Myford super 7 Positioning servo’s on Spindle and main infeed

[Andrew Davies 4Participant @andrewdavies4]

Happy to go over the grind corners with a stone.

Edited By Andrew Davies 4 on 03/10/2018 16:06:43

Edited By Andrew Davies 4 on 03/10/2018 16:07:59

[blowlampParticipant @blowlamp]

Posted by Andrew Davies 4 on 03/10/2018 15:53:45:

Hi

Yes they did the feet first and the undersides (picks on request) , the only faces they did not do where the inner vertical and the inner underside. I do not think this will be a problem.

Can I ask what you think the problem is so I can look into it further? I have clocked all edges and they are fine.

It is easy to be negative from a distance, but constructive input would be better, crappy does not help.

Andrew

Edited By Andrew Davies 4 on 03/10/2018 16:01:49

Edited By Andrew Davies 4 on 03/10/2018 16:06:21

Edited By Andrew Davies 4 on 03/10/2018 16:07:32

Time is important to me, so the fewer the words the better. Crappy is how it looks in the pic and you didn't grind it so please don't take offence.

It looks like it was ground with a blunt wheel or there is a duff bearing on the wheelhead of the grinding machine or something.

The inner/front vertical shear (usually) guides the saddle and so needs to be in good order to work properly.

The guiding surfaces of the saddle are also usually remachined and then scraped to match the newly reground bed. Was this also done?

[Nick Taylor 2Participant @nicktaylor2]

I think the corners will require a LOT of stone work to get a good enough chamfer. The inner shears not being done mean you'll have to do a wide guide conversion if not already, saddle will need a bit of work on all surfaces.

Tailstock allignment will need work as well.

[Andrew Davies 4Participant @andrewdavies4]

Hi

Had a little time to think about this. I now understand the need for a chamfer.

With regard to the saddle, I was going to blue it up and use the bed to show high spots and scrape. Looking at the saddle, you are correct; it does use the inner front edge, this I will need to sort. As this is the only face without adjustment, this must be the datum. Does the back outer face do anything?

Are the two bottom plates ground to the correct size or is tighten the bolts that hold them all that is needed

As the bed is now narrower than before, will the adjustment screws not take care of this?

I think the solution is to get the bed back on the grinder to sort out the chamfer and inner edges.

This electrical engineer is learning a lot quickly! This was always going to be a learning process, I am sure I will have to rectify a few more mistakes before I am finished.

Many thanks for all your input

[Nick Taylor 2Participant @nicktaylor2]

If the lathe is a narrow guide machine, then you are correct – the smaller face is the datum and the rear face does nothing. However, I would do a ‘wide guide conversion’. This means that the smaller inner shear does not contact the bed at all and instead the saddle runs on the much larger rear shear as the datum and front gib for adjustment.

The two saddle strips will probably require work (I refinished mine on my shaper) but if you have access to a grinder it would be nice to do. They amount of saddle lift allowed by these plates is controlled by shims which are fitted between the plates and saddle casting.

I would also get the bearing surfaces of the saddle ground – but make sure they set the saddle up correctly in relation to the cross-slide dovetails. Having the inner shears ground is necessary if you intend to use your tailstock!

As for the bed being narrower because of the regrind – yes, the gib adjustment should allow for this, if they haven’t removed too much. Did the grinders not tell you how much they removed? What you’re probably going to struggle with as well is half nut/ lead screw alignment as the saddle will be sitting lower than before. The other option is to have the saddle ground and then have turcite fitted to bring the saddle back to its original location – to do this the grinders need to remove a specific amount depending on the grade of turcite you intend to fit (it is available in different thicknesses).

As for the bearings – if the front bearing has not been starved of oil the chances are that it will be perfectly serviceable. Replacing the rear bearings is a very easy thing to do, whilst you have the machine apart I would replace the front bearing wick and clean out the oilways in the head as well. You could of course re-scrape the front bearing if you wish.

Plenty to think about! Just be methodical!

[Andrew Davies 4Participant @andrewdavies4]

OK

I have spent time this morning looking and thinking about the feedback.

I am going to finish the corners that are a problem (not all of them are as they are not used.) with a dremel, not the perfect aesthetics but will be OK, I will take my time.

I have put the saddle on the bed, I think I can compensate for the grinding with shim. I have tried the saddle on the bed and running smooth without movement using bits of shim as a test.

I am going to clock it up when I have purchased a selection of shim strips.

What sort of tolerance should I be looking for; bearing in mind this is a hobby lathe?

All the best

Andrew

[Robert Atkinson 2Participant @robertatkinson2]

Posted by Muzzer on 27/09/2018 12:33:58:

Posted by blowlamp on 25/09/2018 13:13:59:

Buy a kit from cncyourmyford.com

Martin.

Wow. £3300 plus painting and a lot of fitting. Pigs and lipstick come to mind. For that cost plus the cost of a Myford you could probably pick up a proper CNC machine and spend your time bringing it back to life, with some likelihood of ending up with a decent machine.

Murray

Plus stepper controller / drive x 2, power supply, case connectors and wiring. I'd have thought the bit's that are selling are the "easy" bits for the average model engineer, and the electrical bit's being more of a challenge.

Robert.

[MuzzerParticipant @muzzer]

Yes, good point. the electronics and controller software don't come cheap, nor do they wire themselves up magically.

No idea how many (if any) they have sold but if course, if you don't ask you don't get….

Murrat

[Andrew Davies 4Participant @andrewdavies4]

Thank you Nick, your input is great. I will look at a wide guide conversion.

With regard to the electrics, this I know a lot about and can do no problem.

I retired through ill health earlier in the year at 56. I get my driving license back in Feb 2019, this is filling my time and is great fun. Start working part time next year.

Andrew

[Andrew Davies 4Participant @andrewdavies4]

Hi Nick

Just looked at the wide guide conversion, this make total sense and very easy to do. I will do this.

Many thanks

Andrew

[Andrew Davies 4Participant @andrewdavies4]

A question

How do I stop the new shim on the rear vertical slide moving on the conversion. I have seen a person using super glue. is this a real solution?

Would I use carbon steel or brass shim?

Andrew

[Nick Taylor 2Participant @nicktaylor2]

Hi Andrew, I would use epoxy and some gauge plate (pre-ground) I think Radford (original inventor of the idea) called for 3/32" thickness (just under 2.5mm) but don't recall exactly.

Not sure if Radford's write up is available anyway.

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Nick Taylor 2 on 05/10/2018 09:12:32:

Not sure if Radford's write up is available anyway.

.

It's in his book:

**LINK**

https://www.model-engineer.co.uk/forums/postings.asp?th=130088

MichaelG.

[Andrew Davies 4Participant @andrewdavies4]

Servo motor mounted for ball screw, and bearing mounts and nut mounts fitted. Fitted shim and now using the two out sides of the bed. Designed main spindle motor mount and worked out the two pulley ratios required and identified components and keyless couplings.

[Andrew Davies 4Participant @andrewdavies4]

Added more photos to my album.

Myford super 7 upgrade

[Andrew Davies 4Participant @andrewdavies4]

Hi

Come on a long way since last post.

Added photos to Album.

Ball screw fitted, controls nearly sorted and spindle motor mounted.

Happy Christamas to all

Andrew

[Michael GilliganParticipant @michaelgilligan61133]

That's looking good, Andrew

MichaelG.

[HopperParticipant @hopper]

Posted by Andrew Davies 4 on 04/10/2018 21:49:13:

A question

How do I stop the new shim on the rear vertical slide moving on the conversion. I have seen a person using super glue. is this a real solution?

Would I use carbon steel or brass shim?

Andrew

I used ground steel gauge plate 1/16" thick on mine. Available in half-inch wide strips, just right. Thickness needs to be more than the existing gap you can measure there (at both ends) so it moves the saddle back off the front shear. This means apron/halfnut /leadscrew alignment will need to be adjusted to suit. I secured the gauge plate strip by two dowel pins about 3/16" diameter, holes drilled and reamed through the saddle and strip while all clamped together. Strip was then retained with Loctite for good measure, and easy assembly. I would not trust adhesive alone to hold on for the next 50 years, hence the dowels as well. Dowels were just bits of common silver steel rod.

Once you have done the wide guide conversion, you can remachine the inner vertical surface of the front shear so it guides the tailstock truly without loose and tight spots. This operation can be done by running the saddle back and forth by hand, using the wide guide conversion to keep it running true. A vertical slide can be attached to the cross slide and long piece of half-inch square HSS ground like a shaper toolbit (or a lathe toolbit turned sideways in effect) can protrude downwards and remachine the shear surface like a planer as it goes back and forth. Depth of cut is determined by the cross slide, feed by the vertical slide.

If you wanted to get really particular, you could finish off with a Dremel or similar grinder in place of the HSS toolbit. However, I found the hand-planing method gave a very nice finish on the cast iron with a light cut, quite good enough for the job of guiding the tailstock. Knock the sharp edges off with a 10" single cut mill file etc.

Neil has a couple of articles on file for both these operations, so they may appear in MEW at some point.

[Andrew Davies 4Participant @andrewdavies4]

[Andrew Davies 4Participant @andrewdavies4]

Really pleased with the the resprayed cabinet.

[Andrew Davies 4Participant @andrewdavies4]

[Andrew Davies 4Participant @andrewdavies4]

Looking more like a real one

[Niels AbildgaardParticipant @nielsabildgaard33719]

I am following because I have dreamt of eletronis screwcutting and cone making for Years.

I had a Myford 7 with a friend more than fifty years ago

He is still using it at home

https://www.youtube.com/watch?v=3j00T-fhvvc.

My granite based Boxford got a new home in his summer cottage and he says it is a better lathe than the Myford.

Sounds better,nicer surface etc.

A canadian followed my advice and put his Myford on a big block of concrete.Very systematic guy so he made a cut before movement and one after; same piece of material same tool etc.Nigth and day finish.

If it is not to much bother can You please put the cabinet bottom up and photograph the underside of the lathe mount plate and surroundings?

.My friend and I and associated women are not so young anymore and his Myford is kind of caged in.

If I have a picture of Yours I think I can persuade him to liberate cabinet,fill the top from inside with crushed stone -epoxy mix and then his Myford will turn better than my former Boxford.Very important this.

 

 

Edited By Niels Abildgaard on 20/12/2018 18:07:27

[Andrew Davies 4Participant @andrewdavies4]

Hi

It will be very difficult to turn upside down.

When I was cleaning the base up, I realised the top slides vertically off, hence the small bolts in each corner. There are heavy plates under the plate steel top for stability.

In my opinion you have to know when to stop, after all this is a Myford 7 and always will be.

I have taked many photos whilst carrying out the renervation, a lot of these are in my album, I have many more if you have a particular area of interest. Unfortunately I do not have a photo with the top plate removed.

I still think I have about 200 hours to completely finish the project and complete all the software.

Andrew

[Niels AbildgaardParticipant @nielsabildgaard33719]

Hello Andrew

Thank You for explanation.

I thougth it was a standard thin-plate top cabinet that can surely be made more rigid.

There is someone not so far from here who has an old Myford and I will go with my phone and make a picture from floor level and up against the standard top plate.

Good luck and we are, I think,many who want to read about it.

Edited By Niels Abildgaard on 20/12/2018 22:09:56

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