Lennox (pullmax) shrinking problems

[suhrsc]

Hello,
I was hoping someone might be able to help me get these dies figured out.

I recently bought a Lennox Tru-edge machine and it came with a set of shrinking dies.

I have been trying to get them set up.
It seems no matter where I place them in relationship to each other I am getting tooling marks on the aluminum I am working with.

I tried to polish off the dies a bit more then they were but I don't want to remove any material that might be necessary for them to actually work.

The major lines are on the top of the metal on the back of the upper die... on either side of the recess.... there is a bit of a tighter radius at this point which I believe is causing it... but I don't want to take it away too much as it seems thats where the compression is happening to actually gather the metal?

Here are a few photos of the dies.

Does anyone have any insight?
or photos of your dies that work well?

These do actually work to shrink the metal and after rolling in the English wheel I got a nice blended shrink but the tooling marks are still there, which will cause problems if it is needed to leave a part in bare metal.

thank you
Zach

http://i673.photobucket.com/albums/vv100/zachsuhr/metal%20shaping/lennoxside.jpg
http://i673.photobucket.com/albums/vv100/zachsuhr/metal%20shaping/IMG_9975.jpg
http://i673.photobucket.com/albums/vv100/zachsuhr/metal%20shaping/IMG_9976.jpg
http://i673.photobucket.com/albums/vv100/zachsuhr/metal%20shaping/IMG_9985.jpg
http://i673.photobucket.com/albums/vv100/zachsuhr/metal%20shaping/IMG_9977.jpg
http://i673.photobucket.com/albums/vv100/zachsuhr/metal%20shaping/IMG_9978.jpg
http://i673.photobucket.com/albums/vv100/zachsuhr/metal%20shaping/IMG_9979.jpg
http://i673.photobucket.com/albums/vv100/zachsuhr/metal%20shaping/IMG_9980.jpg
http://i673.photobucket.com/albums/vv100/zachsuhr/metal%20shaping/IMG_9981.jpg
http://i673.photobucket.com/albums/vv100/zachsuhr/metal%20shaping/IMG_9982.jpg
http://i673.photobucket.com/albums/vv100/zachsuhr/metal%20shaping/IMG_9983.jpg
http://i673.photobucket.com/albums/vv100/zachsuhr/metal%20shaping/IMG_9984.jpg

[BarryA]

Hey Zach

There will always be a trade-off: Aggresive shrink vs. Marking. Blending and polishing may help to some degree. You may not entirely resolve the issue though. And lose the efficacy of the dies.
You don't show the marking. Others could give their input on how yours compares.

That said there is a vendor (Clay Cook?) offering phenolic thumbnail dies for aluminium. I'm guessing for just this reason...

[jlrussell4]

Stan Fulton also offers a plastic die set to lessen the markings.

[suhrsc]

Thank you Barry and Jim
I forgot to take a photo of the aluminum last night... and posted this morning from work

I was thinking that your reply might be the answer.... dealing with the marks related to the the amount of work going on...

I will have to look into the softer dies if it poses too much of a problem... Just got the machine running over the weeked... so haven't spent a ton of time yet

Thanks!
Zach

[Pete's Metalshaping]

Do you know who's dies they are? It looks like they have quite a few marks on them from someone trying to clean them up. There is such a thing as tuning these dies; which would involve figuring out where the contact points are.

[Rick (madera)]

It looks to me that you don't have enough clearence on the upper die above the thumb. The material should not touch the upper at that area.
good luck

[suhrsc]

thanks
I have no idea who made them

The marks on them are from me cleaning them up with a scotchbrite pad ... they were a bit rusty when i got them... its more of a brushed finish on the dies... I figured I would polish them up once I got the shape tuned in better

the marks im getting on the metal are not from that though.... the metal is getting gouges in it...

Rick, I see what your saying... maybe I need to grind a bit deeper there
I am actually getting gouge marks on the inside(bottom of panel) also, right in the center...

should the contact area be U shaped or just a flat behind the male and female shapes?

thanks!
Zach

[Pete's Metalshaping]

Zach,

Do you have any pictures of what the metal looks like after it has been through the dies?

[Pedalcar]

I am with Rick

Ben

[Overkill]

I find that the relationship of the surfaces to be fairly critical. The best way I've found to find out exactly what is happening is with clay. I use the kids stuff, Play Doh, which I keep around this type stuff.

Put the dies in the machine, clay between them, and run the machine over by hand. Coating the top die with WD40 will keep clay from sticking to the top. Then take a razor and slice the clay up to see what the clearances actually are. Perhaps you need to move the bottom die in or out. Perhaps you have to grind on them, it will give you an accurate read on what's going on vs holding them in your hand where the relationship isn't really showing.

I find the base of the thumbnail to be critical, as well as the 'smile' which actually does the shrinking. If the area right at the base is too tight, it will make all sorts of trouble.

Afterwards, totally clean the dies and oil. Some clays have salt in them and you don't need the rust issue.

[suhrsc]

Thanks everyone
I will take photos of the actual metal tonight...

and give the clay/playdough a try too if I have time

thanks
zach

[oldgoaly]

Zach,
I've seen a few problems over the years, one thing some people do is run the dies too tight, what gauge are you using and what gap between the dies? If you have .063, the gap has to be greater than .063, around .070 is good, remember the metal get thicker when shrunk! Another important step, some dies were designed to be set up with the rear of the dies flush, some others are not! Try starting out with lower die a 1/8" out the back farther than the upper. When shrinking feed the metal in fast and pull slowly out! funny how many do just the opposite. The only thing I see on your dies the upper die thumbnail recess the edge looks to be a little sharp. Now any movement, in / out or side to side in the dies will play havoc with the finish, and we are talking just a few thousandths, I've had a dial indicator on my T3 trying to find what was flexing or moving, it isn't easy! If you can take "good" pics of the pattern of the marking it can lead to a fix it is hard to get a good pic!. I always use aluminum to final check my dies, if it's good on aluminum, it will be good on steel. tt;)

[suhrsc]

thank you!

Here are a few photos....
I believe the problem may be in the missalignment of the dies?

Also a bit of a rough edge on the upper which seems I could polish off?

first 2 pics are hand turning the motor while feeding the aluminum....
http://i673.photobucket.com/albums/vv100/zachsuhr/metal%20shaping/IMG_9991.jpg
http://i673.photobucket.com/albums/vv100/zachsuhr/metal%20shaping/IMG_9992.jpg
http://i673.photobucket.com/albums/vv100/zachsuhr/metal%20shaping/IMG_9995.jpg

http://i673.photobucket.com/albums/vv100/zachsuhr/metal%20shaping/IMG_9993.jpg
http://i673.photobucket.com/albums/vv100/zachsuhr/metal%20shaping/IMG_9994.jpg

this is a panel that I did to test.... you can see the marks in it... but it really did a good job of shrinking in a short amount of time... nothing was touched on the back 2"... front just shrunk then rolled in an English Wheel to level out...
http://i673.photobucket.com/albums/vv100/zachsuhr/metal%20shaping/IMG_9997.jpg
http://i673.photobucket.com/albums/vv100/zachsuhr/metal%20shaping/IMG_9998.jpg
http://i673.photobucket.com/albums/vv100/zachsuhr/metal%20shaping/IMG_9999.jpg

[oldgoaly]

most definitely a sharp edge digging in, since it is on the top, look for it on the top die! (this isn't rocket science heck nothing blows up!) The edge of the thumbnail recess need to be radiused more, get that rounded over better, then you can smooth and polish them a bit. You will love them! tt;)

[CARS]

Did your stairs fall over???

[suhrsc]

haha... no stairs didnt fall over.... just some free ones i picked up

I got the dies figured out tonight... apparently the lower die was made wrong... the "flat" that goes around the raised thumb.. was/is tapered down towards the throat of the machine... inturn it was not compressing the aluminum correctly all around the "tuck"
i shimmed the upper die to get the flats matched....

still getting some slight tool marks because the dies arent polished... but... its working great!!!

I did about 4 passed on a piece of aluminum and get it to turn almost 90 degrees!
was experimenting a lot so theres some marks on it(pic below)...... but... all in all I am VERY impressed!! :D

a bit more fine tuning still... but I want to genuinely thank everyone who offered up advice!!

Thanks alot!!
Zach

http://i673.photobucket.com/albums/vv100/zachsuhr/metal%20shaping/IMG_0002.jpg

[oldgoaly]

Zach,
when you get them polished a bit, if you have some die grease or plain wheel bearing grease, spread a thin layer on the lower die, then lower the upper so it just makes contacts with the lower die by hand of course. you should have a smile shape contact area just in front of the thumbnail. tt;)

[Tisdelski]

Hi Zach,

Make sure the die holders a exactly lined up, one pic makes the gap in the front looks smaller then in the rear.

Gary

[CARS]

Zach,
when you get them polished a bit, if you have some die grease or plain wheel bearing grease, spread a thin layer on the lower die, then lower the upper so it just makes contacts with the lower die by hand of course. you should have a smile shape contact area just in front of the thumbnail. tt;)


Terry, maybe this should be a separate issue, but isn't trapping grease going to lead to other problems? Like paint adhesion??

I know we are here to metal shape but most of us have a finished product in mind. (primer, paint, plating, etc.)

[oldgoaly]

Chris,
The grease trick is to check the actual contact points or sweet spot of the dies, this will show if the dies are properly aligned. I use the blue machinist grease and it turns everything blue if not careful. You don't need lube when using a pullmax style machine. I have heard of people using it nothing wrong with it. My gloves I use on the pullmax are oily enough to help lube a panel plus I spray sheets stored in shop with WD-40 so they don't rust or stick together. I'm sure a light oil such as WD-40 can help one see tracking patterns as some do wheeling.
Just looking at dies can give one a false impression, die grease shows you the truth! To me clay is rather thick, but if you use it all the time you know how to read it. You need at least 1/4" thick smile, smile should be just a few hairs wider than the thumbnail it's self. 1/2" thick is plenty if you get too much contact area then your cutting down on your shrinking ability. If the contact areas are to small you don't get as good of finish. Remember rule #1 it can not shrink if the gap between the dies is less than the thickness of the metal plus the amount of thickness gained when shrinking!
This is a reciprocating machine, not a Yoder power hammer style that has spring and flex coupling of the die. Critical gap like a english wheel, air planishing hammer more like a Yoder power hammer than a pullmax like machine. The big Baileigh hammer can do both ways well. Ben's and RichardK's designs are good too!

[anders nørgaard]

Chris,

The grease is only meant to be used as die maker's ink. Just to make sure the contact points are in the right place and have the right shape ;)

[CARS]

Thanks for the clarification guys. I was thinking it was suggested as a lubricant.