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Tell me about slitting saws

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  • Tell me about slitting saws

    I want to be able to saw aluminum and steel. I bought a cheap carbide tip trim saw blade and made an arbor to saw aluminum. Tried it twice failed both times, got pieces cut and didn’t loose any teeth but the saw wondered off the line. When I was done both saws were conclaved or convex. I know there is no chance it will work on steel but I thought it would work on aluminum. I tried different speeds and used wd40 for lube.
    I since orderd a slitting saw arbor, I have a couple of saws I just don’t want to mess up the good ones. Click image for larger version

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  • #2
    Saws like to wander around if you force the feed. Did you?

    If you let it cut, it should do OK. BUT..... the ones that do the best are side-cutting, they can straighten out if they get off line, because they just cut to the side.
    1601 2137 5683 1002 1437

    Keep eye on ball.
    Hashim Khan

    If you look closely at a digital signal, you find out it is really analog......


    • #3
      Hey! I like what you are doing. Looks like a nice cut to me.

      The saw blades I use are all around 3" in diameter and one piece HSS.

      I stopped breaking them when I took a break from the shop. When I got back to the shop I got back to braking slitting saws. Oh well. JR
      My old yahoo group. Bridgeport Mill Group


      • #4
        It’s not as nice as it looks. I have two more pieces to do and want to do better.
        i tried to cut shallow cuts and full depth cuts, the deep cuts seemed to work better.
        I tried many speeds didn’t seem to make a difference.
        Last edited by true temper; 10-19-2020, 02:46 AM.


        • #5
          is that a wood saw?


          • #6


            • #7
              I have only used a slitting saw in my horizontal mill and it cut fine and did not wander but not quite the same as in a vertical mill. I have also used carbide tipped wood saws in my miter saw to cut aluminum. Scary but works fine and I wasn't looking for a pretty finish or precision. My guess is that you would have better results with an actual slitting saw that is solid HSS or carbide and much stiffer than that wood saw. If you can push on that blade and it gives I doubt it will work well.
              Last edited by flathead4; 10-19-2020, 07:28 AM.
              Tom - Spotsylvania, VA


              • #8
                Saws that wander usually have two causes. Feeding too fast is one. The other is variable sharpness of the teeth. If one or more of the teeth are not cutting properly the material wants to push the blade away and the next tooth has more to cut and my not have that ability until the saw is farther off the line of cut, Then the force causes the next few teeth to cut the other way until the cut is off the line the other way. Rinse and repeat.


                • #9
                  Slitting saws....thin ones.

                  1) if you do your cutting speed formula, they have to go as slow as a mill will go
                  2) they are fragile
                  3) any cutter mounting on an arbor has to have clearance between the cutter and arbor
                  4) because of 3), SS will always run a bit eccentric.which means they only cut on a few teeth.
                  5) 4) is true any arbor mounted cutter, but with heavier cutters the system gets loaded enough that they'll cut on all teeth....however because of 2) you can't usually do this with slitting saws
                  6) because of 4) & 5), toss the chip per tooth stuff, you'll bust the cutter, unless you always assume because of 4) chip count is say 2 or 3
                  7) As they become thicker, they get more like a horizontal milling cutters and the above goes away as you can start to load them up (basically press the cutter into the work enough that it is cutting on all teeth), 1-7 start to go away.

                  An 8) would be, the thinner they are, the more you have to use an incredibly fine feed (manual, any power feed is too fast) because anything but the tiniest force will bend the saw potentially leading to a less than straight cut. Basically feed in the context that you are going at the mill's slowest speed with the equivalent on a 2 tooth cutter than can only hand a very small chip load
                  Last edited by Mcgyver; 10-19-2020, 11:46 AM.
                  in Toronto Ontario - where are you?


                  • #10
                    It seemed like it was cutting on 25% of the dia of the saw. I need to check the roundness of the saw.


                    • #11
                      Originally posted by true temper View Post
                      It seemed like it was cutting on 25% of the dia of the saw. I need to check the roundness of the saw.
                      See 3 and 4 of Mcgyver's post.....
                      Tom - Spotsylvania, VA


                      • #12
                        Originally posted by Mcgyver View Post
                        Slitting saws....thin ones.
                        toss the chip per tooth stuff, you'll bust the cutter,
                        You meen good ones? HSS? I ended up busting them on accident. As often as it used to happen you would think I meant it, JR

                        My old yahoo group. Bridgeport Mill Group



                        • #13
                          Originally posted by JRouche View Post

                          You meen good ones? HSS?
                          yes, because you are only cutting on a few teeth. If feed as if all the teeth are cutting, but only a few are, that first tooth will have a huge load and break
                          in Toronto Ontario - where are you?


                          • #14
                            I’ve got a very similar DIY arrangement and it seems to work just fine, but certainly doesn’t give great finishes. My saw was new, I’ll assume yours was as well and wasn’t retired from wood service. Like a bandsaw blade I’d think wondering is caused by one side being sharper than the other, as was mentioned above. Mine does run a little truer as well, sounds like it cuts pretty evenly, much better than 25%. Check the tram of the mill in both directions. In steel you do need to run these slow per the formula, you may have dulled it if run too fast. I’ve heard to run full depth of cut rather than small bites, with the exception being if you have a very deep cut to make, them start with a shallow guiding cut or maybe 0.050”.

                            My arbor is 3/4” and was finished on the mill held directly in a collet and that’s the way I use it so that may help me in run out and stick out.
                            Last edited by JCByrd24; 10-19-2020, 11:22 AM.


                            • #15
                              Wood saw blades almost all have alternating top bevel teeth as well. Likely that isn't helping either. For metal you want a flat across tip which in wood working terms is a "rip saw". But they don't come in these small sizes.

                              The wood cutting geometry is also pretty sharp. It's possible that due to the angles and excessive for metal back rake and the issues with chip load due to the slight but important for metal off center running that some of the teeth that took the brunt of the cut with each turn have chipped away the corners of their teeth. If so that would make the saw wander badly. Get out a really good strong magnifier of some sort and have a close look at the very tips of the teeth to see if they've chipped at all.

                              For aluminium one of these wood saw blade likely would work wonderfully. But I think you might find that it needs to be re-sharpened to more like a rip shape tooth and perhaps use a small secondary relief angle at the same time so the edges and especially the corners are more chip resistant.
                              Chilliwack BC, Canada