Slitting saw sanity check, please?

[Flynth]

I have this smooth (keyless, teeth with no set) slitting saw. It is 3.14 in x 64 thou 100 teeth (80x1.6mm).

My calculations tell me I could run it conservatively at 80rpm (20m/min or 60sfpm) and ~16iom feed (400mm/min) which results in 0.05mm (2 thou) feed per tooth.

I'll be slitting mild steel to a depth of 3mm (in one or two passes).

Now it all sounds great, but I once long time ago broke a slitting saw when it slipped on the horizontal milling arbor (being keyless) and the table feed crushed it :-( I still keep the broken bits with my good slitting saws to reaming myself yo triple check when running them.

So, anyone that uses those hss slitting saws (with straight teeth) successfully, please let me know if this makes sense or should I change anything?

 

[Karl_T]

I generally run a bit more RPM and a bit less IPM than that. DOC sounds about right. But I do it by feel- there's a nice sound when running right.

I also do not like the key less saws. But no other way on real small ones. For these I turn my own arbor and then use a bolt in the end of the arbor and thick washer to put it on TIGHT.

 

[WobblyHand]

Having broken one of these slitting saws 0.5mm wide, you have to watch out that the saw tracks straight. Mine didn't, and I wasn't paying attention and it popped. Still have it as a reminder. Thicker saws tend not to wander as much. I hand feed the saw. There's a fine line between cutting well and jamming or spinning. When it's cutting properly, there's a unique sawing sound. In my experience, there's little benefit to making multiple passes, do the slit all at once. Use a lot of cutting oil and have fun. At least on my mill, slitting is slow, so I limit sawing stuff to just necessities.

 

[benmychree]

With 100 teeth, it sounds more like a screw slotting saw, there would be very little room for chips.

 

[verbotenwhisky]

Having broken one of these slitting saws 0.5mm wide, you have to watch out that the saw tracks straight. Mine didn't, and I wasn't paying attention and it popped. Still have it as a reminder. Thicker saws tend not to wander as much. I hand feed the saw. There's a fine line between cutting well and jamming or spinning. When it's cutting properly, there's a unique sawing sound. In my experience, there's little benefit to making multiple passes, do the slit all at once. Use a lot of cutting oil and have fun. At least on my mill, slitting is slow, so I limit sawing stuff to just necessities.

I find that with a keyless saw it helps to clean all the oil off the arbor before putting the saw on it to minimize slippage... And I have been told to make the total depth of cut because the saw will not clear chips correctly if the cut is too shallow.

 

[Flynth]

Thank you for all your replies

With 100 teeth, it sounds more like a screw slotting saw, there would be very little room for chips.

Indeed. I have a full set of them, some as small as 0.3mm (7.5 thou) and 1in in diameter. This is one of the big ones.

Do you think I should modify my speeds and feeds somehow because of it being a screw slotting saw? More rpm, less ipm as mentioned by @Karl_T seems a good idea.

 

[projectnut]

I generally run a bit more RPM and a bit less IPM than that. DOC sounds about right. But I do it by feel- there's a nice sound when running right.

I also do not like the key less saws. But no other way on real small ones. For these I turn my own arbor and then use a bolt in the end of the arbor and thick washer to put it on TIGHT.

I also am not a fan of keyless slitting saws. I have been able to find sizes down to 3.000" x .014" that have a 1" keyed bore. I generally run the thinner ones around 100 rpm (slowest speed on my horizontal mill) and feed by hand.

 

[Flynth]

I also am not a fan of keyless slitting saws. I have been able to find sizes down to 3.000" x .014" that have a 1" keyed bore. I generally run the thinner ones around 100 rpm (slowest speed on my horizontal mill) and feed by hand.

I'm not too happy about having to use them, but I never found any keyed ones thinner than 3mm (0.12in). Here the most cost effective hss tools are NOS and they all seem to be keyless below that thickness.

I have lots of sawing to do so feeding by hand is not ideal. I'm planning to do flat laps in mild steel and a square pattern of notches will to be sawn. If I find more than one saw of each size I'll run them ganged on a horizontal milling arbor. Otherwise just a single one.

I'm using mild steel because ductile cast iron rounds are very rare and expensive where I'm at. If these come out well I might do copper ones next (I wonder how running a slitting saw in solid copper will go...).

 

[projectnut]

I have this smooth (keyless, teeth with no set) slitting saw. It is 3.14 in x 64 thou 100 teeth (80x1.6mm).

My calculations tell me I could run it conservatively at 80rpm (20m/min or 60sfpm) and ~16iom feed (400mm/min) which results in 0.05mm (2 thou) feed per tooth.

I'll be slitting mild steel to a depth of 3mm (in one or two passes).

Now it all sounds great, but I once long time ago broke a slitting saw when it slipped on the horizontal milling arbor (being keyless) and the table feed crushed it :-( I still keep the broken bits with my good slitting saws to reaming myself yo triple check when running them.

So, anyone that uses those hss slitting saws (with straight teeth) successfully, please let me know if this makes sense or should I change anything?

OK, what am I missing. In your original post you talk about a slitting saw that is 3.14" in diameter, and .064" wide. In your latest post you refer to not being able to find keyed models thinner than .012". If the slots you are trying to mill are .064" wide, why does it matter that you can't find keyed saws as thin as.012". You would have to make more than 5 passes with the thinner saw to get the .064" slot you are looking for.

 

[Flynth]

OK, what am I missing. In your original post you talk about a slitting saw that is 3.14" in diameter, and .064" wide. In your latest post you refer to not being able to find keyed models thinner than .012". If the slots you are trying to mill are .064" wide, why does it matter that you can't find keyed saws as thin as.012". You would have to make more than 5 passes with the thinner saw to get the .064" slot you are looking for.

I can't find slitting saws thinner than 0.12in or 120 thou. Not 12 thou. Unfortunately.