Recent Issues with the Myford Lathe being messed with.

The Hackspace Metalworking
1

Hi All,
so recently Jim spent a lot of time calibrating and adjusting the Myford ML7 lathe we have setup in the metal work area. However it looks as if someone has been messing with the grub screws and throwing it out of calibration.

Bearing in mind getting it calibrated and adjusted takes a long time and requires a lot of steps.

This was something posted a few days back

Can we please note that no adjustments, of any type, are to be made to the Myford lathe without first entering into discussion here, or with the metalwork team, and obtaining approval.

Myself and Stephen have worked incredibly hard between us to get some form of normality back to the lathe.

I'm hoping an open discussion will allow minimisation of any errors

Then as a follow up recently this showed up on the Metalwork group

"All", it saddens me to have to raise this, and I am in somewhat of a state of disbelief, but some adjustments have been made to the Myford lathe, I know this as the parts that have been moved were marked, and, they have been moved by a considerable amount.

Could whoever has made these adjustments please make themselves known, and explain, following my earlier request linked to this post, why they have not contacted the metalwork team before doing so, and, obtaining approval.

For clarity, it is not possible for these parts to have moved of their own accord, or by the amount they have moved, and there was no reason whatsoever for these adjustments to have been made.

So outside of a laminated poster or getting the board to email everyone that’s been inducted, the only other thing I could think of would be a camera pointed at the myford area to figure out who’s been messing with it.
However this would likley open up a whole can of worms, since I remember the last discussion on telegram a year or two back surrounding camera’s didn’t end too well.

2

As above, it’s extremely frustrating to have to repeatedly work out what’s wrong with the lathe when calibrating it.

If it was clear what had been done, the purpose of open discussion, then it can be completed within 30 minutes, if everything has to be checked, it can take a couple of hours to get the degree of precision this lathe is more than capable of.

I simply don’t have the time available to have to perform this process every time I visit the space, or more worryingly, calibrate it, then someone interfere with it, and then a later user complain it’s not working, before I can get back in.
Weekdays are almost impossible for me to get to the space, so if someone wants to use it midweek, and it’s not in true, then that’s a fail as far as the space goes, and a member potentially is left with wasted material, an additional cost that’s both unfair, and unnecessary.

I do this on a volunteer basis, and as has been discussed previously, I have spent a considerable sum of money, circa £1000, and an inordinate amount of time to get this lathe back to better than acceptable specification.
When I completed the major overhaul in early January it was within 0.00005 inches, or 0.00127mm, my micrometers won’t measure any smaller, which for us is far more accurate than we need, but we could guarantee anything made on it would be to that as a minimum specification.

Unfortunately now, with the repeated interference, I’m not prepared to go to a greater accuracy than 0.0002 inches, or 0.00508mm, this may seem insignificant, but, when making press fitted parts, you’re running very close to the margin between too loose, or too tight.

3

Disappointing.

Isn’t the lathe usually locked off?

4

It is, by numeric code, so we have two possibilities, firstly an untrained user is just moving adjustment points, or secondly, a trained user is making adjustments without entering into discussion.

As said in my second forwarded message above, this is not a request, it is an instruction , will the person responsible please make themselves known, private message is an available option, and you are welcome to contact any of the other members of the metalwork team to do so.

This is bordering on the decision to reduce the number of registered maintainers, and, mandatory retraining for all current trained lathe users. The discussion regarding cameras has arisen, in the interest of safety, both for users, and the equipment, it may have to be considered.

This is not a decision taken lightly, nor one that anyone of us want to make, but if this repeated interference continues, we may have no choice but to implement more stringent measures.

I do not like situations like this to arise, it is not what we are about, but someone believes rules don’t apply to them, and we need to resolve the issue before it gets any worse.

5

Another option we have is that the lathe gets locked out completely until the person making changes comes forward.

This of course is extremely unfair on the rest of the trained members, and an extreme measure that should be completely unnecessary, considering both the opportunities presented to resolve the issue openly, the amount of time this has been occurring over, now approaching 1 month, and the repetition of some of the changes following correction.

I’m now at the point of not disclosing what needs correcting, or has been corrected, in detail, in group conversation, as the individual knows what they are doing in relation to the corrections, or are countering the corrections as they believe they know better, so appropriate steps have been taken in the interim to prove if this is deliberate or not.

It has been discussed behind the scenes regarding marking adjustment points, as stated earlier, I have marked the adjustment points, the method used has been discussed with few, and is virtually impossible to remove, or interfere with.

6

The only other thought is if perhaps we could cover up the area with a 3d printed box or cap of some description with a tiny padlock on.
Then glue it over the area where the adjustment screws are.
Not sure how practical that would be since I’m not exactly sure which screws have been messed with, I’m guessing ones related to the gib adjustments

7

Another one might be to cover up the grub screws if they stick out with something like a castle nut, then wrap wire around the nut and something nearby to stop it ether being removed manually or vibrating out
although I’m not sure if it’d need to be hand made / threaded given the sizes involved.

I think there are also security nuts with weird fittings, but again given the tiny sizes and imperial thread I’m not sure if they make them that small.
I have got some imperial taps and dies that I got for making fasteners for my own lathe I’m working on, not sure what sizes they go down to though.

8

As the owner of the Myford, and a long-time lathe user in general (god, 40 years), its pretty farcical to claim 1.2micron accuracy - the parts will expand thermally by that, during cutting, unless under flood cooling !

Also, in the Myford world, it was common to lock the cross or topslide WITH the gib screws - one, you should see is longer than the others, on both axes.

Why has someone messed with the gibs ? Could it be because they were way too tight ? Could they have been turning a long job, further from the chuck than usual ? That’s another indication that they are too tight, and when all is said and done, the Myford is well over 40 years old IIRC. Some wear is to be expected.

All the best to Hacman members, from the USA

Steve

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9

Hi Steve,

It’s not just the gibs that have been interfered with, those were something else that’s been adjusted within the last two weeks.

We had repeatable results, with a dumb bell between centres, where each rim was turned at the same tool position, allowed to cool, then measured, it was consistent when measured with a Mitutoyo micrometer when left at the beginning of January, which is in calibration, and verified the rims to within 0.00005" of one another.

Two to three weeks ago it was discovered that one of the bed adjustment leveling feet bolts had be moved by approximately three threads, it was set back, and true.
Yesterday, it was found to have been returned to its out of position setting, flush with the top of the bolt.
Due to the nature of how these are set it’s not possible for both the nut and jacking screw to move three threads and remain tight.

When measured, it was found to be 0.002" out over 12", as was the tailstock.

Granted metal will expand and contract with working, but there shouldn’t have been any reason for the adjustment points stated to have been moved for any reason.
Mainly, with us having asked for no changes to be made without entering into discussion first.

I’m not expecting to get military precision out of the lathe, but it would be nice to turn a cylinder and not a traffic cone.

Kind regards,

Jim.

10

Ouch.
Do you have a precision toolroom level or access to one ? They can ensure your bed is definitely untwisted. Myfords always susceptible to twist. that bed isn’t very deep.

All the best

Steve

1 Like
11

Not at the minute, and I hadn’t anticipated buying one, I spent £650 on the two Mitutoyo micrometers, and now need the one in between :rofl:

I’m fairly happy that it’s reasonably level/untwisted, but I’ll see if I can find one reasonably priced, it does produce repeatable work when left as set, and it’s a lovely lathe to use, one of my favourites, I’ve never liked modern kit, they don’t talk to you when they’re running, figuratively speaking, you know when a Myford isn’t happy.

12

A nice of way of saying its hopelessly underpowered :slight_smile: I have a classic Starrett cast iron level here, but you should be able to find something decent on Ebay if you want one. The Starrett is usable to about 0.0001"/ft

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13

We also have a bigger warco we can use for more power, although the myford is good for precision.

I’ve got these at home
I was planning on trying to see if I could figure out if the surface plate we have is level but haven’t gotten around to it yet.

14

I hate to say it, but I’ve just ordered my third micrometer and Moore and Wright 1 minute level from my supplier who was offering a significant discount, so I couldn’t really refuse.

Edit: @garlicbread you don’t need a perfectly level surface to level a precision level. Take a reading, rotate 180°, and take another reading. If both readings are the same, or extremely close, it’s level.

15

Sorry what I meant to say is straight or flat instead of level, using the British flag pattern method. When we got the surface plate it was a free donation, but we have no idea as to what state it’s actually in.

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16

Gotcha, fair point, if I have time I’ll give it a check too.

17

The way to check a surface plate (unless you have the traditional set of three) is to use an autocollimator.

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18

the problem with an autocollimator is that they tend to be expensive.
a cheaper way is to use a very sensitive spirit level to measure flatness
#Flatness #Measurement by #Spiritlevel | anilkaranjkar - YouTube

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19

The rear bearing was a little warm on Saturday, but oil appeared to be flowing reasonably freely through it, and it didn’t appear more than lukewarm.

When myself and Stephen installed replacement shims on the rear bearing, there was a couple of tenths of play, we cranked the bearing plate fairly tight as the laminations are 0.002", and being brass expected an element of give over a period of time overcoming such a small difference.

If it gets any warmer I’ll check them, but I’m seriously hoping no adjustments have been made as they’re limited supply, and not cheap from Myford.

I’ve also ordered a replacement grub screw, had to buy a set, and copper pad for the threaded spindle thrust collar, and some oil resistant threadlock to make sure it doesn’t come loose.