Announcement

Collapse
No announcement yet.

Bandsaw damper, revised

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

  • #16
    Jim H:

    I agree - as evidenced by the shop-made cylinder referred to above by Mike.

    EddyCurr:

    As a life-long cyclist I find your suggestion intriguing - (I did look briefly at the cylinder from an old-style car foot pump). Cycle pumps, at least those intended to be carried, are traditionally very lightly-constructed and whilst I think you are right in principle, in practice it might be better to build from scratch.

    I am conscious that this thread was started by Evan and wonder if he has found the jack solution satisfactory in the long-term.

    ega

    Comment


    • #17
      Andy,

      The use of a double acting cylinder looks like a nice solution, but how does it work? The swept volume of the rod side is less (by the volume of the rod) than the other side. Unless the cylinder has a rod coming out the other end as well, if the seals seal and the system is oil filled, it should be locked in its present position.

      Did you only partially fill it?

      Ian
      All of the gear, no idea...

      Comment


      • #18
        Originally posted by ega View Post
        Cycle pumps, at least those intended to be carried, are traditionally very lightly-constructed ...
        I agree. However, I have a floor pump of the 'high' pressure single-cylinder persuasion
        that seemed like it might be a candidate for such a project.

        Unlike some floor pumps that suffer from excessive product design, mine is an import
        that has a simple bolt-on cast tread plate - remove that and have a ready mounting
        boss for attachment to the saw. The cylinder wall has some substance, a threaded
        top and a durable piston/rod assy. (I've lost track of how long this has been in service.
        The hose failed at some point and something about it made replacement a headscratcher
        but was eventually resolved - now it is likely to outlast me.)

        All this aside, Bimba-like cylinders can be found somewhat inexpensively in this community.
        Have you exhausted that avenue ?

        Edit: Not where you might find the best options, but Amazon UK has some examples

        Here is a 16x250 Double Acting for £9 ish.

        .
        Last edited by EddyCurr; 01-24-2014, 12:59 PM.

        Comment


        • #19
          It doesn't take much of a cylinder to control a 4x6 band saw. I'd say that a .75" or 1" bore would be plenty. The cylinder needs only to be single acting. The ideal system is composed of a small reservoir, cylinder, check valve, needle valve for flow control, and a ball valve. The needle and ball valves are in line and the check valve is between the needle valve and the cylinder. Both circuits are obviously connected to the reservoir. The check valve allows the cylinder to easily suck in fluid when the saw is raised and the ball valve allows the saw to be locked at any position without changing the rate of sink.

          It doesn't take much of a cylinder since the pressure is really low and thus it would not be difficult to make one. A simple o-ring will work, though a hydraulic cylinder seal would be better. Neither will last long if the bore of the cylinder isn't polished.

          Years ago I had a 4x6 Clausing that had this as a upgrade to it's standard damper.

          Comment


          • #20
            EddyCurr

            Many thanks for the links. I had looked on eBay but not on amazon.

            OT and BTW: when I bought my "Made in Western Germany" floor pump they were called "track pumps" for the same reason that track mitts were so called. It's very stoutly built and I have equipped it with an ingenious hose that helpfully permits the pressure in the hose to be released before the connector is removed from the valve. In UK we now follow the American usage and call them "floor pumps", a label which highlights the fact that the operator has only to push down whereas the portable variety requires the rider to push and at the same time resist his own effort in doing so.

            Comment


            • #21
              Originally posted by Ian B View Post
              Andy,

              The use of a double acting cylinder looks like a nice solution, but how does it work? The swept volume of the rod side is less (by the volume of the rod) than the other side. Unless the cylinder has a rod coming out the other end as well, if the seals seal and the system is oil filled, it should be locked in its present position.

              Did you only partially fill it?

              Ian

              You know, this was talked about before on some thread on I believe the same topic. You may be right in the idea that the cylinder would lock. Possibly all that is needed is a single action ram and the fluid is plumbed from piston side to reservoir side? I always say and think dual acting because of the two fluid tapped points.

              Also like others are mentioning pretty much any cylinder would work, just comes down to the plumbing. Personally if I were to build one I would go look at the local fleet farm in the tractor section and pick out the cheapest ram they have with the right stroke length.
              Andy

              Comment


              • #22
                I was guilty of not checking all the responses prior to making my post. The shop built cylinder in drmico60's post is a variation on the cylinder used on Craftsman band saws. The flap valve on the piston and control valve incorporated into the piston shaft eliminate the need for fancy plumbing and difficulties that would be involved in adapting a hydraulic or pneumatic cylinder or the obvious complications in adapting a hydraulic jack.
                Jim H.

                Comment


                • #23
                  Mine is partially filled with an air gap in the upper half. It's the same as the one in VPT's post #9. The cylinder extends far enough to allow the saw to go right up over-centre where no damping is required.
                  Peter - novice home machinist, modern motorcycle enthusiast.

                  Denford Viceroy 280 Synchro (11 x 24)
                  Herbert 0V adapted to R8 by 'Sir John'.
                  Monarch 10EE 1942

                  Comment

                  Working...
                  X