King 5x6 Horizontal bandsaw worm gear failure

S

slow-poke

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I was cutting a 3" exhaust pipe today and the blade sized up at the bottom of the cut, I switched it off withing a couple of seconds but after that no blade movement.

I opened up the gear box, the gear lube was gold colored and the brass/bronze worm gear is finished.

20 Teeth

I t looks like the easiest way to replace, would be to drill an access hole to punch the roll pin and then hopefully the worm gear will simple pop off the end?
Then thread the access hole and put in a plug with sealant.

Anyone do this repair?
Source for worm gear?

IMG_0130.JPG
 
That is what happens when EP gear oils are used with bronze worm gears; the EP ingredient attacks the bronze and the worm wears off the corrosion until there is nothing left.
 
It looks like there was very little oil in there- a good reason to check it once in a while.
The pin doesn't look like a roll pin, it actually looks like some type of rectangular key
I have seen gears for sale like this on Amazon- 20 tooth seems to be fairly common
Not sure if this would fit your machine- one or more dimensions may be wrong:
-Mark
 
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markba633csi said:
It looks like there was very little oil in there- a good reason to check it once in a while.
The pin doesn't look like a roll pin, it actually looks like some type of rectangular key
I have seen gears for sale like this on Amazon- 20 tooth seems to be fairly common
-Mark
Click to expand...
There are actually two things retaining the gear the key on the end (visible in the picture) as well as a roll pin passing through the collar of the gear ( barely visible end, at about 11:30 position. Looks like the key takes the load and the roll pin prevents the gear from walking off the end of the shaft.

There was plenty of oil, I will need to find some yellow metal compatible gear oil.
 
If the outer diameter of the snowblower gear looks close to yours that would be an inexpensive replacement even if you have to bush the inner bore
or drill a hole for a pin or some other modification. It might be possible to source a gear from another bandsaw manufacturer like Grizzly.
Is the company that made the saw still in business? I would try them first

I was able to remove mine by using small segments of metal rod slightly smaller in diameter as the pin and a small C-clamp as a pusher. I was able to push the pin out that way without drilling a hole in the box.
 
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Looks like the Jet replacement is made of steel. Is there a reason they would have used brass?

The replacement gear costs more than I paid for the entire bandsaw new/used!
968F30EE-EA57-4D3C-A247-FD02A6A848ED.png
 
..So far as oil is concerned, any non Extreme Pressure (EP)gear oil would work
 
I'm not sure why they used bronze gears instead of steel since automobiles use steel gearing and the speeds/forces must be
higher than bandsaws reach-
Maybe one of our mechanical engineer members can enlighten us?
 
markba633csi said:
I'm not sure why they used bronze gears instead of steel since automobiles use steel gearing and the speeds/forces must be
higher than bandsaws reach-
Maybe one of our mechanical engineer members can enlighten us?
Click to expand...
Apples and oranges! the gearing used in cars is all spur or helical and hypoid bevel gearing, not worm gearing; worm gearing operates by rubbing, not rolling like the other types of gearing, a steel worm would gall if run on a steel worm gear, hence the use of bronze (not brass), likely the gear illustrated is cast iron not steel. Cast iron is used in many worm gear sets, it wears well and is cheaper than bronze and not effected by EP oil. There is no advantage in using EP oils in any gearset other than such as hypoid bevel gears, where extreme pressures call for its use.
 
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