|Shaun Belcher||16/11/2019 00:55:10|
|41 forum posts||
OK, ill take a look at that when i disassemble it.
I think it was the drip rate that was most of the problem, but looks like some oil is still getting past.
Would a worn bearing be a cause of this problem?
Im still trying to work out how much if any wear there is on the bearings, will probably need a dial indicator to check this.
Thanks for that drawing, I never realised the stock dials were not resettable.
Im assuming someone may have made a similar mod to mine, but ill take a good look when i strip all this down.
|Shaun Belcher||16/11/2019 08:11:50|
|41 forum posts|
Just pulled off the topslide.
Surprisingly the feedscrew looks OK, compared to the one on the crossslide which has significant wear to the threads.
The threaded nut on the topslide looks badly worn though.
I believe these are made from an alloy that is designed to wear out before the feedscrew does.
Anyway, I cant figure out how the handle and dial is removed.
Ive tried putting the spanner on it and it locks up no matter what direction i turn.
I think the last owner must have added the washers so that it has thread to catch on the feedscrew nut when its wound in all the way, as part of the thread on the outside is missing entirely.
Will probably leave it for now until i get the spare parts.
Does anyone know if this leadscrew threaded rod is available to fabricate your own leadscrew rods?
Would not be too difficult to make myself a set if i can get the rod.
I know ive seen this kind of stuff available for building CNC mills and 3D printers, but have no idea what specification the thread is for these.
|Don Cox||16/11/2019 08:59:11|
|42 forum posts|
If I remember correctly the handle acts as a locknut to the indicator dial, both of them being threaded. The best tactic might be to undo the two cap headed screws, grip the threaded section of the screw in the vice soft jaws and attack it that way.
You might be interested to know that ML8 wood lathes were often supplied with a metal lathe conversion, consisting of cross and topsides, which in my experience, have had very little use. I bought an ML8 and the seller gave me a brand new one, still coated in thick grease, as an after thought just as I was leaving. They occasionally appear on eBay from time to time.
3785 forum posts
YOu hold the dial with a spanner on the two flats. Then turn the ball handle anti clockwise so it loosens off. Then you hold the feedscrew still and tighten the dial until end float is taken up. Then you screw the ball handle clockwise until it locks the dial in position.
Given your beginner level of mechanical experience, you should hold off from disassembling your lathe any more than is absolutely necessary to get it running. It is not a beginner project to put it back together correctly from scratch.
Yes you can get lengths of feed screw blank. It is an Acme thread. 10 TPI. Diameter, I forget but you can measure that.
If you want to convert to metric, you will need instead to buy lengths of metric trapezoidal threaded bar. Pitch I THINK wouild be 1mm But check that with someone who has a metric Myford lathe. So long since I worked in metric I don't remember.
You might find some metric trapezoidal threaded rod on eBay, Aliexpress etc. Otherwise there are several suppliers in the UK who have been mentioned on the forum before so a bit of searching around past threads should find them. But you will need to be able to use a lathe to turn the ends down and thread them to suit the dials and handles etc.
Another old trick is to cut the threaded section off the feedsrew and turn it around and reattach using a spigot etc so the unworn section of the feedscrew is now in the high-use zone. Probably more effort than it is worth these days.
Oil splatter from these lathes is not a problem. It's normal. That's the way they did things back then. It does not indicate anything wrong with the bearings. OIl will come out of a brand new bearing because there is always clearance between shaft and bearing -- to let oil flow through! A strip of rag tied around the gap between chuck backplate and the headstock bearing will stop most of the "fling". And don't stand in front of the chuck. Work standing in front of the carriage or even a bit further toward the tailstock. Keeps you out of the hot swarf zone somewhat too.
To test the bearings, hold a length of solid bar or pipe in the chuck, about a foot (30cm for you metric types) long. Grip the end of the bar and try to move it up and down and side to side. Measure the amount of movement of the spindle right at the headstock with a dial indicator. Or if you have no dial indicator you might get a rough idea by holding a finger on the spindle and bearing and feeling for movement. Should be about one thou (two or three hundredths of a mm) of movement. IE only just discernible by feel and that's all.
Edited By Hopper on 16/11/2019 10:51:29
|Howard Lewis||16/11/2019 16:48:14|
|2452 forum posts|
To have a running fit the bearing has to have clearance, and oil will make it's way through, unless oil seals are fitted, which the ML7 does not have, from memory.
I would have expected Myford to be able to supply new feedscrews and nuts.
Once you depart from the original Left hand thread spec, you will be on your own for replacement leadscrew nuts.
And the "new" leadscrew will have to be modified to take the dial and ball handle.
For what my advice is worth, replace with Original Equipment leadscrew and nut, (Whether Imperial or Metric ) and save yourself (and the next owner ) a load of complication in the future.
In my view, unless you are prepared to convert ALL the leadscrews and Dials to Metric, you would be better to stick with whatever spec is there. A "bastard" hybrid machine will be a P I T A to you., especially a relative beginner. It will be neither fish nor fowl (except to use, with the W replaced by a U )
Think about setting a turning cut in mm, to produce a shoulder to an Imperial length!.
|Shaun Belcher||17/11/2019 23:49:58|
|41 forum posts||
Its all good, I think I was just being overly cautious. The handle was just on too tight. I managed to unscrew it easily enough and take a better look.
Just as i guessed, the washers were added to pull back more thread to catch all the way down since half the thread on the nut is missing and the unthreaded part at the end of the feedscrew would not catch.
Im going to have to rebuild both slides as a minimum.
It seems to be the most need of attention to make the lathe usable.
Good news is that I think the rest of the lathe is in fairly good condition for its age, does not seem to be heavy wear on the bed and minimal wear on the bearing from what I can tell.
Oil splatter, thats good to know its normal, yes where i stand it does not hit me, but it leaves a trail on the walls and floor so I want to address this if possible.
Have made a few cuts on bronze stock and even in the poor state of the lathe, currently things seem to measure up OK.
Right now the lathe is not very usable until i sort out the slides anyway.
Will do the test with a dial indicator to check the bearing wear as you suggest.
Was looking on myford site and yes the imperial leadscrew is 10TPI 3/8 diameter.
the metric feedscrew is quoted as Threaed 3/8" x 2mm pitch
I may just ordering everything from myford, but ive got a friend who can probably machine these easily enough for me which would be useful.
One other question, is with the apron assembly, are you supposed to lock down the power feed lever to stop it moving when making cuts?
I find the saddle will move across the bed if making an end cut with the top slide as I move the cutting tool into the stock. I found locking down the powerfeed lever would help, although i question whether or not it might need tightening up?
|Pete Rimmer||18/11/2019 00:29:53|
|480 forum posts|
I take it you are disengaging the tumbler and locking the half-nuts? That's very poor practice. Use the saddle lock if you need to keep it from creeping during facing cuts, though you should be able to face without the saddle moving.
|Shaun Belcher||18/11/2019 01:21:26|
|41 forum posts||
I did not know these had a saddle lock. I dont see any other levers on the saddle to lock it, I assumed that was the function of the power feed lever to lock it on the leadscrew.
The tumbler would be disengaged with the selector lever would it not?
I am not sure what you mean about locking the half nuts sorry, i just make sure leadscrew is disengaged and I engaged the powerfeed lever, which I assumed was how you locked it.
The topslide also creeps a bit when cutting, this is probably a worse issue TBH. I was not able to face off a part square without holding the topslide handle firm either, hence why this is the main area of attention for me currently.
The saddle seems to creep more if i was cutting directly on the face rather than facing off a part using the crossside.
3785 forum posts
You really need to get a copy of this: LINK
and this: link
to familiarise yourself with the basics on the machine.
|ian j||18/11/2019 08:13:10|
275 forum posts
Edited By ian j on 18/11/2019 08:16:30
|Shaun Belcher||18/11/2019 10:20:13|
|41 forum posts|
Thanks, ill check those books out.
I was assuming there would be a lever. Completley overlooked that bolt.
It seems pretty tight when I put a spanner to it.
Will leave some CRC soaking on it to see if it helps free it up.
I see there is a mod available with a lever, I think thats a good idea rather than needing to use a spanner every time.
|Derek Johnson||08/12/2019 12:25:55|
|5 forum posts|
Oil Leakage from ML7 bearings
About 40 years ago I think I saw an article/letter in Model Engineer that utilised a ring arrgt with internal groove pressed on to the ML7 spindle just behind the chuck that collected the oil while the lathe was running. The ring arrgt has clearance to the machined outside diameter of the bearing. When the lathe stopped the oil drained down to bottom of internal groove with the excess draining to the the lathe drip tray. I think this was based on a design for overhead flatbelt line shafting bearings about 1830 (but my memory may be failing!)
For my ML7 I installed this system over 30 years ago with every satisfaction - no oil on the lab coat!
My apologies for the lack of a drawing I have forgotten the details of the arrangement. If I take ring off to measure it will destroy the ring.
Is there any one who has a comprehensive collection of Model Engineer magazines who could find the original article or letter?
Hope this helps
|1339 forum posts|
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