Prazi SD300 lathe lubrication

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henryr
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Location: Connecticut USA

Prazi SD300 lathe lubrication

Post by henryr » Sat Feb 13, 2021 12:05 pm

Hi all,

I need help on how to lubricate my Prazi SD300. I know how to lube most components but haven’t figured out how to lube the following:

-leadscrew thrust and slide bearings

-drive train stepped V belt pulley
Is this pulley lubed by removing the snap ring and taking the pulley off shaft to clean and lube it?

-Are there any other lube points in the drive train?

Thanks,
henryr

Harold_V
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Re: Prazi SD300 lathe lubrication

Post by Harold_V » Sat Feb 13, 2021 4:22 pm

henryr wrote:
Sat Feb 13, 2021 12:05 pm
-drive train stepped V belt pulley
Is this pulley lubed by removing the snap ring and taking the pulley off shaft to clean and lube it?
I'm not familiar with that little machine, but if the pulley in question is the drive pulley for the spindle, it does NOT require lubrication, as it rotates with the spindle. If it behaves as an idler, floating on the shaft on which it mounts, or if it contains a planetary system within, that may not be true.

Please correct me if I'm wrong.

H
Wise people talk because they have something to say. Fools talk because they have to say something.

henryr
Posts: 25
Joined: Mon Jan 15, 2018 1:20 pm
Location: Connecticut USA

Re: Prazi SD300 lathe lubrication

Post by henryr » Sat Feb 13, 2021 6:16 pm

It is key part of the drive system. The motor drives the pulley via a V belt and that pulley, which spins on a stationary shaft, drives everything else. So I know that that pulley and shaft need lubrication. My question is how to lube them.

Harold_V
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Re: Prazi SD300 lathe lubrication

Post by Harold_V » Sun Feb 14, 2021 1:42 am

Thanks. Not being familiar with the machine, I had no clue.
I agree---it must be lubricated. I suspect that it requires a grease of some description---something applied only occasionally. If it was to be lubed on a regular basis, I would think it would have provisions for doing so.

H
Wise people talk because they have something to say. Fools talk because they have to say something.

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BigDumbDinosaur
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Re: Prazi SD300 lathe lubrication

Post by BigDumbDinosaur » Sun Feb 14, 2021 2:48 am

henryr wrote:
Sat Feb 13, 2021 6:16 pm
It is key part of the drive system. The motor drives the pulley via a V belt and that pulley, which spins on a stationary shaft, drives everything else. So I know that that pulley and shaft need lubrication. My question is how to lube them.
If that sheave is acting as an idler, I suspect it's mounted on ball or needle bearings. As Harold said, unless a grease fitting or other readily apparent lube device is present it likely doesn't need periodic lubrication.
——————————————————————————————————
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henryr
Posts: 25
Joined: Mon Jan 15, 2018 1:20 pm
Location: Connecticut USA

Re: Prazi SD300 lathe lubrication

Post by henryr » Sun Feb 14, 2021 11:37 am

The manual shows it should be oiled before every use but there are no instructions and no grease fitting or oil hole.

pete
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Re: Prazi SD300 lathe lubrication

Post by pete » Sun Feb 14, 2021 1:43 pm

For cnc machines that were designed and well guarded to use in most cases a timed and pumped greaser systems that type of lubrication is quite common. But it's fairly rare to use grease anywhere on a manual machine. And using grease as a replacement for oil despite what a few seem to think on Youtube is NOT a good idea for very logical reasons. In simplified terms grease is just oil in a carrier. And it can retain wear particles, chip contamination etc. Oil tends to help flush all that out during each re-oiling. While I don't know much about those Prazi lathes, they built enough of them that I find it hard to believe someone hasn't uploaded the manual somewhere. Finding where is the only tough part. Using Google and only search terms in English is very limiting in what you get for results. If it were me I think I'd find out the German words for lathe and manual then put the Prazi name in as well as those two German words and see what turns up. I'd also bet that somewhere there's a dedicated user group for the Prazi machines. I might use grease for thrust bearings if the cross and top slide has them for the feed screws. In most cases with those there's no easy access to use oil and they would be well protected from contamination.

Without that manual and knowing for sure what the factory recommended, I'd feel safe using a light weight spindle oil for the rotating parts and change gear axles, gear teeth, and Vactra no. 2 way oil for the sliding surfaces. I've seen some recommendation's to use motorcycle chain lube for lathe change gears. It's simply not needed and again it helps to retain contamination. Lathe change gears are in reality very lightly loaded, a drop or two on each gear each time you use the machine will in a few rotations distribute around the gear teeth. A small amount of oil and doing so often will work just fine. Where I do over oil is on the ways and slides because of there being exposed to the cutting dust and chips. I'm trying to keep those surfaces as clean as possible. And turning any rusty material, cast iron or when filing and polishing on the lathe I always cover the ways between the carriage and head stock with a clean rag. Rust is a lot harder than the parent material it comes from, so is the skin on cast iron. That can permanently embed into the softer bottom of the carriage surfaces, cross and top slides and then slowly grind away even hardened way surfaces. In any area or If your sliding surfaces show a dark or black oil it means your not oiling anywhere close to enough. That color change is showing wear particles and that's helping to wear out those surfaces.

henryr
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Location: Connecticut USA

Re: Prazi SD300 lathe lubrication

Post by henryr » Sat Feb 27, 2021 1:06 pm

I learned that there are two sealed bearings on the pulley shaft.

Harold_V
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Re: Prazi SD300 lathe lubrication

Post by Harold_V » Sun Feb 28, 2021 2:33 am

henryr wrote:
Sat Feb 27, 2021 1:06 pm
I learned that there are two sealed bearings on the pulley shaft.
Meaning that the stepped V belt pulley in question does not require lubrication?

H
Wise people talk because they have something to say. Fools talk because they have to say something.

henryr
Posts: 25
Joined: Mon Jan 15, 2018 1:20 pm
Location: Connecticut USA

Re: Prazi SD300 lathe lubrication

Post by henryr » Mon Mar 01, 2021 10:10 am

Yes, no lubrication.

Harold_V
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Re: Prazi SD300 lathe lubrication

Post by Harold_V » Mon Mar 01, 2021 3:26 pm

henryr wrote:
Mon Mar 01, 2021 10:10 am
Yes, no lubrication.
Thank you. That confirms what I said previously:

"I'm not familiar with that little machine, but if the pulley in question is the drive pulley for the spindle, it does NOT require lubrication, as it rotates with the spindle. If it behaves as an idler, floating on the shaft on which it mounts, or if it contains a planetary system within, that may not be true."

H
Wise people talk because they have something to say. Fools talk because they have to say something.

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