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Thread: Pexto Shear
11-23-2004, 11:41 AM #1
I have an old mechanical Pexto shear. Any of you know where I can get an old repair manual for it? I'm having trouble with the foot switch, it is worn and it doesn't want to disengage all the time. We use the machine everyday and it has made literally over a million cuts. Any help would be appreciated.
11-23-2004, 12:08 PM #2
I believe Roper-Whitney owns the Pexto line now.
Is your shear a flywheel type mechanical shear where the "switch" is a footpedal that trips the clutch? Or is it a converted stomp shear using air or hydraulic cylinders? The reason I ask is because the great majority of Pexto shears are converted stomp shears, and if that's the case then the simplest thing would be to replace the entire foot switch assembly. On the other hand, many flywheel type shears have either a brake assembly or a dog mechanism, depending on the size, that stops the shear at the top of the stroke after each actuation. These can be tricky to adjust, and you definitely wouldn't want to proceed without the correct manual, because if things get out of time the shear can do lots of damage to itself real fast. Some mechanical shears also have a lever that can be moved to provide either single stroke or continuous operation. We had a Wysong for a while where this mechanism was loose and drifting back and forth, causing the shear to single stroke at times and to stroke continuously at other times.
11-23-2004, 12:44 PM #3
Anchor, I have some manuals on Pexto shears.If you can get a model # I,ll see what I have. I might be able to do a visual identification If you can post a picture. Will make copies of what I have. Martin
11-23-2004, 01:20 PM #4
Model number is U1420 Serial # C1563/37
16 Gauge Flywheel type.
Like I said before, the shear has made over a Million cuts. There is a key that slides out of the flywheel and then slides back in after the stroke if you release the pedal. The key is wore. The key isn't engaging into the flywheel completely and it will knock hard several times until it finds it's place. If you hold the pedal down it runs continuous with no problems until it is released.
Thanks for the responses and any help!
11-23-2004, 04:09 PM #5
I hate to oversimplify but can you just make a new key of the original shape, possibly oversized to be a good fit again?
If you are unsure of materials, make 2 from mild steel and case harden one with Kasenite. If the mild steel wears too fast, install the second one.
11-23-2004, 08:18 PM #6
That is my plan Matt, I just don't want to get in over my head with this. I would like to have a manual so I can see all the parts too the machine.
11-24-2004, 09:07 AM #7
Anchor, What you can do in this situation is the following. Remove flywheel,look at the driving anvils these are ussually three round pins with flats that the drive dog (rectangular piece) engages. You can remove these and grind the flat portion until the face squares up. You can also take a light cut on top surface but will have to shim behind pin to keep lenght dimension. To remove these you drive them out through the holes on the back of the flywheel.Check to see if there are allen screws before trying to pound out with dowell pins. Mark with dykem and scribe the location of flat on pins so you can align angular contact area between drive pins and anvils. You can grind the worn surface on drive dog, just grind the width it projects into drive pins usually 1/2"-3/4". Give me your fax # and I have some info on how to do this and parts list etc. Happy Thanksgiving all [img]smile.gif[/img] Martin
11-24-2004, 10:35 AM #8
Thanks a lot for any info you can give me. Maybe once I get what your sending me I will understand what you are saying in your post.
My fax is 724-360-0222.
PS, please reply to this so I know when you read it and if/when you can fax the info.
11-24-2004, 11:56 AM #9
Patrick, I just faxed some info.Hope procedure is clear. If I remember correctly the clutch parts are made from D-2 or D-3 ? steel.Post on board if you got info OK. Martin
11-24-2004, 12:14 PM #10
I was gonna make it out of some tool steel I had around here, not sure what it is but it will work. Thanks for sending the info, it reads like stereo instructions but I should be able to understand it.
11-24-2004, 08:39 PM #11
Anchor, Nine times out of ten the grinding method works fine, if you do make the parts it is VITAL!! you use the correct material or you will wreck the clutch housing which will turn your machine into junk. Martin
01-04-2005, 02:34 PM #12
Gotta bump this up, Martin if you see this. How do I remove the flywheel?
01-04-2005, 05:36 PM #13
Anchor, The flywheel should have a plain bronze bushing in it. To remove loosen retaining collar set screws. slide retaining collar off shaft. deburr area where set screws were and pull flywheel off shaft. You need to support flywheel weight. Greasing the fitting is also a good idea. Good Luck [img]smile.gif[/img] Martin.
01-05-2005, 12:08 PM #14
There is a cap on the end of the flywheel it has 1 set screw in it. The problem is I can't get that cap off.
01-05-2005, 05:28 PM #15
Anchor, Spray the WD-40 etc. in the set screw hole and around shaft. Put a bolt in set screw hole, don't lock it on shaft, then you can tap head with bronze bar and hammer, if you can get it moving back and forth it should free up.If not you may need heat and drill holes in collar face for a puller set up.Persistance pays off keep at it. [img]smile.gif[/img] Martin
03-23-2005, 11:18 AM #16
We just tore into this thing yesterday. Do you know of a company that would have parts for this? I think I have to get into the pedal's switch to fix the problem. I've been looking for a manual but I can not find one.
03-23-2005, 03:28 PM #17