Announcement

Collapse
No announcement yet.

Slowing hydraulic feed on Atlas bandsaw?

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • Slowing hydraulic feed on Atlas bandsaw?

    I have a model 4353 H/V bandsaw, which has the hydraulic damper feed mechanism.

    The idea is fine, but I have found that all the action is in a tiny bit of the adjustment. From "0" to "1" on the dial is more than enough to go from no feed, to a feed best used for pinewood, or maybe balsa. Set to "1" is no good for metal, even aluminum.

    I would like to spread out the adjustment, at least doubling it, so that there is much more settability. it is so sensitive now that it is very difficult to set for any slow feed, and I end up having to hold the tip of the saw frame up during cuts of maximum size steel rounds or bars, so that it does not jam or break the blade.

    Some of this may be that I use an intermediate tooth count blade for everything, instead of replacing the blade for each different size of cut. But the feed is still sensitive and hard to set.

    Options to change the feed to allow more adjustment include:

    A more tapered needle, more like an SU carburetor needle

    A different orifice

    heavier oil

    ?????

    The manual specifies SAE10 oil. It may be that a heavier oil might change the behavior. I am by no means sure whether it would really spread out the adjustment, though. Might just move it so the action is from 0.5 to 1.5, instead of 0-1.

    A change in orifice seems as if it might be about the same as a change of oil.

    I have not taken the unit apart yet (I use it enough to not want to have it out of action), so I do not know if there is room for a more tapered needle.

    Has anyone modified their feed to spread out the adjustments?
    1601

    Keep eye on ball.
    Hashim Khan

  • #2
    Are you sure the needle isn't actually damaged? Happens real easy.

    Comment


    • #3
      Have you looked at the needle yet? If you are contemplating an actual mechanical switch then one way or the other you need to strip down the cylinder anyway. At least partially. So inspecting the existing needle and seat would seem to be the prudent first step.

      If it is a really fast taper that looks more like a cone than a taper then I'd say that you need to look into a new needle that has an actual taper. Nothing as long and slow as a carb needle. That would be gross overkill.

      Consider too that you will likely need to work within a limited length since the threads on the needle are only so long and allow only so much travel. So likely as not you will need to start with a fairly low angle taper that just allows you to fully close the valve and then thru trial and error adjust the taper to spread out the leakage rate while still allowing the dialing to "10" to fully unblock the orifice for easy movements.

      If it were me I think I'd also look at the idea of a parallel ball valve I could use for bypassing the restrictor for manual positioning. That way I can easily lower it to the work then close the bypass and still have the setting for soft feeding intact without needing to fuss over it.
      Chilliwack BC, Canada

      Comment


      • #4
        heavier oil would be the easiest by far. Made an oversize (and not in a good way) difference to my hydraulic press..

        Comment


        • #5
          j
          give us a picture

          Will PM you
          George from Conyers Ga.
          Remember
          The early bird gets the worm, BUT it's the second mouse that gets the cheese.

          Comment


          • #6
            If you use any kind of thinner oil it will not work well. I learned this at my cost to end up having to buy a much thicker variety, as the thinner stuff was useless quite useless actually. I was advised by one of our friends here what to buy ,bought it and never looked back. The pot in general will show a marked improvement in overall performance. Alistair
            Last edited by Alistair Hosie; 03-03-2017, 05:53 PM.
            Please excuse my typing as I have a form of parkinsons disease

            Comment


            • #7
              What about the balance? If there is too much weight pulling it down, then it will go too fast. Could it need a counterweight or perhaps a counteracting spring has become weak or broken. I have one of the ever popular 4X6s and it has a spring that can be adjusted for more or less downward pressure on the blade.
              Paul A.
              SE Texas

              Make it fit.
              You can't win and there IS a penalty for trying!

              Comment


              • #8
                OK, nobody has an Atlas saw.... The thing is pretty standard looking, but has the hydraulic damper to regulate feed. The feed source is the weight of the saw frame, which is considerable. The damper slows the "fall" of the frame. No springs are used, no counterweights, none of the "make do" garbage on many import saws.

                My saw is in very good condition, it is not a "beater", and shows no evidence of modifications or abuse. This link has pics

                http://vintagemachinery.org/photoind....aspx?id=13354

                Cylinder is this, located on the backside of the saw.



                Dial for regulating is this, seen above the cylinder in previous pic



                So....

                The feed is nearly zero with the dial at zero. At "1",as shown in the pic, it feeds at between 1 and maybe 1.5 mm per second, which is not useful for much. At 3 or 4, it is essentially a "rapid", feeding at 5 or 10 mm per second, which is good for nothing but warm butter.

                The 1.5mm per second is a feed rate I would prefer to have at maybe 2 or 3 on the dial. The useful feeds now are mostly between "zero" and maybe "0.5" on the dial. I do not recall ever using even "1", and certainly not "2" or "3", at least not for anything except a "rapid". I could live with a slower "rapid" if I could get a slower feed and more spread-out useful range.

                The design is a one-way valve, so it resets when lifted, no adjustment needed. It then descends at the rate set on the dial. That works, and since it stays "up" at "zero", I do not suspect a leak of any sort that could bypass the valve. If there were any such leak, it should descend even with the flow shut off. But it stays up at zero, and that setting can be used to hold it up while clamping the material, adjusting the blade guide , and so forth.

                The progression of rates seems linear enough, or at least seems to have no spots of sudden change, such as a damaged needle might produce.

                The problem is simply that the useful range of the dial is from zero to perhaps "0.6" or so (estimated) on the dial. resetting is not possible, because the dial has no provision for a pointer, etc, so the tight range is harder to use than would be preferred. With the same range spread out, one could have a better shot at adjusting to a useful rate.

                Also, related to that, the very slow rates, usable for the largest solid pieces to be cut, are compressed into a microscopic range near zero. So I have to manually lower the saw for such pieces, the "damper" is of little use, at least during the middle of cuts on large rounds.

                I have NOT taken it apart, I actually do not know that I need to, yet. I do NOT know what oil is in it now, but since the specified oil, SAE 10, is nearly the thinnest motor oil one can buy, the odds are that there is not a thinner than spec oil loaded into the cylinder. Without a viscosity measurement setup, I won't know what is in it now, so I have no "starting point".

                The question is because I figured others may have already solved this "problem", and may have successful experience to share about it, either in terms of modifications, or in terms of good SAE numbers for thicker oil to use.


                Originally posted by mattthemuppet View Post
                heavier oil would be the easiest by far. Made an oversize (and not in a good way) difference to my hydraulic press..
                Not exactly sure what is meant there.... presume it slowed the action, pumped much slower and harder, etc.

                But what I want is to spread out the range of flows through an adjustable orifice. That might be different, or it might be just what I want. Was hoping someone had tried it and could report they changed from SAE 10 to SAE XX and had such and so results.
                Last edited by J Tiers; 03-03-2017, 11:11 PM.
                1601

                Keep eye on ball.
                Hashim Khan

                Comment


                • #9
                  No experience with that specific model, but much with the hydraulic feed regulating system such as that.

                  Greater viscosity might help the existing feed regulation problem, but might create another. If it is always in a climate controlled environment temperature won't be an issue. If not, viscosity changes due to temperature will be accentuated with the heavier oil.

                  There is no rocket science in that valve, probably not even any algebra. It sounds like it might not even be a needle type. Pull it apart and see what it takes to make it like one.

                  Dave

                  Comment


                  • #10
                    I had to rebuild the cylinder on my Kalamazoo saw and I was surprised how small the hole was that the needle valve seated in, take a look and see what you have. Both my Wellsaw and the Kalamazoo have helper springs to aid the cylinder. I take it that your saw doesn't use springs.

                    Comment


                    • #11
                      I suppose that you already have the manual for the saw. The needle may be busted off.

                      Comment


                      • #12
                        It's a needle type, moved in and out by turn of the dial, IIRC, as stated somewhere that I cannot recall, by one who DID take it apart.

                        I really didn't want to make it a project right now, basically looking for anyone who has experience working with it.

                        The whole thing came up when I wanted to cut some medium diameter stock for a totally different project. Got the feed a little fast, and ended up having to take apart the saw to un-jam the blade. So I figured to set the ball in motion to see if there was any wisdom out there.

                        It IS in controlled temp, 60 to 80 deg year 'round, so viscosity changes are not a very big deal.

                        Looks like I may be the only owner of one of these on the forum..... I did not think they were that rare.

                        Google drive has the manual, which shows the parts list and breakdown at the end

                        https://drive.google.com/file/d/0B6w...w?ddrp=1&hl=en
                        1601

                        Keep eye on ball.
                        Hashim Khan

                        Comment


                        • #13
                          Same saw was sold as Craftsman. I have one. Never paid too much attention to numbers when cutting.
                          i saw one at a flea market last summer...left it there. The nylon bevel gears are a weak spot. Probably NLA by now as with most stuff from Sears.
                          gvasale

                          Comment


                          • #14
                            Originally posted by gvasale View Post
                            Same saw was sold as Craftsman. I have one. Never paid too much attention to numbers when cutting.
                            i saw one at a flea market last summer...left it there. The nylon bevel gears are a weak spot. Probably NLA by now as with most stuff from Sears.
                            OK, so you are saying it never is an issue for you? Does it still feed slowly enough to be reasonable when set at 2 or 3?

                            The gears do not worry me too much. I can make bevel gears, but so far no issues, so no need.

                            Originally posted by digr View Post
                            I had to rebuild the cylinder on my Kalamazoo saw and I was surprised how small the hole was that the needle valve seated in, take a look and see what you have. Both my Wellsaw and the Kalamazoo have helper springs to aid the cylinder. I take it that your saw doesn't use springs.
                            And does not NEED springs. Obviously a spring would only increase the feed, unless it was somehow used to counterbalance the saw.

                            Originally posted by digr View Post
                            I suppose that you already have the manual for the saw. The needle may be busted off.
                            I do not see just how that would be even possible.

                            The saw adjusts fine, over a large range, which seems to suggest the valve is working.

                            If it went instantly from "off" to a large feed, THEN I would suppose it might be broken off. But the adjustment is smooth and wide range, and shows no sort of instant jumps. it CAN be set to any speed you want, from zero to too fast, without the sort of action I'd expect from a broken valve. The problem is that the range is biased toward the higher speeds.

                            I've no idea what would reach in there and break the valve anyway. The unit does not look like it was ever taken apart.
                            Last edited by J Tiers; 03-04-2017, 01:15 AM.
                            1601

                            Keep eye on ball.
                            Hashim Khan

                            Comment


                            • #15
                              I'm betting the needle valve or seat is bad, worn, damaged & needs repaired or replaced. A heavier oil may be a fix but I doubt the right one but if it works. #100 Mineral oil is 50 wt aircraft oil with no additives for about $6/qt. Or can you restrict the air intake?

                              Comment

                              Working...
                              X