Hoppers 4 way toolpost thread ??

[Ady1Participant @ady1]

Totally disappeared in the last 15 minutes. spooky.

[Ady1Participant @ady1]

[HopperParticipant @hopper]

Video unapproved by the authorities re advertising issues in the past apparently.

[JasonBModerator @jasonb]

The ghost hunters have been about.

I'm sure others will have got it popping up on their youtube feeds so maybe we can continue the discusion..

A lot will depend on how you work as to whether a 4-way or QCTP will work for you. he says to leave THE knife tool in the 4-way all the time, problem for me is I generally have two knife tools on the go one with ferrous inserts and another with non ferrous also being a bit tight I like to use all 4 corners of my inserts so also have two holders that use the obtuse corners so that has already filled a 4-way tool post for me.

He also says people don't have enough tool holders, I've built up a good number over the years so most tools are ready just to swap the holder into place that includes tools that mount across as well as along the lathe's axis. Once you start doing that with a 4-way it soon becomes a 2 or 3 way.

Not to worry he shows a special holder for boring bars so they don't get in the way of other tools but that adds extra overhang one thing he says the 4-way reduces.

Then there is the question of how many tool changes I could make to add up to the time spent making said special bar holders, modifying a DTI and making up a set of shims.

I was in the workshop for about 1.5hrs today and made three small parts for a carb and used 9 different tools, 7 were in their holders two had to be mounted in the non-dedicated one I keep for this and only one of those needed adjusting to ctr height done by eye. Luckily they were all non ferrous otherwise I might have needed a couple more tools which even if they had shims already sorted would all have taken longer to change over than they do with my QCTP.

[Clive FosterParticipant @clivefoster55965]

Always wondered how the whole QCTP thing got started. It's an inevitably expensive concept due to needing decent engineering and precise manufacture if it is to work well for a useful lifetime. Not to mention system lock in. Of necessity the tool must overhang the support so it's inherently less rigid than simple block sitting down onto the slide.

From a clean sheet of paper perspective it would seem much more economic to make simple slotted block tool posts held down to an indexing base by some form quick acting lock. Either 1/3rd (ish) turn like most QC systems or some sort of lift over latch. Indeed Holbrook at one time made a 4 way system with a horizontally pivoted spade grip handle that was pulled down to latch it onto the face ratchet indexer after turning. Half way to an easy remove system but Holbrook used the usual nut on a stud to hold things together.

Fixed block tool posts were widely used and most industrial English lathes had a well engineered indexing device under the factory four way posts so adding quick release set-up to the block doesn't seem much of a stretch. Given quick release capabilities tool height can be set by direct measurement on the bench so the most objectionable trial and error aspect of on machine shimming is avoided. A simple block with slot(s) must surely be much less costly to make than a QC toolholder.

Maybe 20 years ago I drew out a Model Engineer / Home Workshop friendly version of this concept using two way blocks built up from stock bar and plate sections glued and screwed together. The blocks were to be held down via a hollow castellated nut screwed into the top passing over a rotating tool post stud cross drilled to take a tommy bar sized to engage between the castellations. A partial turn of the tommy bar from tight would allow it to be withdrawn so the block could be lifted off and a different one fitted whereupon the tommy bar could be replaced and things locked with a partial turn.

Some years later Neil was kind enough to publish in the Letters section of MEW a layout sketch of the system as it would have been applied to the SouthBend Heavy 10 I was using at the time of design. Taking the opportunity to step up from the Heavy 10 to a Smart & Brown 1024 complete with a Dickson set up curtailed development. I was never really happy with the indexing on that specific concept but I know how to do it better now.

If you use insert tooling, with its fixed cutting tip height, purchasing a conventional QC system means you are paying lots of money for a versatile height adjustment capability that you will never use.

Clive

[Nick WheelerParticipant @nickwheeler]

Posted by Clive Foster on 17/06/2023 14:31:23:

If you use insert tooling, with its fixed cutting tip height, purchasing a conventional QC system means you are paying lots of money for a versatile height adjustment capability that you will never use.

Surely the height adjustable feature of QCTPs is a useful freebie from how the holders drop into place? If it was the most desirable part, wouldn't they have been call Height Adjustable Tool Posts?

I consider the QCTP to be the best value tool I've bought for machine tools.

[JasonBModerator @jasonb]

Yep, even though the majority of my holders are locked to the height for the tool that stays in them I still have the easy screw adjustment for the couple of holders kept for all the other cutters be they Insert, solid carbide or HSS

Oh and seeing the Lammas tool post mentioned today, I also have a couple of extended tool holders if needed for additional tailstock revolving ctr clearance where a 4-way either means excessive tool stick out if it is not to hit the ctr.

here are the tools used to make the 3 small parts mentioned above that are in the middle of the photo, two brass one stainless. Had I not saw the part off the stainless bar then a second parting tool could be added to the lineup

[Clive FosterParticipant @clivefoster55965]

Posted by Nick Wheeler on 17/06/2023 15:52:35:

Posted by Clive Foster on 17/06/2023 14:31:23:

If you use insert tooling, with its fixed cutting tip height, purchasing a conventional QC system means you are paying lots of money for a versatile height adjustment capability that you will never use.

Surely the height adjustable feature of QCTPs is a useful freebie from how the holders drop into place? If it was the most desirable part, wouldn't they have been call Height Adjustable Tool Posts?

I consider the QCTP to be the best value tool I've bought for machine tools.

Height adjustment is hardly a freebie.

It's what defines the conventional QC system. If (relatively) easy on-machine height adjustment wasn't considered essential folk would be just swopping blocks and paying shedloads less money for the system.

Bargain hunting means I probably only have £500 or so locked up in the two T2 Dickson / Rapide posts and 20 (ish) holders I have for my two machines. Useful but not, in my eyes, exceptional value. At full price unthinkable!

Clive

[Andrew TinsleyParticipant @andrewtinsley63637]

As we seem to be back to the QCT versus 4 Way Toolpost debate. Perhaps this should be thrown into the mix. I have an original Myford 4 way toolpost and an original Myford QCT set up. Using both, it is quite obvious that the 4 way toolpost is a lot more rigid than the QCT set up.

Andrew.

[IanTParticipant @iant]

Posted by Clive Foster on 17/06/2023 16:14:39:

Posted by Nick Wheeler on 17/06/2023 15:52:35:

It's what defines the conventional QC system. If (relatively) easy on-machine height adjustment wasn't considered essential folk would be just swopping blocks and paying shedloads less money for the system.

Not sure quite I understood this comment Clive.

The Rose blocks I use have the tool set to centre height 'off-machine' and for turning tools that is all that is required. You don't need to change it once set. Nor do you have to fiddle with packing when changing tool (blocks) and in fact I often touch the tool up still in the block. For 'brass' tools there is no top rake and for (small) 'steel' tools I don't use back rake either (just side and top) – so both tool types can be touched up just on the front edge without effecting height settings. This works for me (on the EW) and I don't think changing blocks is that much slower than using the QCTH – but (like many things) inexpensive Asian imports have very much changed what folk use these days – people were a little more inpecunious not so long ago…it does make a difference if you can't afford things – and sometimes old habits die hard!

Regards,

IanT

[derek hall 1Participant @derekhall1]

I have been using Dickson style toolpost and holders on my Myford S7 for years, ever since my apprenticeship and experience in industry. The thought of faffing with shims of varying thickness put me off that route very early on in my career.

However I am well aware that it is not the best toolpost design especially for the Myford, some of my holders never seem to hold the tool height once removed, but it is still quicker to reset the height than hunting around for shims.

Fast forward to now, I am considering changing this style of toolpost to the "piston" style as advertised by Arc Euro as this seems to be a much better rigid tooling system than the Dickson where there is a lot of unsupported overhang.

What do others think about this potential upgrade?, any experience good or bad?

All the best

Del

[Mike PooleParticipant @mikepoole82104]

The Dickson QCTP to my mind did not scale well to the Myford size, the large versions I have used have not had a rigidity problem but the one on my Myford which is a genuine Dickson is not a rock of Gibraltar. The ML7 topslide is not the most rigid either, paying attention to the topslide overhang helps but if heavy cuts are required then putting Myford top slides and QCTPs to one side and mounting a single tool Gibraltar tool post will maximise tool rigidity.

Mike

[Clive FosterParticipant @clivefoster55965]

IanT

I think we are at cross purposes.

I think I'm advocating exactly the same things as you.

Viz

If tool tip height in interchangeable blocks can be accurately and easily set off the machine the sole compelling advantage of the conventional QC systems is the screw adjustment system that makes it relatively easy to set tool tip height on the machine. There is no inherent reason why arranging quick change blocks should be any harder than changing tool holders on a conventional QC system. Whether by your rose blocks, my proposed rotating tool stud or any number of other mechanically satisfactory solutions.

Interchangeable blocks do require an indexing base whilst conventional QC posts can get along without indexing. But plenty of folk regularly shift Dickson and similar 2 or 3 station posts around to different angles without the aid of indexing and the Mulitfix goes to considerable extra engineering effort to include multiple angular settings. It was quite common for industrial users to graft a Dickson onto the indexing arrangement living under the factory 4 way of many makes.

I can't see the extra cost of an indexing base being a significant deterrent.

derek hall 1

The piston post is not inherently better than the Dickson system. Arguably its worse because forces are mostly resolved via the holding piston rather than directly.

In my experience the weak point of a Dickson is that it needs regular cleaning out inside. Mine are positive magnets for itty bitty teeny weeny swarf dust. But it's easy to pop the pistons out and clean. Height retention failures are primarily due to the snail on the locking hex self adjusting the height setting thimble. The lock bolt needs to be tight and the tool holders held in position whilst being locked. Leaving it up to the locking tongue to pull things into position is poor practice. The holder is almost invariably at an angle so the snail rubs against the thimble making upsets more likely. Hamfisted folk can also bend the stud. Which is less than helpful. A quick brush down of the mating surfaces to remove any swarf before fitting is sensible.

Clive

[HuubParticipant @huub]

I use a different style of QCTP for some years now on my lathes. It requires to adjust the tools to fit the tool post but that is a one time procedure. It is "cheap and easy to make" and it doesn't compromise the rigidity of the lathe. It allows for very repeatable (better than 0.02 mm (3S value, 99%) in turning diameter) repositioning of the tools.

I have uploaded an incomplete not edited video of the old design that will show how it works. The new design doesn't require rotating the top plate when changing from inner to outer turning. As soon as I have the time, I will upload a new video.

QCTP video

 

Edited By Huub on 17/06/2023 22:16:55

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