[TheForge] Punch press dies

Wed Jul 20 00:07:00 EDT 2011

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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