Greenlee Punches

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critterkllr

Well-known member
Joined
Nov 5, 2010
Messages
311
Location
Dearborn, MI
I want to buy some Greenlee punches to cut out my own faceplates and chassis. I've used a uni-bit before, but otherwise I'm pretty inexperienced at metal work. What is the actual thing that you use to screw the punch down? Is it a draw stud? Is this it? http://www.mouser.com/Search/ProductDetail.aspx?R=00042virtualkey58610000virtualkey586-00042

Can anybody chime in on common sizes for pot, jack and switch cutouts? I'd like to compile a list of what I'd need to handle most faceplates and chassis. This stuff is kind of scattered everywhere and I can't find most of them.

Neutrik XLR 15/16" - http://www.mouser.com/Search/ProductDetail.aspx?R=730BB-15/16virtualkey58610000virtualkey586-3808
Alpha 16mm pot - 9/32" (7mm) -
Alpha 24mm pot - 5/16" (8mm) -
Switchcraft Open Frame 1/4" jack - 3/8" (10mm) -
Neutrik M Series 1/4" Jack - 1/2"?? (11.4mm) - http://www.mouser.com/Search/ProductDetail.aspx?R=730-1/2virtualkey58610000virtualkey586-3801

 
Perhaps for the XLR hole but I've never seen greenlees used for small holes. The greenlee will need a small pilot hole itself to work. The greenlee is a two piece self contained punch and die set that uses a threaded bolt to drive the punch through the metal, the die behind the metal insures a clean hole.

Greenlee are especially useful for unusual shapes and larger holes.

JR
 
Usually use these...and a file, easy when you get used to them,
And far cheaper

http://www.amazon.co.uk/Stepped-hole-Cutter-Titanium-Coated/dp/B000PTO520/ref=sr_1_2?ie=UTF8&qid=1408636393&sr=8-2&keywords=stepped+hole+cutter

For Deburring

http://www.vargus.com/Shaviv/

;)
 
Gold said:
I think you would be better off staying with the step bit. Punches are made for sheet metal and don't work particularly well on aluminum.

Odd...For decades, I've used Greenlee punches on aluminum (up to 1/8") panels with no probs.  I guess I'm unskilled with a "Unibit" since I always went "one toke over the line" and ended up with an oversized hole.

Bri

 
Brian Roth said:
Odd...For decades, I've used Greenlee punches on aluminum (up to 1/8") panels with no probs.  I guess I'm unskilled with a "Unibit" since I always went "one toke over the line" and ended up with an oversized hole.

Bri

I always found that the punch needed a lot more elbow grease than the unibit. I keep a caliper at hand when using the unibit and go slow when I'm getting there.

I use stick cutting wax too. It makes for a pretty clean cut. Then I use a deburr tool to take off anything left. You can also run the unibit slow from the back of the panel to take off any burrs.
 
I've used punches for the XLR's on every single Gyraf unit made to date, both on steel and alu. For 16mm or less, I use drill bits.

g1176_construct02.jpg


Jakob E.
 
Thanks for the input everybody. Sounds like I'll stick to a unibit for everything except the XLRs. Normally, by the time I'm done drilling, the holes aren't lined up precisely anymore. I was looking at the punch as an easy solution for a cleaner and better aligned cut.

So, the draw stud and punch are the only two things I'll need? Is there another piece to it?
 
I wish i had known the bliss of hole punches from day one of my panel work. Oh the amount of back panels i have ruined with stepped drills. Those things require skills i don't have and higher quality additional tools that i don't know. I am happily punching xlr and other holes through 4mm aluminum these days with perfect clean results.
 
My panel drilling/punching steps:

1.  Apply masking tape to the panel.

2.  Using a metal ruler which is marked with 1/32" increments, lay out various "grids" for the various holes on the masking tape with a fine-tipped ballpoint pen.  I also make a note on the masking tape of the final hole size, be it drilled or punched.

3.  For each hole to be drilled, use an awl (pointed tool, with a tip that looks like a small nail) and a hammer to tap an indent through the crosspoints on the masking tape, and thus an indented "dimple" onto the underlying metal piece.

4.  Drill 1/16"  pilot holes using the indents made with the awl.

5.  With pilot holes drilled, then finish each hole with the drill to the final desired size.

Use a piece of wood behind the panel while drilling.  The masking tape also serves as a surface protector for the panel while drilling.

My holes are always perfectly located...if I laid it all out correctly in "step 1"  <g>

As I mentioned, my Unibit skills are my weakness, since I seem to invariably drill out the holes with too large of a diameter.  Hence, my large collection of Greenlee punches.

Bri

 
critterkllr said:
TNormally, by the time I'm done drilling, the holes aren't lined up precisely anymore. I was looking at the punch as an easy solution for a cleaner and better aligned cut.

It's very difficult to get things to line up. My method would work with a punch or a step bit. I do the same thing as Brian. I measure, scribe and use a center punch to mark the center drill holes. Having a square helps keep everything straight. I raise and support the material on 3" square aluminum tubing. A piece of tubing at each end of the panel. Also one piece of tubing that I move around under the panel for support while I'm drilling. That way there is open space under the panel for the drill to go through and not hit the table. This way you don't generate saw dust or go through wood panels.

If you need more than a few xlrs then lining them up straight is important. After the center holes are drilled I clamp a straight edge to the panel where the upper edge of the xlr is supposed to be. Then i use an xlr connector as a template while keeing it firm against the straight edge. I use a transfer punch of the correct diameter to mark the screw holes. This makes things come out well.
 
I feel the need to add that whether you're using a punch or a step bit, squirting a little cutting oil (or even a shot of WD-40) on the bit and/or the material can make a world of difference with the ease and cleanliness of your cut. Not to mention it will undoubtedly preserve the life of your bit/punch.
 
I like the stick cutting wax like this http://www.mcmaster.com/#lubricant-stick-wax/=tebtcr  It binds to the chip but doesn't run all over the place. It wipes off clean with acetone or alcohol.
 
These are my desert island layout tools. From top to bottom. Combination Square, assorted Rulers, Caliper (inch, decimal inch, and mm), Scribe, Center Punch, Dead Blow Mallet.

I use other stuff and have more of the same but I could get it done to my satisfaction with these for layout.

LayoutTools.jpg
 
I'm missing two, both of which I've not known of their existence and have hacked away their function thru other means. Thanks for the ideas, I have a shopping list now and it's cheap. Also due to some moronic twist I had forgotten how useful a combination square is.

[edit]

One important detail that is missing and may not be immediately obvious is that none of the above work perfectly unless you have a drill press. It can't be an entry level model either due to stepped drill requirements. I don't, and I've had to resort to drilling by hand which even with perfect technique only gets there 90% of the time. This is mainly why a stepped drill is out of the question for me.
 
Kingston said:
One important detail that is missing and may not be immediately obvious is that none of the above work perfectly unless you have a drill press.

I started with a drill press but now I use a hand drill for everything. As long as you mark and scribe everything accurately I think it's faster and just as accurate (for relatively thin material). I use the Taig mill only for things i can't do any other way. Since the mill is really too small for what i need it takes forever to clamp, mill, move, clamp, mill, repeat. It's also very difficult if not impossible to move the work piece and maintain good accuracy. I consider it a big success to get within 0.01". A real machinist goes for 0.001"

I like using a small 3/8" capacity hand drill. I use a Hitachi D10VH which wasn't expensive. I lust after a Fein BOP6 but at eight times the price of the Hitachi I can't really justify buying it.

I have a radial arm drill press which allows for large work pieces. Even with the capacity to hold a large piece like a bottom panel you have to clamp and unclamp a million times. It takes forever. I disassembled my drill press because i don't use it and I don't have room to keep it set up.

The thing I have spent the most time figuring out is how to hold the workpieces. I've never heard it mentioned around here but just like everything else, setting up the job correctly is a large portion of the battle. I have a lot of  C clamps including very large ones to be able to reach in far on a table. There are all sorts of fancy clamps you can buy but I've found a simple C clamp to be the most useful.
 
I'm quite surprised you choose hand drilling over any press.

Gold said:
I consider it a big success to get within 0.01".

I hold a similar standard usually hitting somewhere between 0.3-0.6 mm accuracy (maybe 0.01-0.02" it seems). But only for back panel work and with drill bits (hand drilling still a no-no for stepped drill bits). Having gotten used to CNC front panel work I don't see myself ever touching front panels by hand except for final installation. Let the robots do the only thing they do really good. I occasionally screw up the CNC (dxf file) measurements by some fraction and proceed to file away or somehow pad the mistakes by hand. These are prototypes afterall. 1-2 more stages of that and they'd be ready for mass production I assume.
 
Kingston said:
I'm quite surprised you choose hand drilling over any press.

The reason I choose to use a hand drill over a drill press is to get similar accuracy but faster. I found using the drill press tedious.

I am making face plates because I'm building a whole console. I started almost 10 years ago and would have spent thousands of dollars on prototypes. I ended up spending thousands of dollars on tools. A much better use of funds IMO. I am also a computer phobic. I don't know how to use any CAD/layout software and I knew I would make many mistakes if I tried to design something without being able to look at it first. Then all i would have to show for it is a big pile of bad face plates.

The face plates I'm making are obviously not practical for a commercial product. Even a simple one takes hours. I really enjoy making them though. Just like electronics I never imagined i would be so into metalwork.
 
Gold said:
I am also a computer phobic. I don't know how to use any CAD/layout software and I knew I would make many mistakes if I tried to design something without being able to look at it first. Then all i would have to show for it is a big pile of bad face plates.

Let the robot spit out a couple of completely horrendous and scary things while it tries to rip itself apart from sheer amount of misguidance and bad tooling set up. It'll get the first fear out of you even of the only thing you have to show for is some bent and/or scratched useless metal. Then even accidentally guide it to do inverse cuts (you're only left with the bits you meant to throw in the bin). Oh yeah I've managed all that - and through subcontractors! :D Anyway later on there's always the first perfect and perfectly replicable result.
 
I have been designing product packages for decades and i really love the modern 3d cad that allows us to avoid making stupid mistakes that used to take us multiple prototype attempts in the past to find.

There's always small stuff to fix but the big mistakes don't happen any more.

JR

 

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