which lathe?

[jamie creighton 1Participant @jamiecreighton1]

Posted by SillyOldDuffer on 28/11/2019 12:00:35:

Posted by jamie creighton 1 on 28/11/2019 05:26:46:

But I recommend focussing on what exactly is essential in the way of 'tight tolerances'. In practice, when making a simple bearing, I doubt many of us would insist on a machine capable of working to tight tolerances in the sense used in manufacturing were it's important to make parts interchangeable.

A slightly different technique considerably reduces the need for sooper-dooper machinery. Parts aren't reproduced from their measurements directly. For example, this bearing could be made by first drilling a hole slightly undersize through bronze, brass or oilite rod and then carefully boring the hole out to size. Likewise the outer diameter would be turned slightly oversize, and then carefully removing excess metal until the part fits into the turntable. In both cases 'size' is judged by reference to the shaft it's intended to fit, and the hole in the turntable. There's no requirement for lathe's dials to be spot on. When working by comparison, any lathe in reasonable condition will do the job.

cheers dave,

thats basically my thoughts on how to do it .

just to clear the is or isn't it an oilites bearing up here's a video of myself putting the oil back in them under vaccum.

**LINK**

you can see the air being removed from the bearings so the oil can get into the pours.

many thanks for your replies so far

[RedsetterParticipant @redsetter]

I have just had a look at the video.

With respect, you do not need to re-lubricate oilite bushes using a vacuum because the oil will displace the air anyway. You just have to soak them for a few hours. And it is quite wrong to remove the bearings from the housing before doing so, because they will probably be damaged in the process, and they will never go back exactly as they were. They are a consumable item. If you take them out, you should fit new ones.

[Neil WyattModerator @neilwyatt]

" The TTS-8000 is now widely regarded as the second best turntable Sony ever made (first place goes to the company's PS-X9, aimed at studios) "

http://www.hifinews.com/content/sony-tts-8000-vintage

[VidarParticipant @vidar]

That one seems quite special Jamie. I can see why you're willing to spend time and money on it.

[Howard LewisParticipant @howardlewis46836]

What ultimately determines the accuracy of work produced on a machine is the operator.

A skilled operator can produce good work off an old worn machine.

Any fool can produce bad and inaccurate work on a high quality machine.

For the sort of tolerances to which you need to work, most of the machines available, in the hobby market, from reputable suppliers of new machines, will produce what you require.

You need to decide to what use you plan to put it, afterwards, in terms of centre distance, swing, and mandrel bore.

If I were in the market for a new lathe, I would probably buy a SC4 or a SC6. But that is me, and may very well not not suit a lot of other people.

Starting with a new machine, from a reputable supplier, will be a help. If you are inexperienced, do join your local model engineering club, and take advice and instruction from the members, (Everyone will want to ride their particular hobby horse- we all do! ), and the machine supplier. If all else fails, read the instructions.

Howard

[SillyOldDufferModerator @sillyoldduffer]

Posted by Redsetter on 28/11/2019 18:38:39:

I have just had a look at the video.

With respect, you do not need to re-lubricate oilite bushes using a vacuum because the oil will displace the air anyway. You just have to soak them for a few hours. And it is quite wrong to remove the bearings from the housing before doing so, because they will probably be damaged in the process, and they will never go back exactly as they were. They are a consumable item. If you take them out, you should fit new ones.

Sure soaking will get some oil in but it's not how Oilite is made. New Oilite is first filled with oil by both vacuum and then high-pressure processes. The history:

"In 1927, Carl Breer observed that a car’s clutch would slip when oil, grease, or graphite was packed in. GM made a bushing of compressed powdered copper and graphite, but it crumbled. He hired an outside engineer, paired him with metallurgist Bill Caulkins, and helped them work on a new way to make self-lubricating bearings.

Together, Sherwood and Caulkins were able to compress powdered copper (88.5%) and tin (10%) with some graphite (1.5%) in a die, heat treating it in a furnace in the absence of oxygen (a process called “sintering&rdquo.

The resulting metal was “astonishingly high in physical strength” and about 40% porous; so they put it into a high vacuum, then released the vacuum by exposing it to oil, rather than air. They finished up by pressuring the oil, forcing it into the metal of the bearing. When the final product was clean, it seemed dry; but when there was friction, the higher temperature brought the oil out. It was re-absorbed when the temperature dropped again.

About a third of the volume of the “Oilite® ” bearings were oil; so much that they usually needed no service after installation. Oilite bearings would be used in distributors, generators, starters, and ball joints as well as water pump and clutch pilots, starting around 1932."

It would be possible to measure how much oil gets back inside tired Oilite after an ordinary soak by immersing it in a known volume of oil and seeing how much is left after the refreshed bearing is lifted up and given time to thoroughly drain back. Ideally Oilite should absorb oil up to about a third of its own volume. Bet it doesn't!

In any case, old bearings might be beyond hope because ancient oil gums up particularly if it gets hot. The porous structure could be bunged up. It could be totally lacquered!

Dave

[VidarParticipant @vidar]

Interesting.

Now I feel this really weird urge to try and make oil filled bearings. Or maybe sliding surfaces. I feel another totally counterproductive project coming on. Better call the wife asap so she can tell me No! with conviction and force. (She is good at that! )

[jimmy bParticipant @jimmyb]

I have machined Olite bearings a few times. Re oiling is not a problem and actually standard practice link

Jim

[Grindstone CowboyParticipant @grindstonecowboy]

Standard procedure when fitting a new Oilite bush in the rear of a Lucas dynamo was to stand the bush on your thumb, fill it with oil, apply finger to the other end and squeeze until you saw oil oozing out of the surface.

[DellParticipant @dell]

Hi all

i just purchased a second hand Warco cj 018 mini lathe direct from Warco and the have another one the same fully serviced and 6 months warranty hope that helps

they are in Guildford

Dell

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