disappointing results with aluminum

Joe:

A Dremel motor tool is the wrong tool.

You should get either a metal cutting bandsaw, a table saw,
or mitre saw.  For the table saw or mitre saw you need a
carbide blade.  It cuts through aluminum like butter.
Note that hot metal aluminum flakes can potentially
ignite the saw dust that tends to collect around
a table saw that is used for cutting both wood and
aluminum.

You should see if you can find a Harbor Freight retail
store in your general area.  They sell the same Chinese
import stuff that Home Depot does, but at significantly
reduced prices.  The reason for buying retail is so that
you can return stuff if it is a "lemon".  The fit and
finish of the Chinese import stuff varies all over the
map -- some is total junk and other stuff is quite
functional.  Buy it, try it out, and if it works,
keep it; otherwise return it for the cost of gas required
to drive it back to the store.

I usually cut aluminum on my bandsaw (an old Sears
Craftsman with speed reducer that predates Harbor
Freight by a decade or so.)  I prefer the bandsaw
because it is harder to cut off a portion of your
body with a bandsaw.  (Also, with the right blade,
my bandsaw will cut steel, which a table saw will
not do.)  I don't own a miter saw, but I suspect
that they are pretty safe, too.  I think the bandsaw
is a more flexible tool than the mitre saw; more
expensive too.  It is a real bummer that good tools
cost real money.  Sigh.

-Wayne

Based on what he seems to be cutting, a small bench top bandsaw may
work well.

If it were my fingers, I would prefer a bandsaw over any rotating
blade saw if an accident occurs.

A small bench top bandsaw would be useful in future robotic building
so it would be a good investment.

The small benchtop saws do work well with wood and aluminum...no steel
though without slowing the blade speed up alot and a different blade.

Also remember that when using a saw blade, one wants three teeth to
always contact the item being cut to prevent damage to the blade.

TMT

Wish you had asked before about this (or I overlooked it)
The Dremel is a great tool to have in your box, but it's a pain as you have
found out when you need to do a lot of cutting. No - it's not you. It really
is just a pain. See below for more info on better ways ...


Hey Joe. I just use a $99 Ryobi saw from Home Depot (like model # TS1341 ) .
I paid almost that much again for a special non-ferrous metal cutting blade,
but I do a LOT of cutting aluminum with it. You *might* not need a special
blade - just get one with as many teeth as possible and be SURE to wear your
safety goggles! Here's a link to the one like I use:
http://www.homedepot.com/webapp/wcs/stores/servlet/ProductDisplay?storeId 
051&langId=-1&catalogId053&productId0085278

Here's what I've learned from a couple of close calls:
1) Make SURE the aluminum is seriously clamped down.
2) After the cut is complete, continue to hold the saw down when you release
the power trigger and let the blade spin down. Only then do you let the saw
raise back up! Otherwise - you risk launching any free pieces like a missile
in an unpredictable direction.

Some other tips for cutting aluminum with what you have on hand are:
1) Mark the cut line with a sharpie or even pencil
2) Drill several holes down one side of the line
3) Use a hack saw to cut through the holes. This way you don't have so much
to cut with the hack saw.
4) To get a good finish (and SAFER, too) use a file to clean up the raggedy
cut line.

Also, the people on the metalworking newsgroup have been invaluable to me.
Sometimes there's a lot of Off Topic stuff posted on there, but just ignore
it ( or even read it if you just want to feel better about yourself ! Ha! )
The guys that answer your posts will be more than willing to listen to your
"dumb questions" ... just like they did - and still do - with me.

Here's the newsgroup:
                                        rec.crafts.metalworking

A couple of guys from this robot newsgroup show up on there now and then,
too. I would post on that group - telling them exactly what you want do -
and let them guide you in your tool selection. Then you can come back to the
robotics group for info regarding building the bot itself.

Good luck !
JCD

    You should be able to cut common aluminum alloys with a hacksaw
with very little trouble.  Are you using a metal cutting blade?
Also, when cutting aluminum, use liquid soap as coolant.
Get a bottle of liquid soap with a pump and apply to the cutting area.

    Did you possibly pick up some alloy like duralumin?  Most hardware
store stock won't be a hard alloy, but surplus might be.  If so,
just get a carbide hacksaw blade.

    You're using a real hacksaw, right?  Not a hand jigsaw.

    The way you get a clean edge is by cutting, then cleaning up with
a grinding wheel or file.  You can put a grinding wheel in the Dremel tool,
although a small bench grinder is more effective.  Wear goggles.

    This should be a three minute job with hand tools.

                    John Nagle

Thanks to all for the advice.  It sounds like the Dremel is, in fact,
simply the wrong tool for the job, but the hacksaw should have worked.

What I have really is a hacksaw, not a jigsaw; the standard kind with a
frame (but the frame is plenty big enough for this 1-inch angle stock).  
I don't know what kind of blade it is, though; it's just whatever came
with the saw when I bought it.  I'll look into getting a carbide blade
for it; it sounds like that's the best for cutting metal.  I also wasn't
using any lubricant or sealant; I'll try some liquid soap or cutting oil.

As it happens, there is a Harbor Freight right here in Fort Collins, and
I've been there a couple of times -- for some reason I often forget
about them when I run out for tools (probably because Home Depot and Ace
are both significantly closer).  I'll check them out today.

I did some searching for power miter saws yesterday; I'm glad to hear
that Pogo has had good luck with the Ryobi TS1341, since that's the same
one I was thinking about trying.  At $99, it's not bad for what will
probably be an extremely useful addition to my toolset.  I'm going to
have to wait a while before getting it, though, so it's still worth
seeing what I can do with hand tools.

Finally, thanks for the pointer to rec.crafts.metalworking; I've
subscribed and I'll probably follow up with additional metal-working
questions there.

Best,
- Joe

--
"Polywell" fusion -- an approach to nuclear fusion that might actually work.
Learn more and discuss via:  <http://www.strout.net/info/science/polywell/>

grinding aluminum is usually not much fun.  it is softer than iron and
has a tendency to gum up grinding wheels really fast.  circular saws
will generally produce much cleaner cuts than band/hack saws since the
blade is stiffer.  i've found the best way to make aluminum look
pretty is to cut it a little large then finish it on a mill, but doing
that is seldom worth the effort.

also, you may want hearing protection in addition to goggles.  i
suppose this depends on the saw/blade/clamps/material/etc, but i've
generally found that when sawing aluminum the noise is much more
irritating than the swarf.

if you don't have the right tools and are not overly price or accuracy
sensitive, onlinemetals.com will, for a fee, do custom lengths in
small quantities.

-chris.

Worry more about the swarf and wearing goggles, after spending 4 hours
in the hospital I found its much harder for them to pick a non-
magnetic shard from the centre of your pupil than it is to get a chunk
of steel out :-)

A Dremel isn't good for applications like this, for exactly the
reasons you cited.

For cutting, I have had a great deal of success with hacksaws (I can't
imagine what the problem could have been with yours -- hacksaws cut
mild steel quite nicely, and barely notice aluminum) and jigsaws.
Drilling is also easy with a high speed steel bit.

A Dremel is totally unsuitable for this type of work, and something is
seriously amiss if the hacksaw did not even scratch the aluminum. You could
try a simple miter box - get a good blade for your hacksaw and it should
easily cut the aluminum.  A large clamp might also come in handy to hold the
miter box and the aluminum angle to your workbench while you do the cut;
that way it will be steadier and you can use both hands on the hacksaw which
will give you better control.

Buy a decent woodworking mitre box - they use saw blades which are about an
inch wide, give you a better cut than a traditional hacksaw.

This will give you perfect cuts in ali and mild steel - use a little oil
when cutting.

Make sure that there are at least two teeth in contact with material when
you are cutting - this will usually mean going for 24 tpi blade or finer. It
is ok to use a fine blade on thick material, but it will seem slow, the
teeth will tend to clog with the swarf.

OK, your blades will have a comparatively short life when cutting steel, but
they are cheap to replace and everything is safe and controllable ! I have
cut slices off a 3 inch steel bar in about 5 minutes.

Another gadget worth knowing about is a 'sheet metal saw'. This can do
infinite length cuts, unlike a normal hacksaw where the frame gets in the
way.


Dave

1/6" is a funny number. Is that a typo from 1/16" ?  If it is 1/16",
that is pretty thin stuff and sheetmetal shears or tinsnips are the best
answer. 1/16" is too thin and floppy to saw very well.

If it really is 1/6" (0.1667"), then the saws that others have mentioned
will work well. For power tools, a saber saw will work. A small
horizontal bandsaw will be better for angle stock and tubing. A vertical
bandsaw works pretty well for small sheet parts, but large parts get
into trouble on the back side of the vertical bandsaw. To use hand saws,
you really need to clamp the work to something. If you are cutting
angles, a simple miter box with the work clamped to one face works as
well as any hand saw arrangement.

Working with the mechanical bits is as much a skill as the electronics
or software. If you could find someone local who has the skills and
tools to help you through the first project or two, it would be a good
thing. It is the path that many people have taken.

Good Luck,
Bob



and also some

Yes, good catch; I meant 1/16".


Hmm, that's an interesting thought.  It doesn't seem at all floppy to
me, but that's probably because it's angle stock; I did notice that flat
stock of the same thickness was pretty floppy.

I just bought a cut-off saw, but if that doesn't work out, mayble I'll
give the tin snips a try.


No doubt.  I asked on my local club mailing list, and didn't get any
takers, so I guess I'm on my own -- with the help of kind folks here and
in rec.crafts.metalworking.

Thanks,
- Joe

--
"Polywell" fusion -- an approach to nuclear fusion that might actually work.
Learn more and discuss via:  <http://www.strout.net/info/science/polywell/>

I would suggest you put a better blade on your hacksaw to be honest,
angle is a bit unpleasant to cut at the best of times, but I can use
my junior hacksaw to cut inch by inch by 1/8th stainless steel angle
in 5 mins, alu should be no problems at all!

As others mentioned, a [good] hacksaw blade [chuck the one you have if
it won't cut soft aluminum!] and miter box will work fairly well. If
you're going to build an entire large robot this way, you might invest
in a cut-off saw. On sale now.

http://www.harborfreight.com/cpi/ctaf/displayitem.taf?ItemnumberD829

They should have them at Harbor Freight in Ft. Collins. [BTW, Ed.Rupp
in FRRC has one].

Forget the following one, it's a total piece of crap. Use for plastic
only, not metal as advertised ... get the real one above.

http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumberB307

Thanks -- I was there yesterday, and bought a similar item, also by
Chicago Electric, but that uses 6" wheels.  For the 1-inch stock I want
to cut, the size certainly shouldn't be a problem, and if it doesn't
work, I can return it.  (It was on sale for $18 -- a mistake,
apparently, but they manager let me have it anyway; the regular price is
$40.)

I'll try it soon, after carefully reading the manual and finding
something to put over my ears (I suspect that these abrasion wheels
scream like a banshee when cutting metal).  Will report back.

Best,
- Joe

--
"Polywell" fusion -- an approach to nuclear fusion that might actually work.
Learn more and discuss via:  <http://www.strout.net/info/science/polywell/>

Dremel tools are great for doing itty-bitty detail work. Other than
that, forget it.

A hacksaw with a good metal cutting blade should work. I use a sawzall
with a metal cutting blade and clean up the cut with a file and/or hand
grinder. 3 inch steel angle is a cinch this way.

--
Paul Hovnanian     mailto:Paul@Hovnanian.com
------------------------------------------------------------------
43rd Law of Computing:
Anything that can go wr
fortune: Segmentation violation -- Code dumped

Everyone has already responsed about the Dremel.

As I've said before, I built EVERY robot in the original Robot Builder's
Bonanza using only rudimentary hand tools, including a hacksaw I bought
at Builder's Emporium for $1.99. The drill I used was an old Black &
Decker that didn't even have a reverse or speed control on it. I discuss
using these tools in RBB, which you can get at most any library. I have
more indepth coverage on basic metalworking and tools in Constructing
Robot Bases, which  is out of print so you can probably find it in the
remainder bins.

Obviously, you need new and sharp blades made for non-ferrous metal.
Blades are different, with different teeth spacings and set. You
probably wouldn't get good results using a fork to comb your hair, so
likewise, there's always the right tool for the job.

-- Gordon

    --A hacksaw will cut aluminum without any problems. I suspect you've
either got the wrong blade or a dull blade; probably both! If you're
starting out from scratch with nothing but hobby tools the very first thing
you've got to do is get a good vise and bolt it to your workbench which is
hopefully not the kitchen table! Once you can hold the stuff you're trying
to cut in a good vise you can have at it with a new hacksaw blade.
    The next thing you should get are some decent files that you can use
to refine the edges that the hacksaw leaves ragged. After that you'll need a
hand drill or, better yet, a small drillpress and a good collection of drill
bits. Next thing to get would be a tap handle and some taps, then you'll be
able to make stuff and connect the dots.
    --For more on what you need to know you should go over to
rec.crafts.metalworking and find the FAQ (posted weekly) and give it a read:
it's a real education.. :-)

--
        "Steamboat Ed" Haas         :  A steaming pile of          
        Hacking the Trailing Edge!  :  obscure information...
                          www.nmpproducts.com
                   ---Decks a-wash in a sea of words---