Member postings for Mike Donnerstag

Thanks chaps - I knew I could rely on you all to help me out!

There is an assembly with springs at the back of the spindle, inside the motor. This definitely moves when the motor starts up, so I assume this is the centrifugal switch. Do you think I would still be able to reverse the motor?

Mike

The motor images are below:

I assume a VFD with a new 3-phase motor would be around £400?? Also, do the VFDs all create that horrible high-pitched whine?

Mike

I’ve just added a couple of photos of the motor connections to my album, though I can’t work out how to add the photos to this message (I’m writing this on a very small-screen iPhone!)

Motor plate shows the following:

Ref. BPA56P42900 B56 Fr.

0.55KW 0.75HP 1425RPM

240V 1Ph 50Hz

5.6A Class B CONT Rtg.

No. ZBM02641 Amb. 40degC

Start Capacitor 120uF 275V

Run Capacitor (no details)

IND. MOTOR BS5000 Pt.11 CE

Apologies for the large font!

I only intend to use the reversing facility for returning the carriage to the start of a screw thread.

What connection terminals should I expect on the motor if was reversible?

Mike

i have a Myford Super 7 without its original motor or Dewhurst reversing switch. Instead, the motor is a single phase 3/4HP one made by AER Ltd. Ashford, wired through a simple no volt release (NVR) switch.

Having tried to contact AER Ltd., I have had no replies and they are not answering their telephone. I was wondering whether anyone has dealt with the company and whether anyone is familiar with these motors. I am hoping, however, that they are fairly standard. The connection terminals are as follows:

AZ - wired to the live wire from the NVR switch

A - wired to the neutral wire from the NVR switch

Apart from the earth, the other two motor terminals are labelled K and Z, but are not connected to any wires coming into the motor.

Can anyone tell me whether it is possible to wire the motor to a reversing switch like a Dewhurst, and if so, how I would connect this up?

Many thanks,

Mike

Zan: I completely agree, though this assumes one can get hold of a 34T changewheel, as I don't have the facilities for making one myself, at least not yet. I sent a message with the specification to HPC yesterday. Let's see what they can come up with.

Mike

Fantastic - I'll give it a go.

Many thanks chaps!

Hi Ian,

Is Adam related to John? How can I contact him?

Many thanks,

Mike

That's great Thor - I'll buy a 33T from RDG.

Does anyone know where I can get the 34T?

Mike

I’ve just read the article in MEW August 2018 on metric overlays for the Myford gearbox. This uses 33 and 34 tooth gears to replace the existing gear, to enable most of the common metric thread pitches.

Can anyone tell me how this compares with using the metric conversion set, as it certainly seems simpler and cheaper.

Can anyone tell me where I can source the 33t and 34t gears?

Many thanks, Mike

Thanks everyone for some very useful replies. I ended up removing the saddle, though with the power cross-feed apron it wasn't quite as easy as Chris Trice suggested, as I had to remove the rear saddle strip to tilt the assembly enough to clear the apron gearing.

Removing the saddle gave me a chance to clean it throughly, free off a seized eccentric for the carriage lock and drill out the broken screw. I ended using a screw extractor held in the pillar drill chuck, rotated by hand, which worked perfectly. I thought two screws had sheared off, but it turned out that one hole was just full of dirt, not a broken screw.

As for the felt wiper and housing, I decided that, since it plays a key part in 'bed preservation', I'd bite the bullet and order ones from Myford.

Once again, many thanks for all your help.

Mike

I recently purchased a Myford Super 7 with gearbox and power cross-feed, made in the early eighties. The lathe was missing the felt wiper and housing, normally attached to the carriage. I noticed that two of the four screws that would have secured it had sheared off and will need to be drilled out or new holes tapped. Can anyone advise me on how to remove the carriage? Is it possible to remove the carriage without removing the apron and lead screw?

Many thanks,

Mike

Brilliant! No more deafening squeal from the clutch. I was scared to use oil in the wrong place if there is friction material.

Many thanks chaps,

Mike

I'm in the process of cleaning and lubricating a Myford Super 7 made in the early 1980s. The manual states the cone clutch should be lubricated as follows: "With the clutch disengaged apply two or three drops of oil weekly". However, it isn't obvious to me how to do this. Can anyone enlighten me?

Many thanks,

Mike

In a previous post on this thread there was a question of interest to me that wasn’t subsequently answered. I quote:

I have been offered a Myford Super 7 with a 'big bore conversion', from a chap who modifies Super 7s to give a 32mm spindle bore. Also, instead of a morse taper, the new spindle has an ER40 collet taper.

I have several concerns which I invite your comments on:

1) The headstock has some modifications to accept the new spindle, including a change from the original plain bronze bearing to tapered roller bearings. The Amateur Lathe book suggests that roller/ball bearings generally lead to chatter at the tool. What do people think?

2) Do you think the boring of the spindle may leave it with walls that are too thin?

3) Are there any significant disadvantages to having a spindle without a morse taper?

4) Do you think that having a non-standard spindle leaves me open to spindle problems, since a replacement would not be able to be sourced and would need to be re-made, probably at a high cost?

Many thanks,

Mike

Great advice, Hopper - many thanks!

Neil, where did you find the photograph of the nylon square ER collet? It's exactly what I was thinking of. The closest thing I found on the net was the tapping collets, but they are designed to hold a square and round shaft of course, with the square part being deep inside the collet.

Mike