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which lathe?

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jamie creighton 127/11/2019 19:11:34
15 forum posts

hi,

i would like some advice please on which small lathe (new or old) would be best for making some new bearings for my sony turntable.

i would like to make them in bronze or maybe delrin and also have a go and make the bearing housing in the same also.

could you guys advise on what lathe to go for that will turn to tight tolorences.

i should say im new to lathe work but my job is a steel fabricator.

here are some pics of the original housing and bearings.

thanks in advance.

Redsetter27/11/2019 19:54:07
108 forum posts

This doesn't directly answer your question, but is there anything special about the bearings? They are quite likely to be a stock size (though may not be available from Sony), if so, there is no point in trying to make them. Also if you are concerned about high precision you will have to consider possible wear on the shaft.

jamie creighton 127/11/2019 20:18:26
15 forum posts

hi,

the turntables dates from 1974 and is a high end example,no spare parts are not available anymore.

the oilites bearings are approx 11mm id and 16mm od,ive checked online a few times and it would seem the size is not a standard stock item,besides theres no fun in just buying off the shelf

JasonB27/11/2019 20:22:20
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17315 forum posts
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How approximate are those sizes, 7/16" x 5/8" is a standard size

jamie creighton 127/11/2019 20:34:54
15 forum posts

ah ok,i figured the japanese didnt use imperial

Bazyle27/11/2019 21:14:19
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5009 forum posts
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By the way if oilite you can't turn them or ream etc easily 'cos doing so smears the bronze over the pores and blocks them defeating the object.

Versaboss27/11/2019 22:07:22
433 forum posts
51 photos
Posted by jamie creighton 1 on 27/11/2019 19:11:34:

could you guys advise on what lathe to go for that will turn to tight tolorences.

Turning to tight tolerances lies in the hands from the one at the handles, more than a problem of the lathe itself. Anyway, buying a lathe for repairing or rebuild a turntable bearing is a very expensive proposition!

I built several turntable bearings myself, although not with such complicated housings (which would be very difficult to making on a lathe). But I can say that I used Delrin (and Torlon, if you can find and pay that stuff!) with very good success.

Kind regards,
Hans-R

Hopper27/11/2019 23:34:00
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4165 forum posts
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Posted by Bazyle on 27/11/2019 21:14:19:

By the way if oilite you can't turn them or ream etc easily 'cos doing so smears the bronze over the pores and blocks them defeating the object.

OIlite literatiure says you can as long as a sharp tool is used. **LINK**

jamie creighton 128/11/2019 05:26:46
15 forum posts

So any lathe recommendations?

Ron Laden28/11/2019 06:55:51
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1721 forum posts
314 photos

Jamie, it does seem an expensive approach in buying a lathe just to make up some bearings but it sounds as if that's what you want to do so who are we to argue. Let's not go all around the houses if you can afford £590 get yourself a Sieg SC2 from ARC it's currently at a discounted price. It's 12 inch between centres or the SC3 which is £690 and 16 inch so a bit longer. They both have 500 watt brushless motors and you don't hear much bad press about them so they are decent mini lathes and if I were looking for a mini lathe at the moment it would be my choice. Others may advise other machines but the Sieg SC, s would be my recommendation.

Ron

Nick M0NPH28/11/2019 06:56:27
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24 forum posts

Hi Jamie

i have just got a new Chester DB10 lathe and up to now am very happy with it

but of corse it depends what you want to spend on a lathe as mentioned above if its just to repair a turn table

it's an expensive way to go but generally i think Chester machines are quite good for the money

JasonB28/11/2019 07:29:06
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Yes Oilite can be turned OK but reaming will smear the surface.

Also be aware that Oilite bearings as supplied are a little oversize and only take on the correct size when pressed into the housing so bear that in mind when taking measurements and sizing the fits.

If modifying Oilite it won't be so much the lathe but how you hold the work to ensure concentricity and avoid distorting the bearing.

Robert Atkinson 228/11/2019 07:29:21
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554 forum posts
21 photos

If you want to turn thin wall bearings accurately then how you hold them is important. Make sure that the lathe you buy can accommodate a collet chuck of suitable size. The SC2 will take one

**LINK**

**LINK**

The collet chuck can also hold an arbour to mount the bearing while you turn the outside diameter.

Robert G8RPI.

Hopper28/11/2019 07:47:46
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4165 forum posts
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Are the originals even Oilite/sintered bronze? They look very much like plain brass or bronze bushings in the pics. You can buy pre-made bronze bushes in a wide variety of sizes from bearing suppliers.

john fletcher 128/11/2019 07:50:24
572 forum posts

If you join Vintage Radio (which is free). On there are experts who used to repair such things and maybe still do, who just might have that spare part as (NOS) new old stock. John

Journeyman28/11/2019 09:15:00
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734 forum posts
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The answer to the original question "Which Lathe?" is likely to generate a myriad of suggestions as per normal for this illustrious forum. Have a look at Journeyman's Workshop for a few ideas.

John

Vidar28/11/2019 09:34:05
56 forum posts

I don't know much about turntables, and thus the scale of that thing is a bit of an unknown, but I would think most lathes would do the required precision. (And there are many workshops that could do that for you if that is your only purpose).

That said I'm with the comments above - Sony most likely used standard sized parts, and that does look like a plain bronze bearing. That should be fine for the speeds of a rotation table so it makes sense. The bearings will include tolerances for fit and rotation so the measurements will be slightly off from round numbers even new.

The housing itself seems be a die casting that has been finished off on a lathe. (The small stand up rounds around the center might pads for the die casting ejection pins). A lathe only is not the natural fit for making that.

Is casting the entire thing (house and bearing) in bronze and finishing off on a lathe an option?

Nick Clarke 328/11/2019 11:43:48
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571 forum posts
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+1 for SC3 from ArcEuro - unless the bench space is an issue as the next job may be longer so SC3 was my choice in place of the SC2.

You need to include the tools that you need to complete your jobs as well, so the collets Robert suggested and a drill chuck as well as cutting tools ought to be on your list - but buy as you need and don't try to get everything possible at once - I suspect many of us have bought things to fully equip a lathe that have never been used in practice!

SillyOldDuffer28/11/2019 12:00:35
5367 forum posts
1090 photos
Posted by jamie creighton 1 on 28/11/2019 05:26:46:

So any lathe recommendations?

Jamie asked in his first post 'could you guys advise on what lathe to go for that will turn to tight tolorences.'

The answer is most of them, but!

Machines that will turn accurately using nothing but the dials cost big money. For a lot of small-scale accurate work, the Cowell's is a good machine, but it's too small for general purpose work. People like the Sherline too; not as accurate or solid as Cowells, but still a decent machine. Mini-lathes are handy for small rather than miniature work, but if you have space, buying bigger is usually a good idea for general purpose work.

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.

Best advice I ever got was 'buy the biggest lathe you can manage'. Crudely put, a big lathe can usually do small work, but a small lathe can't do big. After that the choice is between second-hand and new. New lathes in the price range hobbyists are prepared to pay are made in the Far East, and they are a little rough. Second-hand industrial lathes are available at the moment for tiny money compared with their original cost because Industry and Education have dumped them wholesale in favour of CNC machines. Three problems with second-hand, they tend to be big (size and power), condition is all important buying anything second-had, and the cost of spare parts is often eye-watering! I feel choosing a lathe is more about one's attitude to risk than the machines technical virtues:

  • Buying second-hand is at your risk.
  • Chinese, bit rough but you get a lot for your money. Plenty of choice. Buying new in the UK is low risk because consumer protection and the supplier's generally positive attitude to customers, means an unacceptable dud can be sent back.
  • Ex education, and industry. All second-hand, condition ranging from as new to total carp.
  • Myford, good reputation for good reasons, not all of which are still valid! Historically the easy answer to any model engineer asking 'which lathe' Mostly second-hand but also available refurbished. Expensive, personally I think overvalued for what you get, especially when the machine is in poor condition due to wear or abuse. Beware of reading:
    • Secondhand MYFORD, instead of
    • SECOND-HAND Myford

Hope that helps,

Dave

Dave Halford28/11/2019 12:05:19
615 forum posts
5 photos

Hi Jamie,

Literally any small lathe will do what you want, even an 100 year old one.

However, why should it need new bearings? There's next to no side load with the turntable levelled properly and with a dab of oil having them run too tight will overload the motor and make noise. A good platter should run for at least 30 sec up to nearly a minute without drive before it stops.

You can make that housing out of something deader to vibration if it bolts to the platter.

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