Punching with a shop press
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  1. #1
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    Default Punching with a shop press

    I have have a couple railing jobs for a regular customer & I dont have a punch. I have checked how much to get pre-punched channel or have another shop punch it for me but I would rather do the punching myself. I came across Unipunch which are mainly for use in press brakes but I think they could be used in a shop press. I need a way to punch 1/2" square holes in channel I think this may be the way to go. If anyone knows anything about these punches or another product that could do what I need please comment. I have found all sizes of Unipunch products on e-bay I just don't know which one will work for what I need to do.

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    Don't know why it could not be use with a shop press.

    I've seen those mounted on many kind of press.

    Can you post a picture of your press?

    Jeff

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    About six months ago, I also started down this road with exactly the same goal as you. I did not lose interest... I just got distracted.

    I bought some of those press dies - or whatever they're called - on ebay. There appears to be no reason they could not be used ganged in a hydraulic press. At this point I've largely forgotten what I learned at the time. But I seem to remember that the manufacturer's web site had some information on the tonnage required to punch holes in different configurations and different thicknesses of material. I came to the conclusion that with a manually operated (hand pumped) press it would be pretty slow and tedious going.

    Maybe your quest will induce me to get back on track.

    V

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    here is a link to a tonnage chart that tells you how to calculate square hole tonnage-
    Basically, a 1/2" square in 3/16" is about ten tons, and in 1/4" material is 13 tons. Figure 15 tons, to be safe. One hole, its fun. If you are hand pumping, I would guess after fifty it wont be fun anymore.

    http://www.unipunch.com/products/Uni...leThing110.pdf

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    What part of the channel, legs or the flat section? I it formed or structual channel? On standard structual c channel, the legs being tapered to the inside might cause problems. If punching on the flat, you will need to verify that the unipunch frame has room for the channel

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    I put a 20 ton air/hydraulic jack in my shop press that runs on a foot pedal. I use to dread pumping that sumbitch, but life got much better with the upgrade.

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    It will depend upon the material you intend to punch, the thickness of the material, and the number/location of said holes. Buying a used punch on Evil-Bay is acceptable provided it has the correct die clearance (which is based upon the material/thickness) and whether you have the means for sharpening the punch and die in your shop (surface grinder). There's also whether, as another member has posted, there's enough physical room in the throat of a "C" type. If you can answer yes to all of these then there's no reason you can't do this yourself. I will state that alignment between punch and die is critical, should you decide to fab something up yourself (I have) then alignment within .001 must be maintained if you're punching more than a few pieces. There are several other provisions for doing this but we'll wait until you make a decision about this, write back when you're ready to pull the trigger. Drawings/photos help.

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    At the time I looked into this, my objective was to punch holes in cross bars for grates and railings. After looking into it, doing it on a small scale made just buying the pre-punched bars - and rolling that into the cost of the product - began to look a lot more appealing. I came to the conclusion that for the short term, buying the pre-punched bars was the way to go, and that in the medium term, perhaps buying a used ironworker might be a logical next stepping stone.

    V

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    I punch using unipunch dies in my press, I have a 100 ton electric hydraulic press. They work well but be sure and set a stop or you will crush your unipunch frame. They are designed to be used in press brakes with set stops. A regular press does not have those stops and you can flatten your punch.

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    Its just a 20 ton press & I am going to get an air over hydraulic jack if I do this. I would rather get an ironworker but can't seem to find one in my price range of less than $2000. One job I may need it for I need to match an existing fence channel which is 1x1/2x1/8 with hole on 4 3/8 center spacing. No one stocks that & the cost to have another shop punch it I can get my press set up with a punch. I would rather spend my money on equipment than just get a job done by someone else. Thats why I built a small brake for my press as well.

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    I have a roper whitney no 20-1 punch which could be bench mounted. It appears from their site that a square punch can be used with them, with an aligning stripper.

    ROPER WHITNEY: Portable, Heavy Duty Punches

    There are several on ebay now.

    Don't know that a square punch could be adapted easily to this but it would be faster than a shop press:

    Manual Sheet Metal Punch, Hand Punch HP-160 | Baileigh Industrial

    I looked into unipunches a long time ago and it's hard to figure out all the sizes/configurations.

    Also, they don't SEEM to have the space to feed channel in there like an ironworker.

    King Architectural Metals doesn't have the punched channel you need? I know they have the small punched channel for fence building...maybe worth a call for your specific needs:

    http://www.kingmetals.com/Catalog/It...temNumber=8665

    ^^^4 1/2 hole spacing here in stock.

    edit: sorry I didn't read well enough now I see you looked into channel pricing, sorry

    Good luck,

    James

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    I tried to set up my press, a 50 ton Dake with a unipunch and I abandoned the idea after a few test punches. I still have the unipunch ( for sale cheap!)
    I was pushing the limits as I needed over 30 tons to punch a 3/8" x 1' oblong through 3/8" plate mainly. The setup worked fine for thin material but in 1/4" plate it went off like a gun blast.
    Not something I wanted to do 6 times on each part, many parts to do on some days. I bought an ironworker pretty much right away, no regrets on that purchase. Even the 50 ton Scotchman ironworker goes bang when it punches through 1/4" plate, ironically it goes through the 3/8 plate like it is soft cheese, no noise, no bang, just smooth as silk. I never tried to punch the 3/8 plate on the Dake and unipunch.

    Good luck, you will soon get tired of the slow speed, the hydraulic ironworker is too slow for me now. As I understand it the mechanical ironworkers were much faster and much cheaper to buy right now too.

    Michael

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    Thats down to the wrong clearance on the punch die combo!

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    Adama,
    Perhaps you could elaborate on that a bit for those who don't know.
    In my case after I told the supplier what I was doing ( punching mainly .25 &.375" ms) and they sold me a punch and die set.
    The punch is 13/32 x1" and the die is 7/16 x 1-1/32", there are only two sizes to choose from in this category.
    I would be interested to know what you recommend, less clearance or more clearance.

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    The bang you get when punching can be related to not having the correct punch/die clearances. Also, not having a rigid enough setup, deflection of the press frame that's released when the punch breaks through can be the cause too.

    Adding a shear grind to the punch can help too. That makes a more gradual break through and lessens tonnage needed.

    I use Unipunch's. They're dirt cheap now that CNC punching machines are so common.

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    An ironworker is an investment thats like a truck or a fork lift, You will wonder how the hell you ever lived without it.

    Shearing is way faster then sawing, punching is faster then drilling, bending is faster then welding.

    People see them and ask "What does this machine make?"
    The answer..."MONEY"

    Iv seen old 100 ton mechanical buffalo iron works sell dirt cheap at auctions because they are heavy as hell. There is not much to go wrong with one so they will punch a bazillion holes.

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    10% of thickness all around (in practice 7-10% works well, but go much over 10% and burrs become a headache in mild steel). ie in simple metric land a 10mm punch needs a 12mm die in 10mm thick material but in 6mm thick only needs a 11.2mm die (not exactly a good dia any how, ruff rule of thumb is to never have punch at or less than material thickness in diamiter - narrowest section). punching 6mm and 10mm thick with the same punch won't work well as you have found out. I don't play with fractions bellow 1/8" so no idea what you actually have there, but if im guessing right, 1/32" aint enough at 3/8" material, kinda only about half what you really need.

    Decide Punch size based on what hole size you need, then die size based on the 10% rule and your laughing, what they do is the irrelevant bit, its what you need, if need be buy small and open it out!

    You can also gauge it by the drag and shear thats clearly visible on the hole edge, Ruff target is to limit the shiny bit to about 1/4-1/3rd the plates thickness.

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    Quote Originally Posted by oldbikerdude37 View Post
    An ironworker is an investment thats like a truck or a fork lift, You will wonder how the hell you ever lived without it.

    Shearing is way faster then sawing, punching is faster then drilling, bending is faster then welding.

    People see them and ask "What does this machine make?"
    The answer..."MONEY"

    Iv seen old 100 ton mechanical buffalo iron works sell dirt cheap at auctions because they are heavy as hell. There is not much to go wrong with one so they will punch a bazillion holes.
    Too true, in a former life I had access to one (for a packet 20 cigarettes / hour ) the time it saved me - and money it made me, made it more than worthwhile sorting out and trucking materials and cutting lists etc on a 10mile round trip.

    IMHO - A true invention of the gods.

    P.S. I was never lucky enough to find one at anything like my budget

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    I hope I can find a real ironworker in my budget someday. But until then I will keep using what I've already got. If I can make a slow ironworker out of my shop press thats better than no ironworker at all. I already made a 6" brake for it. By the time I get done making tooling for my press it may be almost as good as an ironworker. Keep all the info coming about punching. No matter how redneck my equipment is I still want it to work good & be reliable.

    uploadfromtaptalk1412790610776.jpg
    uploadfromtaptalk1412790700212.jpg
    uploadfromtaptalk1412790893209.jpg

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    Love the welded stacked nuts, maybe next time try some bar and tap it? Or find some of the long nuts used to join studding, very useful to have a few of those kicking around!


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