Quick change tool post

Useful Bergström Patent here: **LINK**

https://worldwide.espacenet.com/publicationDetails/originalDocument?CC=GB&NR=661450A&KC=A&FT=D&ND=3&date=19511121&DB=EPODOC&locale=en_EP

MichaelG.

All this talk about quick change. Has anyone ever timed how long they take! I have 5 different types all have there pros and cons. They are:-

Multifix. Very repeatable very expensive. Toolholders are impossible to make Very nice though.

Dickson. Toolholders are more common but hard to make but still a good system.

Dovetail type model 200 (as sold by Arc) I really like these. They are repeatable enough for my needs and you can easily make new toolholders.

Dean Smith and Grace type. Very solid but hard to find the holders at a sensible cost. Wouldn't be too dificult to make though.

All of the above are great if you have a massive range of tools but quick change they are not. If you want speed you have to go to number 5 on the list.

Herbert 2D 4 way toolpost. I tried to time a tool change with this but couldn't easily do it. So I changed from 1 to 2 to 3 to 4 and back to 1. It took just under 3 seconds. Obviously you can only hold 4 tools and then you have the issue with boring bars and turning tools in the same configuration but all the same it is a pretty impressive thing.

I recently bought a load of them off ebay and plan to take one apart to see what makes it tick.

Just my thoughts.

David

I have a Dickson type (clone) toolpost also sold as a boxford type, The piston pulls the tool holder in against the dove tails and looking at it in action I think Neil has a good point. This type only has the edges of the piston crown pulling the tool in, I guess th epush type uses the whole face of the piston and thus has a greater area/friction etc.

But as often, I could be wrong

QCTP's are the business, I don't know anyone who got one and decided to turn back.

The use of them soon turns into the proliferation of tool holders, FOR EVERY SINGLE TOOL!

So my point is if it was that bad, then why does this development seem so common among M.E's, is it because they might actually be a good idea?

Like I said, find someone who got one, decided it wasn't for them, and turned back. I can't find a single guy, so what gives? Even all the tool rooms I've worked in used them.

So arguing against their versatility is a moot point, it's already well proven, the only argument you can rest on is personal preference or expense. 

Michael W

Edited By Michael-w on 02/10/2017 19:20:07

After many frustrating years of fumbling with assorted packing pieces on my 4 way tool post I decided to indulge in a quick change tool post. I purchased the "Dixon" type from RDG Tools, I was very pleased with the finish of the item, it was nicely ground all over. When I came to fit it to my lathe ( a warco bv20 ) the mounting stud is twelve mm and the clearance hole through the tool post was only 11.2 MM so I was faced with opening out a hardened steel hole, not an easy task. My mill,a Chester V20, doesn't have a coolant system so I thought if I take it easy with a 12 MM Cobalt drill it should manage to open it out. Ever the optimist I embarked on the task only to find progress was extremely slow and eventually ground to a halt, too much heat was being generated to make any progress, I tried an end mill and that was a no go as well. Reflecting on the problem I realised that I would need to flood the operation with coolant so would need to construct a temporary coolant system to experiment with. Then a thought flashed through my muddled brain how about some form of diamond cutting tool, I remember seeing that Arceurotrade sell diamond core drills for cutting ceramics and glass, fortunately they sell a 12 MM one. I remember reading that someone recommends them for removing broken taps. Armed with the diamond core drill I resumed the task and found that it cut through almost like a knife through butter, success at last but it rendered the core drill scrap, not a problem as it was a small price to pay for achieving the objective. The QCTP is now installed and operational, have already purchased more tool holders to build a collection of ready to use tools. No connection with either retailers mentioned, just a happy and satisfied customer.

Dave

Another vote for the RDG 'Dickson' tool posts. I use the T1 size on my Chipmaster and have a mixture of original Colchester and new RDG holders and they all fit the Colchester branded Dickson perfectly.

As well as a quick change tool post I would say that a quick change gearbox is also a huge leap forward in usability. Utterly necessary? No of course not, but they mean less time faffing and more time actually enjoying my hobby.

I am the proud owner of a couple of Dickson units and maybe 15 toolholders. Nicely made by the person who used to make them for Myford. I am very pleased with them, but there are some drawbacks.

At least in the Myford size, they are less rigid than the old fashioned Myford clamping system. I do not think this is any deficiency in the manufacturing, simply in design.

The other snag is that if you are doing really precise, repetition work, they don't cut the mustard. I have a GHT 4 position tool holder and this gives appreciable better repetitive results.

I made this GHT design a goodly time ago and was muttering under my breath that I didn't really believe George's claim about the repetition accuracy. Well he was right! I got my Dickson system later on. It is an excellent way of swopping tools especially if you have oddball things.

It really depends on what you are looking for with your toolholder. The Dickson system doesn't have it all its own way! There is room for both systems. and I am honest enough to admit this! So reflect a little and don't divide into two camps over this subject!

Andrew.

Well I have a wedge type to try out on the SC4 soon, but for the first article on turning I will use HSS in the 4-way toolpost as that's where 99% of beginners will start.

Neil

Out of interest what size wedge?

jim

Bison - Dickson copy.

1 in the toolpost. 1 spare on the lower shelf. 20 ready to go on the top shelf. 22 in total. No more!!!

Original Boxford indexing 4 way toolpost on the lower shelf used only for clocks and DTI's, always on CH.

No more? I thought that with 6, then 8, now 20 for me!

You know what, i'm inclined to agree with that sentiment, I love QCTP's and I would never go back, but to begin with I did just use a four way post with tin can shims and off cuts underneath them.

Still, good to keep the aspiration to a Dickson type or whatever floats. They are definitely worthwhile. It isn't worth throwing out the idea just because it can't be done immediately.

It's a relatively simple modification to make a new T clamping bolt to the right length and handle to suit. The only thing I would keep an eye on would be the length of travel on the adjuster height screw, relative to the height of the lathe ofc.

Michael W

Edited By Michael-w on 03/10/2017 18:21:10

Andrew Tinsley:

It was good to hear from someone who has used both the Dickson and GHT fourway toolposts. I have no experience of the former but the change between the four tools on the GHT is virtually instantaneous. One of these days I will do a proper test to see whether the repeatability of mine is anything like the impressive results he achieved.

One of GHT's reasons for favouring the fourway over the QCTP was that in his day he found that few QCTP users had the large number of holders which is common in these more affluent times.