ML7 Topslide Angle Limitations

I'm a relatively new ML7 user, and this evening I realised for the first time that the top-slide clamping arrangement doesn't give you the full range of angles. It can't come within 30 degrees or so of being perpendicular to the lathe axis, as would be required for turning a blunt taper. This must mean that there are certain turned components which it is impossible to make on an ML7 - a truly shocking thought!

Or am I missing something?

Not impossible. Just takes a lot of faffing about making a sub-table out of flat plate to go between the cross slide and top slide. Can't say I've ever needed to do it though.

As with so much else, the answer lies in GHT's Workshop Manual.

Where?

That is why they changed it on the S7 so that it rotates through a full 360 degrees.

On the S7 it is secured by two screws, one on each side of the cross slide.

I may never need to do it myself, I just find it slightly annoying that if ever I did want to do it, I wouldn't be able to! I'm surprised I've never heard anyone mention this limitation before.

I can see how a sub-table would solve the problem, but it would also further raise the top slide which is already about 3mm too high to take full advantage of quick change tool posts.

But how far are you wanting to set it over? I know you can get it around to 30 degrees from square to the lathe axis because it's done regularly by some for screwcutting purposes. You have to take the two bolts out of the topslide clamping flange and move the T nuts to the other ends of the slots to allow a fresh range of movement. I can't remember there being any problem with doing that.

But I am one of those who usually leaves the topslide in the standard position for screwcutting and add a bit of topslide movement with each cut, so the tool moves forward about half the amount it moves inward, resulting in screwcutting on one edge of the tool same as if the topslide were angled.

For turning a five degree flat cone or such, which is pretty rare, you might have to make some clamping arangement to allow movement of the slide past the ends of the slots. T-bolt clamps as used on the mill or faceplate might suffice.

Probably not mentioned much because its not a common thing to need to do. Or maybe that's why JA Radford and others made their own alternativbe top slides.

After all ,  the ML7 was a budget hobby machine in its day so did not do everything. Ironically its predecessor the M-Type Drummond had a 360 degree top slide.

Edited By Hopper on 12/03/2021 08:35:36

I can't immediately say and it may be a case of mea culpa!

I posted from memory of an arrangement involving a pair of long tee nuts extending each side of the cross slide.

I'll keep looking.

Incidentally, in some ways the ML7 method seems sounder than the S7.

In ME volume 152, number 3720, Januari 1984 John Wilding in his article "Repairs to a shooting stick" gives a short description of the construction and shows a picture of his cross slide with a method of obtaining extra setover.

I cant remember having seen that but it sounds like something the old GHT would do. Extended T nuts anchored on the other end into the T slots would do the trick.

Hopper:

The best I have found thus far is in this thread and John Stevenson's post:

https://www.model-engineer.co.uk/forums/postings.asp?th=90683

I think my original suggestion may have been based on a confused memory of GHT's useful device for fine adjustment of the topslide angle shown on page 143 MEWM.

Ah yes. Excellent thread for the OP to peruse. I like JS's comments re "the flat earth society will have a baby because I drilled a hole in a Myford". LOL

I was thinking of Ian Bradley's book on the Myford 7 series where he suggests a plate between the topslide and cross slide that has bolts down into the T slots and two extra bolts either side of the cross slide so teh topslide can be turned at a full right-angle. It also raises the topslide so the handle will not hit the handle on the cross slide. But yes, tool must be clamped directly to the topslide by the old "shoe" type clamp, so no QC toolposts here.

But the thread shows an alternative with two pieces of steel clamped either side of the cross slide to achieve the same bolt location without raising the topslide. So plenty of ideas to play with.

Thanks for this. JW's solution again relies on using the tee slots but I am not sure I quite followed the detail of the text or the rather grainy photo which was the norm in those days.

He refers to an earlier description in ME; can anyone pinpoint this?

Ian Bradley does, however, point out that raising the top slide has the incidental advantage of reducing the potential of fouling between top slide and cross slide handles.

Thanks for pointing out that thread. There are some interesting ideas in it.

Thanks to everyone who has replied.

Funny how the same questions come up, I asked this 7 years ago and got some great replies that probably covered most of the solutions **LINK** here is a live link

Mike