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General 490 blade alignment

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  • General 490 blade alignment

    Having a problem with the bandsaw blade on my 490…blade tension is good, no fluttering, yet the blade rubs a little on the pulley doors when closed..can’t seem to find any other adjustments.
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  • #2

    Re: General 490 blade alignment

    Is it the blade rubbing on the doors, or one or both of the wheels? Hard for me to imagine the blade rubbing if it is centred on the two wheels, unless one or both of the doors is/are warped….. but I have been wrong before! Is there a way to move both wheels back from the doors to provide extra clearance, both would need to be moved the same amount to maintain coplanarity. Roy
    Are you solving the problem, or becoming part of it?

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    • #3

      Re: General 490 blade alignment

      The wheel can be adjusted to not run against the door, it tells you in the instruction how to do this, hope you do not have too much tension on the blade ??

      This picture shows you the bracket that keeps the wheel in position, that can be adjusted by the knob on the back of the saw, the write-up tells you how to do this.

      I'm assuming all else is in proper condition, like Roy mentions, things could have been bend or warped.

      Click image for larger version  Name:	Blade tracking adjust.jpg Views:	0 Size:	69.6 KB ID:	1336820
      Click image for larger version  Name:	wheel cantilever.jpg Views:	0 Size:	89.5 KB ID:	1336821
      Last edited by Leo Van Der Loo; 07-16-2021, 11:06 AM.

      Have fun and take care
      Leo Van Der Loo

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      • #4

        Re: General 490 blade alignment

        there is probably adjustment for alignment on the lower wheel as well but dont play with that if you haven't' as it shouldn't need to be adjusted. normally you will see 4 bolts with lock nuts near the lower wheel's axle. If you ever need to remove them or remove the axle dont loosen more than two that are beside one another so you don't break that adjustment. you probably only need ot back off two of them about 1 or two flats so if you dont go loosening all of those then you can then return it as it was after if you remove the bottom wheel with it's axle included.

        back the guides all away then put them near the blade after you have it running on the wheels properly and that way you don't have a situation where the guides are fighting and "trying" to control the blade position , their job is to prevent movement of the blade from it's position It is not intended for the guides to alter the tracking. the guide behind th eblade sould be just lose a tad and when you begin cutting it bears against the bearing or guide behind th eblade and when you are not cutting it should be as close as possible but nt running against it. If it is continuously turning the bearing it adds wear.

        the type above suggests to make adjustments and then turn the machine on. Be careful here. make sure you spin the wheels a few rotations and see where the blade wants to go and then normally when you do turn it on just bump it on and off for an instant, and then off, so it isn't running up to full speed. You dont want a situation where the blade isn't tracking right as you turn it on and then it can result in the blade coming off at full speed. that can be avoided with preemptive care in checking the tracking before it ever sees anything close to full speed.

        the blade tracking adjustments can be touchy. so go slowly if you ever adjust tracking. you are better to make several tiny adjustments in one direction to achieve the right position than you are to over-adjust and reverse the direction of adjustment. If you move it much at once then you will be all over the place with changes that are too radical.

        some of the new imports have bad tires, they come off, some aren't even rubber but made of a plastic material to save cost. rubber is porous and grips better than fake rubber that is in fact plastic and not porous. . some have ceramic guides that can fall out easily as they aren't bonded to the blocks well enough. they spark too and can remove theset from blades. I had a fairly new machine with low miles where the tires came right off and they weren't even glued or clamped down Its basically a quality control issue. I put a new tie and it fell off I then used crazy glue to try to hold the plastic tire on the wheel. one that I recently worked on had a plastic handle for the tracking adjustment, fisher price makes better quality stuff. I'm familiar with another bandsaw that makes a lot of noise on startup because it uses an inverter and I think it's getting a rough pulses as it goes through acceleration. Ive seen some bearings go bad on some within the wheels and the guides, cheap made in china bearings that failed under 100 hours or so. most bandsaws have a brake for emergency stop it also turns off the motor and some of these new machines have really inferior friction devices. the older ones had brake pads that were much like a car and likely hasd some asbestos friction material. Some are little more than a piece of rope, what can happen is the friction material wears fast and then the drum can get rough as its basically acting like a brake drum. If it becomes metal on metal it will pick up on the brake surface just like a car with worn out brakes and you may have to have a machine shop machine it smooth again. If you are in around the bottom wheel Id have a look to see if yours has a good brake , see how that's wearing or if its cheap chinese/taiwanese garbage. many let the machine coast to a stop but some insist on stopping the blade before they leave the machine for safety. If I was using it in a room by myself I'd seldom use the brake and it wouldn't be an issue but that depends who may be around that could harm themselves and safety policies. one GI failed almost immediately and had issues with the motor, the motor has a long shaft and its metric and so there was no bolt in replacement motor available and because the motor mount wasn't made to a standard type of mounting, it was a proprietary motor and motor mount so that made repair difficult without some modifications. It was obsolete almost straight out of it's box. older ones often used more standard motor mounts and most north american motors used standard shafts , not metric. most of the older bandsaws had a lot less issues so I prefer those , I've seen many run for generations with no repairs required and very few adjustments and no special lubrication. maybe they have a few bushings to oil. work with what you have but if you are replacing a machine there are still older and more reliable ones to be found often at the same or even lower prices than the new offshore ones. some of the older generals were really good quality but personally I wouldn't touch the chinese/ taiwanese GI ones or their offshore price competitors if it were my money.

        Last edited by stickman; 07-16-2021, 05:39 PM.

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        • #5

          Re: General 490 blade alignment

          Thanks for all the replies...the bandsaw is a General 490...serial number V-4913.....I think it was manufactured in 1983.....just picked it up from an ad in the paper....everything was working fine...I backed off all guides, then made sure the blade was tracking on the centre of the wheels ( and it is).....the problem seems to be the slight angle of the lower door when closing...the blade does not run parallel to it, so it touches it lightly even with maximum blade tension (no fluttering)....I am going to try and add a pic to clarify.

          Comment


          • #6

            Re: General 490 blade alignment

            From the second pc it looks as if a previous owner tried to address the same problem, as it appears to me that some of bottom doors right edge has been removed in an attempt to reduce blade interference. Is it possible to reset /shim the bottom door on its hinges to get the blade-door clearance desired? I am assuming that the bottom wheel is perfectly round and is not inducing a flutter in the blade, Roy
            Are you solving the problem, or becoming part of it?

            Comment

            • Thread Continues Below...

            • #7

              Re: General 490 blade alignment

              Hey Roy…the strangest part of this problem is the lower door aligns itself perfectly all the way around and there is no sign that it was tampered with in the past, but as it is, the angle of the blade will always cause it touch the top part of the door.

              Comment


              • #8

                Re: General 490 blade alignment

                This is where the blade comes off of the lower wheel going back up, right ??

                Is the blade running the center when it comes off of the lower wheel going up ??

                If it is, then I would either hammer that edge up/out or cut it out altogether like I mark it in the picture here below, as I see no problem with doing this, surely better than having the blade hook or rub on the door edge

                Click image for larger version

Name:	bandsaw door.jpg
Views:	82
Size:	61.3 KB
ID:	1336937

                Have fun and take care
                Leo Van Der Loo

                Comment


                • #9

                  Re: General 490 blade alignment

                  Leo...yes, that is what I thought I would have to eventually do...cut out a small part of the door....it seems like the only logical conclusion....thanks for your input.

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                  • #10

                    Re: General 490 blade alignment

                    I agree with Leo but looks like the previous guy was a hacker leaving a rough edge. When you cut it use a file to clean up the edges and with a paint touch up would look much better
                    If your dreams don't scare you, you are not dreaming big enough

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                    • #11

                      Re: General 490 blade alignment

                      maybe the tires were changed at some point to a thickness that differs from original? that might shift the blade a little.

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                      • Thread Continues Below...

                      • #12

                        Re: General 490 blade alignment

                        Never thought of the tires…they appear to be in very good shape but certainly not newly replaced..and the wear on them is even…no signs of a tire problem…thinking of taking the doors to a machinist to have him bang out a groove in each to clear the blade.

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                        • #13

                          Re: General 490 blade alignment

                          Hi, is the back of the blade square to the table?

                          Regards, Rod.
                          Work is the curse of the riding class.

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                          • #14

                            Re: General 490 blade alignment

                            Yes...it is square to the blade.

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