrinker with smooth jaws, and how well it works. I could grind
off the serations and if I lost 3/4 of the ability to stretch/shrink, it
would still be acceptable since it works so great now. But if they don't
work at all with smooth jaws, I won't bother.

Thanks,

Bill Chernoff


I think it is the way they work. You jsut need to learn how to do bodywork.

Photos would be great. I'll also take some of mine for interest's sake.

Bill

I have a set that was made by a company called DFS in the UK,
unfortunately not longer in business, but similar units are still
available I am told. What differentiates them from the cheaper units
which are commonly available is a preload device that allows clamping
the metal prior to shrinking so the metal surface is relatively
undamaged. I got the set with medium serrations, coarse, fine, and epoxy
jaws for minimal marking were an option. I have done a back to back test
against some like those supplied by frost, eastwood etc and those are
brutal to the metal surface in comparison to the set I have. Let me know
if you want some pics in the dropbox I may be able to take some tomorrow.

Bill Chernoff wrote:

Hello all,

I just bought a set of tools consisting of a metal stretcher and a
shrinker. They work unbelievably well. The problem is they leave marks on
the metal due to serations on the jaws. I was wondering if anyone has a
stretcher/shrinker with smooth jaws, and how well it works. I could grind
off the serations and if I lost 3/4 of the ability to stretch/shrink, it
would still be acceptable since it works so great now. But if they don't
work at all with smooth jaws, I won't bother.

Thanks,

Bill Chernoff

Let me know if you need any more detail. I guess these unit are
comparable to the swiss Eckold units shown in Fournier. They were not
cheap compared to the ones commonly available.

http://metalworking.com/DropBox/dfsshrink.txt
http://metalworking.com/DropBox/dfsshrinkpatentpic.jpg
http://metalworking.com/DropBox/dfsshrinkside.jpg
http://metalworking.com/DropBox/dfsshrinktop.jpg

From the ideas shown it may be possible to improve the cheaper ones to
include this type of preload device. As you have a set you could see
what you reckon. I can dig out the rest of the patent if required and
post the angles given for the wedge and preload spring force tomorrow.

Bill Chernoff wrote:

Photos would be great. I'll also take some of mine for interest's sake.

Bill

With reference to the dfsshrinkpatentpic.jpg . The faces shown 15 have
an included angle of 136 degrees, the wedge 21 has an included angle of
20 degrees, and spring 22 is set to preload the wedge to 12 lbs when the
jaws are at rest. That info is from the patent spec.

David Billington wrote:

Let me know if you need any more detail. I guess these unit are
comparable to the swiss Eckold units shown in Fournier. They were not
cheap compared to the ones commonly available.

http://metalworking.com/DropBox/dfsshrink.txt
http://metalworking.com/DropBox/dfsshrinkpatentpic.jpg
http://metalworking.com/DropBox/dfsshrinkside.jpg
http://metalworking.com/DropBox/dfsshrinktop.jpg

From the ideas shown it may be possible to improve the cheaper ones to
include this type of preload device. As you have a set you could see
what you reckon. I can dig out the rest of the patent if required and
post the angles given for the wedge and preload spring force tomorrow.

Bill Chernoff wrote:

Photos would be great. I'll also take some of mine for interest's sake.

Bill

thanks for the info. The serations on your jaws look a lot finer and
smoother.

the photos of my test piece are in the drop box:
http://www.metalworking.com/DropBox/shrink-strech1.jpg
http://www.metalworking.com/DropBox/shrink-stretch2.jpg
http://www.metalworking.com/DropBox/...etch3_jaws.jpg
http://www.metalworking.com/DropBox/shrink-stretch4.txt

Nice curves!. Have you considered getting sponsored by the maker. I
didn't have any examples about at the time to add but could run some off
if you are interested. Most marking I have found is on Al but its not
much, its noticeable due to the marring of the surface. I did some SS
the other week and I couldn't see any surface marking corresponding to
the jaw pattern, only a surface change where the metal was shrunk.

I looked up the details of the jaws I got and the quoted thicknesses for
various materials are as follows.

Aluminium 12swg
Mild steel 14swg
Stainless steel 18swg
Nimonic 18swg
Titanium 20swg

Those are british gauge sizes and although similar to US are not quite
the same.

I look up "metal shrinking" on google and found the following

Probably like yours
http://www.irvansmith.com/catalog2/p...tretcher.shtml

Sit down before you look at the Eckold shrnker price.
http://www.irvansmith.com/catalog2/p...tretcher.shtml

Bill Chernoff wrote:

thanks for the info. The serations on your jaws look a lot finer and
smoother.

the photos of my test piece are in the drop box:
http://www.metalworking.com/DropBox/shrink-strech1.jpg
http://www.metalworking.com/DropBox/shrink-stretch2.jpg
http://www.metalworking.com/DropBox/...etch3_jaws.jpg
http://www.metalworking.com/DropBox/shrink-stretch4.txt

David,
Can you please post a link to the patent directly? Is there any
reference to the face serrations or head material in the patent?

It can be found at the european patent office site, this link should
take you straight to the patent

http://v3.espacenet.com/textdoc?DB=E...X=GB980790&F=0

The patent doesn't give detail of the serrations that I can find but the
makers leaflet I have says the following. "Teeth on the gripping
surfaces can be supplied in three grades, Standard, 50 TPI-, Fine teeth
80 TPI-, and very fine 100TPI, the later being used only where the
minimum marking of the metal is important", as well as an epoxy based
material.

wrote:

David,
Can you please post a link to the patent directly? Is there any
reference to the face serrations or head material in the patent?

Nice curves!. Have you considered getting sponsored by the maker.

HA! The piece in the photo was my very first try at it. Thats why I was so
impressed with the whole shrinking/stretching process.

I
didn't have any examples about at the time to add but could run some off
if you are interested.

No rush, but I would be interested in how smooth the surface finish is with
those smooth(er) jaws of yours.

Bill

ps I take it you are in the UK? gotta love the internet. I'm in western
Canada.

----- Original Message -----
From: "Bill Chernoff"
Newsgroups: rec.crafts.metalworking
Sent: Thursday, June 30, 2005 2:07 AM
Subject: metal stretcher & shrinker

No rush, but I would be interested in how smooth the surface finish is
with
those smooth(er) jaws of yours.

Bill

Hi Gents
You may already be aware, Kent White has some new jaws out that are a lot
smoother.
Have not seen them in the flesh.
https://www.tinmantech.com/html/lanc...l_stdjaws.html
All the best.

Peter E.
Newcastle - Australia