I was going to use some of the same carbide burrs that I use to shape
steel to do some mild porting on an aluminum cylinder head. A friend
told me that burrs made for steel will fill with the soft aluminum and
Is this true? On one hand, I can imagine the soft aluminum filling
the bit making my raise my blood pressure to new record levels. On
the other hand, I'm not too sure this is would be true. However, at
$8.95 a pop, I'm much more incline to ask first and cut second.
Git a bar of parrafin(they usta use it to melt & pour on toppa homade
Zonk yore kutters in the paraffin-(-while runnin) FIRST and frequently
thereafter commencing the aluminium kuttin.---if werse comes to werse,
you may hafta
clean out the burrs with a pointy thing every once & a while...
It's true. The carbide burrs that are made for steel will clog up with
aluminum in a heartbeat. I don't know that it ruins them, but you'll spend
a hour with a sharp pick prying the wadded-up aluminum out of the grooves in
the bit. The bits that are made for aluminum are much coarser, and tooling
suppliers sell a wax stick to coat them with to keep them clean. They'll
still clog up sometimes, but there's only a few big grooves to pick the
aluminum out of instead of a whole bunch of little ones.
I should backtrack and qualify this. What Jerry said is correct. If you
just have a little metal to remove, and go very careful, a regular carbide
burr might be a better choice. The rough-fluted burrs will take a lot of
aluminum away in a hurry.
Jerry & Walt - thank you for the info. I spent quite a bit on my set
of carbide burrs for steel. I think I'll do some more digging at Enco
and MSC and see what they have.
If you have any recommended vendors, please let me know. I use
regular 1/4" die grinder bits and I'm just going to get 2-3 to get the
job done + the wax or whatever lube is recommended by the maker.
It depends to some extent on the aluminum alloy, and the nature
of the work. Soft aluminum, such as unalloyed (1000 series)
used for extrusions and soda cans are almost impossible to
cut with conventional cutting tools. Annealed aluminum alloy
can also be a pain. Solution heat treated alloys such as 2024-T5
and 6061-T6 are much easier to machine.
The second trick is to NEVER let the workpiece get hot! When it heats
up even a little, it gets much softer and gummier, and the ball or
snarled aluminum is the result. Various coolant schemes can be
used, from a squirt bottle of water to immersion in a tank.
Just keeping the tool moving so you don't develop local heating.
Cylinder heads will usually be a silicon aluminum alloy, often with a
lot of silicon and other alloying elements, and are pretty tough.
The mass of the head probably allows pretty good heat removal, too.
The wax idea is good, although cutting oil or "Edge-Lube" (a waxy
hydrocarbon cutting lube in a stick form) is probably better for
this. Keep the cutting tool loaded down at a lower speed, especially
with an air die grinder. With an electric flex-shaft or Dremel
tool, you can regulate the speed, so keep it moderate, and take light
cuts. I think you will find your friend is wrong, if you follow
these general suggestions.
The project in question involves doing a quick port job on a Toyota
cylinder head's exhaust ports. The block is a cast alloy, but I have
no idea just what kind it would be.
I see Enco has what they call "Carbide Aluma Cut Burs" and I'm
thinking of just getting the four I need, some wax and then have them
on-hand for the future.
First & most important thing to remember is if you use any cutter on steel it
will not cut very well (cleanly) from then on any aluminum.
Any softness or grade of steel will take the micro fine sharpness/edge off a
Price mentioned for your cutter would indicate a pretty cheap tool. (Harbor
Find a machine shop tool supplier & buy a better grade of cutter. More money
but- Much better to use & better finishes also.
Fine to medimum teeth on cutter is safest.
H.S.S. cutters cut cleaner then carbide ones also. Better (sharper) edge on
H.S.S. in new condition. Same for drills, lathe tools etc.
Carbide last longer generally. Either type will work reasonably well.
Dampening the surface /cutter is best way to help stop clogging of teeth. Wax,
bees wax, WD40 etc work well. WD40 cleans up easier on the many times you will
have to clean out & inspect the progress of work you are doing.
Keep chips/swarf cleaned out so you don't cut it all a second time.
Wear good eye protection also.
Best to do any larger size job at different times if you can. Git tired & a lot
of damage can happen real fast from a mistake. I usually do any larger job of
your type in three different segments if time allows. I think my eyes git
tireder quicker now after all those years of metalworking &
I've never tried it. Would it attack the brazing that's used to fix the
carbide cutters to the steel tool? That'd be a bummer to stick your cutter
in the solution, pull it out and have all the carbide teeth fall off
He said it, and it sailed right over your head: "Paraffin" in the
UK is "Kerosene" in the USA - the liquid form that can be used in
Dietz Railroad Lanterns, tiki torches and space heaters.
When we talk "Paraffin" in the USA, you're thinking PAROWAX - the
same basic stuff but in a formula that is a solid at room temperature.
I have a bar out in the shop for screw threads, neater than soap.
I'll bet either one would work for the purpose.
Should be OK on metals other that Al (and Mg?). I'm not aware of any brazing
alloys containing these and even then if the Al is only a few% (ie as
intermetallic compounds) it should be OK. It works well with solid carbide
(actually I think they are fine WC in a Co matrix) and HSS mills and drills
Amen to that. Bigger is not necessarily better, smooth is not necessarily
better than rough. Etc. A flow bench tells part of the tale, but even that
can be misleading since the flow in an operating engine is a series of
pulsations rather than a smooth flow. Frequently, a deliberate mismatch
is desirable to prevent reversion. Intake flow is also wet flow, and that's
different from dry flow.
Here is a decent book on cylinder head work:
"How to Build, Modify, and Power Tune Cylinder Heads" by Peter Burgess &
David Gollan. ISBN 1-901295-45-1.
I have this book, it's not great but overall is worth having. There are
plans for a home-made flow bench included, along with lots of examples on
how misleading the flow bench figures can be relative to actual engine
performance. The overall conclusion is that flowbench work is "suggestive"
of actual performance. At least it gives a person a place to start. There
are other books that address the topic of cylinder heads but without info on
flow benches and how to use them. A good one is "Four Stroke Performance
Tuning" by A. Graham Bell. Sorry, don't have it handy so I can't give you
Second, about those burrs... In my experience, nothing works better than
beeswax to reduce clogging by Al. You need pure, solid beeswax, not the
fou-fou crap that is sold for making candles. I found a pound of it (enough
for, oh, 15 years or so of steady use) at an artist's supply store.
To apply the wax, heat the burr gently, then touch a lump of wax to the
burr. The wax will melt and flow into the grooves. Don't overdo it, you
don't want to fill the gullets because the cutting edges require some relief
to work correctly.
The burr will still clog up eventually, quicker in some types of aluminum
than others. To unclog the burr brush it gently with a stainless wire brush
( a small brush like welders and platers use) or heat it gently with a torch
or hot air gun. When the wax melts, the Al comes right off with the wax.
Reapply the wax every second or third cleaning. You will find that this
combination will work well on some alloys such as 5052 or 6061, but it will
clog quickly on very soft or "sticky" alloys.
Beeswax is also excellent for lubricating taps. In fact, I got the idea from
a commercial product called "Tap Stick," a solid tap lubricant that I
suspect is mostly beeswax with some coloring and perfume added to make it
seem like a high-tech, proprietary formula. I don't know, maybe they do put
something else in there, but beeswax works just as well and it's about 20X
Also, I have found that double-cut burrs don't clog as easily as single-cut
burrs. Of course, the ideal are the "Aluma-cut" burrs, but they are quite
expensive, on the order of 3X a quality double-cut burr.