Subject: Re: Hole Saw Clogging

From: [email-masked] (Ray Spinhirne)
Date: 15 May 1996 04:17:48 GMT

Edk4 ([email-masked]) wrote:
: Does anyone have a solution to the problem of *chips clogging the groove*,

: when you're trying to cut a hole in metal or plastic with a large diameter
: hole saw?
: Once the saw cuts deeper than the gullets of its teeth, my troubles begin.

: Any saw, over about 1", begins to scream and overheat very quickly, even
: with
: lots of lubricant and slow SPM. The problem seems to be that there's no
: easy
: way to get the chips out of the groove. Simply lifting the saw and
: brushing off the
: teeth doesn't solve the problem. 

: Is there a way to modify the saw (maybe with slots to bring the chips up
: out 
: of the  groove) or is there a particular type of lubricant/coolant that
: will make 
: a difference?

: I've even tried cutting a 3" hole in a piece of 5/8" Aluminum plate, on
: the lathe,
: using back gears at the lowest speed (probably about 60 RPM)  But, despite
: frequently withdrawing the saw, cleaning off the teeth and applying as
: much
: AlumTap as possible, it was a *very* long, nasty, noisey and tedious job.

: ------------------
: Ed Kingsley 

When doing work in a drill press I have had good luck by simple drilling
a 1/2 inch or so hole tangent to the outside of the hole you need drilled.
(On the inside of the larger hole if the outside is the "good" part
or on the outside of the larger hole if what you really wanted was the
"donut" ).  I have used this in 3/4 inch AL plate in order to cut blanks
for gears or pulleys with good success with up to 2 1/2 inch holes (my 
largest hole saw).  I have found some of the softer AL is very hard to work 
with any tools as it always seems to bond to the tool no matter what
cutting fluid I use.  I have been able to get some indication of the
ease of cutting when selection the next bit of scrap AL by hitting the
part.  If it rings that seems to mean it is fairly hard and easy to
machine, if it has a dull thud then I usually leave in the pile at the
scrap yard.

---

From: [email-masked](Alan D. Bartz)
Date: 15 May 1996 01:53:17 GMT

In <[email-masked]> [email-masked] (Edk4) writes: 
>
>Does anyone have a solution to the problem of *chips clogging the
groove*,
>
>when you're trying to cut a hole in metal or plastic with a large
diameter
>hole saw?
>Once the saw cuts deeper than the gullets of its teeth, my troubles
begin.
>
>Any saw, over about 1", begins to scream and overheat very quickly,
even
>with
>lots of lubricant and slow SPM. The problem seems to be that there's
no
>easy
>way to get the chips out of the groove. Simply lifting the saw and
>brushing off the
>teeth doesn't solve the problem. 
>
>Is there a way to modify the saw (maybe with slots to bring the chips
up
-snip-
>------------------
>Ed Kingsley 
Ed,
I usually drill a chip relief hole through the piece tangent to the
inside of the hole saw's path.  usually a 5/16" or so.  the chips
simply fall through the hole and don't accumulate to clog.  This also
works great when cutting hole in wood with a hole saw.

Hope this helps,

Alan

---

From: [email-masked] (Felice Luftschein)
Date: Wed, 15 May 1996 20:18:41 GMT

I've cut holes in aluminum with cheap hole saws, and it's important to lift 
the head up as soon as it stops freely cutting, stop the drill press, and 
using a hook or dental tool take the chips out of the cut circle groove, and
the hole saw itself (a lot of chips get packed into the saw body) Also, flood
the cutting area with oil. A slit in the saw body would help I guess, as would
injecting coolant through the spindle.

In article <[email-masked]> [email-masked] (Edk4) writes:
>From: [email-masked] (Edk4)
>Subject: Hole Saw Clogging
>Date: 14 May 1996 20:34:35 -0400

>Does anyone have a solution to the problem of *chips clogging the groove*,

>when you're trying to cut a hole in metal or plastic with a large diameter
>hole saw?
>Once the saw cuts deeper than the gullets of its teeth, my troubles begin.

>Any saw, over about 1", begins to scream and overheat very quickly, even
>with
>lots of lubricant and slow SPM. The problem seems to be that there's no
>easy

>Is there a way to modify the saw (maybe with slots to bring the chips up
>out 
>of the  groove) or is there a particular type of lubricant/coolant that
>will make 
>a difference?

>I've even tried cutting a 3" hole in a piece of 5/8" Aluminum plate, on
>the lathe,
>using back gears at the lowest speed (probably about 60 RPM)  But, despite
>frequently withdrawing the saw, cleaning off the teeth and applying as
>much
>AlumTap as possible, it was a *very* long, nasty, noisey and tedious job.

---

From: [email-masked] (Robert Grauman)
Date: Wed, 15 May 1996 23:11:30 mountain

It sounds to me like you are doing everything right.  I just cut 24 2" holes 
in 1/2" steel plate.  I ran at 38 rpm on my (big) drill press, and used plenty 
of Rapid Tap.  The saw has to be cleared of chips very often.   A second too 
long in the hole will result in chips packing the teeth.  I use a stiff flux 
brush to clean the saw and apply the Rapid Tap.  I have found that decreasing 
the speed will invariably stop the squeeling, although sometimes increasing 
the feed pressure will quiet it down.  It is indeed a tedious job.

				RJG

---

From: Steve Wellcome <[email-masked]>
Date: 17 May 1996 12:48:54 GMT

Wot he said...drill a "drain hole" for the chips somewhere along
the cut.  It helps a lot.  Maybe use some lubricant stuff to keep
the chips from welding to the saw teeth, if they have a tendancy
to do that.

---

From: [email-masked] (Raymond Frye)
Date: Thu, 16 May 1996 17:28:00 -0800

References: <[email-masked]> 

Ed Kingsly wrote:
EE> Does anyone have a solution to the problem of *chips clogging the
EE> groove*, when you're trying to cut a hole in metal or plastic with a
EE> large diameter hole saw?
<snip>
EE> Is there a way to modify the saw (maybe with slots to bring the
EE> chips up out..<snip>

EE> I've even tried cutting a 3" hole in a piece of 5/8" Aluminum plate,
<snip>
EE> it was a *very* long, nasty, noisey and tedious job.
--------

You might visit your local machine tool vendor and ask about boring
cutters (names like HoleHog, RotoBroach,...). They look a bit
like a shell reamer and cut leaving a center slug. The good news is no
centerdrill is required and interrupted cuts still come out clean. Bad
news is it costs more and is not a hand drill operation.

If you go the whole route and get a gear reduction mag drill set-up it's
easy to spend over $2k. But with that we can cut a precise  1 5/8" hole
in 2" thick 304 SST in under 20 minutes including set-up. The cut takes
about 2 minutes because we like a smooth cut. With a lathe or mill you
just need the cutter.

For our application we follow up with a disk of sandpaper on a stepped
mandrel to get a finish for an O-ring face seal then switch to a stepped
plate with 4 drill bushings that bolts in place for drilling holes to
tap for M6 screws. We end up with a NW40 port in under 2 hours anywhere
we can rig the mag drill. On a side note I was able to punch my Ford
truck bumper to 1" during a 1/2 hour lunch including clean-up.

Ray

To save mail: The mag drill is attached to mild steel rigged in place or
              rigged of a forklift to drill 304 SST.

 * RM 1.3 02229 * Save Skippy!