Triumph 2000 rebuild advice slideway play

[lee gilesParticipant @leegiles21499]

[lee gilesParticipant @leegiles21499]

Hi All

I am rebuilding a triumph 2000 and would appreciate some advice please

Can you tell me how much play/end float is acceptable in the apron and cross slide please?

we have adjusted the back lash but I think the slide ways are worn as when we take the play out in the main working area it becomes very tight at each end of the bed.

Which brings me on to my next question, are the slideways ground or scrapped? is there a repair procedure for worn slideways please?

Are there any specialist repair companies that can come out and do this in situ? I am in portsmouth.

Many thanks

lee

[Brian WoodParticipant @brianwood45127]

Hello Lee,

From your description it sounds to me like the bed is worn; it will be over the most heavily used area which is why it tightens either side.

I don't know the Colchester lathes as such, but I imagine the beds and ways were hardened and ground, not scraped as would be the case for unhardened beds. Look for the characteristic 'frosting' marks in an unworn area up by the tailstock to see what that looks like, if it is present.

It is unlikely to be possible to put that right in situ, so you must decide whether to live with it and adjust slides to a sort of optimum setting and use the lathe in that form, or go to the expense of a bed regrind with a firm who has the equipment to do that for you.

It may well be you can perfectly well cope with it by making due allowances, a lot depends on the grade of work you will be undertaking on the lathe.

Regards

Brian

[AjohnwParticipant @ajohnw51620]

I assume you are talking about the saddle being tight so there must be some sort of plate holding the saddle down on the slides by running on it's underside ? Getting that tight isn't so important on lathes with it's style of bed but any wear will be reflected in the work. In the extreme this can introduce a significant taper in the work. The plates also wear. Sometimes it's possible to turn them over to get a "new face" but that's likely to make the tightness worse.

I googled portsmouth machine tool reconditioners and didn't find any but that might be because I am in B'ham.

Slideways are generally ground and have been for a long long time now in fact for even longer than that scraping has been cosmetic. Some feel it leaves oil reservoirs but it also reduces contact area. Some of the machine tool recon companies do offer on site work via scraping if the machine is suitable but I'd guess they would advise a regrind. The more sophisticated regrind machines carry all of the parts in one go to ensure that they all align correctly. They generally remove around 0.030in and make up the loss with materials that are stuck on. I understand some can also fit machines with wear strips that can be replaced. They can also just regrind the cross slide parts but if you do that I would mention that lathes only face concave by a very small amount, sub thous ideally so that they take a bit of extra care setting the work up. The reason for removing 0.030 is set up time. I thought about having it done to a lathe once and told them I wanted no more than 0.005" removed as that would take all of the wear out and the machine would still go back together – answer OK but come and do it yourself. They would have to position the lathe bed much closer than that which would take extra time.

John

–

[David Clark 13Participant @davidclark13]

Check the saddle gearbox. You may find it is full of soluble oil and the gears are all rusty. Very expensive to replace.

[KWILParticipant @kwil]

You still have to spend time correctly setting up the bed on the slideway grinder, however much you finally grind off. Setting time is not a variable, but grinding time is. I have had 0.005" taken off without any complaints!!

Edited By KWIL on 10/08/2015 11:02:44

[Brian WoodParticipant @brianwood45127]

David,

The saddle gearbox may have the trouble you describe, but that would be an additional problem to what seems to be the result of a worn bed. A tight saddle gearbox will be tight over all the saddle movement and not just over a selected portion of the bed

Brian

[Clive FosterParticipant @clivefoster55965]

Looking at the parts book your Colchester has long gib strips on the front and rear underside of the apron to ensure that the saddle is held down onto the bed preventing chatter or misalignment of the saddle under heavy cuts. Its quite normal on an older machine for the bed and strips to (slowly) wear during use. The amount of wear being proportionate to the amount of use any particular section of the bed gets so, clearly, will tend to be greater where the machine si most used. Hence things get tighter at the less used parts of the bed close to its end. Unless the variation is large normal practice is to pick a compromise setting and just live with it. Its not uncommon to find machines set so as to be easy, but not real loose, in the normally used part of the bed whilst being almost too tight to move very close to the headstock with the last few inches at the tailstock end being so tight as to be unusable. Although not ideal such machines are perfectly useable. If you don't do collet or faceplate work overtightness in the last 5 inches or so of saddle up to the ehadstock is immaterial as the chuck gets in the way preventing the saddle moving that far along.

The Triumph 2000 has a pretty heavy saddle assembly so minor slackness has negligable affect on the general run of cuts. The sheer weigh being pretty effective at keeping it in place. If you have not done so its worth giving the bed a very good clean on the top and underneath where the saddle and gib strips run. Over the years old oil and general crud tend to be pushed along by the saddle and gibs into the less used portions of the bed building up into a tough, varnish like, coating which can build up enough to make things very stiff or even immobile. The symptoms of such build up are pretty much identical to that of bed wear. Either way there is more clearance in the middle than at the ends. Be warned the stuff can take a deal of shifting and it appears impossible to remove every last vestige by conventional means. If you have had varnish problems its helpful to wipe fresh way oil over the bed on a regular basis, concentrating on the affected regions, then leaving overnight or for a couple or three days before wiping off and re-anointing. My practice is to wipe with way oil before shutting the shop for the night and to wipe off and re-anoint before starting work so the leaving time varies considerably. The ways on my Smart & brown 1024 were very discloured when I got it and saddle movement didnt feel good. Over 6 months or so the way oil treatment, I use Castrol Magna BD68, lifted out most of the discolour and greatly improved saddle movement feel. Its still abit tight at the ends but well under half as tight as it was when I got it. I imagine there is something in the oil that slowly dissolves teh varnish and lifts it out of the pores in the cast iron.

Clive.

[Nigel McBurney 1Participant @nigelmcburney1]

I have a triumph 2000,and according the info I have ,the bed is induction hardened and ground, If you are only making large models or some restoration work I would not worry too much about bed wear,the weight of the saddle,will it keep well down on the bed ways,and compared with the general run of work very little will done with the saddle hard up to the tailstock end of the bed. I suspect that a bed regrind would be quite expensive particularly if your machine is the long bed version,I never did see why Colchesters bothered to produce a short bed 7.5 inch lathe. Should a bed grind be undertaken ,check the centre height of the tailstock ,along with the bed the base of tailstock casting can wear badly through constant movement up and down the bed when drilling,and it is a lot more difficult to put the tailstock right, no point in grinding the bed if the tailstock is already too low. It could be cheaper to sell it on and buy a better one.

[Brian WoodParticipant @brianwood45127]

Nigel's comment reminded me of the bodge I had to carry out.

The purists had better look away for a while, but I had to correct 'nose droop' on the tailstock of the DS&G lathe I used at my last place of work. It was low at the front by 0.018 inches from wear caused by sliding it up and down the bed over many years and made drilling of work in the chuck a rather imprecise business.

There was no-way a properly built up and reground bed shoe for the tailstock was forthcoming so I split it at the joint between shoe and tailstock, inserted an 18 thou shim cut from the ultra useful RS plastic shim pack I had at home, bolted it up, re-aimed the offset to true and work then continued apace.

It continued to serve in this fashion long after I left.

Brian

[AjohnwParticipant @ajohnw51620]

Posted by KWIL on 10/08/2015 11:02:18:

You still have to spend time correctly setting up the bed on the slideway grinder, however much you finally grind off. Setting time is not a variable, but grinding time is. I have had 0.005" taken off without any complaints!!

Edited By KWIL on 10/08/2015 11:02:44

0.030 is common round here with all of the ones I am aware of. My father had machines reconditioned regularly. His solution was to tell them to stand the bed upside down on parallels aligned with the feet and take their 0.030 off the feet. The aim being to remove any errors in the slideway grinders bed. He followed that with the comment that he would mic up the bed and if they took more than X off he wouldn't pay them. He took a very dim view of taking 0..030 off and packing up the saddle. It's pretty common. My last place of employment bought a recon'd chipmaster – new bearings, bed regrind and the saddle packed up in this case with metal strips. I recently saw mention of the use of plastics but this might be to get smoother movement. The saddle and cross slide etc will have been reground as well. Some machines carry the saddle on a sub table to ensure it is an exact fit on the bed.

Actually I will be visiting a recon place shortly and will ask about thou level regrinds. They charge around £40 an hour which isn't too bad for small jobs. I'm assuming this is a flat rate. Could be time on grinders also has to account for the cost of the machine.

John

–

Edited By John W1 on 10/08/2015 17:37:51

[lee gilesParticipant @leegiles21499]

Thank you very much for the advice!

I am just working on a problem with my 3 jaw chuck (the jaws pivot when clamping and only contact at the very back edge). I have a new (second hand) 3 jaw coming with little use.

Then I will turn a test piece and see if I can back off the cross slide gibs to allow the apron to move more freely hopefully with out reducing accuracy on the job.

We have rebuild the apron gear box, the oil seals were leaking apron oil into the suds…….

you are right, the gears were in a bad state and we have replaced all the gears that were above the oil leak (and therefor not in oil).

I seem to spend more time working on my workshop and machines than i do on my projects!!

Many thanks

lee

[AjohnwParticipant @ajohnw51620]

Headstock bearings may be your other problem. High precision will cost rather a lot but you may find that they are a standard size and while standard bearings wont be so "good" they are likely to be better than scored and worn high precision ones. Depending on the arrangement this area may be why some of the gears haven't faired too well. The shells wear oval over time.

The bearings on some lathes are adjustable – I understand they aren't on Chipmasters pass on this one. If you do change them it will probably pay to find some one with a bearing heater and a press especially the press. That's why I need to visit some recon people. Getting the spindle out removes the rear one but I would probably damage the spindle if I tried to get the front one off. Getting the shells out is usually easy but it's best to have some preturned discs available to press them back in with a hefty length of all thread and some arrangement to make sure that the all thread is pretty precisely axial. Then ensure they are seated properly. The method of preloading bearings varies – I use heat. I expect to be able to feel some heat inside the spindle adjacent to the rear bearing after the lathe has been running for say 1/2 hr.

John

–

[davebParticipant @daveb17630]

Posted by Clive Foster on 10/08/2015 11:04:17: I imagine there is something in the oil that slowly dissolves teh varnish and lifts it out of the pores in the cast iron. Clive.

Methylated spirit is a good solvent for dried oil

Dave

[Author]

Posts