[TheForge] Punch press dies

Tue Jul 19 21:06:12 EDT 2011



-----Original Message-----
>From: Andrew Vida <osan at netlabs.net>
>Sent: Jul 19, 2011 9:07 PM
>To: Bob Ehrenberger <eforge at centurytel.net>, Blacksmithing List Sponsored by ABANA <theforge at mailman.qth.net>
>Subject: Re: [TheForge] Punch press dies
>
>Unless your home made press is very accurately built for high 
>repeatability, I would recommend against using it  as a punch press.  I 
>have had a die go cockeyed in a 130 ton press.  The D2 punch split and a 
>very sharp bullet sailed across the shop and took a good divot out of 
>the block wall.  I am confident in saying that had a person been in its 
>way, it would have passed right through whatever flesh and bone stood in 
>its path.
>
>My only advice is to be very careful with this sort of thing.  These are 
>operations that require a certain mechanical precision.  If you cannot 
>guarantee the necessary tolerances, better you .not go there.  I would 
>hate to hear you were injured or killed.
>
>On 7/19/2011 7:30 PM, Bob Ehrenberger wrote:
>> Frosty,
>>
>> It is for a home made forging press that I want to make dual purpose.  I
>> think I will look into the Whitney punches that Ries mentioned.
>>
>> Robert Ehrenberger
>> Shelbyville, Mo.
>> eforge at centurytel.net
>> 573-633-2010
>>
>> ----- Original Message -----
>> From: "Jerry Frost"<akfrosty at mtaonline.net>
>> To: "Bob Ehrenberger"<eforge at centurytel.net>; "Blacksmithing List Sponsored
>> by ABANA"<theforge at mailman.qth.net>
>> Sent: Tuesday, July 19, 2011 3:18 PM
>> Subject: Re: [TheForge] Punch press dies
>>
>>
>> I can't say with any accuracy, Dad usually made out punch press dies but I
>> wasn't involved at all. first I don't know what kind of punch press you're
>> talking about. The only good advice I can offer is buy them from someone who
>> knows just what they're doing and has insurance.
>>
>> Jer
>> ----- Original Message -----
>> From: "Bob Ehrenberger"<eforge at centurytel.net>
>> To: "David E. Smucker"<davesmucker at hotmail.com>; "theforge"
>> <theforge at mailman.qth.net>
>> Sent: Tuesday, July 19, 2011 2:51 PM
>> Subject: Re: [TheForge] Punch press dies
>>
>>
>> David,
>>
>> Thanks,  I have seen Lou demo which is why I was thinking there was a rule
>> of thumb with the clearance being a percentage of the stock thickness.
>>
>> Robert Ehrenberger
>> Shelbyville, Mo.
>> eforge at centurytel.net
>> 573-633-2010
>>
>> ----- Original Message -----
>> From: "David E. Smucker"<davesmucker at hotmail.com>
>> To: "Bob Ehrenberger"<eforge at centurytel.net>; "Blacksmithing List Sponsored
>> by ABANA"<theforge at mailman.qth.net>
>> Sent: Monday, July 18, 2011 6:01 PM
>> Subject: Re: [TheForge] Punch press dies
>>
>>
>> Bob,  Good information from Ries,  You might also consider if you can have
>> some "lead" on you punch.  That if you have the stroke in your press than
>> you can start the cut on one side and not have all of the shear action take
>> place at once, or you can start on two sides and still greatly reduce the
>> force required.
>>
>> If he can still give you the information Lou Muller used to have all kinds
>> of rules of thumb for die work.
>>
>> Dave Smucker
>>
>> --------------------------------------------------
>> From: "Bob Ehrenberger"<eforge at centurytel.net>
>> Sent: Monday, July 18, 2011 5:44 PM
>> To: "Ries Niemi"<rniemi at fidalgo.net>; "Blacksmithing List Sponsored by
>> ABANA"<theforge at mailman.qth.net>
>> Subject: Re: [TheForge] Punch press dies
>>
>>> Ries,
>>>
>>> Thanks for your reply. Yes, that is what I want to do.
>>>
>>> I have a home made press and was planning on making my own punches and
>>> dies.
>>> Right now most of my sheetmetal work is in 16 ga and 14ga material.  I
>>> don't
>>> expect to go past 1/4" plate.
>>>
>>> I have already made a holder for 1" rd tools, it is a pretty loose fit, I
>>> hold the top tools in place with a set screw. I chose 1" rd because that
>>> is
>>> the same size my kick press uses, and the top tools could be interchanged.
>>> I
>>> have already made 3 round tools for making bowels and plates, 5 different
>>> sizes of fullers for making grooves and creases in sheetmetal, and a
>>> veining
>>> tool.
>>>
>>> Drilling large holes in light sheet is a pain because it tends to bind, so
>>> I
>>> thought it would be nice to be able to punch them. I also make several
>>> sconces that have key holes for hangers, which require drilling and filing
>>> also a pain. A key hole shaped punch would save a lot of time.
>>>
>>> It sounds like 1/32" clearance or a little less would work. I was
>>> concerned
>>> that if it was too close the punch would get stuck.
>>>
>>> Robert Ehrenberger
>>> Shelbyville, Mo.
>>> eforge at centurytel.net
>>>
>>>
>>> ----- Original Message -----
>>> From: "Ries Niemi"<rniemi at fidalgo.net>
>>> To: "Bob Ehrenberger"<eforge at centurytel.net>; "Blacksmithing List
>>> Sponsored
>>> by ABANA"<theforge at mailman.qth.net>
>>> Sent: Monday, July 18, 2011 2:37 PM
>>> Subject: Re: [TheForge] Punch press dies
>>>
>>>
>>>
>>> On Jul 18, 2011, at 10:45 AM, Bob Ehrenberger wrote:
>>>
>>> I'm thinking of making some hole punch dies for my press.  I know that
>>> there
>>> is a formula to determine the clearance between the punch and the bolster.
>>> Do any of you know how much oversized the bolster needs to be?
>>>
>>> Robert Ehrenberger
>>> Shelbyville, Mo.
>>> eforge at centurytel.net
>>>
>>> Are you are talking about punches and dies?
>>>
>>> If So you want to know "punch clearance".
>>>
>>> this varies depending on the material being punched, and the thickness.
>>>
>>> Here is a quick chart for mild steel-
>>>
>>>
>>> CLEARANCE FOR A-36 and MILD STEEL MATERIALS
>>> Recommended clearance for punching
>>>
>>> MATERIAL THICKNESS              RECOMMENDED CLEARANCE
>>>
>>> 1/4" to 1/2" / clearance- /1/32"
>>>
>>> 1/2" to 3/4" /clearance-  /1/16”
>>>
>>> 3/4" to 1”  /   clearance-  /   3/32”
>>>
>>> 1” and over/ clearance-  /1/8”
>>>
>>> So, for the vast majority of blacksmith needs, 1/32" total clearance is
>>> good. That means the punch is 1/32" under the die size.
>>>
>>> If you order ironworker punches from someplace like Cleveland punch, they
>>> will ask you thickness, and size your punch and die accordingly.
>>>
>>> If you are asking about the punch holder, that you slide the punch into,
>>> it
>>> can be a loose fit, oversize, just as long as you have set screw that
>>> holds
>>> the punch in place. This works for smooth shank punches, which were used
>>> on
>>> many older, lighter duty punches like pexto, niagara, and whitney.
>>> Usually,
>>> I grease mine, so they will come out again, so clearance is probably .010
>>> or
>>> so.
>>>
>>> A better system is a quick release system, which uses a lock nut to hold
>>> the
>>> punch in, and relies on the lip at the top of the punch to hold the punch
>>> in
>>> place. This is for ironworker style punches, which have that lip on  top.
>>> In
>>> this system, its the accuracy of the threading of the retaining nut that
>>> centers the punch, not the diameter of the hole and the clearance between
>>> the hole and punch.
>>>
>>> What type of punches will you be using?
>>> homemade, or storebought?
>>> For round, square, and oval holes, storebought are better, and pretty
>>> reasonably priced. For oddball, specials, you will probably make them
>>> yourself, but it makes sense to pick a standard size/type so you can
>>> interchange with commercially available stuff.
>>>
>>> there are several major suppliers of punches and dies, and most stock
>>> coupling nuts as well.
>>> http://www.americanpunchco.com/punch_stems_coupling_nuts.htm
>>>
>>>
>>> Ries Niemi
>>> Industrial Artist
>>> http://www.riesniemi.com/
>>>
>>>
>>>
>>>
>>>
>>> Ries Niemi
>>> 6988 Bayview Edison Road, Bow, Wa. 98232
>>> 360.766.8004
>>> www.riesniemi.com
>>> rniemi at fidalgo.net
>>>
>>>
>>>
>>>
>>>
>>>
>>>
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>>
>>
>>
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>>
>>
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>>Perhaps a guided die set is called for here?
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