Thread: When Ally aint Ally!

Hey bob, ally comes in all shapes sizes and hardnesses, some of the ones with a T6 rating will do that to your saw no problems, only problem with buying from a scrap yard is you dont know what it actually is.

Steve

Yep aluminium comes in many different grades, alloys and hardnesses. We find that out when people at work ask us to "Just TIG this together will ya" and you have a poor cast grade and hard pure grade alloy you are trying to make stick. We do it, but it is not that easy.

Not good Bob can see some fine cracking/distortion in the disc area also
at least now you can have a go at this with whats left https://www.woodworkforums.com/showth...highlight=sumu

Originally Posted by peter_sm

"Just TIG this together will ya"

Usually stated in conjunction with
"It will only take five minutes"

It is the the five minute jobs that take up the time. The bane of a welders existence.

Bob, you certainly are a lucky fellah as you did not wear any of those teeth.I too, have had a high speed meeting with flying saw teeth.My fright was from a 30 inch industrial metal cutting blade
Fortunately it was in the depths of winter and I was wearing my winter woollies and a welding jacket and a full face visor. No damage apart from a bruise or two on my shoulder

Both incidents are lessons we can all take note of.

Grahame

Originally Posted by wheelinround

Not good Bob can see some fine cracking/distortion in the disc area also

Hi Wheelin,

They aren't cracks but very fine gaps cut into the blade designed to minimize noise and vibration. This was one of those low noise blades which really worked - it ran and cut very quietly. You would think if a tooth was to break off it would do so adjacent to one of those fine gaps.

Cheers

Originally Posted by BobL

Hi Wheelin,

They aren't cracks but very fine gaps cut into the blade designed to minimize noise and vibration. This was one of those low noise blades which really worked - it ran and cut very quietly. You would think if a tooth was to break off it would do so adjacent to one of those fine gaps.

Cheers

Bob I mean these ones

Hi BobL,

Did you use any coolant whilst cutting? I would have thought a blade with less teeth (the pitch is still less than the thickness of the plate) then would allow the swarf to get away easier.

Just a thought.
MH

They look like finger & thumb prints to me Wheelin.

Originally Posted by wheelinround

Bob I mean these ones

I agree, they look like cracks but they're waxy thumb prints - blade and teeth are liberally covered in wax before each cut and wax is rubbed along the path of the cut as well .

I followed my BIL's lead (he's been in the ally boat building business for 25 years) where he uses standard ww power tools and wax or meths as lube. I've cut chunky pieces of ally before with that blade with no problems. I have since discovered that Duralium, or 2000 series ally, when heat treated can nearly be as hard as mild steel. Apparently it can be cut with a CT tipped saw but it has to be done v..e..r..y s..l..o..w..l..y. .

Bob,

looks like you got yourself a new shop clock there... insert a clock mechanism into the arbor hole and your an uncle

Originally Posted by Gra

Bob,

looks like you got yourself a new shop clock there... insert a clock mechanism into the arbor hole and your an uncle

Yeah - good one! - it would be a good talking point for when people come around.

Here's something else I messed with yesterday. About 18 months ago I was given a used diamond tipped 14" rock cutting saw blade. Following Andy Mac's suggestion I decided to have a go a making a herb cutter. I managed to cut out the basic shape with an angle grinder and thin kerf cutting wheel on a my small TS. Interestingly I found it was a laminated blade with a 0.5 thin layer of copper inside!. Then I tried to form a basic bevel on the cutting edge using an 8" bench grinder. I had no idea there was so much diamond grit still left on the blade edge and wore away about 5 mm off the grinding wheel before I gave up. Because its curved I can't even use it as a wheel dresser!!!

Originally Posted by BobL

After two cuts about 200mm long the saw developed a wild wobble so I switched it off and found!!

Bob ,
I reckon it gets back to blade cooling.

The dedicated ali cutting saws have much deeper and different rake gullets.If you were cutting like as in how one cuts a wide flat board,the solder solder melting temperature was probably reached.

Carbide tipped circular saws use special low temperature
s/solder brazing alloys specifically used to keep the temp down so as the saw blades don't warp.

On a quick docking cut one can get away with it on thinner material.

Grahame

Yep..... that's what happened.

The dedicated ali cutting saws have much deeper and different rake gullets.If you were cutting like as in how one cuts a wide flat board,the solder solder melting temperature was probably reached.

Carbide tipped circular saws use special low temperature
s/solder brazing alloys specifically used to keep the temp down so as the saw blades don't warp.

That's what I thought happened but none of the carbide bits of the teeth came off the metal part of the blade. I agree thought that the teeth were probably too narrow and couldn't stand the heat/stress of being pushed into the duralium.

Anyway lesson learned and hope others can learn from this as well.

Cheers