Dickson Clone QCTP Test on Myford S7

[Nick HulmeParticipant @nickhulme30114]

There was so much complete guff being talked about the inadequacy of Dickson QCTP clones and holders a while back somewhere on 'tinternet, most of it clearly based on Armchair Experience rather than actual use I decided to video a quick test on some 30mm 304 taking 5mm OD reductions.

There was great excitement about Multi-Fix as a better option too, presumably because they had missed the presence of the hole for an indexing pin in the main block of Dickson QCTPs and their clones, allowing the savvy engineer to create indexing points for the useful angles of their own choice (15, 30, 45, 90, rather than the arbitrary and mystifying divisions of the Multi-Fix).

– Nick

Edited By Nick Hulme on 02/09/2017 10:55:02

[Nick HulmeParticipant @nickhulme30114]

[MuzzerParticipant @muzzer]

Very attitudinal!

Speaking for myself, my reason for buying a Multifix clone was because of my concerns about rigidity. The idea that you'd jettison a perfectly good(??) QCTP system just to gain indexing is somewhat bizarre. I agree as you say, the Multifix steps of 9 degrees are suboptimal if you want increments of 15 degrees. Perhaps 7.5 or 15 degree steps would have been better.

I used my Dickson in anger for over 20 years before getting the Multifix. I'm guessing your disparaging comments are based solely on your own armchair experience of the latter?

To me, the weakness in the Dickson design is the cam locking pin combined with the twin vee location which puts a high load on said pin under load. I know, I know, they shipped many Dickson systems over the years and many users were perfectly happy with them.

Murray

[Steve PaveyParticipant @stevepavey65865]

I've used both. They each have their merits – I like the repeatability of the Multifix, as well as its' rigidity. I don't think I'd lose any sleep if I was forced to use a Dickson or an Aloris, it's just a preference. Some even use a lantern style toolpost very successfully* – clearly there are other factors besides rigidity, and clearly rigidity is not solely dependent on the choice of toolpost.

* Just to go slightly off topic, it's worth checking Dave Richards Steam Powered Machine Shop on YouTube – superbly produced videos, often showing him using his lineshaft driven lathe complete with lantern style toolholder.

[Nick HulmeParticipant @nickhulme30114]

Posted by Muzzer on 02/09/2017 12:55:55:

To me, the weakness in the Dickson design is the cam locking pin combined with the twin vee location which puts a high load on said pin under load.

Yes, I worked out from the armchair that 9 degree indexing is "Sub Optimal", maths is funny like that, I determined empirically that the Dickson clones are entirely up to the job on a Super 7 – see the video.

That's a 10+ year old Dickson clone in the video with 5mm OD reductions on a 30mm 304 stainless bar, the shortcomings of the cam locking pin combined with the twin vee location can clearly be seen during the cuts.

– Nick

[Neil WyattModerator @neilwyatt]

Are these what they call "The Clone Wars"?

Neil

[Nick HulmeParticipant @nickhulme30114]

Posted by Neil Wyatt on 02/09/2017 17:31:14:

Are these what they call "The Clone Wars"?

Neil

It's never popular when you show people what they say doesn't work working, especially with the spend that often results

[Nick Taylor 2Participant @nicktaylor2]

The Dickson design is used with 20hp behind it so I doubt it's going to be a problem for us 'home gamers'. I have the original Colchester tool post on my Chipmaster, that's only 3hp but I've been taking some stonking big cuts in some en19 using the cheap (£22) holders from RDG and it works great.

I also have a wedge style Aloris copy on my super 7 (from arc) and that has really surprised me, it's the small 000 version but is still more than rigid enough. It is as small as I would go on the Myford though.

I think someone worded it very well when they said that the multifix posts were of higher general quality because the design needed high accuracy for it to work at all. They look great but the cost just isn't worth it in my opinion.

 

Edited By Nick Taylor 2 on 02/09/2017 19:17:51

[Nick HulmeParticipant @nickhulme30114]

Posted by Nick Taylor 2 on 02/09/2017 19:17:09:

They look great but the cost just isn't worth it in my opinion.

I think there is a very good argument for some level of "Placebo Effect" but if paying a small fortune for a posh QCTP makes you feel better about your turning that's a good reason for having it, given that the Dickson and clones can demonstrably do what Multifix purchasers claim they can't I'm just helping them to stop bashing the Dickson by demonstrating it's capabilities 😀

[blowlampParticipant @blowlamp]

Posted by Neil Wyatt on 02/09/2017 17:31:14:

Are these what they call "The Clone Wars"?

Neil

This is post war britain.

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