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Tony
01-20-2012, 09:57 AM
Took a 3" diam slitting saw to full depth this morning (which is maybe 1" or
so).. i'm always afraid of these things -- that they might break I mean.

the cut was 1" wide x 1" deep -- saw is 0.060" abouts.

at the bottom of the 1" cut I found that the saw kerf was crooked..
probably 0.030" off. looking at it dead on I could see the blade flex
when at its deepest. (started hearing some rubbing which tipped me
off).

Didn't think that could happen (assumed they'd break) .. any tips
for keeping them from wandering? speed/feed was REALLY slow.
material is 1040-ish. flood coolant.

Tony

chipmaker4130
01-20-2012, 10:13 AM
Just wondering, after the cut did you examine the teeth? Was there any uneven wear side-to-side?

rkepler
01-20-2012, 10:35 AM
I'm not sure if it's the right way to do it but I usually take a 'shallow' pass of about .050 for the first go, then .100" additional for the next then start chomping about .250 per pass. Slow rpm, fastish feed as there are a lot of teeth. I haven't seen steps in the cut or wandering of the slot.

But that might be the "snapping your fingers to keep elephants away" effect. You know the story - guy on the corner at a busy intersection snapping his fingers. Stranger asks "Why are you snapping your fingers?" and the guy answers "To keep the elephants away". Stranger follows up with "Does it work?" and the fellow answers "Do you see any elephants?" I don't know that the above keeps the saw from wandering, but making a shallow slot to support the blade in a slightly deeper slot that then... I don't know, I might just be keeping elephants at bay, but it works for me on .020 slots.

Rustybolt
01-20-2012, 10:54 AM
Are using the right speeds and feeds? The big problem is feeding too much too fast.
One side is sharper than the other or one side is duller than the other. You pick.
I've actually taken a stone and dulled both sides and had it work. I don't recommend it though, you can dull it too much. Eventually, after a number of cuts, the blade will dull evenly and cut straight.
Instead make some flanges for both sides of the cutter.. Say, in .250 increments. So on your first pass you only go .250 deep. Change to flanges that are .250 smaller than the first, & etc.

Carld
01-20-2012, 11:17 AM
Yes, the teeth were dull on one side of the slitting saw. It's the same effect when one side of a band saw gets dull and the blade starts cutting an arc and binding up and won't cut a straight path.

Buy a new blade and throw the old one away.

SGW
01-20-2012, 11:19 AM
Is you milling head trammed *exactly* 90 degrees? Any variation and the blade will want to go uphill or downhill.

EddyCurr
01-20-2012, 02:44 PM
Took a 3" diam slitting saw to full depth this morning (which
is maybe 1" or so)..

the cut was 1" wide x 1" deep -- saw is 0.060" abouts.

at the bottom of the 1" cut I found that the saw kerf was crooked..
probably 0.030" off. looking at it dead on I could see the blade flex
when at its deepest. (started hearing some rubbing which tipped me
off).Slitting saws have a hollow ground concave relief in the sides, between
the circumference and the center.

Is it necessary to observe some cutting depth limit to avoid contact
between the blade and the material where the relief flares out as it
approaches the center arbor hole ?

.

J Tiers
01-20-2012, 10:48 PM
Slitting saws have teeth only on the periphery, like a saw............ Best not to go deeper than the tooth gullets, although I have pushed it well past that before.

Slotting cutters have side teeth, and clear the slot as they cut..... they don't tend to wander as much, and they are available in thin types, I think I have an 0.062 x 3" diameter one somewhere.