Probably not what you are after but the Geo Thomas rear toolpost with an extended base casting are entirely machineable on the ML7 with a vertical slide, I think Reeves still sell the correct casting. Full instructions are in GHT's invaluable book, along with much else. I made one on just a ML7 years ago and found it excellent.

The small parting toolholders in the book are great little tools too.

Dave

With all respect to Dave Wooton's advice, because we all have differing opinions and experiences, personally I dislike the GHT rear tool post because I view it as being un-necessarily complex, not easy to make due to the accuracy required to get the inclined blades anywhere centre height with a sensible protrusion and I also think it is 'flimsy'. GHT was a great craftsman and deservedly commands a respectful following, myself included, so I cannot be too dismissive of his musings on the subject of parting-off which are well worth reading. I would suggest that you should look to the online auction site or contact one of the several Myford parts dealers. The 'new' Myford itself may be able to assist in supplying an OEM accessory but either way it will cost you. For someone in your position, because we all had to start somewhere and I was as impecunious as the next man in my younger days, I would be thinking of a noggin of 2" x 2" MS drilled through the centre for a tee-bolt with a simple slot milled in the side. You can mill the slot in the lathe itself with an end-mill held in the 3-jaw chuck if you don't have a collet. A piece of newspaper wrapped round the mill will help prevent it creeping out. Drill and tap for a couple of clamping screws to hold an inverted J&S type, Eclipse blade parting tool-holder in the slot. Make sure that the blade has a few degrees of rake ground into it and set it a fraction above centre-height. Use a moderate speed for the material you are parting and if it is steel get as much coolant/lubricant into the parting slot as you can (I nearly always pump it). Once the tool starts to cut be bold and keep it cutting. If it is a particularly deep parting cut you can quickly retract the blade and increase the speed as the diameter of the work-piece reduces. This goes towards prevent any 'graunching' as the diameter of the cut reduces to zero. Rigidity is the 'secret' of successful parting IMO, and that includes the holding of the work-piece, so part-off as close to the chuck as you can and remember a 4-jaw chuck grips better than a scroll 3-jaw. I know some people will disagree with a lot, if not all of this, but I can say that it works for me and I hope it will work for you.

I bought my ML7's Rear Tool-post but I forget from whom. It would have been one of our regular suppliers, probably Myford.

If you make one I would strongly advise not relying on a single bolt in one T-slots. That is too easily a recipe for a broken cross-slide.

The commercial one has that, but it also has a flange with two T-bolts engaging the next T-slot. The underside of the main body also has a tenon to align it in the T-slot.

The top part, holding the tool-holder itself, is a separate QCTP block allowing the tool to be aligned at right angles to the work, though it could be argued that this should not be needed if a single-piece tool-post with tenon is used, holding properly-machined parting-blade clamps. It may be to allow using a matching 2-sided QCTP block, but I have not experimented with that, nor ever found the need.

I align the tool by leaving the central stud slightly slack, gently easing the saddle along until the tool-holder itself is is contact right across the chuck, then tightening the stud while keeping that careful pressure on.

To bring to height my favoured trick (I have still not made that height-gauge) is to face the work-piece then use the centre-spot to set the other tools I will need, in their QC holders. It works for almost all, with the occasional slight tweak.

My rear toolpost is clamped to the T slot by two studs, through the front of the base which protrudes ahead of the toolpost proper. The dowels can be sited either outboard of the studs, or in between them.

In fact, my 4 way indexing post is aligned by two dowels against the rear face of the Cross Slide. I pull the base forward to hold the dowels against the Cross Slide, and tighten the retaining nuts.

My post was made for a 12 x 24 lathe, but one can be made, for any lathe with a slotted Cross Slide, just by altering the dimensions, as either a 4 way, 2 way, or even for a single tool,

If you want to make the toolpost from the sold, rather than from laminations, but don't have a mill, make up the basic tool post and clamp ,it to the Cross Slide.

The slots form the parting tool can be made by mounting an end mill, or even a boring head in the chuck or spindle, and traversing the Cross Slide past the cutter. It will cut a slot above and below the centre line, so that the parting tool holder can be shimmed to bring the cutting edge DOWN to the centre height.

Howard

http://www.hemingwaykits.com sell the castings and materials for a range of rear toolposts, including the GHT version.

Marcus

I use a solid cast iron one I bought second hand.
I suspect it's one of These From Warco, or at least very similar to it.

https://www.warco.co.uk/myford-lathe-tools/303254-myford-7-rear-tool-post.html

When I bought my lathe, it came with two Dickson style, far eastern impost toolposts, so I have also made a mounting/raising block, so I can use the spare one as a rear toolpost for non-parting jobs.

Bill

In defence of the GHT toolpost , it is designed for a relatively light lathe, and the ML7 version has three point fixing to the rear of the cross slide. I used mine for many years on an ML7 with great satisfaction. Not sure if I made one now if I would use two parting blades as the original design, I found most of the time the thicker of the two was used. I have made a slightly larger version for my 254+ from bar stock and used an Arc tipped parting tool, this does save the slightly awkward angled milling operation on the turret, there is only a slot to mill.

I've made many of GHT's tools over the years, and bearing in mind the fact they were designed for the smaller machines available at the time of their publication, they have all worked very well and earned their keep. These were written in the 1970's for the average model engineer. When most home workshops only contained a lathe of Myford size and milling machines were a rarity.

Dave

Swarf Mostly –

Is there no tenon on your tool-post to align it with the T-slot?

Mine does have that. It would be worth fitting one, or even using two dowels. Much better than plastic mesh, as that could compress and put your height setting out, or possibly even act as a bearing washer, anti-slip or not, and help the post slip round.

Yes – in holding anything by T-slots the table flanges must always be compressed evenly between the T-bolt heads / T-nuts and the attachment itself.

A T-nut stud or screw must never ground on the bottom of the slot., and this is often avoided by a staked thread in the nut.

I have a set of those Myford T-fasteners too, and no, I don't think them a very good design either, for the reason you give. They certainly need careful use. Designed more for production than function, methinks.

I made a vice for the vertical slide of my little EW lathe, and that uses a T-bar rather than single nuts under the fixed-jaw end, with screws in counterbores but again with care that they cannot bear on the floor of the slot. The vertical slide itself is nominally held to the slotted cross-slide by a single Tee-bolt (not good) so I made two L-shaped "bench hooks" from steel bar, each held by 2 T-bolts in the adjacent slots, to secure against rotation.

.

(Incidentally, digressing a little, I learnt from this forum that the common T-slot fastener sets sold by many of our suppliers have 3/8" UNC threads. With that information, I augmented the set by buying some shorter, matching bolts, plus nuts and washers, so I can secure things like vices through their slots – sometimes work-pieces through suitable holes existing in them – without galumphing great lumps of steel in everyone's way.)

Is it just me that thinks Chris is getting ahead of himself here?

He's struggled with a bought parting tool, so milling one of GHT's fussy tools in the lathe is likely to be several steps too far. Buying one is a significant cost that needs to be justifiable.

I think he would be better off buying some material suitable for the actual projects he has in mind – practicing on stainless steel is not helpful if most of the parts will be brass – and using the lathe to figure out what he actually needs to use it efficiently. I would put a QCTP at the top of my list, but that's twenty years after buying my first machine.

I've never found any need for a rear toolpost, although I would consider adding one to take another QCTP if doing production jobs. Similarly, I've never turned anything between centres but my powered toolpost spindle gets a lot of use for cross holes and fluting knobs.

My point is that everybody's work is different, and one man's can't and won't do without could end up rusty scrap in another toolbox. Beginners can spend a lot of money and time following well-meant advice.

Edited By Nicholas Wheeler 1 on 25/08/2022 12:40:42

Nicholas, You are not alone.

The rate at which Chris poses questions shows that he is at the bottom of a long and steep learning curve.

My advice to him would be to slow down, read and study, and consolidate what he has already been told, and learned by hard experience, before attempting other more complicated work. .

He is still getting to grips with the basics of using a lathe and is in danger of confusing things by trying to do too many things, too soon.

He needs our help and advice, and to act up on it., before launching into some other "improvement" to his equipment.

So keep the advice coming, but don't let him launch into screwcutting Left Hand threads, for some long time.

Howard