Here is a list of all the postings Andrew Moyes 1 has made in our forums. Click on a thread name to jump to the thread.
|Thread: How Did Lawrence Sparey Make It Work?|
|The photo on p177 of my hardback copy shows the bore of the rear bearing to be larger than that of the front bearing i.e. different to the drawing. I think it's a drawing error and the pulley should clamp up against the inner race.|
|Thread: NewtonTesla systems|
|Dave - I was simply passing on my first-hand experience. The top speed was doubled to 1300 not 2000 rpm. The lubrication was just a couple of drops of oil every hour with the standard drip oilers.|
I'm interested; have you had ML7 bearings that have overheated?
Apologies for joining this thread late but the following may be of interest.
When I first got my ML7 lathe in 1971, I renewed the white metal bearings and carefully scraped them to fit. The measured spindle clearance was 0.0005” using a DTI and long bar in the chuck. After 40 years’ use, the last 10 with a VFD-controlled 2,850 rpm motor and top speed of 1300 rpm, there was no measurable change in clearance.
When I first fitted the 2850 rpm motor, I ran the lathe at top speed for 1.1/2 hours to check for overheating. The bearing caps were moderately warm to the touch but nothing untoward for such a close-fitting bearing. Myford themselves were not concerned as they offered a two speed 1450/2850 rpm motor until the lathe went out of production. It could be fitted to any ML7 but was mainly aimed at Trileva fitted lathes to give instant access to six speeds instead of three. The Trileva used standard white metal bearings.
The idea that Myford introduced replacement phosphor bronze bearings because of overheating white metal bearings is definitely a myth which has unfortunately found its way onto Tony Griffiths’ excellent site and is becoming 'gospel'. I remember the Myford press release at the time which said it was due to the prohibitive cost of obtaining white metal bearings. Phosphor bronze was a cheaper alternative but it meant replacing the spindle with a hardened version as the unhardened one previously used was not compatible with bronze.
If you are buying a new three-phase motor and VFD, I don’t see the point in running a 1450 rpm motor at 100 Hz when a 2850 rpm motor can be run at 50 Hz within its manufacturer’s rating.
Assuming your bearings are correctly fitted and lubricated, and not tight, installing a 2850 rpm motor with a VFD is for me a ‘no brainer’. I certainly wouldn’t swap the lathe because of fears about the bearings.
|Thread: Singer sewing machine motor.|
|The Potts toolpost spindle shown in my album has a sewing machine motor that runs at 9000 rpm on light load.|
|Thread: Banding on turned work|
I have a 2001 big bore machine too. After attention to the headstock bearings, the results have been excellent, much better than my previous ML7. There’s no reason why Bricky’s lathe shouldn’t be the same.
If the banding is at leadscrew pitch, it’s almost certainly induced by the leadscrew. Any leadscrew of ¾” diameter held at 2’6” centres is likely to have eccentricity in the order of a few thou. That shouldn’t translate to the work if the saddle is correctly adjusted even if the half nuts are 'tight on'. So I’m in agreement with those who have suggested readjusting the saddle.
I had trouble with the workpiece diameter not tracking the cross slide DRO reading. I traced it to a slightly loose saddle. I mounted a DTI on an extension to the left, clamped in the toolpost with the DTI touching the workpiece. Having adjusted the saddle as per normal instructions, I forcibly rotated the saddle clockwise and anticlockwise viewed from above and was surprised by the movement seen on the DTI. To take up the last few tenths of a thou, I had to rotate the outer gib adjusting screws and locknuts as one using both a spanner and screwdriver. That eliminated all movement, consistent with the saddle being free to move of course. It made a noticeable difference to the accuracy I was able to achieve and the finish. It’s worth a try.
|Thread: Substitute for wool yarn in bearings|
Hi Clive. The paste was acting as a medium to get oil into the bearing by capillary action. As well as the groove in the bearing bush and the hole through the wall of the bush, the whole cavity around the bearing was packed with the stuff. There was a flip-lid oiler to top up the oil. So although it looked like a grease, the bearing was oil lubricated.
‘Good old’ fractional horsepower motors made by BTH, Met-Vick, AEI, GEC etc in the 1940s to 60s had plain bearings lubricated by wool yarn in contact with the shaft and sitting in an oil reservoir. I dismantled a British motor probably made in the 1970s where the wool was replaced by a white, wet paste which was oleoscopic. I would say it had the appearance of finely ground PTFE. The paste was packed into the cavity and entered the bearing through an oil hole and filled a generous groove that put it in contact with the shaft. As well as lubricating the shaft, the paste picked up debris and was quite black where it was in contact. I was surprised too at how poor the manufactured finish seemed to be on the shaft but it worked OK. Does anyone know what the white paste might be and where it can be obtained? It would be useful stuff to have in the workshop.
Edited By Andrew Moyes 1 on 24/04/2016 09:10:46
|Thread: Myford big bore back gear|
PS - The 60T bull wheel and 16/53 backgear cluster are available from Myford/RDG as spares for the Connoisseur. I am pretty certain these would fit the big bore Super 7 Plus if John wants to upgrade from 67 to 60 teeth.
John S - does that mean you are custodian of the special 18.31DP cutter? Keep it safe, please!
When introduced, the big bore Super 7 had a 67 tooth bull wheel. This number seems to have been chosen to allow Myford to use the same DP as the standard Super 7 but with different gear centres resulting from the bigger spindle. As 67 is a prime number and useless for dividing, by popular demand Myford changed in 2006 to a 60 tooth bull wheel. These are the tooth counts...
Bull wheel Cluster Pulley
Small bore 60 17/53 24
Early big bore 67 16/53 30
Later big bore 60 16/53 30
On the later big bore machines, the 60 tooth and mating 16 tooth gears have a larger tooth form with a non-standard DP. The 53 and 30 tooth gears remained unchanged with the standard DP. The early and later big bore machines therefore have different gear ratios.
All Connoisseurs were produced with the later 60 tooth bull wheel.
All this resulted in a confusion of speed plates. Some early big bore lathes were produced with the speed plate of the small bore Super 7, which was never correct. Later ones had a speed plate which was correct for the 67 tooth bull wheel. This plate seems to have continued in use when the bull wheel was changed to 60 teeth and was therefore incorrect again. I haven't seen any speed plates with the correct ratios for the 60 tooth big bore Super 7 Plus and I suspect it was never corrected but I'd be happy to be proved wrong. The backgear ratio is 6.625:1. The Connoisseur has a different plate as it has poly-vee belts and variable speed drive and is, I believe, correct.
My ex-demo Super 7 Plus lathe was one of the first to be made in 2001. When I bought it from Myford in 2011, it had been converted to the later 60 tooth bull wheel but had (and still has) the incorrect 67 tooth speed plate.
|Thread: myford pulleys slippage|
PS This page from the Myford website
shows the complete 'Vee cone pulley assembly 74/1234'. Immediately below it is the 'Geared bush 70/1229' showing the extension which should be a press fit in the pulley.
The aluminium pulley should be an interference fit on the small brass or bronze gear. Yours has come adrift which is not an uncommon occurrence. I suggest you strip it all down, clean the pulley bore and the gear and fix the gear in position with Loctite retaining compound.. Or buy a replacement pulley assembly from Myford.
|Thread: Motive power for a toolpost spindle|
I went for a sewing machine motor when I motorised a Potts spindle I made from castings years ago. The motor is rated at 9000 rpm no load which gives a useful 1500/2500 rpm with the pulley castings supplied. The motor mounting is made from a scrap piece of channel attached to a collar on the back of the spindle. The motor mounting will rotate 360 degrees and is locked by a grub screw.
I put aside the Potts mounting base and turned and threaded a parallel end on some square bar so it can be mounted in the QCTP. I can fit it in place in seconds for drilling cylinder covers etc. Using the vertical slide and rear QCTP, it can be set up as a light vertical mill which should be useful for cutting clock gears etc.
Edited By Andrew Moyes 1 on 14/10/2015 21:26:02
|Thread: Allchin name plates|
|Thread: Fake Mitutoyo Digital Callipers on eBay|
When I lived in Hong Kong, I repaired my washing machine with a new belt which I thought was a reputable make. When it shredded itself with just 6 months of use, I looked more closely and found it was a Mitsuboshi. Crafty.
|Thread: Poly-vee problem - S7 mod|
|Cabeng - that's a cunning solution. I'll modify mine likewise next time I change the belt.|
Mine were about £13 each, last year. Perhaps I should import a few?
Hi Cabeng - I see our interests coincide again.
I have noticed the same problem with the Z section belt on my Super 7 Plus. Having got it otherwise running like a sewing machine, I wondered why there was a rattle on just the top two highest speeds. A squirt of oil into the headstock pulley bearing confirmed the source was endfloat. The oil stopped the noise for a few minutes until the surplus oil worked its way out. Running the lathe at slow speed revealed that the belt had a sideways lump, for want of a better description. While it is an annoyance, I decided that it was not a 'problem' as such and that I should live with it until the belt is renewed, probably for a Brammer type that has had some positive feedback on this forum.
I suspect that any belt, whether vee- or poly- is going to be imperfect in relation to the 5 thou or so endfloat recommended by Myford. If it is really unbearable then I wonder if there is another approach and that is to stop the metal-to-metal contact causing the rattle. Myford used fibre washers on the ML7 countershaft and that didn't rattle. While I wouldn't choose fibre because it seems to release fibrous material that makes the oil run black, a very thin washer machined out of a slug of PTFE or acetal might do the trick. One washer on each side of the pulley.
By the way, I would be interested to know where you were able to obtain NSK 7007A bearings in the UK. I couldn't find any but bought mine while passing through Hong Kong. I was offered two types, both marked NSK 7007A. One had a pressed steel cage like the Myford originals and the other, for the equivalent of a pound or so more, had a beautifully made machined brass cage. I chose the latter and went to the trouble of machining a thin wall tube to press the outer races in without subjecting the balls to any damage. They are totally silent in operation, unlike the steel caged bearings in electric motors.
|Thread: Recommended Dial Indicators|
Sorry to be late joining this thread. For a beginner, I would not recommend a dial test indicator but one like this...
I have several DTIs, the best being a secondhand Baty and a new Mercer, but the device that gets used 95% of the time is this Starrett no.564 indicator. Mounted at centre height in a quick change toolholder on the arms supplied with the indicator, I can quickly manoeuvre it into pretty well any position. The pointer reads positive for movement of the stylus in either direction and the stylus head can be rotated through 360 degrees. It's discontinued now but I got one for £7 on eBay that was new but not working. I took a gamble that I could fix it and it turned into one of my best buys on eBay. There was a tiny amount of corrosion inside which was stopping it from working. It came in this rather nice wooden box...
It replaced a similar Verdict indicator I'd used for 30 years that didn't have the advantage of the rotating head. Of course, it's a comparator and no use for absolute measurement but in practice I rarely find the need to do the latter. I'd be interested to hear the views of others.
|Thread: Lathe Accuracy|
Sorry Len, I can't help you with that but if you join the group here
you'll have access to that and much more.
Going back to the original post asking for the manufacturing tolerances of the Myford Connoisseur, on the Yahoo Myford lathe group website, in the files section there is
I don't know whether the origin of the information was Myford itself or it is just someone's suggestion but the figures are a pretty good benchmark for a lathe of Myford size. When I checked mine, all but a couple were within tolerance. A little fettling brought them all within the figures quoted.
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