Hi,

Bronze dust would be common in a basic worm drive gearbox especially one that had been assembled but never "run in". I would drain it, wash the dust out and re-assemble with good quality worm drive oil.

I worked for a company where we made worn drive gearboxes for aerospace use and the worm and wheel were lapped in in a jig. When they were assembled and run on the test rig for a couple of days, They were then stripped and if any bronze dust was found, then the whole procedure was repeated (many times!)

The inspector's criteria was that his white glove had to be absolutely clean when he rubbed around in the gearbox to allow the "run in" certificate to be issued.

It must have cost a fortune!

Don't panic! I opened my gearbox a few months after purchase because the rubber gasket started to weep oil. Inside I found obvious signs of bronze dust but no obvious wear on the worm. I changed the oil and bodged the gasket.

Because it was a bodge, the gasket leaked again after about a year. Re-opening the gearbox I again found traces of bronze dust but much less than the first time. Again no sign of damage to the worm. I'm pretty sure the dust was due just to roughly made and assembled gears bedding in.

My bandsaw is the crudest of all my Chinese tools by far. It wasn't lovingly fettled by master tool-makers to meet precision specifications! Nonetheless it works a treat, far better than appearances would suggest possible.

One problem with inexpensive equipment is that what you get is inconsistent even between tools from the same batch. You can't assume because my saw is OK that yours must be too. I'd check the gearbox after some months cutting to make sure it doesn't need remedial work. With luck you'll find nothing wrong.

Dave

When I opened the gearbox of mine it was full of 'liquid gold'.

The gear is badly worn, but I did my best to improve alignment and it has lasted years now and the oil is clear of dust.

The situation is helped as the gear only turns in one direction

At some point a new gear will be needed, though.

Neil

The oil? came out gold coloured suggesting I should have changed it earlier. As there is no filler orifice they must fill it with the saw on its side as it was virtually full. If I am able to repair it then an orifice will be provided.

I have e-mailed Chester on the off chance they will have one somewhere otherwise it is going to give me a headache finding one. It is probably beyond my ability to make one. I will have to make a puller to remove it and although it will come off fitting the new one will require me to remove the worm first. Happy days.

Mine is a Taiwanese made item, but i guess the same as the rest. It too had a small amount of dusty gold in the bottom. No signs of any problems & runs great. I would not worry too much. Try it again in a year & see if it is less. A good gear oil is the way to go.

Steve.

David,

..as you already have the worm, replicating the wheel shouldn't be to difficult – it could (is likely to?) be an off-the-shelf-item in any case..

I must go to work, hopefully this post will help prompt a response to help you.

As these bandsaws are quite generic, may I suggest Machine Mart and their Clarke brand as a source of spares? The other option is Sealey.

The wheel is probably just a normal bronze or even brass. Many years ago we had a wheel go in a servo driven rotary table. The shop made a new wheel from a plain bronze, it lasted about a week, then they asked what it should be made of, aluminium bronze, was still going years later.

I looked out the Instruction Manual and leaflet for my vintage Warco machine and was interested to see that the gear is steel and the worm wheel bronze.

The Manual specifies SAE -30 oil "to lubricate the components" and says that "the drive gears will not require a lubricant change more often than once a year, unless a leak or overhot [sic] occurs." I assume from this that the Taiwanese makers did not think that an EP oil was necessary.

The machine has served me well over decades of light use and I shall probably leave well alone.