Slitting saws - is there a beginners guide?

[Mayhem]

Thanks to those who have responded, as you have answered a lot of the questions I had.

Is it better to use blades with a drive key and what thickness would you suggest for general purpose use?

[TomG]

Darren,

I would not use a key on anything smaller than 1/4". The thinner saws don't require much torque and the lack of a key will allow them to slip if they grab instead of break.

Tom

[DaveH]

Darren,
I agree with Tom - only to say sometimes they don't slip - just break
Some especially the thin ones 1/8" and less don't come with the provision for a key, just a plain hole.

"What thickness would you suggest for general purpose use" Oh dear Darren that is a real difficult question to answer - not so sure there is a sensible answer.

I tend to use ones 1mm (.040") thick -no key slot. That's about the thinnest I use, and I use it for thin slots. If I need a thicker slot I go for an end mill - a 3mm dia end mill. So what happens if I need a 2mm slot normally I make do with a 1mm slot from the slitting saw or a 3mm slot from the end mill

Now there are slotting cutters that cut on the side and face, similar to the side and face cutters for horizontal mills - but they tend to be damn expensive.

That's my best take

DaveH

[NevadaBlue]

Thanks for this information. TomG, that heat sink is amazing, nice work!

So, if I wanted to slit a piece... say a clamp type holder and the metal to be cut is 3 times the tooth depth of the cutter. Can this work? I'm confused on this point. A thin cut three times tooth depth with a saw having no side clearance is what I'm asking about.

[stevec]

(12-30-2012, 10:18 AM)TomG Wrote: Darren,

I would not use a key on anything smaller than 1/4". The thinner saws don't require much torque and the lack of a key will allow them to slip if they grab instead of break.

Tom

Ya but, if you don't stop feeding the instant the saw slips your in trouble there.

[TomG]

Thanks Ken, but it was a lot of work for a silly heat sink.

Slitting saws with no side relief are intended for making shallow cuts like slotting screw heads. Trying to make deeper cuts may work, but they are risky. If you need to go deep, use a saw like the one I used on the heat sink.

Steve: That's why you feed them by hand!

Tom

[stevec]

Tom, My reaction time, especially when I'm monotonously slow feeding by hand isn't quick enough to avoid problems. Let's just say it's my preference to use a key if the saw is equipped with a keyway. I mean the makers of quality machine cutting tools aren't stumbling around putting features into their product if it's wiser not to use them.
Just my take. Please don't consider it to be criticism, I admire the job you did and the skill it required, especially on the treatment of the last slot. I know that would have been my undoing.

[Mayhem]

(12-30-2012, 11:14 AM)DaveH Wrote: ...not so sure there is a sensible answer...

C'mon Dave - that has never stopped you in the past

Just kidding - I knew it was a difficult question when I posted it, given the number of variables but your answer has given me a starting point.

[TomG]

(12-30-2012, 03:56 PM)stevec Wrote: Tom, My reaction time, especially when I'm monotonously slow feeding by hand isn't quick enough to avoid problems. Let's just say it's my preference to use a key if the saw is equipped with a keyway. I mean the makers of quality machine cutting tools aren't stumbling around putting features into their product if it's wiser not to use them.
Just my take. Please don't consider it to be criticism, I admire the job you did and the skill it required, especially on the treatment of the last slot. I know that would have been my undoing.

Steve,

Just to note, it wasn't only the last slot that was a challenge on that heat sink. There was a bad situation where the two cuts joined at a shallow angle and the saw grabbed on several of the 90 passes. Luckily it slipped on the mandrel both times and all it did was waste a little of my adrenaline. Had it been keyed, something definitely would have broken, either the part or the saw. I hear you about following the manufacturers recommendations, but those are based on ideal applications and sometimes they just don't relate to the real world, especially my world.

Tom