The HobbyMat BFE 65 again

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 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)

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

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

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