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Thread: 4 X 6 Metal Cutting Bandsaw Seized Up During Cut

  1. #1
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    Default 4 X 6 Metal Cutting Bandsaw Seized Up During Cut

    I bought this Central Machinery saw in 1981 for $135 (I think) and as expected it cut poorly. The blade came off regularly and the auto stop switch broke within a year of home shop use. So I gave it a tuneup, replaced the grease in the gear box with gear oil, fixed the on/off switch, realigned the wheels and doctored up the the blade guides. From then on if the blade was sharp it cut straight and square.

    Fast forward to the first week in August 2018. I'm cutting up forks from a forklift and the saw starts to squeal then seizes up before the cut is done. When I pulled the cover of the gear box I saw it was bone dry and the worm gear was pretty much hosed but the worm looked ok other than being a light blue color from the heat generated. It will certainly need to be dressed up a bit but it should be fine for my operation.

    This is basically a Harbor Freight saw even though Harbor Freight hadn't been started yet so I figured I'd buy a new worm gear from them and get back to cutting. So I ordered the worm gear for $21.66 plus $11 for freight. When it arrived several days later it was clear that the worm drive parts had changed somewhat in the past 37 years. The old gear has 20 teeth and the new one has 24.

    This was my first time buying parts from Harbor Freight and I found out that they have little to no description/spec's for the parts. Basically a picture of the part and a skew number is all I was able to get. Tech service couldn't even tell me how many teeth the gear had.

    Anyway the photos show what happens when you don't check the oil in the gear box. In my defense, I never noticed anything leaking but then it probably just blended with the cutting oil so I never noticed it.





  2. #2
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    sounds like you got your money's worth out of that 4x6
    Work hard play hard

  3. #3
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    A few more photos of the saw and parts. I'll probably be making my first hobb in the next couple days.




  4. #4
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    could be that the surface at least of the steel was hardened, dulling the blade. The only forklift tine I've cut through had a ridiculously hard surface. Couldn't cut it with a saw and had to use a grinder with a cut off wheel to get through it.

  5. #5
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    You can walk away from your 4x6m i sure can't. .they are a POS.
    Why a hob, grind a single point tool, mount in bar stock with hole and setscrew, mount that in a collet.
    Now incline your blank on the dividing head, start dividing and cutting.

  6. #6
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    Quote Originally Posted by 754 View Post
    You can walk away from your 4x6m i sure can't. .they are a POS.
    Why a hob, grind a single point tool, mount in bar stock with hole and setscrew, mount that in a collet.
    Now incline your blank on the dividing head, start dividing and cutting.
    Would that work?

  7. #7
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    Is the new wheel about the same other than the number of teeth, if so wouldn't it be easier to make a new worm to go with that, rather than trying to hob a new wheel to go with a worn worm.

  8. #8
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    Quote Originally Posted by nc5a View Post
    I bought this Central Machinery saw in 1981 for $135 (I think) and as expected it cut poorly. The blade came off regularly and the auto stop switch broke within a year of home shop use. So I gave it a tuneup, replaced the grease in the gear box with gear oil, fixed the on/off switch, realigned the wheels and doctored up the the blade guides. From then on if the blade was sharp it cut straight and square.

    Fast forward to the first week in August 2018. I'm cutting up forks from a forklift and the saw starts to squeal then seizes up before the cut is done. When I pulled the cover of the gear box I saw it was bone dry and the worm gear was pretty much hosed but the worm looked ok other than being a light blue color from the heat generated. It will certainly need to be dressed up a bit but it should be fine for my operation.

    This is basically a Harbor Freight saw even though Harbor Freight hadn't been started yet so I figured I'd buy a new worm gear from them and get back to cutting. So I ordered the worm gear for $21.66 plus $11 for freight. When it arrived several days later it was clear that the worm drive parts had changed somewhat in the past 37 years. The old gear has 20 teeth and the new one has 24.

    This was my first time buying parts from Harbor Freight and I found out that they have little to no description/spec's for the parts. Basically a picture of the part and a skew number is all I was able to get. Tech service couldn't even tell me how many teeth the gear had.

    Anyway the photos show what happens when you don't check the oil in the gear box. In my defense, I never noticed anything leaking but then it probably just blended with the cutting oil so I never noticed it.




    In the picture of the worm I see there is a sealed bearing . Would this not be better to be an open bearing so it can be bathed in oil. I see mine is not sealed. Also what is the black rubber thing before the pipe spacer. Is it an oil seal?If the bearing is sealed would it not be impossible to get oil past the sealed bearing so what is the point of it.?

  9. #9
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    Quote Originally Posted by Robin R View Post
    Is the new wheel about the same other than the number of teeth, if so wouldn't it be easier to make a new worm to go with that, rather than trying to hob a new wheel to go with a worn worm.
    Thats what I did.
    http://bbs.homeshopmachinist.net/thr...t=bandsaw+gear

  10. #10
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    As Matt stated, isn't that fork hardened? I remember when I was working on my first big and exciting project in my newly discovered machining hobby. I was building a completely custom rear-end for my buggy using a GM torsen differential. I needed to make custom stub axles with GM splines that slide into the GM torsen diff so I bought a Z-28 rear end just for the splined axles. I think I went through two blades on my 4x6 before I realized I was just scratching the axles. That's when I bought my first 14" cut-off saw. Ok, after I had cut both axles so I had a pair of stubby axles with GM splines, I tried turning the non-spline end down to size and same problem until I got myself some carbide inserts on the lathe. And also my 1st 1/4" solid carbide end mill which cut the 1/4" key-way I wanted in those axles like butter.

    http://www.bbssystem.com/pictures/diff1.jpg
    http://www.bbssystem.com/pictures/diff2.jpg
    http://www.bbssystem.com/pictures/diff3.jpg
    Last edited by 3 Phase Lightbulb; 08-09-2018 at 03:50 PM.
    Work hard play hard

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