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Piercing thick sheet


#1

I’m working on a project that requires a significant amount of
piercing on many small pieces of 1.4mm thick sheet. This is thicker
sheet than I am used to working on. I find that I’m having problems
with binding blades and blade breakage that I don’t have on thinner
sheet. I’m using 3/0 blades (good quality) and a Knew Concepts 3"
frame (one of the early models). I can’t use a heavier blade and
still get the detail that I need. Any tips or ideas would be
appreciated.

Thanks in advance,
Jamie


#2

Try,

beeswax, candle wax, car engine oil, gear oil, domestic soap, wash up
liquid 50 50 with water, lathe cutting fluid, ie, water miscable oil,
looks like milk, Whatever works best for you. just try all or any on
some scrap.


#3

Use heavier blades to rough out the holes then come back in with the
3/0 to clean up

James Binnion
James Binnion Metal Arts


#4

I used to have lots of breakage with the Knew Concept saw, but found
that I was tightening my saw blade too tight–probably just because I
could! :slight_smile: Once I backed off the breaking stopped dramatically. Just a
thought!

Beckie


#5

Jamie, I don’t do a lot of piercing, and I’m sure you know more about
it than I, but a thought did come to mind. I assume you’re
lubricating your blade? It certainly keeps it running smoother and
lasting longer.


#6
Try beeswax, candle wax, car engine oil, gear oil, domestic soap,
washup liquid 50 50 with water, lathe cutting fluid, ie, water
miscable oil, looks like milk, Whatever works best for you. just
try all or any on some scrap. 

I forgot to mention that I was using beeswax. Turns out that 99% of
my problem was related to sawblades. I open up a new package of
blades today. I sawed for over an hour before I broke a blade.
AMAZING. Just goes to show that sometimes the variables that you
"think" have been eliminated, haven’t been.

As an aside, I received an offline recommendation to change from
beeswax to camilla oil with enough and justification for
me to order some to try. Thanks to B.L. for sharing this.

Thanks everyone for your comments,
Jamie


#7

Jamie, if you’re using lube , then the blades are most likely binding
because you’re not able to hold the saw frame consistently vertical.
I’d suggest getting one of the Knew Concepts saws that has a guide
built in. It’s possible you’re not tightening the blades enough.
Sawing steel for dies, sometimes 2+ mm thick, using a guide and lube
(though lube sometimes makes the blades saw crooked), the only
binding issues I have are when the saw stroke goes a little too far,
and catches where the teeth are phasing out.

Shelton
http://www.sheltech.net


#8

Hello Jamie,

There are a couple things to consider, saw blade size and
lubrication.

The correct sized blade has three teeth on the metal at a time. I
think you need a heavier blade. According to Tim McCreight’s “The
Complete Metalsmith”, 1.4mm sheet is about B&S 15 gauge, for which
the chart in the book recommends using a blade size of 5.

You are probably using a lubricant - or at least you should be. :wink:
In addition to lubricating the blade, rub the wax or whatever on the
metal, along the line you will cut. I have also had good results with
using Oil of Wintergreen as a lubricant - advantage is the fresh
smell!

Since you are using the Knew Concepts saw, your tension should be
good - it should give a nice high-pitched “ping” when you pluck the
blade… you probably knew that!

Hope this helps,
Judy in Kansas, where it’s a coolish day and the turtles are sluggish.


#9

Some folks swear by spit (saliva); I’ve tried it and it does work
pretty well. Of course some will be deterred by the ick factor. :slight_smile:

Ruthanne Robertson
Metals & Silversmithing, Art Department
Johnson County Community College


#10

Judy,

Thanks so much for taking the time to reply. Your replies are always
so insightful and kind.

I’ve learned a lot in the past 40 hours of piercing.

The reference to three teeth on the metal at a time is a reference to
the minimum of teeth, and will give the fastest cut rate (learned
from owning a metal machining company for 25 years) LOL. I needed to
use the size 3/0 on this thick metal because of the fine detail that
I needed to cut out. It would have very vague definition with size 5.

Yes, I’ve been using beeswax. I started out using it regularly and
consistently. When I solved my blade problem (see below) I started
using it sporatically. And by about the 20th hour, I almost didn’t
need to use any. Totally the reverse of what we are taught…
however… I know from highspeed metal machining that the only
reason that we use any lubricant is (a) to keep the cutting tool
from getting too hot and losing its temper or (b) to keep the
workpiece cool enough to cut temperature-sensitive dimensions
(usually ten-thousandths of an inch or less). So it makes sense to
me that in this biz, we really don’t need lube on manual tools like
a saw (but yes on flexshaft tools).

It turns out the my #1 problem was the quality of the saw blades
that I was using. I’m embarrassed to say that I think they were a
package from Harbor Freight that made their way from the garage.
Once I opened a good pack of 3/0 blades, it solved 99% of my
problems.

The next 1% of my problem was solved when I realized that I was
tightening the Knew Concepts Saw TOO TIGHT. All “pings” are not
created equal, and just because you can tighten them that tight
doesn’t mean that you should!!

Once these problems were resolved, I’ve been able to get up to 2
hours cutting time off one blade. And every time I pop one, I know
what I’ve done wrong. So, I was pretty happy with myself, and began
to use Lube less vigorously… and then less… and then none. No
change in my cutting speed or blade popping. But big plus in
productivity, because all of the swarf blows off easily and I can
see the pattern that I’m cutting without having to stop and wipe the
metal clean. Who knew. The lube thing covers up skill problems, as
do larger size blades. Maybe we should all have to do projects like
this when we’re learning.

Upside: The probject is done and I’ve learned a lot about piercing.
Downside: I think I kicked up tendonitis in my right wrist from
repetitive motions. Fortunately, I’m going on vacation tomorrow!!

So thanks for letting me tell my WHOLE tale to someone,

Jamie


#11
The correct sized blade has three teeth on the metal at a time. I
think you need a heavier blade. 

It sounds as though you may have resolved your difficulty, but I
still want to comment. I do a LOT of very detailed piercing, and,
though I like to use very small blades, I find that I can get the
same fine detail with larger blades-- though for me, “larger” is
usually not more than 2/0, as I generally use 4/0 or 5/0. I’m betting
you could go up a size or two without it actually being any problem.

Noel


#12

You also may want to use a precision sawing guide to keep the
piercework perfectly perpendicular to the sheet, especially if the
design is intricate, with a lot of piercing.


#13

Good on you, Jamie,

I’m glad you persevered and worked your way through the problem.
Thanks for sharing your discoveries and lessons learned! That thing
about using quality blades - yeah. You make a valuable and important
point, especially for newbies. In the big picture, the cost of a
better saw blade is minor when it lasts longer and causes less
frustration.

Interesting comment about tension. I go for a ping that is E flat
over high C, or thereabouts. :wink:

Judy in Kansas, where it’s time to get another pick-up load of
compost and the strawberries are ripening.


#14

The 3 teeth rulke isn’t something written in stone ; more like a
generalization about optimum performance, not universally true in all
situations. One situation I have all the time is sawing 1/16" thick
tool steel with a #1 blade, which works out very close to exactly 3
teeh for the thickness of steel, but it’s not necessarily the fastest
blade. I can saw faster with a #2 blade but it’s physically more
demanding, and since using a bigger blade also requires increasing
the sawing angle on pancake dies - which is where I do almost all my
sawing these days- I choose not to do it. It’s mostly because of the
added difficulty.

I also use the same #1 blades on thinner steel, which violates the 3
teeth rule (less than 3 teeth), but I do choose to do that often,
precisely because I can saw faster with a #1 than with a #0 or #1/0,
and pushing the #1 is within my comfort zone, and in spite of the
fact that it increases the angle. It gets a little complicated
explaining it all in detail, but basically I use as big of a blade as
I can most of the time, because bigger blades saw faster, until I
start to run into the wall of difficulty. The wall is ok to launch
one’s self at sometimes, but I do have to pace myself and be careful
of repetitive stress issues.

Anyone who’s tried sawing 1/16" tool steel with a 4/0 blade will
understand my desire to do that as infrequently as possible, and only
when required to do so in order to obtain sharp detail. In general, I
choose blade size determined first by degree of detail required, and
as stated, I go with the biggest blade I can get away with, up to #1
and sometimes #2.

Lube is a funny thing ; I use beeswax when I use anything, because it
causes less steel dust to stick to the die plate. Sawing dies,
keeping the blade cool is not the only reason to use lube ; lube can
help blades from binding when the steel shifts and tries to pinch the
blade. It also functions like it does in an engine to some degree; it
prevents metal on metal wear, which is definitely an issue sawing
tool steel. I said a few days ago that wax can also cause blades to
veer off course, which may sound weird, but it does happen, though
I’m not sure why. It’s more than a little annoying to have a perfect
line going, put some wax on, and have to fight to keep it going, or
have your butt kicked by a stupid blade (^;. Sawing normally, with
the sawing hand doing the turning, I don’t recall ever noticing this
(and I was exceptionally good with a saw long before I took up die
sawing), but with dies, the sawing hand doesn’t do the turning, so
the difference is noted in adjustments that have to be made in
turning the die plate as you saw around your design. There’s no
question that wax helps cutting tool steel. I wouldn’t use a tap or
threading die without oil or tap lube, so it isn’t 100% about keeping
the tool cool in all situations.

D. Shelton
http://www.sheltech.net


#15

Sarah,

You also may want to use a precision sawing guide to keep the
piercework perfectly perpendicular to the sheet, especially if the
design is intricate, with a lot of piercing. 

This particular probject is piercing entirely curved shapes.
However, I amcurious what is a “precision sawing guide.” Thanks,

Jamie