The Hot Rod Gauntlet Thread

[ZooCity]

Maybe I should call it the "rat rod" Gauntlet thread but I wanted to start one for doing mods/upgrades to older GTs. 

I'm going to tackle the following and figured I might as well share the experience and I'm sure a lot of you have had the experience already. This is the stuff that was obvious to me after running around 6k pcs on "Glen", our '92 GT-6 this past week or so:

• Platen and arm deflection
• Chopper and stroke pressure
• Stroke length adjustment
• Cycle speed
• Mitigating the constant squeegee pressure on the screen at rest.

Here's a first installment- chopper pressure v. platen deflection.

FYI, the  1 1/16" chopper cylinders do fit a 91-92 GT-6 just fine. 

I do believe there's a reason the machine was spec'd with 3/4" choppers- there is some serious deflection going on on the outside of the press on both the pallet/pallet arm and the print head when running at higher pressures such as for WB/DC.  Both the print head and the pallet/arm deflect away from each other like an alligator opening it's jaws.  So it's a bit of a catch 22 where you can up your chopper pressure but you are simply causing more deflection if you use it.

All the same, I think the larger bore is an upgrade in that we seem to have more consistent pressure at various settings with these, including very light strokes with plastisol.

I think the deflection issue could be solved by installing the head supports (like used to mount an omni flash) and bolting the supports to the ground, preventing the head from flexing up.  Then you'd need some sort of platen tip extension that would be supported from below at each print position, like on older American presses.  If you could rig those two items up then you open up the door to using higher pressureconsistentlyacross the print stroke without frustrating registration and constantly throwing your press out of parallel.  This sounds like the M&R all over setup that I've seen, maybe an older version. 

It's probably overkill for such a small machine with a whopping 15" long image area and I'm surprised that a machine that was clearly very well built just flexes like crazy right where it really counts.   Any other ideas to mitigate the deflection?

[mk162]

I often thought the best way to handle the head deflection without downriggers(which look cheesy and get in the way a little) would be to go over the top with steel tubing to a center "shaft" that will force the head to stay down

the platen deflection might be easiest to fix with angle iron bolted on under the print arm...most of the defection is in the arm from what I remember.

[Homer]

cross out number 3 and 5...no dice on either one.

[mk162]

my thoughts on that one...the late 90's gauntlets had a thing that got rid of the pressure at rest, but they failed to work properly.

[bimmridder]

You can make the print stroke shorter, but I've never seen it lengthened. (My life story)

[mk162]

I was in the pool!!!

[Homer]

haha, love that show....from what I have been told, you can move the flags but it is not going to do you any good. Something about the air in the cylinders needed to stop the head so it's going to screw up the stroke. I tried it once and fkd the whole thing up...oh it was a scene man....

[rmonks]

Interesting to my knowledge this is the first time I have seen anyone mention their press by name. I guess i need to get to know my press better and find out what its name is, not even sure if it is a he or a she. Huh!
And this is an interesting thread also.

[mk162]

I haven't named any equipment yet, maybe we will go to work on that

[ZooCity]

Ok then, let's jump to part two- Stroke Length Adjustment.

These look like they'd do the trick.  Abt $135 a pop with the shock bumper.


Another option would be replacing the rear clamp with an updated one but I reckon that's gonna cost more than $135 per head.

Stroke length is important not only b/c, "wth, why is this not on here to begin with" but also b/c your max cycle speed is clipped by how long it takes for the prox to signal the print stroke is complete. 

Alos necessary to shorten the stroke if your specialty platens aren't a full 22" long. 

I don't see any point in trying to lengthen the stroke on a machine- if it's not built for it, it's not built for it.

[mk162]

does your press not have rear stroke adjustment?  if not, BUY ONE(to try it).  that is invaluable to be able to move the back stroke up

[ericheartsu]

This thread rules, as this is all things we are going to be doing to our press next month.

[JBLUE]

First let me say this. I own the same era Challenger. The best way to fix all that is buy a newer machine.....lol  If you bolt down the print arms you will see that the flex is in the pallet arms themselves. When you upgrade to the 1 1/16 you will notice the flex even more. My print arms are bolted to the floor and all it does is push the flex to the next weakest point. All of the older machines flex between the different brands. Some of the new ones even do it.

[ZooCity]

Copy that JBLUE, but my suggestion was using aop style supports with a platen tip support built in so there's nowhere for anything to go. You would need to make the "tips" for the platen mount but I think it would work. This would be very similar to the old Americans with the neck board sticking out.

Probably not cost effective though.

[JBLUE]

You can compensate for it by lowering the off contact a bit wher the stroke ends or even raise the pallet up a little on that side as well. I keep our pallets raked a little higher at the end of the stroke to balance it out. Ultimately what you are trying to even out is the pressure and its affects on dot gain throughout the stroke.