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

  1. #11
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    Feb 2005
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    FWIW. You can not use gear oil on bronze gears. It makes them fall apart. Gear oil has a high pressure addative that ruins bronze.
    Google your heart out and find the info on this.
    I found one company that sells gear oil without the additive. I dont remember the name but they sell parts for model A cars (ford). A model A rear end has bronze gears or at least one is bronze. The oil was called 600 if I remember correctly.

    FWIW alot of people replace the worm gear in snow blowers and have it fail a year later. The cause is the wrong lubricant was used. The culprit is the HP high pressure additive.

  2. #12

    Default Odering parts

    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.




    If you got a gear with 24 teeth WHY NOT go back and order the stub for 24 teeth and install the new parts. Yes, get the right gear oil for brass parts. I changed gear grease two months after getting my HF 4X6 saw. It was stated that the grease needed to be changed even if new. As I had been told about the gear ware is an issue, I ordered a new gear while it still matched what was in the saw. Just my OCD I guess. Again order a matching 24 tooth and go to work.

  3. #13
    Join Date
    Feb 2012
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    Metcalfe, Ontario, Canada
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    1,118

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    Quote Originally Posted by ahidley View Post
    FWIW. You can not use gear oil on bronze gears. It makes them fall apart. Gear oil has a high pressure addative that ruins bronze.
    Google your heart out and find the info on this.
    I found one company that sells gear oil without the additive. I dont remember the name but they sell parts for model A cars (ford). A model A rear end has bronze gears or at least one is bronze. The oil was called 600 if I remember correctly.

    FWIW alot of people replace the worm gear in snow blowers and have it fail a year later. The cause is the wrong lubricant was used. The culprit is the HP high pressure additive.
    I would say you SHOULD use gear oil with bronze gears. But what gear oil?

    The easiest gear oil to find is rated GL-5, and likely will have additives that are damaging to bronze to a greater or lesser degree.

    Real GL-4 oil would probably be fine for bronze gears in moderate service, but NAPA, big box stores and the like carry oil rated GL-4 and GL-5, meaning, usually, that they have all the additives of GL-5 and meet the wear specs for GL-4 ( for steel).

    Suitable gear oils are available, but finding something locally that you can buy in small quantities is unlikely for most of us.

  4. #14
    Join Date
    Oct 2005
    Location
    British Columbia
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    6,067

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    Quote Originally Posted by ahidley View Post
    FWIW. You can not use gear oil on bronze gears. It makes them fall apart. Gear oil has a high pressure addative that ruins bronze.
    Google your heart out and find the info on this.
    I found one company that sells gear oil without the additive. I dont remember the name but they sell parts for model A cars (ford). A model A rear end has bronze gears or at least one is bronze. The oil was called 600 if I remember correctly.

    FWIW alot of people replace the worm gear in snow blowers and have it fail a year later. The cause is the wrong lubricant was used. The culprit is the HP high pressure additive.
    Probably one of the Mobilgear SHC 600 series of gear oils. Not always easy to come by thru normal consumer outlets. You'll have to go to the folks that sell and service heavy industrial equipment or at least the suppliers to them. Think rock crushers and aggregate handling equipment as just one example. Sometimes they will have open cases of quarts, usually pails and most often bulk, where if talked to nicely they'll dispense a quart or two into your container or sell a couple of quarts from an open case.

    The yellow metal compatibility with EP gear oils is getting better now that a lot, if not most, are utilizing deactivated sulfur instead of the active sulfur used extensively in most EP gear oils of the past. It was this additive that caused the the corrosive attack on the yellow metals and usually more so at temperatures above 80C.

    Remember though that now most EP additives are much more yellow metal friendly than those used in the past. I have personally used Esso GX Extra 75W90. This is a partially synthetic gear oil that meets the now obsolete GL6 specification EP classification. An oil originally specified for use in Ford's 9 inch rear axles due to the high offset ring and pinion and the resultant high sliding forces that it presents to the gear-set.
    Have used this for at least two decades, probably closer to three without issue. A lot of the new full synthetic automotive gear oils are very good choices and will often state their yellow metal safe qualities. They are also much more efficient in regards to reducing friction in this type of gear set which is inherently inefficient by the nature of it's design.

    Like I said not that much of an issue in this application, especially in light of the fact that the gearbox in question ran well for decades , or at least until it ran dry.
    Home, down in the valley behind the Red Angus
    Bad Decisions Make Good Stories

  5. #15
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    Jan 2004
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    Missouri
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    Quote Originally Posted by plunger View Post
    Would that work?
    It can.

    Using a hob will "generate" a correct tooth form. Other methods approximate the correct form, which can be good enough.
    1601

    Keep eye on ball.
    Hashim Khan

  6. #16
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    Jan 2003
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    On the Oil Coast,USA
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    That gear looks very similar to the one I changed in my Grizzly 5x6.I still have the old one if you want me to take a look?
    I just need one more tool,just one!

  7. #17
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    Oct 2005
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    British Columbia
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    For those that are still a little reluctant about using an automotive GL-5 rated EP gear oil or don't know which one is yellow metal friendly, here is a small example of what's available. This picture represents a small sample and is not all inclusive by any means but it is a start.

    The photo depicts the results of an ASTM D-130 test on a sample polished copper strip in order to establish an oil's corrosive effects on that sample. This test is performed at an elevated temperature for a prerequisite time period.
    Anything with a 1b rating or better is considered yellow metal friendly. This what you'll be looking for in a candidate as a replacement oil when doing research on oils not listed here. Just look for the ASTM D-130 test results on the oil in question.

    The good thing is that many of these lubricants are available just about anywhere and in consumer sizes such as quarts or liters.

    Home, down in the valley behind the Red Angus
    Bad Decisions Make Good Stories

  8. #18
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    Jan 2013
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    Alaska
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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.
    Yes, I could walk away from my 4x6 saw when it was cutting any material without concern. In the beginning I couldn't but after I tuned it up it really cut nice. I always bought the best quality blades I could find and usually used cutting oil applied with a pump oil can.

    I thought about just cutting the gear but then decided I wanted to learn how to hobb a gear so that's the direction I'm heading.

  9. #19
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    Jan 2013
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    Alaska
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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.
    Probably would be but I just didn't think of it at the time. I didn't measure the new gear but my gut says it was larger than the old one.

  10. #20
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    Jun 2003
    Location
    Calgary Alberta
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    1,097

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    my 4x6 wore the same way. Hydraulic oil works fine for gear oil.

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