Fixing an old lathe with spindle "droop"

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nurd77777

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Hi Machinists I have had an old lathe and put up with it for so long. Its cast iron and has cast iron bearings which are so worn. Looked at molding some more bearings from aluminium with some tin mixed in but this seems like a lot of messing about. When u haven't got a lathe u cannot do any machining. Just today I looked at adjustable bearing sleeves to be used with tapered roller bearings. Could this be the answer ? There does not seem to be many specifications available so it would be difficult to specify what to order. Anyone have any experience ?
 

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Gordon

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Hi Machinists I have had an old lathe and put up with it for so long. Its cast iron and has cast iron bearings which are so worn. Looked at molding some more bearings from aluminium with some tin mixed in but this seems like a lot of messing about. When u haven't got a lathe u cannot do any machining. Just today I looked at adjustable bearing sleeves to be used with tapered roller bearings. Could this be the answer ? There does not seem to be many specifications available so it would be difficult to specify what to order. Anyone have any experience ?
You could just put in some bronze bushings if you have any way to rebore the mount. The lathe looks small enough that perhaps someone could do it on a mill or a larger lathe.
 

goldstar31

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Sadly your photos are not clear enough for my poor eyes with macular degeneration.
So some guessing is necessary . You say that you have cast iron bearings so are these the split bearings which have a single tightening bolt? If so I would caution you not to do any 'adjusting' as you could crack them.

You could line bore but the odds are that the bed will be worn some 6 inches from the spindle/ chuck.
To cure the bed wear, it could be Blancharded fairly cheaply and the ways built up with Devcon or the equivalent.
Again, I suspect the spindle will be somewhat worn. Maybe it could be built up with Devcon or better built up with hard chroming. Then, I would consider tackling the worn headstock bearings- possibly with Devcon.

Suffice to say, I've done up a couple or more Myfords.

It all depends on what you are prepared to spend in money and obviously time. One can reach a point when it is better to buy a newer lathe.
 

gunner312

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Hi Machinists I have had an old lathe and put up with it for so long. Its cast iron and has cast iron bearings which are so worn. Looked at molding some more bearings from aluminium with some tin mixed in but this seems like a lot of messing about. When u haven't got a lathe u cannot do any machining. Just today I looked at adjustable bearing sleeves to be used with tapered roller bearings. Could this be the answer ? There does not seem to be many specifications available so it would be difficult to specify what to order. Anyone have any experience ?
It appears to me that the bearing housings are part of the bed. I would set it up on my mill and bore the bearings oversize and put/cast in a set of babbit bearings or even a set of bearings from an automobile crankshaft. As a last resort, I'd mill off the bearing housings and install a set of pillow block bearings at the present center height and make a new spindle to fit them with thread to fit the lathe chuck(s) I have. Too bad you aren't here in the US. I'd be more than Happy to help out. My machinery is large enough to handle the job. You could also make a cast iron bearing and bore the present bearing housings to fit them or vice-versa. I have some Oil-Lite bearing material that would also make a bearing for that size lathe.
 

nurd77777

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Thanks all ,I have enclosed a better view of the split bearing they sit in a square housing which is only 45mm wide and the shaft is 33mm so there is no room for a roller bearing. I think the best bet would be to cast some more bearings like the originals and line bore them in place. Dave Gingery did it on his lathe. I could use aluminium with up to 20% tin. We have low lead solder which is mostly tin over here. Its not much use for electronics (it grows whiskers) . Babit metal would be a possibility. I could cast two round billots then square them off to fit in bearing mountings on the mill. Then I could fabricate a boring bar if I can find a good straight rod. This would run between two cast iron bearings. (I have lots of soft cast iron but not big enough for these lathe bearings). The boring bar would be advanced against the bed which is a very solid wide piece of cast iron. Oh I forgot to say the bearings would be split once they had been line bored to allow for wear/testing etc. Sometimes it hard to determine the next course or action that's where friends come in. Regards Keith
 

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gunner312

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Looking at your Bearings, I see that they are a split bearing with the top half squared or perhaps it's the bottom half that is squared, doesn't matter, it's there to keep the bearing from spinning. So, What I would do in your case is mill the split and re-cut (bore) the bearings to fit the spindle bearing surface.

Then mill the bearing top clamp/mount to fit the new bearing height. re-install and Bobs yer Uncle as my friend from Australia says.

The bearing center height stays (almost) the same because you haven't changed the OD of the bottom bearing and the top bearing is held in place by the original fitting.
 

nurd77777

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Looking at your Bearings, I see that they are a split bearing with the top half squared or perhaps it's the bottom half that is squared, doesn't matter, it's there to keep the bearing from spinning. So, What I would do in your case is mill the split and re-cut (bore) the bearings to fit the spindle bearing surface.

Then mill the bearing top clamp/mount to fit the new bearing height. re-install and Bobs yer Uncle as my friend from Australia says.

The bearing center height stays (almost) the same because you haven't changed the OD of the bottom bearing and the top bearing is held in place by the original fitting.
Hi Gunner The bearing in the pic is the top half. The bottom one is worn as you would expect from the weight of the chuck so I would be lowering the spindle if I recut the existing bearings. In the past I have damaged the bottom bearing trying to get it out (to change them round and get round the droop) , somebody mentioned they are fragile. The housing is square all the way round and I could cast some aly/tin cylinders and mill them to suit the housings. Then have a boring bar driven from the tool post with another bearing on the back of the headstock and get as near to the spindle journal dia. Then split the bearings with a hack saw blue them etc and scrape. The lathe originally was a capstan and hardly any spindle height I had difficulty in making cross slides for it. I do not expect to do all this soon but need to sort out a modus operandi first. Cannot help but think there must be many people with similar problems. Thank-you again see you on this forum.
Keith
 

mfrick

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Well I have read the post and here is what I have done. First I have rebuilt lost of lathes with bronze bearings, the fix is simple and yet time consuming. You start with some 660 bearing bronze and split into halves with slitting saw then you soft solider the two halves back together. Before you machine the bearings you need to check the spindle and if the journals are tapered and or not round they need to be machined then polished, you then machine the new bearings to fit once done heat break apart clean up surfaces and install into head stock, you then install the spindle you will have to blue and scrap bearings and put oil passage in you may have to shim the caps. once done your ready to go. Good luck with your project.
MF
 

mfrick

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Well I have read the post and here is what I have done. First I have rebuilt lost of lathes with bronze bearings, the fix is simple and yet time consuming. You start with some 660 bearing bronze and split into halves with slitting saw then you soft solider the two halves back together. Before you machine the bearings you need to check the spindle and if the journals are tapered and or not round they need to be machined then polished, you then machine the new bearings to fit once done heat break apart clean up surfaces and install into head stock, you then install the spindle you will have to blue and scrap bearings and put oil passage in you may have to shim the caps. once done your ready to go. Good luck with your project.
MF
 

nurd77777

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Well I have read the post and here is what I have done. First I have rebuilt lost of lathes with bronze bearings, the fix is simple and yet time consuming. You start with some 660 bearing bronze and split into halves with slitting saw then you soft solider the two halves back together. Before you machine the bearings you need to check the spindle and if the journals are tapered and or not round they need to be machined then polished, you then machine the new bearings to fit once done heat break apart clean up surfaces and install into head stock, you then install the spindle you will have to blue and scrap bearings and put oil passage in you may have to shim the caps. once done your ready to go. Good luck with your project.
MF
Hi mfrick Thanks fer the info. An operation like this is always going to be daunting. I have just ordered some tubing to make a boring bar will have m12 on the inside to lock the cutter in place. i looked at the Gingery method of boring out bearings. I will not be entirely without machines when I take the lathe to bits, I have a small mill.
Regards Keith
 

packrat

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Well I have read the post and here is what I have done. First I have rebuilt lost of lathes with bronze bearings, the fix is simple and yet time consuming. You start with some 660 bearing bronze and split into halves with slitting saw then you soft solider the two halves back together. Before you machine the bearings you need to check the spindle and if the journals are tapered and or not round they need to be machined then polished, you then machine the new bearings to fit once done heat break apart clean up surfaces and install into head stock, you then install the spindle you will have to blue and scrap bearings and put oil passage in you may have to shim the caps. once done your ready to go. Good luck with your project.
MF
mfrick Your post on making bearings is how a machinist showed me how to make bearings for the first large steam engine I repaired..
 

mfrick

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The Aluminum Bronze material is great for slow moving parts that have a source of lubrication such as grease its a very hard close grain material, 660 bronze is a softer material and so it will hold lubrication like lube oil. I would not use Aluminum Bronze for head stock bearings on a lathe. You want a material that will hold the lubrication and not require a constant application, we use Aluminum Bronze in heavy equipment repair along with saw mill applications where there is an extreme force put on it, like debarker press rolls bushing on hydraulic cylinder, bushings on heavy dozer track rollers etc. stick with the 660 bronze.
 

nurd77777

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Both tjwal and mfrick I thank you and note what you say. I shall have to test any alloy for bearing capabilites. I know that a lot of what people cast is a zinc aluminum alloy not pure aluminum. Have tried melting pure aluminum and its a pain to machine it sticks to lathe tools etc. I have to use what I can get hold of and I will need quite a bit if I cast two bearings. Would adding somethink else to the zinc alloy be possible ?
 

tjwal

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The zinc-ali alloys that I’m aware of are mostly zinc with 10 to 30% aluminum.
If you are up to casting aluminum, I would go that route except I would sleeve it with a commercial bronze bushing. You still have to deal with the thrust somehow.
mfrick, thanks for the info on alum-bronze. It’s on my bucket list to cast some to play with.
 

Apprentice707

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As you say it is difficult to do any machining when you don't have an accurate lathe to use. Perhaps if you join your local Model Engineering club or enrolling for a hobby shop course at your local college would give you access to good machinery. I have restored 4 old lathes and where necessary have always used Phosphor Bronze for the mandrel bearings. Does your lathe have a tailstock? If so you could no doubt use it to hold an adjustable boring bar to ensure that the headstock and tailstock center lines are in alignment. Good luck with the project.
 

Gordon

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As you say it is difficult to do any machining when you don't have an accurate lathe to use. Perhaps if you join your local Model Engineering club or enrolling for a hobby shop course at your local college would give you access to good machinery. I have restored 4 old lathes and where necessary have always used Phosphor Bronze for the mandrel bearings. Does your lathe have a tailstock? If so you could no doubt use it to hold an adjustable boring bar to ensure that the headstock and tailstock center lines are in alignment. Good luck with the project.
When I first got married I did not have a lot of money to purchase machines but the nearby community college had an apprenticeship program with a shop and a lot of donated raw material. They offered a beginners shop class for a very reasonable fee and you did not have to be in any apprenticeship program to take the class and you could take the class as many times as you wanted to. I took the class four or five times and I got more than my moneys worth in just raw material in addition to having access to a whole shop full of machines and an instructor who could answer my questions.
 

goldstar31

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Merlin engined Spitfires and Hurricanes kept running during WW2 iin the Western Desert using aluminium bearings as there was nothing else. That was from an old RAF engine fitter who was there.
My father in law was in Burma with RAF 31( The Goldstars) Squadron with DC2's and 3's and they were regularly pressed back into service by somebody driving around the in tractor just to check that 'nothing had fallen or been shot off earlier.

Later , our Spitfires on the Squadron were 'serviced' by a 18 to 19 years old with 6 weeks training. That was 70 odd years ago. One of those 'old girls' and is still airworthy and is with the Canadian Warbirds. The ex 'engine basher' is almost 90 and needs more a very serious overhaul!

Worth thinking about, eh?

Norman
 

nurd77777

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Thanks everybody for coming to my aid. I think I always try to do jobs like this with the minimum of hassle and cost. Firstly why am I bothering its an old lathe and I could probably buy something better. I just like the fact its a table model with big chucks. If I went for the equivalent it would probably be a floor standing one weighing 2 ton. Inspired by all the comments I have been trawling the net. To buy a 6 inch length of oil-lite cylinder the right size costs £260 and it would have to machined for squares and line bored before being split.
Alex Tiranti of London advertises bearing metal presumably this is Babbit , at a reasonable price. There is no waste is you make a mess of machining you just re-melt and start again . There are lots of fascinating vids of people using Babbit for casting bearings in situ but in my case the shape is more complex.
There are also lots of vids of people making bespoke boring bars and using them for re-bushing heavy machinery.
The common alloy of zinc and aluminum is very brittle and when u break it has a crystaline structure . I guess if u were making an alloy it would be a trade of softness and hardness.
So I guess I will be taking the easy way out with Babbit now I have supplier.
Thanks all.
 

goldstar31

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What now seems to be a million years ago, I bought a heap of worn shell bearings and recovered the metal.
One of the byproducts was 'white metalling' the worn feed screws on a Pools Major. I used soot from a candle as the release agent!

Mind you, my late wife used to recover dental gold from fillings that she had done as student or newly qualified dentist. It will not assay as the gold is alloyed with platinum. :mad:

Hint. if you want a good book-which includes line boring as well as the ordinary variety, George Thomas's Model Engineer's Workshop Manual. This was edited for publication by my wife's old dental student friend:D
By Jove how the money rolls in- rolls in!
 
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