I need to make some square ( approx. 50*100 mm ) and round ( approx. 75mm
diameter ) holes in either 2 mm steel or 3 mm aluminum sheet..
I can cut the round holes using a holesaw ( bimetal body, carbide tipped )
in the drillpress, but how do I cut the square holes with a good result?
I have a drillpress ( cheap one ), but I am willing to invest some money (
not a fortune though ) in the proper tools if needed.. A CNC mill would be
nice, but not quite within the budget .-)
Any suggestions will be appreciated
/peter ( another one of those weird scandinavians )
That stuff is often best done with a punch.
Then there is also the drilling out of the hole and filing to size. This is
only done on a onesy type thing tho.
I think that Greenlee has a 1/2" square punch but am not sure.
Losing weight is easy! If you ever want to lose weight, eat and drink less.
Works every time it is tried!
OK.. I can get a limited selection of the Greenlee stuff over here, but 1/2"
is way too small, and I dont think it would work too well if I try to make
overlapping holes ( to get the size right) with a punch ?
The excact dimensions of the square hole I need is 45*108 mm ( 1 mm oversize
os OK )
Another punch-question: I am about to order some Greenlee punches for the
smaller holes I need to make, but from the litterature I can get on the
Greenlee Slugbuster series I cant see if they come with the needed drawbolt
or not... Does anyone know?
I don't know what will be included, it's probably best to confirm that with
There are thrust bearings available for the drawbolt to rotate on, and these
are great for punching with a wrench/ratchet/socket by hand. The plain bolt
will get tedious for numerous holes done by hand.
Another thing to check on would be the head size of the drawbolt.. they have
some square heads that you might not have a socket for, so you might want to
be sure to get the hex head drawbolts in a size that your tools will fit.
For the square holes, while it would be a PITA, you can make a layout,
drill the corners (larger diameter than a blade is wide), then cut the
entire square out with an electric saber saw (jig saw?). Certainly not the
best way to go, but it does work. Be certain to match the blade to the
job at hand if this becomes your choice. Drilling the corners allows for
the blade to make the 90 degree turn, if that isn't obvious to you. This
would be relatively easy with aluminum, not so great in steel.
I agree, if you can get a Greenlee punch that would work, that's the best of
all worlds, even if you have access to a mill. The only thing better would
be a large punch in a proper press. A mill would not address the sharp
corner I assume you desire. .
You may find a specific puch at mcmaster carr http://www.mcmaster.com/ for
the bigger hole - something like an LCD window puch or you can have it
custom made - then you need the hydraulic press to run it - but be prepared
to pay a lot of money - you may be better off producing your panel/faceplate
in a drawing / cad program and farming the work out to someone with a
laser/water jet cutter or if you don't mind a little cleanup a CNC plasma
cutter - for 50 to 100 or so it would be way cheaper than a big punch/die.
If your product starts to move and you need more then you might want to
consider spending the money for the equipment.
The other option is to do it by hand (small square puch the corners then
cut the rest) but given that you have other holes to make and of various
sizes - you would be better off hiring it out - the added advantage is that
you can be spot on with placement & accuracy everytime.
I hate hiring out myself, but when I have produced face panels and such this
has been far more economical (and time saving) than the the Do It Yourself
Answering my own post but... go to http://www.mcmaster.com/ and look at page
2124 of the catalog (DIN punches) the 45mm (1.77in) is no problem but they
only go to 92mm (3.626in)
and the price is US$549 - and then you still need the hydraulic press - like
I said - farm it out
Well I dont need it a 100% perfect fit, but I do need to be able to mount
DIN rail GFCI and fuseblocks thru the holes, while keeping a good
appearance, so I am thinking up to 1 mm oversize will be OK..
You tell me :-)... Sheet is either 2mm steel or 3 mm aluminum..
The 46*92 mm punch is the closest thing yet, but I need the width to be 108
mm ( I posted the excact dimensions somehwere in this thread )..
That hydraulic punch driver.. any clue on cost ?.... Would it be possible to
use one of those cheap hydraulic press thingies like this one?
http://www.biltema.dk/products/productimage.asp?iItemId 854 ( can get
this one for about 150$ wich I find cheap )... It is rated for 5 tons..
Square vs Rectangular :Just shows that I shouldnt post messages in a foreign
language when I got up at 4 am and worked for 12 hours :-)
I don't think that it would work well -- without a *lot* of
special fixturing first being applied.
The hydraulic drivers for the chassis punches -- only my belief,
as I have never had my hands on one, so others can fill in corrections
at will -- has a hollow piston on a cylinder at the end of a hose. The
base of the cylinder rests against the top of the die. A bolt is placed
though the hole in the piston, through a hole drilled or punched in the
sheet metal, and then threaded into the punch. (Hm ... this is for
round punches only. Keyed ones, and rectangular or square punches have
a screw with a keyed shape which goes through the die and the punch, and
(for the sizes which I have used), have a nut to draw the punch down into
the die (and through the sheet metal). Some more complex ones have three
drawscrews which go through the die and thread into the punch. (An
example of this is the one for the DB-25 connector mounting cutout.)
There needs to be some way to assure that the punch and die are
in proper alignment. Your hydraulic press won't do that by itself.
Neither will a single draw screw -- unless there are some guide pins to
either side of the screw to maintain alignment.
Anyway -- the hollow piston hydraulic slave cylinder is powered
by a hand-operated pump, or an electric one -- capable of 10,000 PSI
(sorry -- I don't know how many Pascals that would be -- not used to
Metric units of pressure yet.) Enerpac is one of the makers of such
pumps, and may be the maker for the Greenlee sets, for all I know.) I
believe that the cylinders in question can develop 10 tons of force from
10,000 PSI of hydraulic pressure.
Well ... "square" also can be used to mean "at right angles", so
"square" here distinguished it from round or a parallelogram or
trapezoid, so you can claim one of those meanings. :-)
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I don't know where you are, but you might be able to design and have
made locally a punch set to use in a cheap hydraulic press. My
thoughts on a design would be a punch of the right size with two holes
for alignment. And a die with two rods that align the punch. The
rods would be in the area being punched out.
You could put the punch on the material and get it aligned, then use
it as a drill guide to drill the alignment holes. If I were doing it,
I would have the alignment rods attached to a plate and the plate
attached to the bottom of the die with a couple of dowel pins and a
couple of screws. After punching several holes, you could unscrew the
screws holding the rods and push the scrap on through the die.
Please note that I have never made such a thing, so there might be a
bunch of problems that I did not consider.
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