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Sheet metal punch for stove project


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  • #1919552
    Dan Yeruski
    BPL Member

    @zelph

    Locale: www.bplite.com

    There is a knowlegable sales rep at Roper Whitney that goes by the name of John Yeruski. He taught me all I know about punching holes in thin gauge metal. He'll tell you exactly what is needed. Hint: "Stripper Material"

    Yon is on the right track.

    #1919611
    John Donewar
    BPL Member

    @newton

    Locale: Southeastern Texas

    L O L

    I run Google Chrome and when I highlight a portion of text it gives me options such as "search Google for" among other options.

    I tried this with "Stripper Material" and you wouldn't believe the results that showed up on my monitor. :-0

    Party On,

    Newton

    #1919614
    Jerry Adams
    BPL Member

    @retiredjerry

    Locale: Oregon and Washington

    Please post links to "stripper material" : )

    #1919618
    John Donewar
    BPL Member

    @newton

    Locale: Southeastern Texas

    You're on your own Jerry!

    Party On,

    Newton

    #1919670
    Roger Caffin
    BPL Member

    @rcaffin

    Locale: Wollemi & Kosciusko NPs, Europe

    Principle routes of exposure: Eyes. Skin contact. Inhalation. Ingestion.
    Skin contact: Corrosive. May cause permanent damage.
    Eye contact: Corrosive. Causes permanent eye damage, including blindness.

    Hum ….
    :-)

    Cheers

    #1919845
    Diplomatic Mike
    Member

    @mikefaedundee

    Locale: Under a bush in Scotland

    Here's my take on the subject re clearance.
    A Tool and Die worker will work by this rule, at least in the UK.
    For material thickness less than 0.100", the clearance is 7-10% total. For material over 0.100", it is 7-10% per side. This is a % of the material thickness.

    So for 0.005" sheet, the clearance should be 7-10% of 0.005", so 0.00035 – 0.0005". This assumes the set up is rigid, fixed and everything is properly ground, ie a Die Set.

    #1920484
    Colin Krusor
    BPL Member

    @ckrusor

    Locale: Northwest US

    Mike, thanks for that information. That clearance (0.00035" – 0.0005") is very small, though. That's about ten microns. I'm not sure I could obtain a punch/die set with that little clearance on my budget, not to mention a tool that could accurately line them up.

    This evening, I did my first electrochemical etching experiment and it seems promising. I think I might focus on this for now rather than looking for a high-precision punch. Etching can produce clean cutouts of any shape or size and it requires only equipment that I already have.

    #1920488
    Roger Caffin
    BPL Member

    @rcaffin

    Locale: Wollemi & Kosciusko NPs, Europe

    > This evening, I did my first electrochemical etching experiment and it seems promising.

    DETAILS!!!
    URLs!
    Please!

    Cheers

    #1920521
    John Donewar
    BPL Member

    @newton

    Locale: Southeastern Texas

    Colin,

    I can only echo Roger's interest…

    "DETAILS!!!
    URLs!
    Please!"

    …in this experiment of yours.

    I do have a couple of my own requests.

    Pictures and / or a YouTube video of the process and its results, Please!

    Party On,

    Newton

    #1920587
    Colin Krusor
    BPL Member

    @ckrusor

    Locale: Northwest US

    Roger and Newton, I'll post some photos as soon as I get a chance. I have a presentation and a manuscript submission deadline that will keep me busy into the wee hours for the next week or so.

    This is the jist: most of the DIY metal etching tutorials online focus on copper or steel. Hobbyists use it to remove copper from circuit boards and cottage craftspeople (like knife makers) use it to indelibly put their logo into steel surfaces. Some metals, like copper and brass, can be deeply etched (deeper than 0.01") using just NaCl as the electrolyte:

    http://www.instructables.com/id/How-To-Electro-Etch-a-Solid-Metal-Plaque/?ALLSTEPS

    Other metals, like steel, require acids:

    http://forum.caswellplating.com/electroplating-questions/953-electro-chemical-etching-steel.html

    There are companies that etch titanium foil parts:

    http://www.fotofab.com/cmp_titanium.php
    http://www.tech-etch.com/photoetch/materials_titanium_etching_tungsten.html
    http://www.kemactech.com/titanium-chemical-etching.html

    And companies that sell equipment and reagents for DIY titanium etching:

    http://www.etching-metal.com/etching/titanium.htm
    http://multietch.com/

    And forums that discuss both commercial and DIY titanium etching:

    http://www.finishing.com/134/32.shtml
    http://mrtitanium.info/2011/08/09/q-what-common-materials-can-be-used-to-etch-titanium/
    http://www.researchgate.net/post/What_could_be_the_alternative_for_Hydrofluoric_acid_in_etching_titanium_metal

    Titanium, because of the very inert oxide surface layer, is almost always etched with hydrofluoric acid (sometimes up to 50%). I don't want to deal with hydrofluoric acid. The other options are a mixture of hydrochloric and sulfuric acids, or concentrated oxalic acid. Yesterday I tried HCl+H2SO4 because that's what I had on hand.

    I used a lab power supply (Mastech HY 3003) set to a constant current of 1 amp, and connected the positive lead to a test piece of 0.005" 15-3-3-3 Ti foil masked with enamel paint except for a small exposed area. The negative lead was connected to a piece of scrap titanium.

    The resistance of the oxide layer drove the voltage way up (to about 40V). The etching was rapid and vigorous (lots of bubbling and heat), but the result was uneven pitting of the surface of the foil. I think the oxide layer needs to be removed first. If there is oxide on the surface, the current will find tiny fissures and excavate them, producing pits, rather than uniformly removing material over the unmasked area.

    I ordered some oxalic acid, but I've read that oxalate solutions are very slow for titanium etching compared to fluoride. So, I'm going to try a solution of nitric acid and ammonium bifluoride as well. This is the composition of at least two commercial titanium etching solutions (and the subject of this patent: http://www.google.com/patents/US4314876). This should strip away the oxide and give a much better result.

    I'll post an update as soon as I find a bit more time to work on it.

    #1920838
    peter vacco
    Member

    @fluffinreach-com

    Locale: no. california

    in the world of shearing steel we use the "6 to 7" rule, which tells us that a good place to start is 6 to 7% of the material thickness. when shearing harder alloys (in this case A50, as opposed to A36 steel plate and angle iron) the appropriate starting point is closer to 10%.
    now : a punch is really a shear, just formed into a circle, so the 6% needs doubled to give approx die clearance.

    in the final decision, it is entirely appropriate that die clearance be determined not by formula in any particular application, but by experience and experimentation. there are excessive variables to allow a simple formula to work optimally in All situations.
    still , 6 to 7 yields a fine starting point.

    Harbor Freight = garbage. top to bottom. if you liked fish, you would find most of their inventory is not fit for reef construction.
    HF is a blight on the economy of the planet, and present an excessive challenge to landfill reform.
    if peter was president. Harbor Freight in it's corporate entirety would be shoved onto a very old ship, and sent back where it came. if that country refused shipment .. reef time. (pity the fish..)
    HF ? .. not a problem.

    our own Ken T. once again shows us the way, and this time it's how to drill thin metal.
    Ken is correct. a twist drill is not what you want. in fact, a twist drill is exactly the tool most NOT to be employed in thin material drilling. although a noble item, the twist drill is simply not the correct tool in this instance.
    what you want is the Step Drill, commonly know as a UniBit.

    the U-bit can still rumple up shim thickness materials though.
    ohhh.. that to do ???
    i'll tell ya what to do. go to Lowes (less bad than HF) and buy a sheet of 1/4" .. they will call it masonite, but it's really a composite of wood fibers that look like masonite.
    a 2 x 4' sheet is like what … 6 bucks. it's nothing, and you can pick it up on the way home from work. the stuff cuts like a dream, drills just as nicely, and has enough balls to clamp and hold your tin properly.
    sometimes they call it MDF. but real traditional MDF is a thicker and quite Vile material used by cut-rate mexican roofing contractors to do shlock work.
    the material you want will be found at Lowes and Home Depot (currently recovering from criminally bad corporate management) to have smooth surfaces on both sides,and already cut to the easy-to-put-in-your-car 2 x4' sheets.

    happy drilling,
    peter v.

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