Myford super 7 v pulley/back gear

[Ian KParticipant @iank29388]

Hi Guys,

I am after some advice please, I have recently purchased a well looked after Myford super 7, serial number SK 101389

I am still learning about the machine and have been experimenting with the speed ranges. I have an issue with the spindle v pulley/back gear making a rattling noise when running at the two highest ungeared speeds of 2105 and 1480 rpm

Can i ask if it is normal to have back and forth play on the v pulley to back gear assembly, as this seems to be the source of the rattling noise? I have rotated the the back gear locking key to the opposite side hole but the noise remains.

The machine is running on standard single phase, with good condition drive belts and correctly lubricated according to the user manual.

Any ideas or help appreciated.

Regards

Ian

[Ian KParticipant @iank29388]

[JohnFParticipant @johnf59703]

Hi look at this post–see link– and contact Daren the ex – Myford engineer.

**LINK**

[Ian KParticipant @iank29388]

Hi John,

Thanks for the info, but with a little bit of careful tweaking with the counter shaft v pulley position i think i have sussed the issue. There was a slight alignment issue, causing the belt to rub on the groove sides, resulting in a chattering motion…..all seems well for now!

Thanks again for your response

Ian

[NJHParticipant @njh]

Ian

If you don't have one already I recommend that you change the motor to countershaft belt for a link type. It did wonders for the smooth running of my S7 – especially at the higher speeds.

I bought one HERE but they are generally easily.available.

Regards

Norman

[KWILParticipant @kwil]

Ian,

When you say back and forth movement pulley to backgear, is this rotational slop or is it also side to side?

[Ian KParticipant @iank29388]

Hi Norman,

Thanks for the recommendation re; belts, I have got two of the link type ready for future use……..just in case! I dont fancy stripping out the headstock shaft to do a belt change.

Hi KWIL,

The motion/movement was/is only back and forth or side to side, all the bearings and bull gear lock are nice and smooth, with no rotational slop.

Is it quite normal to have the play or movement in this area? Sorry if this seems a bit of a daft issue but i really would like to know if this is a common issue on the super 7

Thanks again for the collective wisdom guy's

Regards

Ian

[Clive HartlandParticipant @clivehartland94829]

I would suggest you look at the locking screw that locks the pulley to the mainshaft. This is the screw you release to allow you to set the back gear in gear, it freewheels the pulley on the shaft.

Just today i had a rattle and the first thing i found was this screw had slipped out of engagement slightly. I of course assume the ML7 has the same arrangement as the ML10 I have.

Clive

[NJHParticipant @njh]

Hi Clive

Nooo – to the best of my knowledge it's just the ML10 that uses that idea. The Super 7 has a lever operated cam to lock the bull wheel to the cone pulley . With this disengaged a lever is operated to bring a gear wheel into mesh with the bull wheel and a gear on the spindle thus effecting the reduced speed drive.

(However, when I had one, I always found the ML10 method quite satisfactory and if the allen screw was loose it would give the effect that you describe)

Ian

If you have a link belt for the motor to countershaft drive I suggest you change it now – the difference on my machine was quite amazing although the standard "V" belt was in good condition.

I agree with you about the countershaft to spindle belt. At present mine is a standard "V" belt but, when the time comes, much easier (and quicker) I think  to fit a link belt  than to dismantle the headstock! 

Norman

 

Edited By NJH on 21/04/2013 17:02:32

[KWILParticipant @kwil]

There is a grub screw that holds the bull wheel to the main spindle, The axial movement of the pulley is controlled by the clearance between the PB gear on the end of the 4 step pulley and the bull wheel. This gap should be small, adjust bull wheel towards the PB gear and then lock that grub screw.

[Ian KParticipant @iank29388]

Hi KWIL,

I have slackened/removed the grub screw on the backgear, but can't seem to slide it back or forth, am i missing some little trick here. Is it safe to try to lever against the headstock casting, around the front bearing to ease the backgear back a bit?

For info i have 0.40mm back and forth movement on the spindle v pulley to backgear, is this normal?

Regards

Ian

[KWILParticipant @kwil]

No not really, it is possible to reduce it to zero, which of course would be too tight. There is a key on the spindle which located the bull gear and the grub screw is screwed down directly on the key, it would appear that someone has tightened the grub screw and spread the top of the key, hence your inability to slide the bull gear towards the PB gear on the pulley. I would be wary of using a lever. If you were replacing bearings, you would need to drive the spindle out towards the tail stock so at some time the application of a little force will be necessary. Do you have anybody near to you who can assist? We have no idea where you are of course.

K

[Ian KParticipant @iank29388]

Hi KWIL,

Thanks for the info, as you say, the squashed key top sounds like the culprit, sorry for not stating where in the UK i am, I live in Binbrook, Lincolnshire.

Regards

Ian

[Kevin FParticipant @kevinf]

Posted by NJH on 21/04/2013 16:52:26:

Hi Clive

Nooo – to the best of my knowledge it's just the ML10 that uses that idea. The Super 7 has a lever operated cam to lock the bull wheel to the cone pulley . With this disengaged a lever is operated to bring a gear wheel into mesh with the bull wheel and a gear on the spindle thus effecting the reduced speed drive.

(However, when I had one, I always found the ML10 method quite satisfactory and if the allen screw was loose it would give the effect that you describe)

Edited By NJH on 21/04/2013 17:02:32

 

 

 

 

Just for info the ml4 has this set up , when I first removed the grub screw and went to use my back gear ,it was seized and the gear wouldn't rotate on the shaft ,so I squirted a bit of wd40 down the hole where the grub screw was fitted and it freed things up .

Edited By Kevin Fenrich on 23/04/2013 21:31:24

[Ian KParticipant @iank29388]

Hi guy's, especially KWIL,

I have freed off the sticky back gear, from the grub screw key, with very gentle leverage against soft wood wedges. It actually moved very easily, possibly sticking slightly or just being awkward. It slides freely so maybe the key way wedge was not compressed out of shape.

Everything seems fine now that it is adjusted with minimal play, no more rattle.

Thank you to all who have offered advice to this myford novice, hopefully i can ask more questions as i get to grips with the machine over the coming weeks/months.

Ian

[NJHParticipant @njh]

Yes Kevin you are quite right – also on the ML4. I had one of these as my first lathe some 30+ years ago. I had forgotten the back gear arrangements but now I recall grub screw and lever ( with a rather nice red knob) on the headstock to engage the gear – yet another example of increasing forgetfullness I guess! The ML10, on the other hand, needed a spanner to move the gear into engagement.

Norman

[LambtonParticipant @lambton]

KWIL

“There is a key on the spindle which located the bull gear and the grub screw is screwed down directly on the key,”

This is not correct. I have just taken the spindle out of my Super 7 to replace the lubrication wick and I can confirm that the grub screw in the bull gear bears directly onto the spindle and certainly not the woodruff key.

My drive pulley rattled a bit, especially with back gear engaged due to excessive end float of about 25 thou. When reassembling the spindle I set the end float at 5 thou. by adjusting the position of the bull gear along the spindle. This has corrected the rattle.

By the way I found the whole job of removing the spindle and adjusting the rear bearings on re assembly surprisingly straight forward and certainly not to be feared. I studied the Myford instructions very carefully, made myself a proper peg spanned for the left hand locking collar and adapted an existing “C” spanner for the rear bearing adjusters. With these tools, the very clear Myford instructions and taking my time I found the job easy very satisfying.

Eric

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