Rear tool post

[Chris MurphyParticipant @chrismurphy94983]

Hi,

can anyone suggest where to buy a good rear tool post for the Myford ml7.

I don’t have a milling machine or I would attempt to make one.

if you have purchased one for an ml7; can you tell me what its like and where you got it from.

thanks

chris m….

[Chris MurphyParticipant @chrismurphy94983]

[Dave WoottonParticipant @davewootton]

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

[Howard LewisParticipant @howardlewis46836]

When I had a ML7, I made my own from a piece of 2" box section, three pieces of plate and three 1/4 BSF capscrews

You could even make one out of a sold block of steel. The extra weight would add to rigidity

After that, parting off became so much less of a problem.

For my present lathe, I made a Four Way indexing Rear Toolpost (Pictures in my Albums) It also featured in an article in MEW, no too long ago.

It was made by laminating pieces of 1" thick steel together The base was laonger so that it could be clamped using two studs in a shop made long T nut. The upper layers were clamped together by three long capscrews, with the fourth position being used for a dowel for indexing.

Making from laminations, reduces the amount of milling that you have to do..With careful use of the 4 jaw chuck, possibly no milling needed at all, just marking out for drilling and tapping. You can even thinlamination, if you wish, by facing them in the 4 jaw, or on the Faceplate.

Howard

 

Edited By Howard Lewis on 24/08/2022 21:26:27

[Chris CrewParticipant @chriscrew66644]

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.

[Howard LewisParticipant @howardlewis46836]

If you follow Chris Crew's suggestion and drill through a sold lump of steel, or use my lamination method, fit a couple of dowels into the underside of the base to be a snug fit into the T slot, to locate the post accurately, and keep, it square to the axis of the lathe.

Howard

[Nigel Graham 2Participant @nigelgraham2]

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.

[JohnFParticipant @johnf59703]

Chris have a look at your messages John

[Howard LewisParticipant @howardlewis46836]

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

[bernard towersParticipant @bernardtowers37738]

sorry chris but the ght version is well worth the effort

[Marcus BowmanParticipant @marcusbowman28936]

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

Marcus

[Howard LewisParticipant @howardlewis46836]

For a beginner, making any tool can be a good learning experience, as well as producing something which will be of use in the future. Tap Wrenches, Tailstock Die and Tap holders, Drawbars, Mandrel Handle, Centre.Height Gauge, Extractors, of various sorts have all been made and put to use repeatedly.

So, a Rear Toolpost can fall into the same category, especially if the item is to incorporate some feature which makes it unique to that machine, or its mode of operation.

Without a mill, it is still possible to machine flat surfaces. Put the work in the 4 jaw chuck, or fix it to the Faceplate and face it.

When I made my Comparator, the cast iron base was faced with the surface just proud of the jaws of the 4 jaw chuck, before being set very much off centre to drill, bore and ream the hole for the column..

The arm (Box section ), was faced in the 4 jaw on the ends, and the cross ways to face the upper and lower side. In fact, purely for cosmetic reasons, the other two sides were skimmed to cleanup.

Once the internal sleeve had been secured it place, the assembly went back into the 4 jaw to be drilled, bored and reamed to fit over the column..

Howard

[peak4Participant @peak4]

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

[JasonBModerator @jasonb]

Posted by Chris Murphy on 24/08/2022 20:29:56:

I don’t have a milling machine or I would attempt to make one.

Neither did 1000s of Myford owners before you. Most if not all of these old published designs were made on the Myford or similar as 50yrs ago most hobby workshops did not have milling machines.

[Dave WoottonParticipant @davewootton]

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!Participant @swarfmostly]

I have a rear toolpost with a Dickson-style head for an Eclipse parting blade. The head originally came (via eBay) as part of the kit for a Myford 254. The label on the box reads '30/149 Rear Tool Post 254Plus V Plus'. I intended to make an ML7 size base for it but, before my 'planning' time had expired, eBay yielded a suitable base.

The 254 kit includes a central bolt with a Tee-slot head (foot???) and two Tee-slot bolts to secure the front extension in the next slot. The 254 bolt is obviously too long for the ML7 – I have yet to make satisfactory ML7-size central bolt.

Using the tool-post with such improvised bolts as I have tried has not been successful. The head tends to rotate about the central bolt. I have some plastic anti-slip mesh and I wonder whether interposing a square of that between the base and the head might prevent the rotation.

I also have a chunky cast rear tool-post that uses a 'boat' to permit adjustment of the tool height. I think it has a Myford part number but I don't have the literature to hand just now. I haven't found that one easy to use.

Now, a question or two about Tee-slots & bolts:

Am I right in thinking that one should arrange a substantial flat object to pull down on the Tee-slot flange to oppose the upward stress exerted by the head (foot???) of the Tee-bolt? I've always tried to do so.  In the case of the rear tool-post, the body of the tool-post performs this function.

The Tee-bolts and Tee-nuts sold by Beeston Myfords used to have circular heads with two flats to match the width of the slot. It's always seemed to me that such a design lacks contact with the cross-slide (in four places due to the circular shape) just where it's needed. I ought to add a diagram to show what I mean but I'm typing this post 'off the cuff'. (Maybe later! ) What do other folks think?

Best regards,

Swarf, Mostly!

Edited By Swarf, Mostly! on 25/08/2022 10:42:55

[Nigel Graham 2Participant @nigelgraham2]

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.)

[Howard LewisParticipant @howardlewis46836]

A parting tool holder that is too deep, can be placed in a four jaw chuck, and probably using carbide tooling , and faced to reduce the underside until, in a front tTolpost, the top of the tool is at centre height.

If making a Rear Toolpost, it can be made in such a way that, within reason, whatever tool holder is used, the cutting edge can be brought to centre height.

This is what I did when I made mine.

Howard

[Nick WheelerParticipant @nickwheeler]

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

[Swarf, Mostly!Participant @swarfmostly]

Nigel Graham 2,

Thank you for your reply.

Yes, the tool-post base does have a tenon that locates in the cross-slide slot. However, the Dickson-style head has no corresponding feature to hold it square.

Both the base and the head have over-size holes and there is a close-fitting (hardened? ) sleeve that fits half & half in each. So the head is located accurately on-axis with respect to the base but only in 'X & Y', not in θ.

I have pondered drilling for a dowel to give angular location but I have no idea how to drill up into the head and then down into the base with sufficient accuracy to establish squareness of the head wrt the base. Plainly, if not properly performed, things would be worse rather than better with no opportunity for a second attempt. I have seen some heads which seem to have a small offset vertical hole but mine does not. Such a hole would obviously serve to guide the drilling of a matching hole in the base after initially setting up square. Furthemore, my (Dickson! ) head is hardened so I've never tried drilling one. (Smiley intended that time! )

On the subject of Tee nuts, I note that Myford are now listing steel Tee-strip to suit their Tee-slots; drill and tap your own holes.

The bolt that came with the 254 kit has a ⅜" BSW thread. It seems the thing is to use a coarse thread (rather than BSF or UNF ) to avoid excessive tightening forces.

Regarding securing machine-vices to vertical slides: the securing feet of my Myford machine vices have as-cast upper surfaces.  I milled mine flat to give the fixing nuts & washers a good landing.

Best regards,

Swarf, Mostly!

Edited By Swarf, Mostly! on 25/08/2022 13:38:23

Edited By Swarf, Mostly! on 25/08/2022 13:43:07

Edited By Swarf, Mostly! on 25/08/2022 13:43:39

[Howard LewisParticipant @howardlewis46836]

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

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