making spindle bearings

hello all,

id like some information please on the best set up and method for making spindle bearings. i need 2 from bronze .

i have a spare spindle which can be made into a toolmakers reamer and my lathe is a hobbymat md65,i also have the milling machine attachment.

i was thinking of buying a floating reamer head attachment as id like to get a good tolerances.

what do you think? whats the best way forward please?

cheers.

Not possible to say without knowing a number for the tolerance you want to achieve.

Andrew

ok,

the spindle measures 10.985mm so im thinking an 11mm h7 reamer work do it? the spindle only turns at 33. 1/3 rpm.

Why don’t you bore the bronze, that way you will get a nice round hole and you can make it whatever size you wish.

hi,yes thats what im going to do first but being new at this i thought the final hole finish should be reamed?

The MD65 has taper roller bearings which 99% of people would consider preferable. Plain bearings would only be chosen nowadays for ultra smooth no play bearings for a watchmaker or precision lathe.

Are you planning parallel bearings? How will you adjust them after splitting within the design of the Hobbymat head casting?

For readers not familiar with the MD65 spindle see this website

What are you making a spindle for?
Is it for the Hobbymat lathe or are you using that lathe to make the bearings for something else?

Dave

Before anyone can give you any kind of meaningful advice, you need to provide more detail of what it is you are trying to do or make and what the spindle will be used for, what loading, what working environment etc etc. Otherwise it's just a guessing game.

And how are you measuring to one thousandth of a millimetre? Seems unlikely in the home workshop. Hundredth of a mm is as close as you are realistically likely to get.

But, I am guessing from the 33-1/3 rpm you let slip, that the spindle is something to do with an old record player? In which case it is not critical enough to need to use a floating reamer holder. Yes an 10mm H7 reamer available as cheap as chips online would do the job, held in the tailstock chuck. Ideally you should drill the hole then bore it out to nearly finished size and use the reamer to finish is off. But realistically, drill it to 9.5 mm and ream it should be good enough.

Or you can buy any number of ready made bronze bushes, or sintered bronze self lubricating bushes, that come with a 10mm bore and various ODs and lengths.

sorry i should have been more clear,the bearings im hoping to make are not for the lathe,the clues in the rpm of the spindle, 33 1/3

thanks hopper,yes it for a turntable.

im measuring the spindle with a digital micrometer whic is reading 10.985,is that classed as 11mm norminal?

anyway i believe an h7 11mm reamer is the correct size?

sorry for the dum questions but id like to get this as accurate as possible .

Sorry, brain fade on my part, yes 11mm h7 reamer should do the job for you.

Also be aware that a bronze bush will squash slightly if it is a press fit with the housing. Commercial bushes are designed with a specific size/tolerance for the hole in the housing and the bore of the bush is made oversize to allow for the compression when it is installed. A reason to ream the bore to size after pressing in the bush.

An alternative is to machine the bush to the required bore diameter and make its OD a slide fit with the hole and use Loctite to secure it.

Are you designing and/or making your own turntable or repairing an existing one? Aiming at high-end audiophile performance or just want to crank up Black Sabbath until you can't hear your neighbours banging on your front door?

No reamer used for my turntable bearings, just carefully turning/boring (and some 3M microfinish foil)

Kind regards,
Hans

bringing an old classic turntable up to date,rare, exotic and top end japanese direct drive, still good by todays standards.. it uses oilites as standard,id like to try and better the tolerances. i have spares so no harm will come to it while i practise. the end goal will be to substitute the oilites for bearing grade torlon.

the plinth i made myself,its panzerholz veneered in cocobolo.

Edited By jamie creighton 1 on 02/05/2022 14:42:43

Looks beautiful.

Yes beautiful indeed.

One aspect you might consider is that while it might be possible to better Oilite tolerances in a custom made bushing, in use the Oilite would more likely wear better and stay within its tolerance due to the self-lubricating nature of the oil-soaked sintered bronze material.

Hi Jamie,

That is a lovely piece of work, you should be justly proud of that.

Using an H7 reamer will give you the same size hole as the Oilite bush. These are normally supplied to give an H7 bore when they are pressed into a hole which is itself H7.

Hopper has the best option and it is something I have done in the past. That being to machine a custom Oilite bush. Billets of solid Oilite used to be available and this would give a better self lubricating bearing solution.

Torlon in my experience takes on moisture so you might have problems with this material. Especially if it is machined in a humid atmosphere and then lives in a relatively dry environment.

Regards

Gray,

I once had a Sugden Connoisseur turntable which had a very simple but finely machined shaft and plain bearing, the shaft had a very fine ground finish and the brass or bronze bearing was a smooth running fit, in the bottom of the bush was a ball bearing that took the weight of the platen and provided a single point low friction bearing. By all accounts it was a well regarded concept and gave good results. The finish of silver steel is decidedly rough compared to the finish of the Sugden spindle.

Mike