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Member postings for Mike Donnerstag

Here is a list of all the postings Mike Donnerstag has made in our forums. Click on a thread name to jump to the thread.

Thread: Myford Super 7 Bed Wear
28/03/2019 13:21:12

That was my guess too, Russ. Perhaps even a grinding fixture for grinding tool bits? It looks almost as if sparks have eaten away the metal over time. Is that possible?

27/03/2019 20:55:23

Many thanks to you all for your help. The lathe was bought at a relatively low price for a powered cross slide model with a gearbox and being my first metal lathe (I've done plenty of woodturning) it was a risk I took to get me started in metal turning and lathe milling. I'll adjust the shimming of the saddle over the next few days as I assume this may help with milling..

27/03/2019 15:48:59

I have uploaded two photos of my Super 7 bed, which show some rather nasty wear near to the headstock. My question is, does anyone know what this might have been caused by?

I had seen several Super 7's before buying this lathe, and they had significant wear. I have nipped up the saddle gibs with the saddle near the headstock and the carriage only starts to tighten when moved to within 4" of the end of the bed, and even then it is still movable. Would you consider this average wear?

The saddle has no movement when I try to lift it at the rear, so the shims seem to be doing their job. However, there is movement when I lift the saddle at the front, even at the very end of the bed. Is this normal? Do you think I should fit additional shims to remove this movement?

Once again, many thanks in advance,

Mike

Thread: Myford S7 Power Cross Feed Apron Adjustments
27/03/2019 15:31:08

I have a Super 7 with power cross feed saddle. When I received the lathe, the half nut lever was stiff. I slackened the gib screws to ensure the gib moves freely, though the half nut lever only eases off when I loosen the two large screws at the front (LA8 in the manual). Can anyone tell me whether these should be tight and whether I am perhaps tightening things in the wrong order? I have had the saddle off in the past and everything is clean and oiled.

I also wondered what the socket grub screw in the side does (LA58) and whether this should be tight.

The only adjustment given in the manual is for the 2BA cap screw (LA6). I have to admit that I am similarly confused about how this is adjusted. The manual states, "...adjust the setting … until it is in contact with the under side of the upper half of the leadscrew nut". How do I determine this when it can't be seen?

Any information gratefully received.

Mike

Thread: Quick change tool holders for Myford lathe
18/02/2019 21:42:46

I have a Super 7 with a QCTP. As I only have three tool holders I would like to purchase more. The only mark on the tool holders or toolpost is a stamped W on the back of each tool holder. Does anyone know who makes these, or would any Dickson-style tool holder fit, such as those supplied by Myford or RDG?

Many thanks,

Mike

Thread: Fitting a Reversing Switch to a Motor on a Myford Lathe
02/02/2019 18:24:45
Well, I removed all of the wires from the terminals and measured the resistances between each combination. My findings are below:
 
The thick Red and Black wires measure 3.5ohm between them and open circuit to all other wires. I therefore assume these are connected to the run winding.
 
The two Red/Green (striped) wires measure 56ohms between them and open circuit to all other wires. I assume these are connected to the starter winding.
 
The Blue, Yellow and Purple wires measure 0ohms (closed circuit). I'd be very interested if anyone knows where these are wired to.
 
I started by swapping the two Red/Green striped wires over, though this made no difference to the direction of rotation, probably because this is an AC and not a DC motor.
 
I then swapped the Blue and Yellow wires over and, lo and behold, the motor ran in reverse! Hooray!!
I now need some kind of reversing switch, as the lathe didn't come with the original Dewhurst. What do you all think of this one on ebay?:
 
https://www.ebay.co.uk/itm/QS-60-Professional-Drum-Switch-30-A-Forward-Off-Reversing-Motor-Control-TR/132902544459?_trkparms=aid%3D111001%26algo%3DREC.SEED%26ao%3D1%26asc%3D20160908105057%26meid%3D326e5cf24eb04e54a893c05f41c389be%26pid%3D100675%26rk%3D3%26rkt%3D15%26mehot%3Dlo%26sd%3D123613762364%26itm%3D132902544459&_trksid=p2481888.c100675.m4236&_trkparms=pageci%3Ab13ae683-2713-11e9-9629-74dbd180536d%7Cparentrq%3Aaf59a4a31680ad4873ed38e6ffdd39b8%7Ciid%3A1
 
Also, I assume I would need an extra flex with two cores to run between the reversing switch and the motor. How have people done this?
 
Once again, many thanks,
Mike
01/02/2019 16:42:49

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

31/01/2019 20:37:23

The motor images are below:

Motor Connections 1Motor Connections 2

31/01/2019 20:09:25

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

31/01/2019 20:06:37

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!

31/01/2019 19:45:53

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

31/01/2019 19:30:29

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

Thread: Myford 33t and 34t gears for metric threads
29/01/2019 07:10:34

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

28/01/2019 09:41:48

Fantastic - I'll give it a go.

Many thanks chaps!

28/01/2019 09:23:25

Hi Ian,

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

Many thanks,

Mike

27/01/2019 10:44:30

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

Does anyone know where I can get the 34T?

Mike

27/01/2019 09:44:24

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

Thread: Myford felt wiper
12/01/2019 23:10:50

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

11/01/2019 08:59:45

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

Thread: Myford Super 7 cone clutch lubrication
10/01/2019 14:02:49

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

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