advice requested for setting up Myford Trileva lathe

[NICHOLAS ELLISParticipant @nicholasellis10828]

[NICHOLAS ELLISParticipant @nicholasellis10828]

I have had a Myford Trileva for about a year and have just decided to replace the motor with a proper Myford single speed one, which I had in stock, and whilst I was at it decided to replace the belts.

On re-assembly I cannot get the slow speed jockey pulley to track the belt correctly, and the belt keeps coming off. If I tighten the belts there is too much force on the lever. I have checked the pulley alignment. Also the mechanism seems to interfere with the other pulleys..that is Slow and Medium levers seem to touch the jockey pulleys to their left (See Photo).sorry, cannot work this.

Is there anyone out there who has any experience setting this up..I must have altered something vital, as it worked before.

Many thanks Nick Ellis

[Ian S CParticipant @iansc]

The only Trileva Myford I'v had anything to do with had it's origional 2 speed motor as supplied by Myford as standard equipment.

Ian S C

[Ian S CParticipant @iansc]

Double post

Ian S C

Edited By Ian S C on 12/01/2017 10:53:23

[davebParticipant @daveb17630]

Trilevers can be a bit fiddly to set up. It is VERY important that the belts are not too tight. There is often some wear, check the idlers and the detent notches at the top of the sliding arms, the little rollers sometimes sieze and cause wear. Engage the first lever then adjust the countershaft arm position by rotating the countershaft tension lever for approximately correct tension on the first belt. Note the position of the countershaft and set to this position with the screwed adjusters, you will probably have to remove the trilever box to reach the countershaft arm adjusters, you will also have to adjust motor belt tension by moving the platform. Individual belt tension for each lever, there are screw adjusters with locknuts behind the slotted cover.

[davebParticipant @daveb17630]

New belts will not be the same length as the old ones, nor will they be necessarily be the same length as each other. Belt tension is crucial, not a lot is required. Too much tension will cause the idlers (jockey pulleys) to run off and slip in between the belts. It should be possible to operate each lever with light finger pressure, if it needs a heavy pull, the belt is too tight. When correctly set up, these are a delight to use, instant speed change, instant release of drive, instant locking, no clutch necessary. Can be a bit frustrating to get right but well worth the effort!

[NICHOLAS ELLISParticipant @nicholasellis10828]

.Daveb: Very many thanks for your two repliesi

Frstly I do not think I have a countershaft tension lever..just the two screws with locknuts.

I have tried the belts slack, so that there is more wraparound, but almost as soon as the jockey wheel touches the belt it slips off to one side or another.I have tried various belt tensions.

The other problem is that the little idler wheels touch the jockey wheels when using the two lower speeds, which I think they should not do. Presumably this is if there is too much belt tension and the adjuster screws are almost fully retracted. It seems very difficult to get them set sufficiently far forward to clear the jockeys when pulling the levers.I have put the old belts back again, as they worked before, but not very well. Same problem.

I had wondered if the new ones were made of a more flexible material, so would not stay on the jockeys.

I have started to think I should add a flange to the jockeys to stop the belts from jumping off, but that would alter the whole geometry of the thing, so probably a mistake!

[davebParticipant @daveb17630]

Hello Nicholas, it looks to me as if the countershaft swing bracket needs tipping down to reduce the belt tension. The countershaft tension lever is not needed with the Trileva, sometimes it's still there if the Trileva attachment was retrofitted. The countershaft tension spindle remains in position, just the lever is removed. There are 2 flats on the countershaft tension lever spindle which line up with the adjusting screws, when the adjusting screws locate on the flats, the belts are slackest. If your machine was like this (as it should have been) but the countershaft tension lever spindle has turned slightly so that the adjusting screws are not bearing on the flats, the belts will be at their tightest, which will give you the problem you've got. If the Countershaft tension lever spindle has not been shortened, you should be able to put a stiff wire or small Allen key through the hole across the right hand end and turn the spindle until it's in the correct position, when the countershaft swing bracket will drop down. If you look at the 2 adjusting screws, you should be able to see the flats on the spindle. Fully loosen the 2 adjusting screws(turn counterclockwise) This is the point at which you begin adjustment of the Trileva.

Dave

Edited By daveb on 22/01/2017 19:19:16

[NICHOLAS ELLISParticipant @nicholasellis10828]

Hello Daveb: Very many thanks for your posting; I have the type of Trileva with no adjustment to the lever spindle, which is in the correct position.

As I mentioned before I have tried several different belt spacings and positions of the housing on the headstock, all to no avail. I think it is the belt moving off the jockey, rather than vice-versa…hard to be sure though.

The system worked OK before I changed the belts, for about a year, so I must have done something when I did that. I should have numbered the belts, as perhaps I have re-installed them in a different order. I will try changing them round and also to get the new ones exactly the same length by devising a stretching mechanism. (so that if I decide to use these I know they are all equal). I have levelled the housing support to be level with the bed of the lathe.

The other problem is that the jockey wheels foul their neighbours, particularly the LHS one. (They always have to some extent, which is why I wanted to change the belts, to see if it made any difference).

I am presently experimenting with spacers!. I find that if the belts are too slack (giving a good wrap-around) the slow one is squeezed between the jockey wheel and the headstock pulley; increasing the belt tension cures this, but the jockey immediately runs off. The higher the belt tension the further out I have to put the adjuster screws; the further out the adjuster screws the more interference I get between the jockey wheels, clashing when engaging and making a noise with their neighbours when engaged.( I am careful to be sure their slots are still engaged with the jockey wheel carriers). My experiments with spacers help this, but perhaps not the other problem. I only get the run-off with the slow speed.

Wish you were here, as they say, but I am near Darlington and I think you are in the home counties??

I have found a contact in a local ME club, who used to have one, so perhaps between us we can solve it.

Many thanks again

Yours

Nick

[davebParticipant @daveb17630]

Hello Nick, I'm in Essex, quite a way off unfortunately. All this is very familiar, I had similar problems with my own machine. I got it right after a lot of effort. I had a couple of thoughts, check that the drive and headstock pulleys are exactly in line, you can do this with a steel rule, the drive pulley locks with a grub screw, it will move left and right a little. Check also that the Trileva attachment is upright, the top support P shaped bracket can pull it off centre L/R, mine had a spacer each side, they were not the same length. I'm pleased you found some local help, hopefully you can sort it out between you. Dave

[NICHOLAS ELLISParticipant @nicholasellis10828]

Thanks again. I might try to fit a couple of collars either side of the P bracket, but I wonder if it is intended to float sideways as the only fixing is the front nut?

I have found the snagging of the jockeys is cured if the spindle for the fingers is set back to the left a bit; the 2 highter speeds now work silently and the belts are fairly slack.

Many thanks again for your helpful comments. If I find a revolutionary solution I will let you know!

Yours

Nick

[NICHOLAS ELLISParticipant @nicholasellis10828]

Hello again

Just to let you know, if it helps others with a similar problem, I have stretched all the belts using a board to the exact same length. I have taken off the bracket at the back (39 on the Myford diagram) and drilled and tapped it 1/4BSF and fitted a bolt.

I can now fix the back of the trileva unit in any position.

I put it all together and , after some tension adjustment it works. There is still some interference between the LHS jockey and the middle one, and I am tempted to fit a spacer….on the other hand I am tempted to leave well alone! Thanks for all your help. Nick E

[HopperParticipant @hopper]

Posted by NICHOLAS ELLIS on 07/02/2017 17:04:33:

Hello again

Just to let you know, if it helps others with a similar problem, I have stretched all the belts using a board to the exact same length…. Nick E

And just for anyone else facing the same job in future, you can buy sets of matched length belts. They are made to go on those heavy industrial pulleys that have three belts running side by side on one pulley with three grooves in it, so they must be matched lengths in order to all grip correctly. Matched sets are generally readily available from industrial belt suppliers. You may be able to find a set the right size to fit the Trileva.

[NICHOLAS ELLISParticipant @nicholasellis10828]

3 YEARS LATER:

Having muddled along with this for a long while I never quite cured the slow belt coming off. Finally I decided to both replace the lathe;s headstock spindle (It had been faulty when maade) and have now made a tyre for each jockey wheel from a thick walled alloy tube. A bit difficult to do but managed to use the lathe with one pulley direct to the headstock spindle. IT WORKS! I had to decide whether to use concave tyres or convex ones. (Anyone with flat belt experience will know that the pulleys are slightly convex, but discretion won out and i made the tyres concave, and a bit wider.

I would add pictures but cannot see how to do this.

Nick E,

[V8EngParticipant @v8eng]

Advice on how to post photos here:-

Posting photos

Edited By V8Eng on 14/08/2020 20:32:45

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