Myford ML7 not running true and spirals

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Myford ML7 not running true and spirals

This topic has 21 replies, 10 voices, and was last updated 19 October 2018 at 11:20 by Ian m 1.

Viewing 22 posts - 1 through 22 (of 22 total)

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14 October 2018 at 19:55 #375962
Ian m 1
Participant
@ianm1
Hi,

it seems that my chuck is not running true on an old Myford ML7 lathe. I know nowt about the lathe and it has been 40 years since I did an apprenticeship of 1 year and so I'm quite rusty myself. Is there any adjustment if so where, if not what is likely to be worn and can it be replaced?

Also, I get spirals along anything I turn. what should the chuck be spinning at?

To me it seems slow. Is there anywhere I can send cutting bits to, to be sharpened, doing it myself is beyond me.

thank you in advance

Ian m 1
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14 October 2018 at 19:55 #33285
Ian m 1
Participant
@ianm1
14 October 2018 at 22:32 #375995
Neil Wyatt
Moderator
@neilwyatt
Hi Ian,

Sorry to hear of the problems.

How have you tested the chuck and how bad is the error?

When you say spirals, is this just a light surface pattern or is the tool effectively cutting a 'screw thread' in the work? How fast are you running the lathe and are you using power feed – it may be set up for screwcutting rather than fine feed.

Grinding tools is fairly easy, a simple knife tool will do most things.

You may find it cheaper to buy pre-ground HSS tools – most styles are designed for easy resharpening, or you could try inserted carbide tools.

Neil
15 October 2018 at 03:52 #376000
Hopper
Participant
@hopper
Take Chuck off and clean the thread and register collar area and remove burrs might help.
15 October 2018 at 08:23 #376010
Redsetter
Participant
@redsetter
Ian, I doubt if your problems are serious- it sounds as though you need someone to give you a hand to get started. Where are you located? I'm sure someone on here who is within reach would be happy to help.
15 October 2018 at 10:46 #376026
Ian m 1
Participant
@ianm1
Neil,

I would not say light spirals, bit worse then that. Not using power feed. I donit know how fast chuck spins but it seems slow, i will need to check motor plate.

Anything in the jaws of the chuck can be seen not to run true.

Hopper, Ill try that. Thankyou

Redsetter, there is a "Mens shed" group, I'll try them but "Southampton" is where I am

As a teenager my work as a 1st year apprentice was ok.

Ian M 1
15 October 2018 at 11:57 #376032
Mike Bondarczuk
Participant
@mikebondarczuk27171
Hi Ian,

I am also in Southampton and it does sound as if the work piece is turning too slowly and your feed rate along the work is too fast, thereby causing the spirals.

Drop me a line via the private messages and let me know where you are and perhaps I can help you out, as I also have a Myford 7, as well as other lathes.

Mike
15 October 2018 at 19:52 #376108
Grizzly bear
Participant
@grizzlybear
Ian,

Slow speed, is your lathe in back gear?

Run-out, are the chuck jaws clean/ swarf free, this is inside the chuck.

Good luck, keep us up to date.

Bear..
15 October 2018 at 19:58 #376109
JasonB
Moderator
@jasonb
Posted by Ian m 1 on 15/10/2018 10:46:41:

Anything in the jaws of the chuck can be seen not to run true.

How much is that, a few thou would be par for the coarse on a 3-jaw, on the other hand if it is more like 1/16" them check that the jaws are in the right slot, both should be numbered 1, 2 & 3
15 October 2018 at 20:32 #376117
Ian m 1
Participant
@ianm1
Posted by Grizzly bear on 15/10/2018 19:52:07:

Ian,

Slow speed, is your lathe in back gear?

Run-out, are the chuck jaws clean/ swarf free, this is inside the chuck.

Good luck, keep us up to date.

Bear..

is my lathe in what? if you mean reverse, no otherwise sorry i dont know what back gear is

Ian
15 October 2018 at 20:33 #376118
Ian m 1
Participant
@ianm1
Posted by Mike Bondarczuk on 15/10/2018 11:57:45:

Hi Ian,

I am also in Southampton and it does sound as if the work piece is turning too slowly and your feed rate along the work is too fast, thereby causing the spirals.

Drop me a line via the private messages and let me know where you are and perhaps I can help you out, as I also have a Myford 7, as well as other lathes.

Mike

thank you kind of you, where are you?

Ian
15 October 2018 at 20:37 #376119
Ian m 1
Participant
@ianm1
Posted by JasonB on 15/10/2018 19:58:57:

Posted by Ian m 1 on 15/10/2018 10:46:41:

Anything in the jaws of the chuck can be seen not to run true.

How much is that, a few thou would be par for the coarse on a 3-jaw, on the other hand if it is more like 1/16" them check that the jaws are in the right slot, both should be numbered 1, 2 & 3

dont know how much out of true, would need to get a gauge and measure. i have a feeling it's a 4 jaw chuck.

even feeding by hand i expect to get a better finish

the advice so far gives me things to check next weekend, thank you.

ian
15 October 2018 at 20:57 #376122
Grizzly bear
Participant
@grizzlybear
Ian,

"is my lathe in what? if you mean reverse, no otherwise sorry i dont know what back gear"

Not reverse, but reduction, you have to physically put it into , or out of low gear (Back gear).

Check with the lever adjacent to the chuck.

Bear..
15 October 2018 at 20:59 #376123
SillyOldDuffer
Moderator
@sillyoldduffer
Posted by Ian m 1 on 15/10/2018 20:37:14:

Posted by JasonB on 15/10/2018 19:58:57:

Posted by Ian m 1 on 15/10/2018 10:46:41:

Anything in the jaws of the chuck can be seen not to run true.

…

i have a feeling it's a 4 jaw chuck.

…

ian

That might be the problem Ian. Most 4-jaw chucks aren't self-centring. If it's the usual type of 4-jaw each jaw has to be adjusted independently. They're good for holding work like square bar and also for positioning round bar very accurately. But they don't do it automatically. Various ways of setting them up, most usually with a DTI, like this youtube example.

Dave
16 October 2018 at 06:24 #376144
Hopper
Participant
@hopper
Get yourself a copy of L H Sparey’s book The Amateur’s Lathe and start from basics. Also Ian Bradley’s book on the Myford 7 Series will help you understand back gear and other basic operating stuff.
16 October 2018 at 09:08 #376158
Michael Bird 1
Participant
@michaelbird1
When I had spirals it turned out to be the headstock bearing caps were loose on my ML7. I tighten them up and the spirals went away.
16 October 2018 at 09:40 #376161
V8Eng
Participant
@v8eng
Posted by Ian m 1 on 15/10/2018 20:32:27:

Posted by Grizzly bear on 15/10/2018 19:52:07:

Ian,

Slow speed, is your lathe in back gear?

is my lathe in what? if you mean reverse, no otherwise sorry i dont know what back gear is

Ian

I have put a link here to an explanation of “back gear” which reduces spindle speed considerably, hope this might be some help with that particular question🙂

**LINK**

Edited By V8Eng on 16/10/2018 09:46:02
16 October 2018 at 19:09 #376246
Grizzly bear
Participant
@grizzlybear
V8Eng,

Thank you for adding the 'Link'. Re: Back gear.

Bear..
17 October 2018 at 14:57 #376338
Ian m 1
Participant
@ianm1
Thank you V8Eng for the link. I will check tomorrow to see how the lathe is set up. Even reading the explanation I had to read it more then once.

I will also start actioning the advice given, I have been away on holiday and back home today.

I would like the quality of my work to improve but my work will not progress past simple stuff as this is all i need.

Ian M 1
17 October 2018 at 20:29 #376398
V8Eng
Participant
@v8eng
Posted by Ian m 1 on 17/10/2018 14:57:45:

Thank you V8Eng for the link. I will check tomorrow to see how the lathe is set up. Even reading the explanation I had to read it more then once.

I will also start actioning the advice given, I have been away on holiday and back home today.

I would like the quality of my work to improve but my work will not progress past simple stuff as this is all i need.

Ian M 1

In my link the “Back Gear” operating lever is at the bottom right hand corner of picture 1. It is shown in the normal running condition – if the lever is in the ‘up’ position that means the back gear is engagaged and will be giving a 6 to 1 speed reduction, I do not recall ever using back gear personally so cannot be of further help on that one.

Please do head all the warnings about the possibility of damaging gears etc!

I wish you luck with sorting your problem out and hope you enjoy using the ML7, I certainly like mine having owned it for a few decades.

I agree with Hoppers suggested books, also an ML7 manual would probably prove useful if you do not already have one.

Edited By V8Eng on 17/10/2018 20:35:56

Edited By V8Eng on 17/10/2018 20:57:48
18 October 2018 at 08:50 #376435
Neil Wyatt
Moderator
@neilwyatt
I think you also have to disengage the 'bull gear'. Back gear always requires two things – engaging the low ratio gear train and disengaging the normal drive.

Neil
19 October 2018 at 11:20 #376608
Ian m 1
Participant
@ianm1
an update, not really good news

The lathe is not running in back gear and the back plate on the motor shows the RPM to be 1425.

I have a Myford manual that i downloaded from the internet, so i'll go and check how to remove the chuck which is a 4 jaw chuck and all 4 jaws tighten at once. They are not independently tightened.

I'll try cleaning the thread

what is the cross bed feed measured in? looks like it goes to 100. The chuck is worse out of true between jaws 3 and 4. Going by the gauge on the cross bed feed, the chuck is 6/100 or 3/50 out of true. I have "measured" between the face of the chuck and the chuck key holes. Is this withing tolarence

Ian M 1

Edited By Ian m 1 on 19/10/2018 11:41:17

Edited By Ian m 1 on 19/10/2018 11:55:28
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