[TheForge] Punch press dies

Tue Jul 19 22:55:30 EDT 2011

There are.
But the folks who sell punches and dies have 800#s and are eaGER to tell you!

-----Original Message-----
>From: Bob Ehrenberger <eforge at centurytel.net>
>Sent: Jul 19, 2011 6:51 AM
>To: "David E. Smucker" <davesmucker at hotmail.com>, theforge <theforge at mailman.qth.net>
>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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