punch press 101

Looks like a punch press similar to this
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is
following my son home tomorrow afternoon. I know little about these units.
Where do I go for beginner info on what all I can punch and what dies etc. I
need. How do capabilities compare to an iron worker, shear, press brake??
I got the unit for scrap weight value or less, I'm just hoping its not a
boat anchor for the shop. I've got enough of those already.
Karl
Reply to
Karl Townsend
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"Karl Townsend" wrote in message news:7AgZf.170$ snipped-for-privacy@newsread2.news.pas.earthlink.net...
Oh boy! Nice press! What do you want to know...specifically? It's not any of those other tools but it is only limited by your imagination. First, check the safety systems; then the bush in the flywheel and the crank bearings. Make a die that punches out saleable parts and sell the parts for a profit. Count fingers constantly!
Reply to
Tom Gardner
The press is fine, the dies will kill you on cost.
Suggest checking out used book stores for punch and die books although there are probably also some new ones on Amazon. Not much use for 1-off type things although you could probably scab together a bar shear or something. You might be able to angle shear also but again, the die block starts getting expensive. It also has some potential to flatten things without much investment in dies. Best to look into something that you can sell 100,000 of on e-bay and invest in the die.
Koz
Reply to
Koz
Oh that's way cool. One suggestion, at least semi-serious: make a simple post and top pad and you have a really bad-a**ed planishing hammer. Sneer at people with their wussy English wheels. Get all carried away and make shrinking/expanding dies, start making ashtrays out of 1/4" plate. Well, maybe not that last one.
Reply to
Fred R
Oh, I forgot...I use one of my 60 ton to make schnitzel really, really fast!
Reply to
Tom Gardner
--There's a monthly trade pub called "American Tool, Die & Stamping News", probably from Taunton Press or someone like them. It's free and has some good articles on how to use a press.
Reply to
steamer
We haven't got another Kraut in the group? (My grandparents didn't speak English till the end of '41)
FWIW, I think I'll pass on this unit. The scrap guy gets it. Just don't have room for another big tool I won't use.
Karl
Reply to
Karl Townsend
Dont make it into a planishing hammer, or try to forge with it- unlike planishing hammers or power hammers, punch presses are not meant to hit things and bounce back- they break, and pieces fly thru the air. Not healthy.
Punch presses are designed for high production stamping and punching with dedicated dies. As mentioned the dies are the big money item.
You can buy some premade die sets that are blank- you add your own punch, or forming tooling- like this one from MSC-
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*ITPD&PMITEM=03225083 This company also makes a lot of cool tooling that you could buy, if you have lots of money, or copy if you have a good machine shop-
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It is not an ironworker, a shear or a press brake. It hits once, hard. Always the same hardness- so it isnt good for fussy bending. You could make a bending die, but it would need to be sized for the exact thickness of material you are bending, and the right angle. Same with shearing- it will shear, within its capacity, but its tricky to do freehand work on it without losing your free hand.
As far as books- there arent too many- but the best place to look is probably abebooks.com- thats the national database of used bookstores. A few books I have that cover the use of punch presses, but are pretty technical- If you can find it, the Bliss Power Press Handbook has some info. And Practical Design of Manufacturing Tools, by the American Society of Tool Engineers, Mcgraw Hill, has some info. But punch presses were never designed for the home user, so there isnt much in basic books- there are some technical books on die design, but use of the machines was usually taught on the job.
Reply to
rniemi
Dont make it into a planishing hammer, or try to forge with it- unlike planishing hammers or power hammers, punch presses are not meant to hit things and bounce back- they break, and pieces fly thru the air. Not healthy.
Punch presses are designed for high production stamping and punching with dedicated dies. As mentioned the dies are the big money item.
You can buy some premade die sets that are blank- you add your own punch, or forming tooling- like this one from MSC-
formatting link
*ITPD&PMITEM=03225083 This company also makes a lot of cool tooling that you could buy, if you have lots of money, or copy if you have a good machine shop-
formatting link
It is not an ironworker, a shear or a press brake. It hits once, hard. Always the same hardness- so it isnt good for fussy bending. You could make a bending die, but it would need to be sized for the exact thickness of material you are bending, and the right angle. Same with shearing- it will shear, within its capacity, but its tricky to do freehand work on it without losing your free hand.
As far as books- there arent too many- but the best place to look is probably abebooks.com- thats the national database of used bookstores. A few books I have that cover the use of punch presses, but are pretty technical- If you can find it, the Bliss Power Press Handbook has some info. And Practical Design of Manufacturing Tools, by the American Society of Tool Engineers, Mcgraw Hill, has some info. But punch presses were never designed for the home user, so there isnt much in basic books- there are some technical books on die design, but use of the machines was usually taught on the job.
Reply to
rniemi
Dont make it into a planishing hammer, or try to forge with it- unlike planishing hammers or power hammers, punch presses are not meant to hit things and bounce back- they break, and pieces fly thru the air. Not healthy.
Punch presses are designed for high production stamping and punching with dedicated dies. As mentioned the dies are the big money item.
You can buy some premade die sets that are blank- you add your own punch, or forming tooling- like this one from MSC-
formatting link
*ITPD&PMITEM=03225083 This company also makes a lot of cool tooling that you could buy, if you have lots of money, or copy if you have a good machine shop-
formatting link
It is not an ironworker, a shear or a press brake. It hits once, hard. Always the same hardness- so it isnt good for fussy bending. You could make a bending die, but it would need to be sized for the exact thickness of material you are bending, and the right angle. Same with shearing- it will shear, within its capacity, but its tricky to do freehand work on it without losing your free hand.
As far as books- there arent too many- but the best place to look is probably abebooks.com- thats the national database of used bookstores. A few books I have that cover the use of punch presses, but are pretty technical- If you can find it, the Bliss Power Press Handbook has some info. And Practical Design of Manufacturing Tools, by the American Society of Tool Engineers, Mcgraw Hill, has some info. But punch presses were never designed for the home user, so there isnt much in basic books- there are some technical books on die design, but use of the machines was usually taught on the job.
Reply to
rniemi
As others mentioned, dies are the expensive part. Don't even THINK about using it for hammering or planishing, you will bend the crank on the first hit. You unit will likely have a 3" stroke, the force varies with the cosine of the crank angle, max force is at the bottom of the stroke (not in the middle!) The tonage listed is the max the unit will withstand without bending or breaking.
Comparing to an iron worker is apples and oranges. A punch press is high volume with fixed tooling, an iron worker is low volume and universal. A punch press will run something like 70 strokes per minute, crunching out smaller parts, one per hit. You can also get notching and piercing dies that do good work on tubing.
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While it is not required, it is very good practice to mount all your dies in die sets. IIRC, you are near Minneapolis. I have seen stacks of used dies and die sets at one of the suplus dealers, forget which one. Sample:
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Warning: a punch press is a SERIOUS tool that has a disasterous safety record. Proper guards, double palm buttons, light curtains, etc are MANDATORY!!!!!! A 10 ton unit like you showed will move 3" in the 400 milliseconds after it is tripped. Your hands are either clear of the machine or they are gone.
Karl Townsend wrote:
Reply to
RoyJ
Oops! The picture you showed was a 35 ton, not a 10 ton like I assumed. 2-1/2" stroke, but it runs UP TO 110 strokes per minute. That is FAST. Notice the double palm buttons for safety. Sorta.
RoyJ wrote:
Reply to
RoyJ
"Karl Townsend" wrote in message news:7AgZf.170$ snipped-for-privacy@newsread2.news.pas.earthlink.net...
To add to what others have said, you can set the shut height of a press too big as many times as you want. You can set the shut height of a press too low ONCE.
The flywheel in a mechanical press has between 10 and 20 times the press's rated capacity in total stored energy. Setting the shut height too low on a 40 ton press could subject the tooling and the press to some 800 tons of force. Worst I've heard is the flywheel broke off a 1,000+ ton press when it was setup below the die shut height. The flywheel crushed the operator (it fell from about two stories up).
Regards,
Robin
Reply to
Robin S.
Dies are cheap if you have a lathe. It won't bend the crank on a 35 ton, it'll lock the press...been there...lots!
Reply to
Tom Gardner
Dies are cheap if you have an EDM. Lathe only helps for round holes, might as well get an iron worker.
You will only lock the press if get the stroke a few thousandths more than the shunt height. Anything more and it breaks the crank. Either one does not do the press any good.
Tom Gardner wrote:
Reply to
RoyJ
While this is good advice, it's not technically accurate.
On our flange and restrike dies at work, we set the shut height of the mechanical presses below that of the die, sometimes by millimetres (shut heights for our dies ranges between one and two meters) to get the tonnage up such that the part is properly hit. These are straight-sided presses in the 800 - 1,500 ton range. We'll get the tonnage meter to read about 600 tons before hitting a part. The bolster actually gives (down) to accommodate the jamming condition. None of this is required for dies which perform only cutting operations.
When someone goes too low (very rare) we typically have to torch cut the four bottom blocks to unlock the ram.
As far as the little dies are concerned, however, I don't think anything more than a thou or two is acceptable. OBI presses are not of very solid design anyway and will eventually fatigue open if they are run too hard. Assuming you can read the actual tonnage being applied by the press, running at maximum 80% of capacity is a good idea for press life.
Regards,
Robin
Reply to
Robin S.
Oh, as you can imagine I make wire wheel parts, EVERYTHING (almost) is round. I have a limited perspective. I have 10 presses in the 20 to 60 ton range, mostly 30's. I haven't bent or broken a crank yet...thank GOD! But, we've jamed them all up at one time or another to the point of dissassembly of the crank. Round dies ARE easier in every way, even on a shoe or die set.
Reply to
Tom Gardner
However all presses do not have a cushion such as your description:
the jamming condition.<
In fact I don't believe I've ever seen a small press such as this with a cushion. Too long a stroke in relation to the shut height (without a cushion) will definitly damage the press.
dennis in nca
Reply to
rigger
I'm pretty sure it's just the press giving. In all the courses I've taken, I've never heard of a cushion of this type. If the press is capable of 100 tons and you're below shut height but only using 50 tons, it stands to reason that you're not jamming the press.
Without question. Great care must be taken, especially when you don't have a tonnage meter. Indeed trying to run a die which requires more tonnage than the press can deliver will yield similar results.
Regards,
Robin
Reply to
Robin S.
On the large hydroform press at work (6,000 tons) the tie rods have hydraulic nuts for preload. I believe the rods are heated before the nuts are tightened to increase the preload as well. They had to cut a hole in the 3-story roof to get the rods into the press using a crane.
It's interesting that a jam could cause the posts to fail. I wonder where the rod-ends ended up (in another time zone perhaps.)
Regards,
Robin
Reply to
Robin S.

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