Myford S7 long bed

[swood1Participant @swood1]

[swood1Participant @swood1]

Hi all,

I currently have a Myford S7 without power cross feed or screw cutting gearbox. However I have the opportunity to upgrade to a Myford S7 Long bed with power cross feed for the price I believe I should get for my current S7.

Firstly, how much bigger is the long bed and more importantly how much heavier? I got my original S7 with cabinet in the back of a Honda Civic hatchback (with a little care). I now have access to an estate car so hopefully the S7 long bed would fit in the back with cabinet. But, what does the general community think of the S7 Long bed? I dont hear it mentioned much, is it an upgrade?

Regards

Steve

[BazParticipant @baz89810]

Wouldn’t really call it an upgrade, depends on the work you do, do you do a lot of long stuff and run out of room on the standard length machine? You say that you will gain a power cross feed, do you do a lot of facing of large diameters, if so it may be worth having but personally I hardly ever use power cross feed, it it is usually quicker to do it manually. You don’t say if the long bed has a screwcutting gearbox, if it does it makes it a more attractive machine, but don’t forget that the longbed machine will be about one foot longer than the standard machine, do you have the space for it?

[swood1Participant @swood1]

Hi Baz,

To be honest you are spot on with your questions. I only occasionally do long turning. The machine doesnt come with screw cutting gearbox but it is a very good price. But just been reading about the machine on Tony's website, you are correct I didnt realise it was so much longer.

Steve

[Nick HulmeParticipant @nickhulme30114]

Anyone who hasn't owned and used a Long Bed might think it's just a longer version of the same thing but they'd be dead wrong, the Long Bed is a much deeper and far more rigid casting, I don't have any of the rigidity issues which are generally talked about in conjunction with Myford 7 series lathes, parting 30mm stainless is a breeze.

[JohnFParticipant @johnf59703]

Plus one for Nick's point regarding rigidity, but also consider the power cross feed machine will be newer than your machine, however that does of course not necessarily mean it is in better condition and with less wear ???? Much to consider as well as the additional length.

My S7 is a long bed [hardened] with power cross feed purchased new 1977/8? I chose the long bed for particular reasons.

John

Edited By JohnF on 02/02/2020 17:31:42

[Martin of WickParticipant @martinofwick]

Personally I have never had any issues parting off on ML7 or S7 (that were not directly attributable to poor setup or not paying attention).

I now use a S7 standard bed and hardly ever use the power cross feed, I think the only major job I did use it for was to skim the faceplate once. If I was buying again, I wouldn't bother with the power cross feed.

[swood1Participant @swood1]

It would be a tight squeeze in my workshop to be honest, but it just about fit. The serial number would mean it was built in the early 1980's. My current S7 is dated around 1969, mine is in very good condition but I should really go and see this other lathe I think. The seller wants £1,200, do you think that would be a good deal on a good condition S7 from the 1980's?

Regards

Steven

[John HaineParticipant @johnhaine32865]

PXF is extremely useful. For one thing it makes parting off much less traumatic.

[SteviegtrParticipant @steviegtr]

I paid £2100 for my 1977. S7. It has the QC gearbox , power crossfeed, wide carriage. Good condition. But i did take it to bits & rebuild it with new belts & 3ph motor mod. I looked at maybe 30 before purchase & there was always something I did not like about the ones I viewed. Very happy with my purchase. Good luck. Sounds like a good price if all is good with it. Also I travelled nearly 500 mile round trip to pick up.

Steve.

[HopperParticipant @hopper]

The long bed can be handy in that you can park the tailstock further out of the way when not in use.

But to pick the best of the two really depends on the amount of bed wear, which is best measured accurately with micrometers, feelers and a straight edge. You will need a 0-1", a 1-2" and a 4-5" mike to do the whole job.

Main wear will be on the guiding vertical surface about six inches from the left end of the bed ways. Will be the rear vertical surface of the rear shear on wide guide models post 1972 and the rear vertical surface of the front way on earlier narrow guide models. Myford's max allowance there before regrinding is recommended is three thou.

Also the vertical thickness of the ways is critical too, also in the same high wear area . Allowance there is five thou. Measure from the top flat surface of the way to the bottom surface where the carriage catch plate runs.

Also look for wear in the gap between the inner vertical surfaces of the two ways. This is where the tailstock body guide runs and wear there can be surprising.

I would not trade a less-worn standard bed for a more-worn long bed.

[Nigel McBurney 1Participant @nigelmcburney1]

I would go for a long bed and not be bothered with a power x feed, long beds allow the taistock to be moved well out the way , and with the small spindle bore long shafts can only be held in chuck and steady,chuck and centre or between centres, back in around 1973 I had the finance to upgrade from a ml7 to a s7, my local myford agent quoted a delivery of 12 months if i was lucky, calling around i found that Buck and Ryan had 3 off super 7 lathes,if i wanted the gear box they would have to supply a separate gearbox for me to fit. they could not quote for a long bed,delivery unknown, thats how it was then ,my wife had to wait 8 months to get a new Morris traveller and then in an alternative colour. Since those days I kept the S7 and had a number of Colchesters the worst a standard bed student the best which I still use is a long bed master. I would go for a longer bed on any lathe ,particularly if you use the fixed steady a lot as fixed steadys require a lot of room., By having two lathes for over 30 years my s7 is in good condition and not worn but gets used for smaller work. I did make a cross slide screw for one of the colchesters on the S7and it proved how go accurate the myford leadscrew is,and it saved me over £500 , the price Colchesters quoted for a new feedscrew, Small lathes do not need power cross feeds,its a fad rather than an essential,learn to twiddell the feed handle at a constant rate.

[swood1Participant @swood1]

Hi all,

Thanks everyone for your feedback on this. I shall try to arrange to view the lathe and measure said wear areas. I should also use some common sense and measure my current S7 bed for wear too

I need to also check my workshop for space. Hard sometimes to know if you can fit a machine in until you have it in front of you, in the workshop.

Steve

[egaParticipant @ega]

Posted by Nigel McBurney 1 on 03/02/2020 09:31:48:

… Small lathes do not need power cross feeds,its a fad rather than an essential,learn to twiddell the feed handle at a constant rate.

I tend to agree with this but isn't one of the advantages of hand feed that the rate can be varied eg as in facing to centre?

[Nick HulmeParticipant @nickhulme30114]

Posted by ega on 03/02/2020 12:19:54:

Posted by Nigel McBurney 1 on 03/02/2020 09:31:48:

… Small lathes do not need power cross feeds,its a fad rather than an essential,learn to twiddell the feed handle at a constant rate.

I tend to agree with this but isn't one of the advantages of hand feed that the rate can be varied eg as in facing to centre?

Better still is a VFD to increase the rpm as the cut radius decreases, with a little ingenuity an easily built linkage can be produced to actuate a speed varying potentiometer.

[egaParticipant @ega]

Posted by Nick Hulme on 03/02/2020 14:20:16:

Posted by ega on 03/02/2020 12:19:54:

Posted by Nigel McBurney 1 on 03/02/2020 09:31:48:

… Small lathes do not need power cross feeds,its a fad rather than an essential,learn to twiddell the feed handle at a constant rate.

I tend to agree with this but isn't one of the advantages of hand feed that the rate can be varied eg as in facing to centre?

Better still is a VFD to increase the rpm as the cut radius decreases, with a little ingenuity an easily built linkage can be produced to actuate a speed varying potentiometer.

I believe there have been specialist lathes that perform this trick. I do it manually with one hand on the cross slide handle and the other on the pot – rather like the cook and the drummer!

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