Q.C.T.P's

I have been thinking about buying a Q.C.T.P. for the last 3 years or so, but I wonder if I really need one. Basically I use about 10 cutting tools - a mixture of H.S.S., Indexables and a Tangential Tool holder. All these , except the Tangential, have shims glued to them for exact centre height. Changing tools takes me about 20 to 30 seconds maximum. I know many will say I am still living in the Dark Ages, but I will probably stay this way until I fall off my perch.

I must admit, I’m looking for a QCTP for my second lathe, it’s a nice to have item.

Because I have two different size lathes, I like to swap tooling between them, and then the rapid height adjustment is great.

If you’ve only got the one lathe, 2 or 3 well laid out 4-way tool posts is probably quicker than a QCTP!

Dark ages? Don’t the manufacturers still supply new lathes without QCTPs?

You will gain quite a lot with new tool post.

You will be less rich after the spend, including all the extra tool holders (unless you have facilities to make your own).

You will gain lots and lots of time - think of how many times you need to change tools (and, of course, it takes a finite time to change QC tool holders).

You will have more tool overhang, using a QCTP.

What tool post do you have currently? Perhaps a four way tool post might be a sufficient progress from the dark ages? Then you could have two (at least) tools available most times. Even two tool posts might be an option.

Also, it depends on how much you use your lathe - a measure of the seconds saved per annum, maybe!

Your current set up may be just as good as any alteration. Just your choice, of course.

I have a QCTP on my Warco 250MV & apart from using it for the boring bar & internal threading tool it stays in the cabinet. There is simply far too much flexing in the whole unit (& lathe) for it to be worthwhile & certainly operations like parting off have to be done using the 4 way tool holder. So no real advantage. Then there is the cost of all the tool holders to consider

Thank you for your quick replies. I do use two 4-way tool posts, and I think a third one would be an excellent idea. Thank you Same for you thoughts about tool flexing, something that crossed my mind when I was thinking about Q.C.T.P.'s.

Cheers from sunny Oz and thanks for returning the Urn.

Edited By Neil Wyatt on 10/01/2018 09:11:11

I love QCTPs.

Others don't.

It's only worth getting one if you intend to build up a decent set of tool holders.

Neil

P.S. use the 'reply' box below the thread rather than creating a new thread for your replies or people will struggle to link your reply to the original. I have moved your second post to this thread. Thanks.

Edited By Neil Wyatt on 10/01/2018 09:15:26

I too have a WM250 and have fitted an Aloris style AXA QCTP. No problem with rigidity and can part off quite happily feeding the tool from the front. I did however have to re-engineer the mounting arrangements as the tool-post was not a direct replacement. In the process I made an extra toolpost fitting that mounts directly on the cross-slide and find that I use this most of the time.

It is a simple matter to swap in the top-slide if I need the angle facility. The QCTP is set at the same height for either the top-slide or the cross-slide fitment so no need to adjust heights once the tool is set. More details *** HERE *** I am slowly building up a collection of holders (about 15 at present) and find the QCTP to be a most useful addition to the lathe. The original 4-way tool post is still available and fits directly on the post so best of both worlds!

John

I only use QCTP now. I had some issues with rigidity, but switched from a "piston" style to "wedge". Its now bliss.

Like has been said about the cost of the holders, I seem to add a couple to every order......

Jim

Me too. Mounting the toolpost directly on the cross slide gets rid of all the flex and backlash in the topslide. In practice I find there aren't many situations where a topslide is needed but it would be simple enough to swap it over. And before getting too wound up about flex, it's worth checking how long since the gibs etc were tightened up.

Murray

Refering to Sam's message above, I have also tried a Dickson style toolpost, of the 73 x 73 x 51 approximate size, on my Warco WM250VF. I agree that the arrangement is insufficiently rigid, due to flex in the top slide and clamp arrangement, and certainly aggravated by any extended overhang of the tool.

I have been through a similar exercise to that shown on **LINK** , but still using the Dickson style toolpost. I first built a 'Rock of Gibraltar' inspired post using a machined lump of 100mm diameter cast iron mounted on a cross slide base plate sold by Warco to replace the top slide. This is about as solid as possible on this machine! I am very happy with the performance of this, and have been using it when the functionality of a top slide is not needed.

I very recently built a variation of the 4-bolt clamp unit on **LINK** but again using another cross slide base plate from Warco, to replace the supplied 2-bolt clamp to hold the top slide. This appears to work satisfactorily but I have not done much with the lathe since: I think I might however stick with the 'Gibraltar' for most work.

Martin

I see that 'The Journeyman' has posted since I started writing this message.  Thanks for your inspiration, John!

Edited By Martin Whittle on 10/01/2018 10:49:04

I too like a solid toolpost

Jim

Stephen;

One item that makes me love them is that, when making batches of parts, they all come out the same, as when you mount a new tool, it goes exactly where you want it to be.

One mistake I made at first was to have a handle on the toolpost that allowed me to swivel it around. It should be locked in place so that tools go back on in the correct orientation; for instance, a parting tool simply drops on, and no faffling about ensuring that it is aligned properly. One set of vees parallel to the centre line, one set at right angles - lock it down and forget about moving it after that.

I've got two QCTPs; on my smaller lathe, I have a small piston type made of aluminium, and it's not very good for taking heavy cuts, but the usefulness outweighs the flimsy-ness. It'll get replaced by a 0XA one maybe this year. (or, 000 as some suppliers, like Arc Eurotrade call the size) My larger lathe has a BXA toolpost, which is as rigid as Gibraltar.

John.

Another advantage not mentioned by NDIY above is that each holder enables you to invest from £20 to £40 so that when inflation makes you become one of the impoverished pensioners mentioned on the radio this morning and you have realised they are not as essential as you thought you have something to sell each week for food.

Earlier this week I put in an order to Arc for a toolpost and one toolholder of the 100 size for my Warco WMT300. If it goes well, I'll fit one to my Clarke CL430 when it's CNC'd so I can simply use the same tools on both and have the tool offsets stored on the machine.

Later this month I'm going to try an experiment, casting blank toolholders from aluminium and then machining them on my shaper. The 100 shape is much easier to replicate than the Dicksonian ones. If the compound slide and possibly angle slide is replaced with a big block, I suspect the fact the toolholder is aluminium will be irrelevant in all ways except wear. It'll also be something that can be replicated for the CNC lathe. With pen making, my loads are light, so I don't think deflection will be a problem. We shall see.

Regards,

Richard.

This prompted me to check how much I have 'invested' in QCTP holders.

34 in total - 19 for the Myford 254S, and 15 for the Boxford 330

I do the same thing. I’m sure on my lathe a four way is more rigid than a QCTP.

As for dark ages, that’s exactly what a QCTP is. Modern stuff is CNC and using the correct tooling and inserts means they are always on centre height.

At the point where you have permanently shimmed your tools to centre hight, and have tool changes down to 30 sec. I'm not sure you will see sufficient benefits from a QCTP to justify the cost.

Me ... I like mine ... but I can't be bothered to permanently shim each and every tool ... and between chips and grit my 5 sec. tool changes are never quite so quick.

And you can't really realise the investment in QCTP unless you have one for every tool ... which gets quite expensive quite quickly.

If it ain't broke ...

As has been said the major benefit to QCTP systems is that the tool repositions exactly to both centre height and extension so if you have a repetition job needing several tools you never need to worry about working to different dial readiness after changing. 4 way types with a decent ratchet underneath have same advantages but are limited to 4 tools. Not to mention the porcupine effect from sharp edges pointing into the operators hand area.

For many years I used a set of 4 ways as a poor boys QC system on 3 successive SouthBend lathes. Tee slotted topsides made it easy to interchange pre-loaded 4 ways but with no proper locating system I had to check tip position after each change. Worked just about well enough for me not to change things but not ideal.

I never understood why QC 2, 3 or 4 slot block systems were never developed as such would seem cheaper than a conventional QC. Either simple pin-in-hole or a version of the face ratchet system commonly found under the 4 way systems supplied with the better class of British lathes would seem to give adequate positional repeatability. On a commercial system an interrupted thread, big naval gun breech style, seems a practical and suitably inexpensive quick way of locking the tool post block in place with partial turn of the handle. Holbrooks used a very neat top lever operated cam action lever to lock some of their 4 way systems which looks to be potentially excellent if translated to a QC block system. A more home-shop manufacture friendly quick locking system is the castellated nut, rotating stem and slide out tommy bar system I proposed when this topic previously arose. Neil published a letter in MEW about it but the illustrative concept drawings didn't make it into print. I think Neil was hoping for a proper write up. Something I couldn't in good conscience provide as I no longer have machines of an appropriate size to fit a prototype to so verifying that things actually work properly at typical home-user machine sizes. Got me interested enough in the whole Poor Boys QC substitute topic to start on a proper write up of what could be done. Which rather got away from me but did bring home the fact that the common low end tool mounting systems are, basically, crazy and a modicum of design effort could have made things far better.

A QC block system lends itself to off the machine tool setting removing one of the major issues with conventional shimming to centre on the machine. On the bench its easy enough to measure tool tip height for right first time shimming and a jig to set projection is almost trivially simple. If you plan to use carbide inserts a conventional QC system means you are paying lots of money for height adjustment capabilities you don't need.

Bolt up construction from standard plate and bar sections works just fine for slotted tool blocks in our sizes.  If you have accurate QC arrangements two slot blocks would be fine lessening the porcupine thing.

Clive.

Edited By Clive Foster on 10/01/2018 16:50:15

Edited By Clive Foster on 10/01/2018 16:51:21

Edited By Clive Foster on 10/01/2018 16:51:52

Used the Dickson type from Myfords on my ml7 when I had it, and now on my 254s, would not be without them.

No more cuts from the tools in the old 4 way post, or looking for old lumps to shim up seldom used tools.

I use them for a couple of parting tools even though I have a rear toolpost for parting, which lives in the dark recesses, rarely even have to reduce speed to part off.

Each to his or her own though, but you could try and if you did not get on with them they sell easily enough.

Edited By Ian Hewson on 10/01/2018 17:49:18