Multifix – Myford S7

[HillclimberParticipant @hillclimber]

Does anyone have direct experience of using a Multifix toolholder on an S7?

I am looking at sizes. The Aa looks dinky (but has a max toolsize of 12mm, which makes it sound 'normal&#39. While the A looks a bit chunky on the topslide.

What are thoughts/experience on choice of size for an S7?

Also, I am assuming that the smart move is a sleeving bush on the toolpost bolt to help secure the Multifix? And will the standard Myford bolt do the job as far as size?

Final thought is on holder AaJ – what is it for? The obvious answer seems to be a boring bar, but at 15mm its bore is a mighty strange size?

Cheers, Colin

Edited By Hillclimber on 05/09/2017 15:03:49

[HillclimberParticipant @hillclimber]

[Mark RandParticipant @markrand96270]

I have a Hardinge HLV with Multifix A toolpost and an ML7 without a QCTP. The Multifix A would not work with an ML7, the largest tool you could use would have a 7mm shank!

With the size Aa Multifx, one could go up to a 10mm shank and still get it on centre without modifying the toolholder.

If you made a new topslide with a radiused end to clear the toolholder, you could go with larger tools, but that would be a messy compromise and there's not much meat in the existing topslide for any modifications.

[Clive HartlandParticipant @clivehartland94829]

Colin, the holder you refer to as a boring tool holder holds a bar with a fixture on the end for screwcutting. The tool on the one I used to use held the screwcutting tool in a dovetail groove for height adjustment and then the bar could be rotated for the angle of the thread.It is a versatile system and maybe not for offhand use but semi production.The bar is at right angles to the work so you can get the screwcutting tool right up to a shoulder.

Clive

[SteveIParticipant @stevei]

Hi,

Whilst I have not got a myford lathe I have seen a few in the flesh, including one running an Aa, and do run an A size on my lathe. I can tell you an A size is completely wrong for a S7. Much too big. It would not be optimal. The original manufacturar(s) sizes from smallest to large are Aa, A, E, B, C, D1, D2 etc. So you have 1 mainstream choice really Aa or choose a different type of QCTP. (I have heard a German company supplies a chinese made size in between Aa and A but I have no details and besides this would limit you to one supplier and again it may well be too big for the S7 anyhow.). I know a chap that switched to Tripan after deciding the Aa was too small and the A too big for a Schuablin 102, but tripan stopped production earlier this year and I don't know if anyone has started making copies.

The AaJ type with ID of Ø15mm is I agree a seemingly strange choice. For the AJ it is 30mm again a strange choice when it could have been 32mm. By the time you get to the EJ it is 40mm which is standard. Clive has described the original tooling which I have seen in A size and it is nice.

In practice the bore size doesn't matter. You would make a split sleeve or similar to match the size of your tool to the 15mm. I've found it to be a superior way of mounting boring and threading bars than the H type and if you use solid carbide bars it is recommend to hold them this way rather than with screws bearing down on them.

It would be a nice simple project to knock up a 6,8,10,12mm set of split sleeves for the Ø15mm holder . For my A size I've made more than a dozen sleeves from 30mm to 6,8,10,12,16,20,25mm and have a plan for a few more to cater for imperial sizes.

Steve

[Steve PaveyParticipant @stevepavey65865]

I had an Aa size Multifix on my Boxford and it was fine. It would certainly be ok on a Myford. I used the boring bar holder with two different size boring bars – each with an appropriately sized sleeve which I turned from brass bar and split with a hacksaw.

For suppliers I would go to Rotagrip (they sometimes have special offers on Multifix) or direct to Create tools in China. There is another supplier called Pewe in Germany, but have not read any good reports of them. I have bought direct from Create on two occasions and cannot fault their service. I suspect Create supply both Rotagrip and Pewe.

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