Printable View
Hi John
(sorry to hijack your thead Irving)
you mentioned the atlas 10, do you know of a fix to repair the bed? I was given one because the previous owner cut two slots in the bed to machine a disc brake..........Unfortunatly I was mis-informed by a local welding shop who said they could fix it no probs........ and you guessed it I now have a bananna shaped bed. I know its probably a lost cause but its a shame because the rest of the machine is in perfect condition.
As you know, the Atlas system is based on a single heavily webbed and rigid girder that everything is bolted on to. I would think anything which compromised that would render it useless, and personally I wouldn't even try a repair, unless you have the 48" bed, then you might be able to cut it down to a much shorter length and get rid of the bad bit. You would only need to shorten the leadscrew and drill a few holes and you would be back in business.
But all is not lost, because of the way it is made, just replacing the girder would bring everything back to spot on, especially if you could get the top face of the second hand part ground up.
Over the last year or so, I have noticed that some 10F's can be picked up for well below £100, and that would make a very good donor for the girder, plus a spares bank as well. The 10F was made in three different lengths, 36", 42" & 48", mine was 42". If you do manage to find one to replace yours, you would need to make sure the leadscrew matched for length, as mentioned above. I managed to buy a brand new 48" screw for mine, and cut it down to length.
As a starting point, I would put an ad on here to see if anyone has one in the back of their shed. Don't forget to say please and thankyou.
http://www.homeworkshop.org.uk/
Sorry I can't be of any more help. When I sold my machine, all my contact addresses for spares went with it.
John
Thanks John
Much as i suspected, shorting the bed might be an option tho so thanks for the idea, mines a 42" as well with the taper bearings. Thanks for the link I will have a look.
I was tempted to replace the girder with and RSJ ( with the webs stiffened) and fit linear rails for the bed ways......any good?
Even if you had to cut 12" off the length, you would still end up with a very desireable and useable, plus more rigid compact lathe.
I never really used the full distance between centres, so anything over 15" would be perfect.
John
Thanks John.
This was a "one day I'll fix er up" but since a 16mm dia, ball screw wont fit through the chuck on my working Granville lathe (Myford7 Copy) then its just come to the top of the list. Its not as simple as cutting the bed is it? the motor mount and the screw cutting gears will be lost no?
Maybe Id better start my own thread if this has options...........( sorry Irving)
Ross
If you look at how the lathe is built up, you should find that most of what you are worried about is mounted onto the detachable head not the main bed girder.
The girder will have to have a few holes recut in the correct places, namely the head hold down bolt holes, the reverse mechanism holding screws and one end for mounting the foot. There might be a couple of others to drill and tap, but nothing of any consequence.
The leadscrew would need shortening at the tailstock end, but that can be left until the very end, but that would need a lathe to recut the threads on the end, as your lathe won't be able to do it because you are working on the required threading leadscrew. Catch 22. I was lucky in that my old leadscrew was in position while I cut the new one down to size, so I used the Atlas to do the job.
For someone who knows what he is doing, maybe 3 to 4 hours taking it steady, and that is for the whole job.
Yet again, you are a little far away for me to assist with my machinery.
If you do raise a new post, I can show you a couple of easy mods to do that make the lathe even more accurate and easier to use, as I still have a few pics of some of the mods I did.
You must also realise that I am quoting from memory here, so I just might have forgotten a few things.
John
Here is my rather poorly Atlas 10" thats needs some work.
I was given it because the previous owner needed to do an emergency repair to some bike brake parts and cut two grooves in the bed to get them in. :eek:
I have also added to the problem (bad advice from welder) and had the bits welded back in, which as you would expect its now a bannana :sad:
So I believe my options are;
1 - replace bed
2 - shorten the bed
3 - make new bed with linear rails and cnc it :smile:
Open to other ideas...........................
Seems to me you have the opportunity here to have a proper gap bed lathe? cut it out and allow for a drop in piece when you need that close in work. It would be easier to beef up the side with nuts and bolts rather than trying to weld a bits in. At least you would have a first? maybe
You make it sound so easy. New post started in the lathe section.
Is it posible for you to copy your previous posts across?
Many thanks
Moderater: Copied older posts across, they appear above due to timestamps
cheers but theres two problems I can see with that; the first is strength, gap beds have a lot of material around the gap to make up for it and I think just adding to the sides at low level wont help much.Quote:
Seems to me you have the opportunity here to have a proper gap bed lathe?
The other problem is the apron is large and actually goes past the front edge of the headstock for normal turning. so the dropin piece would be permenatly in.
If i remake the bed then I will definetly make it a gap bed as i can design in the additional strength.
In hind sight I should have just bolted strengthing plates to the side as you suggested and filled the holes with chemical metal.
I didn't realise how bad it was. I thought maybe one cut, somewhere close to under the chuck. But having two, so far apart puts a different light onto it.
A gap bed just isn't feasible, due to the way the lathe is actually made. My new lathe, even though massively built compared to the Atlas, has a gap bed, but as soon as it is removed, all guarantees are down the river, as they can't ensure it will go back in exactly the same position as it came out. The Atlas would just bend like a banana in the middle.
The first option would be the best bet in the beginning, but you would need to ensure that you got a bed to match either the 42" (rather rare) and not have to cut the leadscrew or the 36" version and hope that the person selling has retained the leadscrew to go with it, or you will end up cutting the one you have. If you can find a 48" one with leadscrew, then great, snatch his hand off. The price of a new leadscrew (about 10 years ago) was around £125. I daren't even consider the cost of a new bed. Clausing USA still stock most new spares for these machines. Putting a wanted ad on John Stevensons site would be one option, or trawling ebay for "Atlas 10F" will eventually come up with something that might be OK. I got a lot of bits off there, and even in the last few months, I have noticed a few.
For a repair job, and now having seen it in the flesh, I would cut it off at the weld under the chuck, leaving the cast in bridge next to it intact, then dress the remaining cut off end to the same as the end you have cut off, and put in all the required holes
Doing it that way, you could dress the welded part of the bed under the head down to or below level of the main bed. You can then easily shim up the head to get it back into the right position if you had to go low. Anyone with a mill with a largish table should be able to machine that for you.
With regards to putting in linear rails. I personally don't think you could get a lathe of this size rigid enough with just rails. It would be nowhere as near as rigid as the girder. Once you get over a certain diameter of cutting on a lathe, the cutting forces required can get very large indeed, and do require large masses to keep everything stable.
You said over on the minilathe post that I make it sound so easy. In fact in my eyes, it is a dead easy fix to do, IF you have the machinery to do it, and the experience of fixing large items such as this. I can't help it if I have both. The main problem is I am not there to do it for you, so I, and hopefully other people, will have to try to give you as much info that is required, so that at least you stand a chance of completing it.
John
I never said it would be easy.. Ask yourself a question? you would not be here if you were not up for a challenge?.... Seriously though falling short of repairing it or replacing it then you are only left with shortening it or shorten it with gap still but smaller and remake the portion on the back end?
Theres a 10F on ebay right now... but finishes in 10mins
Thanks John, you are the lathe master, and I really appreciate your advice (just wish it was a year ago before i had it welded) So the best option is to hold out for a replacment bed and do it properly.
With regard to shorting it the only bit that cant be moved is the mounting foot as this has a wider casting at that point. I would also have to redrill the tray and move the stand legs closer. The other option is to just reposition the headstock and ignore the screw cutting stuff, replace the lead screw with a ballscrew and fit an indexer on the spindle shaft for cnc screw cutting, while I wait for a new bed.
Ive just converted a pillar drill to a cnc mill so yes I'm up up for a challenge :smile:Quote:
I never said it would be easy.. Ask yourself a question? you would not be here if you were not up for a challenge?....
Its just that Ive learnt from my mistakes and there are no shortcuts, eventualy you end doing as you should have done in the first place but it costs more......:heehee:
Damm didnt see your post, looked like a 36" anyway and complete so would be a shame to break just for the bed...Quote:
Cheers anyway
John
Ok I've placed a few wanted ads and saved an ebay search so hope fully one will turn up...(Flying pigs etc...)
In the mean time would you care to expand on the other mods you talked about? Thanks
Don't worry Ross, I haven't forgotten, but when you have to root thru thousands upon thousands of picture files to find what you want, it is rather time consuming.
John
Sorry John didnt mean to rush you, especially as it might be a while before I get another bed. Although i must admit that the idea of a short but working lathe is growing on me. I might have to see if can use a freinds lathe to turn down the leadscrew, I normally wouldnt be to bothered but since this for maching ballscrews i need the thead cutting capability.
even if i dont start for a while I'm sure there are others who will benifit from your wisdom.....
thanks again
If you are contemplating doing any length of thread turning to any sort of precision, you will have to have at least some sort of travelling steady, and a tailstock in very good condition.
A travelling steady was one thing I never managed to get hold of for my Atlas, they were like rocking horse crap, rather rare.
For fixing a droop snoot, I did a write up here.
http://www.homemodelenginemachinist....p?topic=2114.0
Bogs
HSA. If I had 1% of your talent I would be happy.............that is amazing. If there were more people with your can do attitude we would still make things in this country........not throw them away
Ross,
I suppose I only work like thousands of other mechanical engineers in a production environment.
When you are responsible for multi squillion squids worth of machinery, and it goes down, with replacement spares going to take say 3 weeks to get there, you have to come up with quickie solutions to get it running again. Some can be temp fixes to last that 3 weeks, or in the case of my tailstock, permanent. It is all just part of the job, with a few years experience thrown in.
I am sure that you have talents that I would greatly admire, being able to program CNC for just one example.
John
That maybe but I'm cheating and using cnc to get the accuracy that you acheive by hand.:redface:
Many thanks for suggesting the homeworkshop site, what a jem and strongly recommended
So I have now got a new bed for the lathe:dance::dance: :dance:
Techincaly its not an Atlas but the Uk version badged Halifax. I've looked at John Stevensons site and it appears that the beds should be the same and its only the carriage that is different.
So I will need some advice on the best way to get it milled or reground if you have the time please.
Ok so I'm spoiled for choice now as I have just bought a complete Halifax 524 with lots of accessories.Its was just down the road and a bargin at £120. It came with a 6" 4 jaw chuck, Milling attachment, tool post grinder, fixed and traveling steadies and the best bit is the replacement tee slot table for the cross feed.
The carridge is definatly better than the Atlas as the dove tails are bigger but there are so many broken bits that I will have to rob them from the atlas. The levers and wheels on the atlas are much more substancial and I'm not sure about the plastic pullies either.
So now I'm not sure wether I should rebuild this to original spec as its "British" (well almost) or wether to combine the best bits form both and create the B*****D chilld of Mr Atlas and Miss Halifax to create a good working lathe??????:smile:
Ross,
You now have the makings of a machine that will give you a lifetime of use. Forget about getting it back to original, there is very little intrinsic value in doing so, just concentrate on getting the best lathe you can out of the two.
All you really need to worry about at this stage are the centre heights of the head and tailstock. Choose which is the better of the two matched pairs, say one has a plain head and one has a roller, go for the roller, if they are both roller heads, go for the one which is the smoothest. If they have been left for any length of time in a pre loaded state, they will be very 'ratchety'. A new pair of bearings will require a remortgage of your house, unless you are lucky as I was, and got a friend to regrind the special outside races for me.
Clean off the new old bed with scotchbright and oil, that should clean things up rather well. Measure it up around the high wear areas, normally from the chuck mount to about 6" towards the tailstock, a thou or two should be OK, anything over that and you really need to get the top refaced. Only then see how the matched pair fit to the bed. you might have to do a little realigning of the head and tailstock, a fairly easy job, Once you have that done, concentrate on the saddle, leadscrew and gear areas.
Once you have the bits on the machine you want, and they are running together well, then start to rob the leftover pieces for better looking or replacement parts.
Once that stage is reached, you can start to get it fine tuned and modded to make it an exceptional lathe.
It looks like you have got all the attachments you will ever need, especially the rocking horse travelling steady, and the toolpost grinder, if it is any good. If I was you, I would empty the wooden box all the bits came in, and put it on a sheet of plastic (a bin bag), line it out with newspaper, put all the siezed and rusty bits into it (not electric motors), then dribble over the whole lot with some cheap engine oil, put newspapers over the top of that and pour some oil onto that as well. After a week in there, the parts should be ready to clean off and work on.
John
Thanks Bogs,
Glad to see you back. I wanted to make one good lathe lathe out of them but didnt know if it was ethically viable.......after all it should work to its best eh.
I'm glad all this stuff is slowly sinking in as i have only cleaned it with oil an scotchbrite. The problem is that when I put the straight edge across the ways there are no ridges or wear grooves but when I put it longatudinally there is a small dip in the bed, is this a sagging belly or just thefact that there is no other bits causing moments or stesses in it?
They are both taper bearing head stocks and seem very smooth. the Halifax one has the removable half bearing straps on the spindle like a crankshaft. Is this better or structurally weaker? also on the halifax the plastic pullies have worn and move lateraly on the shaft. are they inter changable or are they best left as is?
Since there is so much that needs concidering perhaps it is best if i start with the leveling the bed? I plan to mount it on the Atlas legs and I have an engineering level to check it but should I be testing the bed or the Carridge?
Ross,
Rather than just sticking the normal legs straight on, I would suggest you try to introduce a little more strengthening to the main bed.
This has the effect of reducing sagging in the middle.
If you have access to welding equipment, I would get some 2.5" or 3" heavy duty square section tube and make up an oblong frame, as long as the ends of the lathe support feet and the same width as the feet and bolt the lathe to that first, then bolt the legs underneath. I would also put in a couple of cross braces into the frame to stop the twisting effect.
This will have a great effect on making the lathe more rigid.
I would go for the later designed head, it will allow easier stripping down and belt changes, but put the metal pullies on to begin with.
The head will need the taper bearings preloaded as you get towards running it. You can read up on it, or I can tell you how to do that a little later.
I had a Babbit plain bearing head on mine to begin with and the surface finish results were much better than the bearing head, but it just couldn't compete with the high speed the bearing head offered. You can run a Babbit (white metal) bearing straight off, as soon as it has had a lube, whereas with all taper bearing lathes, you should allow the lathe to run for a few minutes for the spindle to warm up and thus spindle to 'grow' before taking you first cuts. That is the reason for the preload, the bearing is tight while the machine is cold, but after the spindle has warmed up and extended, the bearings are in a perfect no end load position.
Another couple of days off now
Bogs
Had to have a few days off myself to finish some Uni work. :sad:
Got a bit of time now before the next batch........
Anyway back to the lathe. I'm looking at using 2 lengths of 4x2 box on their side next to each other. I know normally it would be best to use them the other way up but the more I look at it the more I'm sure that once its all bolted together the legs are more than capable of taking all the loads, The problem seems to be the fact that as the bed is used as part off the structure and it is impossible to set the base up level to attach the bed. As simply over tightening the hold down bolts could flex it.
So the plan is to use the 4x2 to keep the top of the legs level and the correct distance apart so I can then level them and bolt it all down solid. the only thing is I'm not to sure wether I should weld it as this would cause more potential twisting problems no?
Ross,
Sorry I haven't answered before now, a major job broke out on the house, and it took me a fortnight to get the lads into shape and do it as I wanted.
I actually had my stand welded up by a mate who does it for a living, and by the time he had tack welded it to his 6ft x 6ft welding table, and got the full runs in, then ground things flat with an angle grinder, I only had to use about 0.010" shimming under one foot of the lathe and everything was spot on. I am a certified welder, but I am so far out of practice (over 25 years), I could never have achieved what he did. I keep thinking about buying another little welder, just to do those odd jobs about the shop.
If you bevel all the edges, and tack up and straighten as you get to way points, I shouldn't think you would have too much trouble getting it straight, or straight enough where a few thin shims will correct things as it is assembled.
It is this making everything rigid that pays off in the long run, without this intermediate frame, everything you want to achieve will be a stab in the dark.
Another project has come on line, but I should still be able to help if needed.
Bogs
No worries John, I've been busy myself. Nothing to serious with the house I hope.
I will definitely make it as strong as possible. Am I doing it the right way by making the frame more rigid, bolt it down level and then add the bed, or should I be looking at starting with the bed and work down?
I can weld but never had to worry about heat distortion, maybe I'll just tack it and get someone else to finish it........Probably a bit OTT to get it stress relieved :heehee:
Reply when you can, Im in no rush and gratful for any advice, perhaps I should wait and just ask when I get to the Head - Tail stock alignment :wink:
There's another Atlas on ebay just a smidgin north of me, at £100 with 20h to go, but with a reserve... and no bids... 10", 46" bed
Thanks but I don't think I need another one.......3 lathes is enough for me:heehee:
Or are you tempted??? I think I had a good deal with the Halifax tho..as that is just the lathe for £100+ (they didn't do a 46" either!)
Yet another cry for help :wave:
I've finally got around to looking at this again, welded up a frame, bolted it all down and leveled it up so its now rock solid, but I'm stuck on removing the spindle from the Atlas fixed headstock to rob the metal pulleys. The split caps on the Halifax were a doddle compared to this.
Ive looked at the 'atlas press' guide online and it makes it sound so easy...:rolleyes: I just cant get enough clearance between the main pulley and the bearing housing to remove the woodruff key so the main shaft can slide out.
And I'm completely lost with disassembling the backgear from the eccentric cam...Anyway I'm sure there is some clever person on here that knows :whistling:
I'm sorry I haven't been available recently, health and bereavement issues reared their ugly heads.
I have done the spindle removal many times, and there is a definite knack to it.
It is very tight indeed, and the first thing you need to to is get the bull gear back towards the change gear end as much as possible, and the spindle as far forwards as it will go.
Then a slight tap on the top of the key in the position shown on the sketch should rotate the key in it's half round slot. As long as where you hit is further back than the centre position of the key, this should work.
Attachment 2255
Bogs
Thanks Bogs. sorry to hear you are not well again. :thumbdown:
Unfortunately I couldn't get that to work as I could only see about half of the key. I have no idea how this was assembled in the first place...... I had to resort to the rather drastic solution of filling the key down so it would slide out through the oil seal/collar.
That turned out to be the easy bit as once the shafts were out it was apparent that they are different. the Atlas spindle (top) has only one step in it whereas the Halifax spindle has 3 steps
Attachment 2287
So rather than just putting the metal Atlas pulleys and gears on the Halifax spindle I had to use the Atlas spindle as well, but due to the different oil seals that meant changing the bearings as well :mad: (although its probably a good idea to keep the rollers and shells together anyway.)
The back gear was another pain, I had to use the Halifax mounts, shaft and eccentric cams with just the Atlas gears. I probably didn't need to change it but the Atlas gears are definitely stronger and they also had the spring washers to stop it sloping around.
I think its fair to say that the Halifax isn't a direct copy of the Atlas and not all parts are interchangeable, even the bolts have a finer thread.
Ross,
You can make it a lot easier for future events, the dust cover nearest the key can have a small close fitting cutout filed into it, that will allow the shaft to come out with the key still in position. As long as you keep the cutout at the top when you fit the cover into the casting, it will still do it's job of retaining oil in the bearing for as long as possible.
That would also help in getting the outer dust cover off, as the key would push on the inner bearing race and knock the outer cover out when it moves the bearing.
If the bearings have been pre-loaded for any length of time without being run, you will find they may have 'brinelled', they feel ratchety, and as such are of no further use.
The Atlas bearings have a specially shaped outer race and as far as I know, are special order only from Clausing (the genuine US Atlas spares company) themselves, and worthy of a second mortgage.
The inner race is a standard Timken part. I had a friend regrind the inner faces of the old outer races, and then I fitted new Timken inners. That came to a fraction of the cost of new bearings all round. I now have my own facilities to do that sort of regrind if you need it.
John
Thanks. Thats a good idea and makes perfect sense now I know how the oil system works. Hopefully I wont have to do it very often as I will be using the removable clamp headstock of the halifax.Quote:
You can make it a lot easier for future events, the dust cover nearest the key can have a small close fitting cutout filed into it, that will allow the shaft to come out with the key still in position. As long as you keep the cutout at the top when you fit the cover into the casting, it will still do it's job of retaining oil in the bearing for as long as possible.
Not so sure on the the bearings tho. they seemed a bit ratchety when I was cleaning them and rotating by hand but now they are back in the head stock they seem nice and smooth. Which is the best way to tell?
Do you have supplier details and specs for inner timkin bearings? and how much would you charge for the regrind? (rubber cheque book at the ready...lol)
At the moment I'm just rebuilding to make sure every thing works and fits correctly. I will then tear it down to repaint and fine tune. I presume that damaged bearings would give poor surface finnish and could be corrected later?
just out of interest to anyone repairing a halifax with atlas parts. the cross slide screw is the same size and overal length, but the halifax has a longer treaded section and therefore extra travel. I opted for the shorter atlas one as IMO it is a better set up with the adjusting nuts to take out all the slop in the system.
Ross,
You need to preload the bearings before checking anything.
With all taper bearings, they need to be overtightened slightly, and when the machine is started after a non working period of say 1 hour or longer, it needs to be run without any cutting being done for about ten minutes.
During this time, the bearings will generate heat, and the lathe spindle will then heat extend by anything up to about 0.005". This then cancels out the preload and you end up with perfect running bearings with no end float. If you don't do this warm up period, and use the lathe straight away from cold, anything you machine, until the spindle has warmed up, will tend to have bad surface finishes and tolerances.
Then, only after this warm up period, can your check the bearings for brinelling. They should feel as smooth as silk, if not, they either need to be replaced or have the races reground.
I wouldn't charge for any work done, just you pay the postage charges. Unfortunately, I am in no fit condition to get into my shop at this time.
If you take the bearings to any bearing factor, they will recommend what is available to you.
For preloading, you should really get the friction figures for the bearing, and using a spring balance and an arm in the chuck, you check the 'pull off' pressure, that is the figure required to get the spindle to turn from a standstill position before spindle warmup, and adjust the end nut until the correct reading is obtained.
If the figures for the bearing are not available, I usually tighten up the spindle until you either start to feel friction against turning or there is no end float, then turn the nut between 1/16th to 1/12th further. This will give a general setting that will work in most cases.
Most the people who have tapered bearings don't do this preload setup, and start to complain when they get rough finishes, then they blame either the bearings or machine, rather than themselves for not setting the bearings up correctly in the first place.
If you are not going to be using the machine for say a fortnight or more, I would recommend you release the preload on the spindle, and preload again when you next come to use the machine. The bearings should then last a lifetime.
I can't work in my shop at this time, but I still go in once a week and spin the lathe up for quarter of an hour. This ensures that the bearings don't 'settle' in a fixed position and they get a bit of lubrication.
John
OK thanks I'll get it preloaded before testing then. Atlas recommends 1/16" turn (equivalent to two spindle gear teeth). so i will try that.
Its interesting that you recommend to remove the preload if its not being used, being able to look after and set up the machine correctly seems to be more important than knowing how to use it!!!
Thanks for the offer to regrind for free, maybe when your well enough and have finished all your over projects that have been stacking up eh...
With regard to the brinelling is it the rollers that deform or the races? (or both?)
If you don't mind me pestering you (or anyone else in the know) I also have another problem that I'm not sure of the best way to resolve. on the Halifax lathe the apron drive cog and reducing bracket was broken and there is a small groove under the rack were the cog had been rubbing the bed. I have replaced it with the atlas one but when the gibbs are tightened the same thing happens and the drive goes tight and binds.
The easy solution that I can see is to put a thin piece of shim steel on the side of the way to push it over a bit,(not sure how to secure it tho). Or the better but harder option is to pocket the mounts and sink the assembly in a bit. I did think of milling the bracket down but as its made of ZAMAK I didn't want to weaken it.
Do any of those options sound feasible? or have a missed a blindingly simple alternative:heehee:
Usually Ross, it is both races that get socketted. Hence my suggestion to get a new inner, and regrind the old special profile outer.
I changed my Atlas from a plain bearing head to a taper bearing one, and the second hand head must have stood preloaded for a few years. It was like trying to turn over a ball bearing detent fixture, it jumped out of one impression and clicked into the next one, hence that is when I found out about grinding and costs of bearings for the head.
BTW, if you used a plain bronze bearing head, you would find that the surface finishes on components are far superior to a tapered bearing head. The taper bearings were introduced to up production rates as they could have a faster running spindle, what you gain in quantity, you lose in quality. I noticed a definite quality reduction when I swapped over.
Another thing worthy of note, the bearings should be oil fed only. If you try to pack a taper bearing with grease more than half full, you run the risk of 'hydraulicing' on the rollers which can lead to roller damage, little and often for oil lubrication, if necessary, fit drip feed oilers if you can.
I can't really understand about what you are saying about the saddle gear and rack, but there is an adjustment cage on the back of the apron that allows for slacker or tighter engagement of the gear. There is an adjustment bolt for it just to the rear of the handwheel. that allows you to move the cage up and down. Also, you will find that if you slacken the two top apron screws, you can shim in the joint to 'kick' the apron in whatever direction is required, but you must ensure you realign the leadscrew afterwards, so that it doesn't deflect when the half nuts are engaged. That is done at both ends of the leadscrew, by shimming up and moving about the reversing box where it bolts to the bed, and the same again at the other end at the break away sacrificial support for the leadscrew.
BTW, don't ever be tempted to replace that break away bearing with anything else more solid, that is a safety feature to protect your very expensive gear castings and apron area plus leadscrew in case you ever have a massive jam up, where the saddle stops and the head carries on turning. That piece is designed to break under such circumstances, when the leadscrew tries to carry on turning, and screws itself backwards thru the half nuts. You should see that it is cast with weakening cut out 'wedges', to control how and when it is to break.
I have seen these lathes where people have made massive bearing block replacements or had a broken one welded up. A very bad idea.
John
thanks John, concise as ever, so should i upgrade to babbit bearing then?????
Sorry im not very good at explaining things. I meant the adjustment cage you talked about that mounts on the apron and drives the rack but it is rubing on the side of the main bed below the rack.(see pic)
Attachment 2305
So when I adust the gibbs on the saddle it pulls the saddle over even more.hope that helps.
heres some pics of the lathe as it stands, not pretty but hopfully functional
Attachment 2306Attachment 2307