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benmychree

John York
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This is the sort of wear that happens when EP (extreme pressure ) lubricants are used with bronze worm gears, the lube corrodes the surface and the worm wears off the corrosion in a continuous process; EP lubes should NEVER be used with bronze worm gears; of course, I do not know that is what happened in this case, but it is familiar look/ failure. If only someone spoke Portuguese, we could ask ---
 

cathead

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This is the sort of wear that happens when EP (extreme pressure ) lubricants are used with bronze worm gears, the lube corrodes the surface and the worm wears off the corrosion in a continuous process; EP lubes should NEVER be used with bronze worm gears; of course, I do not know that is what happened in this case, but it is familiar look/ failure. If only someone spoke Portuguese, we could ask ---
John,

Thanks for the explanation on EP lubricants with bronze gears.... very interesting.
 

benmychree

John York
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Also, this shows what is possible in a pinch. The only shortcoming is that the hob is not relieved, hence the slurry of bronze goop; if it was relieved, even with a file, it would cut rather than just abrade the bronze. This process of gashing the blank and hobbing by allowing the blank to freely rotate is shown In Brown & Sharpe's publication "Practical Treatise on Milling and Milling Machines". In production, it would be done on a hobbing machine, where the hob and blank are geared together, and the hob can have sufficient clearance to cut freely.
 

celsoari

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the saw was used every day for 1 year. The oil recommended by the manufacturer was used in the reduction box. I believe it is natural wear and tear from overuse. (Sorry my English is not so good)

grettings from Brazil
Celso Ari
 

GrayTech

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Many modern EP lubes are brass and bronze friendly. Always a good idea to make sure though.
Great job on the gear!
 

markba633csi

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If you make a gear on Halloween do you get visited by the "Hob-goblin" ?
(cousin to Great Pumpkin)
 

cascao

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Some syntetic oils for gears can't be used with bronze too. It's a issue when bearings have machined gage in bronze too
 
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