Few secrets about HSS Steel Hole Saw - Application: drilling aluminum sheet

[Kiriakos GR]

I am writing this topic with mixed feelings, I got a low cost HSS Steel Hole Saw  so to use it in just one application.
I did a wise choice speaking of how it should look like speaking of design, but even so this has lots of imperfection over it speaking of tool quality.

In the pictures bellow they are two small Hole Saw Japanese tools from the era of 70s,  also one large one also from the same era.
And now we have one comparison which this driving in to several conclusions.

Design award goes at two small Japanese ones,  because the end that goes at the power drill this is actually locking in there.
Third larger Japanese Hole Saw this has fine quality cutter tooth, fine quality removable pilot drill, but top end this is turned as fail because when new was somewhat conical and over the years it started getting damage at the axle.

The fourth this is what you buy this days from China for 6.5 EUR shipped.
Hole Saw has acceptable cutter tooth,  axle for power drill this looks acceptable too, but pilot drill this is plain garbage.   
 
I took apart third larger Japanese for tacking pictures and pilot drill this is also branded by NACHI Japan.

Main problem with tools of 70s ~80s this is product documentation,  any one doing metalworking for a living, he is aware that its one cutter has it very own cutting speed and power drill rpm they must be adjusted accordingly.

Now here are the tips:
When you are not familiar with Asian languages, you should use common sense.
In case that there is a note of two speeds,  the faster this is always for wood, and the slower for metal.

Another rule of thump this is that the larger the diameter of the cutter working  rpm this is slower.

Now also beware that they are power drill out there with adjustable rpm but minimum can be translates to 600 rpm and not less.
While small in diameter Hole Saw they can be used with caution over portable power drill, larger than 3 centimeter in diameter they must be used with power drill over a stand.
Such power drill over stand ( base ) they offer much more stability, much more speed control, and much more safety the ones using pulley and belts ( as mechanical speed control).

Now if you wish having a tool healthy for several years, then you need a mix of soap mixed with oil and water, one friend of my machinist made for me 1L of this cocktail and I am just using it ( over the years).

Regarding the Chinese tools, it screams that quality control this never take place, neither engraving of tool dimensions this was not made properly.
Pilot drill this is regular drill chopped down, and what makes it a huge FAIL this is it cutting edge and length of it.

Pictures below are very apocalyptic, just examine them carefully.
   

[Kiriakos GR]

Every specialized topic becomes another opportunity for me so to expand my vocabulary.
Gentlemen this thing called as Hole Saw Arbour  

And most of those shiny pilot drills are made by cobalt.
Our own Hole cutter Wikipedia this is now complete.