Hydraulic Knockout Punches UK/ Metric

Discussion in 'Tools' started by Sharpie, Apr 19, 2019.

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  1. Apr 19, 2019 #1

    Sharpie

    Sharpie

    Sharpie

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    Hi,
    Anyone use these tools, specifically the cheaper chinese versions?

    My question is, as most of the sellers copy & paste the same vague spec sheet: Does anyone have info on the supplied draw bars?

    They refer to the smaller pilot hole 11.5mm for the smaller punches, then fail to give the larger one.

    I'm hoping someone can confirm this is 20mm with an m20 fine thread pitch?

    TIA
     
  2. May 5, 2019 #2

    Wizard69

    Wizard69

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    The only knock out punches I've used are Greenlee and mostly in inch sizes. They do make metric punches. If you need one specific size I'd simply order a Greenlee punch in the size needed. I would be surprised if there isn't a similar high quality manufacture in the UK.

    As for Chinese tools I've been burn't so many times I don't even bother to buy them anymore unless I can inspect for quality before hand. As you may know there are good imports and sadly a whole lot of crap imports. To that end post a link to the item you are looking at in the hopes somebody has dealt with the vendor before.
     
  3. May 5, 2019 #3

    Sharpie

    Sharpie

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    I hear you on the chinese stuff but considering 85% of re-badged tools originate there these days...

    Greenlee punch here, $800 - $900 similar chinese $80 - they both punch holes, I'd rather put the $800 - 900 towards a powered iron worker which would give even more flexibility long term.

    After a lot of further research, inc some tool makers around europe, it appears M10 & M20 are the standard sizes.

    More difficult to find is different length drawbars. One US supplier was charging $19 for the drawbar then another $36 to send it.

    I think I've found another way to solve this. I have limited access into the part I'm repeat punching, esp the first 6 holes on first side (working inside aluminium tubing). The standard draw bar is short, so struggling to get enough thread onto the punch, (which is what happened when I tried to use it like a Qmax, the only m20 fine bolt I could find then was just 70mm long). In the hydraulic punch, the standard draw bar plus using the standard m10 and rear bolt for additional traction was too long to fit inside. So I now have on order a variety of high tensile m10 grub screws, which should give me options.

    So far, though I was unsure on the hydraulic knockout punch for some time, actually turned out to be a smart idea. In fact so useful, I plan a base mount for it soon.
     
  4. May 13, 2019 #4

    Wizard69

    Wizard69

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    Wow that is a stiff price on Greenlee punches.

    One option here is to make your own punch sets. That way you can thread them for whatever thread you need. You actually have me wondering what thread size Greenlee uses in the USA. The pitch is fine, well finer that what you would expect from Unified course.
     
  5. May 13, 2019 #5

    Sharpie

    Sharpie

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    I understand Greenlee use the same, 20mm & 10mm metric or at least in current set up, though only casually looked.

    The longer draw stud has proven fantastic, I did 24 holes today in no time 80mm diameter, proving to be a lot simpler and less messy than drill press & holesaw.

    Next task, I'm looking for draw studs that will allow me to use a range of Q.max punches.

    I have several of these but they too are all different threads. I can't be the only one that uses both, so if I can't find step-up or step-down draw studs or car manifold studs, I'll commission some. Right now (as I can't find my pitch gauges just now), I'm unsure as to what mine uses, the tech spec says 1.5mm thread, it isn't, it could be 1.25 or 1mm. When I get caught up I'll have a better look for my gauges and solve that puzzle, for now machine is doing the task I needed help with and doing it well.

    I like a bargain.
     

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