[TheForge] Punch press dies

Mon Jul 18 19:01:42 EDT 2011

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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