Hi,
I have been searching with no solution, hopefully someone here has already
tackled this. I have a small Serpac case that I need to drill holes in. Of
course it is nearly impossible to make the holes stay on center from the
beginning of the pilot hole until you step up to the final size you actually
need. Then the controls are off center or out of line with each other. I
read on another forum where someone said they used a "self centering hand
punch" but I can't find anything suitable. Has anyone found anything? This
case is plastic so it doesn't need to be too heavy duty. Thanks for any
help.
FJ
Or you can buy punches from Mouser or Newark catalogs. However I don't
remember if theirs (Greenlee and another brand) included a hand operated
arbor or if they were only the kind with a lead-screw.
I get a LOT of use from mine, but there is the restriction that
the piece you are punching must fit within the "throat" of the
punch tool. Great for flat pieces like front and back panels,
not very useful for 3-d pieces like molded case tops/bottoms.
> Hi,
> I have been searching with no solution, hopefully someone here has already
> tackled this. I have a small Serpac case that I need to drill holes in. Of
> course it is nearly impossible to make the holes stay on center from the
> beginning of the pilot hole until you step up to the final size you actually
> need. Then the controls are off center or out of line with each other. I
> read on another forum where someone said they used a "self centering hand
> punch" but I can't find anything suitable. Has anyone found anything? This
> case is plastic so it doesn't need to be too heavy duty. Thanks for any
> help.
> FJ
At 11:05 AM 29/11/2004 -0600, you wrote:
>Hi,
>I have been searching with no solution, hopefully someone here has already
>tackled this. I have a small Serpac case that I need to drill holes in. Of
>course it is nearly impossible to make the holes stay on center from the
>beginning of the pilot hole until you step up to the final size you actually
>need. Then the controls are off center or out of line with each other. I
>read on another forum where someone said they used a "self centering hand
>punch" but I can't find anything suitable. Has anyone found anything? This
>case is plastic so it doesn't need to be too heavy duty. Thanks for any
>help.
>FJ
Hi
You don't say how big the holes are.... ,but
if you're drilling into plastic, you must use 'wood' bits. You're probably
using a 'steel' bit, which is a simple point. Below is the approximate
shapes. You'll have to excuse the art. I've used them and they work
beautifully in plastic.
I believe the 'proper' name for those wood bits is "brad point bit".
FWIW I perfer to do my panel openings on a small milling machine. Overkil
for sure, but they do come out nice :-)
-Denny
> Hi
>
> You don't say how big the holes are.... ,but
> if you're drilling into plastic, you must use 'wood' bits. You're
probably {Quote hidden}
> using a 'steel' bit, which is a simple point. Below is the approximate
> shapes. You'll have to excuse the art. I've used them and they work
> beautifully in plastic.
>
> steel bit
> ^
> / \
> / \
> | |
> | |
>
>
> wood bit
>
> . ^ .
> |\/ \/|
> | |
> | |
> | |
>
>
> Regards
> Roland Jollivet
>
Greenlee makes a lot of panel punches used by electrical contractors. They can be hand operated and can be centered on a small hole drilled into the encloseure. They are not cheap., and only come in sizes corresponding to standard conduit sizes.
-- Lawrence Lile, P.E.
Electrical and Electronic Solutions
Project Solutions Companies http://www.projsolco.com
573-443-7100 ext 221
Hi,
I have been searching with no solution, hopefully someone here has already
tackled this. I have a small Serpac case that I need to drill holes in. Of
course it is nearly impossible to make the holes stay on center from the
beginning of the pilot hole until you step up to the final size you actually
need. Then the controls are off center or out of line with each other. I
read on another forum where someone said they used a "self centering hand
punch" but I can't find anything suitable. Has anyone found anything? This
case is plastic so it doesn't need to be too heavy duty. Thanks for any
help.
FJ
In addition to the other excellent ideas given by others, I find better
quality holes in thin plastic using a "Unibit" stepped sheet metal drill,
compared with the standard drill bits for drilling metal.
For small holes (under 1/4") near an edge, I second the use of a
Roper-Whitney hand punch -- it yields clean holes.
If the hole you're making is >1/4", you might try using a hole-saw. I've
had good results in both metal and plastic cases, but the flimsy metal ones
need a decent backing for this to work. Harbor freight usually has a decent
selection of cheap smallish hole saws.
Have you considered the purchase of a small drill-press?
The last one we bought was $35.00 US and works better for small work than the Large one.
A homemade jig is bolted to it's plate and shims are used to position the additional holes.
On Mon, 29 Nov 2004 11:05:13 -0600, fred jones <boattowspam_OUThotmail.com> wrote:
> Hi,
> I have been searching with no solution, hopefully someone here has already
> tackled this. I have a small Serpac case that I need to drill holes in. Of
> course it is nearly impossible to make the holes stay on center from the
> beginning of the pilot hole until you step up to the final size you actually
> need. Then the controls are off center or out of line with each other. I
> read on another forum where someone said they used a "self centering hand
> punch" but I can't find anything suitable. Has anyone found anything? This
> case is plastic so it doesn't need to be too heavy duty. Thanks for any
> help.
> FJ
Any time you are drilling holes by hand, it is nearly impossible to
eliminate drill bits walking or being off-center. However, you can
minimize this by using a punch or awl or whatever to make an
indentation where you want the hole to be, then drill a pilot hole
with the smallest drill bit you have, then work your way up in size to
enlarge the hole.
Regards,
Bob
____________________________________________
> Have you considered the purchase of a small drill-press?
A good investment. And if you've bench room there are plenty of
cheap import workshop presses that are perfectly adequate for
hobbyist or light industry
> Any time you are drilling holes by hand, it is nearly impossible to
> eliminate drill bits walking or being off-center
If you've a few to do it can be helpful to have the pattern of holes
drilled into a wood or metal sheet (eg aluminium is easy to work
with at home). This is placed over the plastic, which has already
got pilot holes, and stops the bit wandering sideways
> > Have you considered the purchase of a small drill-press?
>
> A good investment. And if you've bench room there are plenty of
> cheap import workshop presses that are perfectly adequate for
> hobbyist or light industry
>
> > Any time you are drilling holes by hand, it is nearly impossible to
> > eliminate drill bits walking or being off-center
>
> If you've a few to do it can be helpful to have the pattern of holes
> drilled into a wood or metal sheet (eg aluminium is easy to work
> with at home). This is placed over the plastic, which has already
> got pilot holes, and stops the bit wandering sideways
If you're going to use a small drill press, I HIGHLY recommend
getting some of what McMaster calls "Combined Drill and
Countersinks". Basically, it's a big fat rod with a short drill bit
at the end. I can't really describe it; if you go to McMaster.com
and look at page 2316, you'll see what I mean (the long plain
style is what I prefer). They are a little pricey, but should last
a long time since you will only be doing a little drilling each time.
The diameter of the body means that you can start a fairly small
hole without walking (assuming your setup is rigid). Then replace
with the desired bit and drill away!
Mike H.
____________________________________________
> I have been searching with no solution, hopefully someone here has
> already tackled this. I have a small Serpac case that I need to
> drill holes in. Of course it is nearly impossible to make the holes
> stay on center from the beginning of the pilot hole until you step
> up to the final size you actually need. Then the controls are off
> center or out of line with each other.
Properly center-punched with sharp bits on a drill press with
the correct rotational speed, you should be able to hold the
larger holes centered on your original layout points.
For soft material like plastic or wood, you can use a brad-point
drill bit or a Forstner bit to make large holes in a single step
that are centered on the orinal layout point.
> I read on another forum where someone said they used a "self
> centering hand punch" but I can't find anything suitable. Has
> anyone found anything? This case is plastic so it doesn't need
> to be too heavy duty.
A Whitney punch works well if the item fits into the throat
of the punch. Whitney punch is similar to a heavy duty hand
paper hole punch. Punch & dies interchange from 1/16" up to
9/64" (in mine anyway). They can punch up to 16 gauge steel.
Thanks to all who gave help on this. The greenlee type punch is exactly
what I'm looking for. It self centers and cuts precise holes in the
original center. The problem is that the smallest size is 1/2" as they are
designed for conduit size. Similar punches in a smaller size would be
ideal. I found a similar type device that I would like to try but haven't
yet found a source to buy it. The manufacturer hasn't responded to my
inquiry. It's made by Osborne model K-156. I think it may be suitable but
don't know without trying it. The whitely punch doesn't cover the range I
need :(
Thanks,
FJ
At 08:11 AM 11/30/2004, fred jones wrote:
>Thanks to all who gave help on this. The greenlee type punch is exactly
>what I'm looking for. It self centers and cuts precise holes in the
>original center. The problem is that the smallest size is 1/2" as they
>are designed for conduit size. Similar punches in a smaller size would be
>ideal. I found a similar type device that I would like to try but haven't
>yet found a source to buy it. The manufacturer hasn't responded to my
>inquiry. It's made by Osborne model K-156. I think it may be suitable
>but don't know without trying it. The whitely punch doesn't cover the
>range I need :(
Couple of things: the smallest Greenlee punch I have is 1/2" - it has a
1/4" draw stud. They might make smaller but I haven't seen them.
Be careful when looking at punch sizes that mention conduit: a 1/2" conduit
knockout punch is actually 7/8" diameter. The Greenlee knockout punches
are nice in that the punches are marked with both sizes: the pipe size &
hole size. The punches I have from Enerpack have only the conduit sizes on
them. This is something that catches new guys in the shop.
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