119 forum posts
I admit it, I bought this little beast without seeing it run, without being able to test it. My bad . In truth, I wasn't asking that much of it up until now. I was using it for the odd bit of turning off of bolt heads, etc... mostly garage type stuff, without really sweating the tolerances too much.
Well, I finally decided that I would produce a crank for the main spindle. To that end I chucked up some stock between centers with a lathe dog driven from a stud off of the faceplate... to turn it down to size... and was most very disappointed with the results.
The workpiece looked like the dog had chewed it. So I decided to use the (now useless) shafting as a test piece. I rechecked (and tightened) all the gibs - bed, cross-slide and tool slide - as far as I dared and ran another test cut. Still miserable. Along a 7cm length the measurements varied from a low of 14.775mm to a high of 14.83mm... and not in a smooth, uniform fashion, but rather more 'ribbed'.
Chucked up a dial test indicator in the spindle collet holder and attempted to double check the centering of the tailstock center. For the first test the tailstock ram was pretty well fully extended. My tests showed the center to be correct with respect to fore and aft, but low. I slid the tailstock further forward towards the headstock, retracted the ram and tested again. Now the measurements indicated that the center was even lower than before.
I suspect that the bed of the lathe has become 'saddle backed' and that the tailstock is pointing downwards as it slides into the dip in the bed way caused by the movement of the carriage over the years. This dip in the bed way would also explain some of the cutting deviation while turning between centers.
I then went back to re-examine the main spindle. This is the original ML10 version with hardened spindle running in cast iron journals. I chucked up that length of shafting in the 3-jaw and exerted pressure on it - first from below, then from above - a dial indicator reading from the body of the chuck near the front bearing area. Total measured deviation = 0.04mm = 0.00157 inch
Did I forget to mention that there is a very slight 'bow' in the leadscrew? Sometime in the history of this tool, someone overtaxed it while moving the machine. It isn't really visible unless one holds something against it while it is rotating, even then, very slight.
Rather a littany of faults accumulated over the years.
Is there anything to be done with this old unit?
The leadscrew could be dismounted and brought true under a press. One could opt to have a total regrind of bed, carriage, tailstock and slides. The main spindle? Perhaps loosen the journal and peel back (or grind down) the spacer a bit? And even then I have no idea of the amount of wear on the leadscrew and cross-slide screws/nuts.
But the main question. All of this requires time and/or money (especially a regrind). Would it even be worth it or should I sell it off for parts and invest in a newer machine??
|not done it yet||31/07/2018 09:23:59|
|4893 forum posts|
Doesn’t seem so much that cannot be rectified. Suspicion of a fault is not definitive - it may even be perfectly OK - so needs checking properly.
Seems like you want to just break it for spares and need someone to encourage you to do that, or are testing the water for those that might want parts of it.
If the lead screw has so little apparent bend, it is likely close and/or in spec. Is it really visible or not?
What was the ‘stock’ that you chucked up? Good free-cutting or nasty scrap? What cutter, what speed, what feed? They can all make a huge difference to the finish.
Were you actually turning between centres?
Seems to me, that you need to do some properly controlled checks, before coming to any conclusion.
|Mick B1||31/07/2018 09:27:32|
|1661 forum posts|
I'd say it depends - almost entirely - on your attitude to the work and expenditure. Of course, you probably have to source a bed regrind, or work up to doin' it thysen.
If you'll enjoy the work and overcoming the undoubted setbacks, go for it.
Otherwise, do remember that after all the work, what you'll have is something with capability broadly similar to a good Chinese mini-lathe.
I wouldn't take it on, but I do have some admiration for those that do.
|Nicholas Wheeler 1||31/07/2018 09:50:45|
|362 forum posts|
Do you just want a lathe that will efficiently make decent parts? If so, then move it on and buy one that works.
Do you want a longterm project that will result in a good as new ML10? Congratulations, you already own a good starting point.
|Martin of Wick||31/07/2018 09:54:17|
|196 forum posts|
you are dealing with very small issues, taking it from the bottom, a bow in the leadscrew that you can only just see will have no effect on accuracy assuming all gibs are properly adjusted.
If you lever on barstock in a chuck you will get some deflection - you report about 1 thou inch so check deflection of spindle with no chuck mounted by pushing up and down and side to side on the bull wheel. If you still detect play, this can be adjusted out easily.
The ML10 iron bearing is very robust, unless abused by not oiling, and can be adjusted by taking out a shim and tightening the bearing clamp screw (this needs some care to do to avoid snapping the shoulder so I suggest you get a manual).
Put a 2 ft straight edge along the bed and shine a light from behind, If the lathe bed is as worn as you believe you will see the extent. If you slide a 2 thou shim underneath, that may confirm your diagnosis. The other check is to adjust gib strips with the saddle close up to the chuck, then move the saddle by hand to the tailstock. If it tightens significantly, then there may be a problem with significant wear on the bed. Even if this was the case, you can still use this machine to carry out accurate work.
You don't say what the tailstock vertical and lateral deviations are, or whether your test piece is parallel or not. Tailstocks are notoriously fiddly to set accurately in all dimensions, so you may need to spend some time adjusting - Vertical adjustment to be co planar with the bed are often overlooked, not least by the manufacturers! This only becomes a problem when drilling deep holes- Are you snapping a lot of drills?
You report that the work piece looked 'as if the dog chewed it'. with properly adjusted gibs, fully locked tail stock and correctly ground tool at the proper height, there is no reason you should have a bad or inaccurate finish when turning between centres in the way you describe, even with the 'wear' as reported. I would check those issues again, especially as your reported inaccuracy is only 2 thou, on a ribbed finish.
Of course, if you don't want the lathe, I will take it off your hands for the cost of a pint or two!
4780 forum posts
+1 on what Martin said above. It sounds like a bit of "massaging" could bring the old girl up to shape.
And before you decide to scrap it, try some more test pieces of known quality mild steel with different tool bits etc. Try them held in the chuck without tailstock. Get the basics working first, then align the tailstock later.
6193 forum posts
I agree with both NDIY and Mick:
With the ML10, I think Myford departed from the design philosophy behind the Seven family. Myford Seven series lathes can be readily life extended in that worn parts can be replaced and the bed reground a few times. In comparison the ML10 offers far less opportunity. Like almost everything else manufactured since WW2, a worn out ML10 should be replaced with a new one.
Mick mentioned work and expenditure, I would also mention time. Doing up a seriously worn lathe will take a fair bit of admin and workshop time. Fine if that's what you enjoy. But if other tasks are pressing, an order made today could have a new lathe delivered to your workshop next week.
Assuming it really is a bad as suspected, I'd sell the ML10 to a Myford fan who wants spares or a doer-upper, and replace it a mini-lathe, or - even better - one of the bigger Chinese machines. That's just me though, I'm sure others will have equally good reasons for restoring the Myford, if it's possible.
Edited By SillyOldDuffer on 31/07/2018 10:19:51
119 forum posts
Martin, Hopper, SillyOldDuffer,
How would one remove play in the spindle if so detected? I do have a manual that I purchased from Myford UK, but not a word about that procedure. In fact, my machine predates even the drawings of the earliest machine in the manual. I know this because my countershaft (which suffered a lack of oil and suffered some galling) is shaft-running-in-iron-journal rather than the shaft-running-in-oilite-bearing as found pictured in the manual.
I can see some daylight even under my 19 cm long machinist's straight edge. Under a longer straight edge I can 'just about' slip a .04mm shim (= 0.00157 inch). I don't have any thinner shimming material at hand, so cannot qaulify further on this point.
Yes, with the saddle gibs adjusted up at the headstock end and then moved towards the tail it does definitely get tighter.
I would have to check the tailstock unit, itself, as regards vertical/lateral deviation. True enough the unit might not have started life being completely parallel and level with the line of the headstock spindle. Haven't snapped any drill bits to date, but using mostly fairly large ones.
That dog-chewed look was before I rechecked and tightened all the gibs. After tightening I had the following measurements along a turned 7cm length of shaft (do note: not really great steel, probably 'nasty scrap' )
>> 14.795mm, 14.785mm, 14.785mm, 14.775mm, 14.8mm, 14.815mm, 14.83mm
Anyway, I'll run some more tests on better steel later in the day and report further.
By the way, I rather like the old girl and hate to just junk it. Even if I had to scrap her it would be best if I could use some of her parts on another, larger Myford. I am referring to the change gears, 3-jaw chuck, 4-jaw chuck and so on.
Edited By Ignatz on 31/07/2018 10:24:46
4780 forum posts
Myford's literature on their old (ML7/S7) reconditioning service says that up to five thou of wear on the top surface of the bed is allowable before a regrind is needed, and three thou on the vertical surfaces of the ways. So your 1.5 thou is rather good actually.
The process to tighten the bearing was described in one of the posts above. Basically remove a small shim from the split in the housing and retighten VERY CAREFULLY. Others can probably tell you more about this. I'm an ML7 guy.
Vertical height of tailstock is not critical. It takes a lot to make a job tapered. And you can always shim between the base and body of the tailstock. Sideways is done by adjustment, so no problem there.
Keep working on it. You'll get there.
Edited By Hopper on 31/07/2018 10:38:45
|pgk pgk||31/07/2018 10:50:06|
|1890 forum posts|
Even if you unlimately decide it cannot turn accurately enough there may still be reason to keep it if shed space allows. There's a heap of low tolerance jobs as you have been doing and often quite handy to have one lathe set-up with a faceplate or different jawed chuck. If the cross slide is good enough then flycutting stuff mounted there could be handy r skimming the surface of a rusty bit of plate.
There's simple low tolerance jobs where visual appearnace is more important than being bang on size - a couple of small acorn shaped knobs roughed out and then filed on the lathe to shape for instance. So long as they look like others in this old house no-one is going to take a mike to them....
4780 forum posts
And if the bed is worn beyond use (which it does not appear to be at .0015" wear) you can always use the topslide set to turn parallel for jobs up to four inches long or so. Plenty for most model and small engine work etc. Many old lathes used like this in "professional" workshops when needs must.
|Michael Gilligan||31/07/2018 11:07:35|
16203 forum posts
But do also be aware of Myford's specific comment about the ML10 bed ...
Please see my post [i.e. the first response] in this recent thread: **LINK**
|Martin of Wick||31/07/2018 11:13:12|
|196 forum posts|
from your description, just like my M10 -
you will / should see on the headstock an allen bolt at the front of the bearing clamp locations front and rear of spindle and in the clamp a slot filled with laminated shims or a solid shim. WHEN you have carried out the check I suggested by checking both front and rear spindle play and ONLY IF you confirm play in the bearings approaching 0.002 thou first try gently tightening the allen bolt 1/16 at a time.
If you cannot, (please do not start levering hard on this bolt) loosen off and remove the laminated shim pack and remove one of the 2 thou shim foils, replace shim pack and gently repeat the tightening process 1/16 turn at a time.
In case there is no shim pack, but just a solid shim, you will have to gently lap the shim by the amount of play you measure.
Please please please do not attempt to over tighten the adjustment allen key or attempt too large a thinning of the shim otherwise you will REPEAT WILL! snap the headstock bearing clamp and scrap your lathe headstock. You should aim to remove play but still have free turning by hand of the spindle. Following adjustment, monitor temperature of bearing clamp.
The wear you report on the bead is trivial. Again you don't quantify how tight the saddle gets - they all do tighten on beds that have been used. If you can still push the bed by hand up to the tailstock end all is OK (assuming gibs are properly adjusted - neither too loose AND ALSO not to tight)
Re bowing of the lead screw - forgot to say you may need to check adjust the nut position on the apron, but as you say it is small, you can do this later.
If the tailstock was significantly out, you would see the effect in deep holes of the drill flexing, so then check for coplanar motion in tailstock barrel vertically and horizontally
Please refer to copious material on web reference tailstock adjustments - it is not a trivial job, and to do well will take you a long wet sunday afternoon to get spot on, especially if you need to shim to be coplanar vertically,. In any case, this is the least significant dimension, so a tolerance of 2 thou between barrel in and out would be ok. Once you have got it right, you will never want have to adjust it again!
From the measurements you give, the work piece is being bowed which suggests the cutting action may not be quite right.
The finish issues described are more likely down to poor material, cutter, feeds and speeds, settings, nothing inherent the dimensional accuracy you report would lead to the finish issues - you don't ay what cutter, suggest you use accurately HSS to start with if not already using.
I see no significant problems with this lathe.
|Andrew Tinsley||31/07/2018 11:18:47|
|1170 forum posts|
Anyone know why Myford say that an ML10 bed cannot be reground? I know of one that has been reground without any apparent problems.
4780 forum posts
Probably they meant that they could not regrind it. Or would not. Maybe not cost effective for them. It probably would need the carriage regrinding to match. But a good machine shop with a suitable grinder machine should be able to do it. Although, it sounds like this particular one does not need grinding.
|Martin of Wick||31/07/2018 11:38:28|
|196 forum posts|
I assumed that the headstock is also co planar XYZ with the bed? if you have not checked, get an MT2 test bar and carry those checks and adjust if necessary (google rollies dads method etc). sometimes previous owners get to fiddling about with headstock bolts as well as tailstocks.
As you were turning between centres, headstock would not show up significantly on your workpiece, but would with normal chucking - when you have resolved cutting issues, try turning a chucked test piece as suggested above and measure for parallelism.
6193 forum posts
Michael's link from the other thread takes you to an account of what Myford do when refurbishing their lathes. An interesting read! Myford don't say the bed cannot be reground, rather they say 'It is not possible to do a full bed and saddle regrind ...' The reason given is a limit to the amount of metal that can be removed. 'At best the top of the bed can have 0.005in. (0.127mm) removed, a once only operation, so your visual inspection is crucial.'
I interpret this as meaning 'a ML10 can be reground once provided the bed is only slightly damaged'. They're much more optimistic about sevens suggesting up to 5 regrinds should be possible depending on how deep each grind has to go to get back to good metal.
Michael's link is revealing about what else Myford do to to restore a worn ML10. For example, rather than shimming the spindle to remove play at risk of cracking the headstock, Myford don't muck about - they replace the spindle. It doesn't mean that shimming is 'wrong', just that there's a better way which will cost a bob or two more.
|not done it yet||31/07/2018 12:09:23|
|4893 forum posts|
I would guess that the bed is only surface hardened to a minimal depth - a matter of reducing cost at manufacture - so it would wear very quickly if ground through that harder surface. Nothing more, I suspect.
|Trevor Drabble||31/07/2018 12:15:02|
211 forum posts
Andrew , Malcolm of Myford Beeston told me you could not regrind the bed because ,unlike the 7 series , the cast end bracket would not allow the lead screw to be repositioned following the regrind . Must admit , I didn't question it but simply took his word for it .
Ignatz , Maybe worth seeking the opinions of the 2 ex-Myford service engineers who have been mentioned several times on this site , assuming they still working ?
Edited By Trevor Drabble on 31/07/2018 12:16:53
|Andrew Tinsley||31/07/2018 12:40:52|
|1170 forum posts|
The normal Ml10 beds are not hardened, so I doubt that is the reason. The cast in lead screw bracket seems more likely a good reason. Although I am not certain, the bracket on the ML10 that I know has been reground, has been bushed off centre. I will check on this however as my memory has been known to play tricks!
Please login to post a reply.
Want the latest issue of Model Engineer or Model Engineers' Workshop? Use our magazine locator links to find your nearest stockist!
You can contact us by phone, mail or email about the magazines including becoming a contributor, submitting reader's letters or making queries about articles. You can also get in touch about this website, advertising or other general issues.
Click THIS LINK for full contact details.
For subscription issues please see THIS LINK.