Arc Euro Trade ML7 cross slide leadscrew modification

[SteamgeekParticipant @steamgeek]

Has anyone completed this modification **LINK** to convert the ML7 cross slide leadscrew to thrust bearings ?

Mine has a fair bit of backlash on the cross slide, which is to be expected for a lathe that was built before I was born, and I found this solution and wondered if anyone has actually completed the mod and what their thoughts are.

[SteamgeekParticipant @steamgeek]

[John CParticipant @johnc47954]

I was lucky enough to have my Super 7 modded by a certain Mr Stevenson while he was researching the same job for the Super 7. It has been in use for a few years now and is just as good as the day it was done. I would highly recommend the mod.

Rgds,

John

[DMBParticipant @dmb]

John Corden,
I am a bit confused as you said Mr S was researching for a Super 7 mod. Not so long ago, I enquired of Arc about a Super7 version and they said they dont do
one.

Edited By DMB on 08/10/2013 16:38:04

[egaParticipant @ega]

SteamGeek:

Isn't your backlash in the nut/leadscrew?

GHT wrote the book on improving Myford cross-slides.

[KWILParticipant @kwil]

Because of the way the adjustment is on the ML7, the wear on the front bracket is a problem, fitting needle bearings deals with that, but NOT the backlash in the nut.

I have fitted needle thrust bearings on my Super 7s both on the topslide and cross slide as well as the main leadscrew. Some slight modifications are needed to the bracket which I have fitted with bronze bearings as well. Makes for a smoothly operating arrangement.

[John CParticipant @johnc47954]

DMB,

Mine was a S7 power cross feed. There was some extra work required to clear the auto disengage stop. I don't know how much further John got with it. I don't know about the regular S7. Having said that, are the ML7 and non -PXF Super 7 cross slide screws the same? If so the could the ML7 mod be made to fit?  And having said THAT, I realise the ML7 and S7 cross slide brackets are not the same – different  depth of cut indicators for one thing. 

Rgds,

John

Edited to add last sentence after engaging brain!

Edited By John Corden on 08/10/2013 17:48:48

[BrianParticipant @brian]

I would recommend doing it. I did my Ml7 and think its the best mod one could do, I would also change the nut at the same time cheep as chips but makes a world of difference.

Brian

[KWILParticipant @kwil]

One of my modified S7s is a PXF.

[DMBParticipant @dmb]

My S7 is pre PXF and Arc told me that their mod-kit only suitable for ML7s, not “Supersonics” but I didnt know that Mr S was working on such a project.

[ThsParticipant @ths]

Having done it a few years ago, I can only agree with Brian. Well worthwhile, a great upgrade. Hugh.

[Clive HartlandParticipant @clivehartland94829]

I have carried this mod out on my ML10 and one trick is that as you have to machine the bracket is that you take the bracket off a Myford Vert slide and machine it. Then swop onto the lathe, the one on the lathe then goes onto the vertical slide.

Otherwise you have to buy a spare one or do it on another lathe. It does smooth out the movement of the spindle and reduces the backlash. I also fitted a new nut.

I would also like to do something about the right hand end of the leadscrew, it is difficult to eliminate backlash there. Also I would like to modify the leadscrew graduated collar to a slipping scale. Any ideas ?

Clive

Edited By Clive Hartland on 08/10/2013 22:28:12

[NJHParticipant @njh]

Hi Clive

When I had an ML10 I did this for the leadscrew dial. The aluminium disc was fixed to a bush which was a close running fit on the end of the leadscrew. A hole was tapped in the bush to take the screw ( made from a bit of phosphor bronze hexagon – that I happened to have by me!) and this nipped it to the LS when required. All a bit Heath-Robinson maybe but it served me well for 20+ years! The only problem was that of inscribing 125 divisions on the periphery of the disc to match the 1/8in. pitch of the screw. Despite access to a well equipped college workshop and knowledgeable tutors the best they could come up with was 124 divisions. In the event that proved quite satisfactory for all the time that I had the lathe!

Regards

Norman

Edited By NJH on 08/10/2013 23:05:53

[Douglas JohnstonParticipant @douglasjohnston98463]

One of the joys of this forum is the never ending gems of information that keep cropping up. I bought the cross slide mod from ARC about two years ago for my Speed 10 and never got round to fitting it, mainly due to the problem Clive pointed out. All the time the solution was just begging to be noticed in the form of my vertical slide. Thank you Clive, that's one problem solved, now just 1001 others to sort out and life will be perfect!

Doug

[Tony JeffreeParticipant @tonyjeffree56510]

Posted by Clive Hartland on 08/10/2013 22:25:09:

I have carried this mod out on my ML10 and one trick is that as you have to machine the bracket is that you take the bracket off a Myford Vert slide and machine it. Then swop onto the lathe, the one on the lathe then goes onto the vertical slide.

Otherwise you have to buy a spare one or do it on another lathe. It does smooth out the movement of the spindle and reduces the backlash. I also fitted a new nut.

I would also like to do something about the right hand end of the leadscrew, it is difficult to eliminate backlash there. Also I would like to modify the leadscrew graduated collar to a slipping scale. Any ideas ?

Clive

Edited By Clive Hartland on 08/10/2013 22:28:12

I would second your approach of modifying a spare bracket and then swapping it for the cross-slide bracket – its really the only practical approach. In my case, I replaced the bracket with one that I had fabricated, because it was also acting as a stepper mount for my CNC conversion, but the principle is the same. The improvement in the "feel" of the cross-slide movement is significant, and it eliminates all backlash except for play in the screw and nut.

Hemmingway do a kit for sorting out the RH leadscrew bracket – see:

**LINK**

I fitted this to my ML7, also as part of my CNC conversion, and it works a treat.

Regards,

Tony

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