Member postings for Sam Stones

Hi Michael,

I may attract an outburst from some ME members when I explain my method of finding centre height.

Like Topsy, it just growed.

First, I have to say a few things which will actually take me longer to write than it will for you to set the tool height.

1. My eyesight is not the best either, requiring a 4" binocular magnifier to handle most of my small work, especially when making 1mm diameter dowels for the skeleton clock.

3. Even though I had a four-way tool post on the Myford, and an (upside-down) rear tool post for parting off, I adopted a `one-tool- suits-all’ for general facing and surfacing, and even parting off. The latter was a little bit time consuming in operation but often saved time in setting up. More shudders!?

Unlike the `height-gauge’ shown by Terry which will allow you to not only see but `feel’ the correct height, my method does require close-up inspection.

For a few quid, (I’m not sure of the price), you might also choose to buy yourself a `centre and edge finder’ normally used in the milling machine to pick up hole centres and edges. I’ve never used one in the lathe, but I don’t see why not.

Have fun,

Sam

Hello Chris,

One book I bought when I began building the skeleton clock (ME Feb ‘72) was W.J.Gazeley’s "Watch and Clock Making and Repairing" published by Robert Hale - London.

While this book is well advanced, it starts where it should, at the beginning. There’s a huge amount of information in both text and an abundance of drawings and sketches. It is especially useful in describing simple tools and gadgets which can be made without too much effort. Just browsing through this book was/is, to me at least, a real pleasure.

As Norman (NJH) advises, I would also stay away from spray-on lubricants. The clock I started to build in the mid 70's has stood around (unfinished) for all those years. It is now a fine example of what happens when you spray with lubricant. The mixture of grime and whatever didn’t evaporate from the WD40, takes quite a bit of shifting.

Being a non-smoker, I found that toothpicks make good oil applicators.

Good luck.

Sam

While looking for a plastic material which offered high creep resistance, I was handed a short length of 50mm dia. glass filled polymer, possibly polyacetal. The glass was in the form of spherical beads less than about 0.1mm in diameter. It machined easily in the lathe with the swarf falling more as a powder than a continuous thread.

Suddenly,  the saddle of my Myford ML7 jammed .

Glass beads had found their way past the felt lubricating strip and then between the saddle and the bed. I realised in the nick of time what had happened, and stopped everything rather than try to move the saddle any further.

Clearly, during the machining process, the glass beads had remained intact while the polymer was being shaved away as normal. That part of the machine required a complete strip-down to get rid of all the beads.

Luckily for me and the Myford, the top section of the saddle can be unscrewed and lifted vertically. Even more lucky, the saddle wasn’t traversing under power.

I trust that my experience serves as a warning to ME members and others.

Regards,

Sam

While looking for a plastic material which offered high creep resistance, I was handed a short length of 50mm dia. glass filled polymer, possibly polyacetal. The glass was in the form of spherical beads less than about 0.1mm in diameter. It machined easily in the lathe with the swarf falling more as a powder than a continuous thread.

Suddenly, the saddle of my Myford ML7 jammed.

Glass beads had found their way past the felt lubricating strip and then between the saddle and the bed. I realised in the nick of time what had happened, and stopped everything rather than try to move the saddle any further.

Clearly, during the machining process, the glass beads had remained intact while the polymer was being shaved away as normal. That part of the machine required a complete strip-down to get rid of all the beads.

Luckily for me and the Myford, the top section of the saddle can be unscrewed and lifted vertically. Even more lucky, the saddle wasn’t traversing under power.

I trust that my experience serves as a warning to ME members and others.

Regards,

Sam

Thanks to you Joe, John, and Martin. As with others who have contributed to this thread, I really appreciate your comments both electrical and mechanical.

I must also apologise if I keep repeating myself. My own knowledge of electrics and electronics is relatively flimsy, and although my father was an electrician, I still rely heavily upon others like yourselves for technical support and confirmation. Conversely, my friend has a respectable background in these fields, and used various pieces of test equipment to determine the motor issues.

With mains connected directly, ie. bypassing the START/STOP solenoid etc. the motor runs up to speed. However, there is a distinct hum which concerned my friend. As I’ve mentioned before, the centrifugal switch can be heard operating, but according to the current-meter reading, there is current flowing through the capacitor.

To close a few loose ends, when I tried the solenoid START/STOP operation with the motor disconnected, it failed to latch. But it did produce the pulsating mains hum I mentioned before. So there’s a `Non-latching’ fault which needs fixing. I suspect that if the centrifugal switch has failed to open and therefore failing to disconnect the capacitor during the running mode, the protection circuit may have suffered.

We didn’t investigate the centrifugal switch, but this afternoon, I removed the cowl, the nylon cooling fan, and the die-cast cover over the centrifugal switch. A long brass screw passes through a bush and the motor shaft to keep the rotating parts of the switch in place. However, without a puller tool, I wasn’t prepared to try removing the bush and the rotating parts. The bush was firmly stuck to the shaft!

It wasn’t possible to see the switch contacts or the wiring Martin, although I could move the sliding part of the switch, ie. the part which is usually toggled from one position to the other and back again. The mechanical parts all appear to work freely against their respective springs.

Having reached this point, I have decided to leave things alone until I’ve spoken with the owner of the HobbyMat lathe/mill. He may choose to take this on board himself, and I need to get on with finishing the clock.

By the way, although I don’t know what the current-meter is actually called, it has large, heavily insulated jaws which open to surround and close around a single wire. I presume that it determines AC amperage by means of the induced magnetic field.

Joe - thanks for your description of how to place the T-nuts. I did it once before, but it was all lying on the bench, and the bolts were at 12 and 6 o-clock. The first one went in a treat, but I had to jiggle around for the second one. A good blob of grease will do fine, but would you believe that my tin went out the door when I got rid of my workshop? Currently, that section of the mill is now on the vertical column, and the bolts are at 3 and 9 o-clock. I expect that I’ll have to fish a little.

Given more time, I would be inclined to machine a ring of wood or similar material to fit loosely in the T-slot. This would be cut into two pieces removing the extra material where the T-nuts normally sit. Given more time, a ring made of steel could be used, suitable threaded to completely replace the T-nuts. Of course this would require unscrewing more screws to access the back of the T-slot.

Thanks again.

Sam

Good day Gentlemen,

In my friend’s workshop yesterday, tests of the electrical component of the BFE 65 mill revealed several issues and anomalies. Before I continue however, I have to thank again, those ME members who, through this thread, have offered their comments. In return, I trust that the following details may be of help to others with similar experiences.

A couple of theoretical (possibly trivial) aspects are noted, such as :-

a) The circuit diagram show the capacitor’s value as 8mf/460V~ while the actual capacitor is rated at 40mf/320V~. I’m told that a larger capacitor may improve the motor torque a little.

b) The circuit diagram shows the motor rated at 220V which immediately drew suspicion from my friend. Whenever I’ve measured our domestic supply, it has been a healthy 250V. However, the tiny motor indicator plate displays 240V.

The 40mf capacitor passed every electrical test, but started to heat up when the motor was placed directly across the mains for a few seconds, (ie bypassing the START/STOP contact breaker circuit).

The motor’s insulation to earth via a high voltage test meter got an "OK!" when it showed a very high resistance.

Using a current meter around single (input) wires in the motor terminal box, motor current on the two windings measured about 7amps and 5amps. We didn’t try to identify which winding was which.

When the motor was removed from the gear box, the shaft could be spun by hand with no mechanical resistance. In fact, it turned very smoothly. Thanks for the warning about the loose key Joe! As you might expect, Murphy placed it face down, but we were ready.

Prognosis -

1. Probable shorted-turns in the motor.

2. An unexplained fault in the starter circuit.

I was expecting closure on this thread. Murphy should take a holiday.

Thanks again for all your comments and help.

Sam

You beaudie, as they say down here in OZ.

Thanks again for all your information, I’ll get back with a report shortly.

Meanwhile, I’ve opened a photo album for the skeleton clock, starting with a HLR (hidden line removal) image from my KeyCreator file via Photoshop CS3.

Finishing this clock is my prime target.

Thanks to all.

Sam

Gentlemen,

Thank you so much for all your advice wrt the BFE 65 mill. Those initials are getting to me, and I’ve wondered if they have a secret meaning. Any ideas?

Anyway, I really appreciate getting this sort of help from you people, especially the circuit diagrams and the effort you have all put into solving my problem. Had this been my machine (its only on loan), perhaps I would have pulled it apart without hesitation. But since it isn’t, and the failure happened while I was at the helm so-to-speak, I feel obliged to get it fixed as professionally as possible.

I have a couple of pieces of news. A good friend has offered to take a closer look at the electrics, and to apply various electrical tests. My guess is that he’ll have the right gear. He also pointed out that since the machine has stood around for a considerable time (information I gathered about the machine a few days ago), and has only been used a couple of times in that period, there is a strong likelihood that the capacitor has deteriorated.

There are a couple of snags to this offer. For various other reasons, we will carry out the tests at his place. Also, not being as fit and tough as I used to be, lifting is becoming a "NO NO!" (That’s the wife from the kitchen). This morning I stood pondered the problem of how to get the BFE 65 mill into the back of our car without any serious lifting. Of necessity the whole unit needed to be given a straight lift upwards to extract the vertical column from the bracket attached to the back of the lathe. Years ago, as a toolmaker, I was obliged to carry out this simple (clean & jerk) movement, while splitting plastics moulds apart on the bench. Using the quill to jack the whole caboodle from its resting place, and somehow progressively insert blocks underneath turned out to be futile.

However, I decided to avoid a strained back, and split the head at the swivel point, bearing in mind that those two inaccessible `T’ nuts will drop down into the wrong place when I reassemble. I’d done this `trick’ before on my Jack Jones, so I tried again and it worked a breeze. The gearbox and motor are not that heavy, so they're sitting in the back of the car ready for tomorrow’s trip. Those circuit diagrams should help a lot too.

Here’s hoping for a good (final) posting and an end to this thread.

Best regards,

Sam

Hi John,

Thanks for your very prompt reply. Although the titles may not match my text, here are a few notes about each picture :-

The blue and brown wires (bottom right of picture) come from the capacitor. The brown wire is connected to U1, the blue wire is connected to Z1.

(See 5516---Terminal-connection-diagram)

Thank you - John O, Steve, and John S. Your combined advice is much appreciated, and I trust will be of help to others too.

Further investigations of the BFE 65 reveal the following :-

To confirm that twisting the quill by hand is getting through to the motor (it felt as if it was), I removed the fan cowl. I can see the motor turning (forwards or backwards), while twisting the quill in any gear . This, I have presumed, rules out the gearbox, but such a simple test was well worth investigating. Thanks Steve. I also took a risk and tried a quick spin of the quill by hand while stabbing the START button. Nothing!

Other than pressing the START button a few more times, I haven’t carried out any other tests, choosing to continue using the lathe for some very basic milling and then filing parts to shape. Tiny clock parts in brass are my number one priority.

However, the `growl’ response which I mentioned is emanating from the motor, and for what it’s worth is quite low in volume. What I don’t understand is the random `pulsing’ I can hear coming from behind the START/STOP panel when I hold the START button in for a few seconds. Also, why doesn’t the starter switch latch anyway? Does latching only take effect from the motor current? Sorry, the only circuit diagram I have seen is on a label inside the lid of the terminal box. If this is of any use, I’ll photograph it and add it to my postings.

Is the above sufficient for a remote diagnosis? I welcome any comments.

By the way Steve, I’m inclined to follow your choice regarding plastics. Although I’ve been in the plastics industry since 1950, I would shy away from buying a machine with plastic gears, especially when the demand could include severe shock loading. Although not exclusive, there’s a particular weakness which dogs the plastics industry in almost any form (FRP to a lesser degree). It’s called notch sensitivity, a predominant phenomenon emanating from toolrooms producing injection moulds. Additionally, there’s ESC (environmental stress cracking). Now perhaps I’ve opened another `tin-of-worms’?

Thanks again,

Sam

Hi Martyn,

I’m not sure if the following is relevant to your situation other than in terms of the slideways clearance. However, while serving my time in the toolroom in the 50's, we had a 24" shaper mostly being used by a very elderly gentleman.

The machine (I can’t remember the make, but it was pretty old) had a Whitworth quick-return linkage, as opposed to a hydraulic ram drive. Changing speed and clutch operation was via large joy-sticks emerging from the side of the machine.

Occasionally, the shaper became available for use by others. None of these people, including myself had little if any problem cutting large slabs of (mostly) nickel chrome steel. Incidentally, I did have to stand on a box to reach the top slide handle.

Anyway, the machine had one problem when set for a finishing cut. There was a few thou wear in the main (ram) slide. In use, this was taken up by a film of oil, which meant that the last (finishing) cut had to be continuous, and the machine had to be left to run across any workpiece until the cut was complete. If, for any reason, the machine stopped mid-traverse and was left for a period of time, the next stroke would be deeper by the amount of oil missing from under the slide. The usual practice was to leave the finishing cut either until after lunch or to take a late lunch break.

If you look at the basic forces involving the ram, and depending upon the style of cutter already discussed previously, these forces would tend to cause the front to dip and the rear to lift. Could this relate to your problem?

In closing, I’m reminded of one unfortunate chap who was using this same shaper to put a 15 deg bevel across the edges of a steel blank. Rather than tilt the work-piece, he chose to set the top slide over by 75 deg and then hand feed across and down the slope.

Hello Jack,

For what it’s worth, if you are keen to determine the `nature’ of a plastics (polymer) material, I know from experience that raw material manufacturers normally have standard testing laboratory facilities, and routinely test their product for quality. Identification tests can also be carried out in their more extensive laboratories to determine more closely, the type, grade and therefore application suitability.

However, finding a raw material company who will carry out basic tests and at what cost could be the stumbling block.

Another possibility is to locate a technical college who teach polymer science, and who are equipped with polymer identification facilities.

Generally speaking, homopolymers will be hard and brittle while copolymers are softer but tougher.

With regular questions from new arrivals (like me) in ME about various issues, like what to buy and, at the risk of prolonging the anguish from established members, I offer the following comments :-

Some years ago, when I was self-employed and earning what I considered to be an acceptable living, I wanted to progress from setting up my ML7 for jobs other than those to be turned, eg. milling and dividing. I should add that every part of my skeleton clock and many other items which required machining in some way, advanced by way of the Myford. So I bought a mill/drill apparently built to an Eastern philosophy.

Yes, it was cheap, and I should have expected cheap results, but I didn’t. There were lots of things on this machine which I should have recognised as cheap. But I didn’t. It was full of surprises at no extra cost. Well, not at first. But what makes something cheap? Who are the value analysts who generate cheap?

As an occasional expert witness in the plastics industry, I have seen some appallingly cheap products coming out of the Far East. You know, the ones that fail and cause serious injury in the process.

About the mill/drill - how about being in the process of drilling a hole when suddenly the grub-screw gripping the cross shaft with about two and a half turns of thread, lets go? Surely, fixing-screws in any machine should be long enough that the threads don’t strip? That’s real penny pinching.

And what about sand in the castings, such that parts which actually turn inside them, make grating and crunching noises.

I patiently accepted my mistakes, and decided to buy a milling cutter head and several collets similar to the Clarkson’s I’d used in the toolroom years ago. The parts of this Asian variety looked nice and shiny in their cardboard box, but when I came to use them, not one of the collets ran true. Eccentricities measuring up to 0.12mm TIR were revealed. When I took them back, I was offered a small box of collets from which to choose `good' ones. As opposed to taking them home, measuring the collet’s wall thickness with a graduated calliper was my only convenient and comparative means of determining concentricity. There were none to be had with an acceptable accuracy. Why would I want to mill an item when only one side of the milling cutter was actually doing any cutting?

But I’ve left the best of this saga till last.

On this particular mill/drill, the two lead-screws had a 3mm pitch. OK so far. Also, the hand-wheel scales could not be zeroed. Still OK.

Then I discovered that the hand-wheel scales where calibrated with twenty main graduations, ie. the wheel was stamped from nought through to nineteen. That would be OK for say a 1mm movement, and perhaps I could get used to 1mm equalling 6.6r graduations. But without a zeroing facility, and this obtuse calibration, imagine the albeit brief mental arithmetic if (say) 1.7mm needed to be removed from a cherished work-piece.

Was the manufacturer’s approach intended to cut costs even more, or was it just plain stupidity? Fortunately, and although they would be the same in any language, the hand-wheel graduations were in English numerals, and machined off a treat, to be replaced with something that made sense.

I've just remembered one other concern I’ve had with drilling through-holes in (especially) thin brass etc, and which certainly reflects upon what has been said by the good gentlemen above.