Myford Super7 toolpost/modification for 12-mm/1/2-inch tooling

[malleusmagnusParticipant @malleusmagnus]

Hello all from across the pond.

I’ve recently purchased a little used Super7B and lots of tooling, some of it 12-mm.  Obviously, the 12-mm tooling won’t reach the centerline of the workpiece, being to high to do so.  I’m a bit baffled about why this tooling was in the cabinet, but it’s RDG stock and nearly new, if not unused, so I’m loathe to chuck it.

I know I can cut the top slide down, but I’d rather not.  I’ve looked for a QC toolpost to satisfy this tooling, but, if they’re available, I’m missing the specs to confirm it.

What is the current state of the art solution?

Thanks in advance for your kind consideration.

[JasonBModerator @jasonb]

I’m not sure about state of the art but you could go old school and do what Myford did by simply clamping the tool to the top surface of the top slide with suitable packing under it to bring the tool to ctr height. You can still buy the clamping plate or not a hard thing to make.

[malleusmagnusParticipant @malleusmagnus]

Jason,

Thanks for the suggestion.  I had considered that, but I was looking for a QC toolpost solution so that I could put the large number of toolholders that came with the lathe to use.

Also, just for grins, here’s the lathe and its nicely done cabinet:

[malleusmagnusParticipant @malleusmagnus]

Well, that wasn’t the glamour shot I wanted.  Let’s try this one:

[JasonBModerator @jasonb]

The “Dickson” type toolpost you have won’t allow much over 5/16″ tooling.

Anything else to take 12mm tooling would be too weak as you would only have about 3/32″ thickness on the bottom of the tool holder.

[Ady1Participant @ady1]

12mm is way too big, if you get a jam up the tool will be the strongest bit in there and your chuck jaws amongst the weaker links

You could slide it in upside down via a rear toolpost… but its huge

I use my big chunky HSS bits as parallels and supports

[malleusmagnusParticipant @malleusmagnus]

Yes, I’m currently limited to the Myford/RDG/other 8-mm tool shanks I have, with the current toolpost. So, I’m stuck with cutting the topslide surface to lower the toolholder?

I also considered doing what Steve Jordan did with his toolholders, namely cutting a step on the inner lowest corner, but I dropped that idea as soon as it came to mind, for exactly the reason he cut his topslide – you can’t pivot the toolpost if you do that.

[DC31kParticipant @dc31k]

Clamp the tooling sideways in the toolpost.

Clamp endmill in collet in spindle.

Mill off base of tooling until it is of suitable height.

Pre-treatment with a 1mm slitting blade in a grinder and final finishing in the lathe could speed this up.

[JasonBModerator @jasonb]

unless it’s HSS tooling that he has. may be OK if they are insert tooling depending on level of hardness.

[Michael GilliganParticipant @michaelgilligan61133]

I’m with Ady

Use the big tools for some other purpose [or sell them/swap them/give them away]
They are simply too big for a Myford Super 7B top-slide, and will only end up causing you grief, one way or another.

MichaelG.

[peak4Participant @peak4]

I’ve only got a couple of 12mm ones that I use on the Myford, but I originally milled the shanks down to a shade under 10mm thickness. Now I’ve got a small surface grinder working OK, I tidied them up to 3/8″ which give a little adjustment.

Seems to work OK for me, as some of my Dickson style toolholder have slots 12mm wide, so they fit quite snugly, and look designed for the job.

I originally use a QR toolholder based on a round post with blocks of metal which clamped around it.
Some of those blocks had conventional slots, one was drilled for a boring tool, but another had a ½” rebate in the corner; as in a slot, but no base to support the tool.
I then cleaned up and welded a cut down piece of bed angle iron across the corner; this gave me a very thin base, but still supported on the outer edge. Obviously this isn’t so easy with a Dickson style holder.
Screenshot from my Facebook album, as it doesn’t look like I uploaded it to Flickr; It used to be in an album on the old forum.

This is a different toolholding block but illustrated the square reinforced  “hole”

The one in the lower photo will also accommodate ½” HSS blanks. It’s been handy in the past when I’ve needed to work on something awkward which needed lots of room to keep the top slide & toolpost out of the way. If need be a small jack can be made to sit on the cross slide, to support the large overhanging tool bit.
Bill

[bernard towersParticipant @bernardtowers37738]

Trying to use a sledgehammer to crack a nut here I think.

[David KParticipant @davidk77137]

You can buy Dickson tool holders with a step from RDG Tools, i just cut my own with a cutting blade in my grinder and a little jig. Cut a lot easier than i thought.

As for turning the tool holder , i can’t think of many times i have needed to and if i do i can just use a smaller tool.

[Roderick JenkinsParticipant @roderickjenkins93242]

On my Myford S7 I use a Dickson tool post with 8 or 6mm tooling, mostly carbide insert, which has served me well for the past 40 odd years.  I do however have a few large form tools and boring bars which benefit from being as stiff as possible:

For these I remove the top (compound) slide and attach my Gibraltar tool post

The casting for this is available from Hemingway

https://www.hemingwaykits.com/HK1090

Judging by the number Hemingway products being manufactured on YouTube recently, acquiring one from across the pond shouldn’t be too difficult.  However, the designer of this tool post, Tom Walshaw (AKA Tubal Cain), made his version from a lump of mild steel.

Hope this helps,

Rod

 

[malleusmagnusParticipant @malleusmagnus]

That toolpost is a beast!  Aptly named, for certain.

[malleusmagnusParticipant @malleusmagnus]

I have to look for those tool holders.  Thanks for the suggestion.

[malleusmagnusParticipant @malleusmagnus]

Anyone have thoughts, pro or con, on multifix type toolposts for a Super7?

[Howard LewisParticipant @howardlewis46836]

Although not QCTP user, I would advise against machining the existing toolpost.

The object is for the tool holding to be rigid, so that the tip does not deflect.

nachining away the original toolpost will weaken it, so although larger tools may be more rigid, the complete assembly may not be. Once weakened, there is no going back with the original post, any tooling set up will tend to flex.

The rigidity will be the combination of toolpost and tool.

A 1/8″ toolbit in a Gibraltar will be more flexible than a 5/16″ in the same post

FWIW don’t weaken the toolpost, but use the largest tool shank that you can set to centre height.

Howard

[Dave Shield 1Participant @daveshield1]

I have just replaced my dickson tool post with a multifix from Germany. Much better tool post, the holders all fit unlike the ones for the Dickson post

Dave

[SteviegtrParticipant @steviegtr]

I did this with my Super 7 some years ago & it is one of the best mods i have done with it. This is with a 13mm hss cutter. Look for steviegtr on youtube , all the mods i have done to the Super 7 are on there.

[Rod ClemettParticipant @rodclemett60985]

Regardless of whether you stick to the Dickson-style toolpost, or jump ship to the no doubt superior Multifix-style, with any system mounted on the topslide you are almost certain to face similar limitations.
I have about 20 toolholders for the Dickson toolpost on my Super7, and only about three of them have a base sufficiently thin to permit a 10mm tool to hit centre height – just.
It’s an exercise in futility though, as to achieve this the lower face of the (carefully selected) toolholder must then effectively rest on a scrupulously clean topslide surface – a position which is beyond the range of the usual height adjustment screw, and which negates at least one advantage of a QC toolpost.

I think you can find the dimensions of the the various Multifix-style toolholders on the pewetools.de website, if you want to check if they offer you any significant dimensional advantage, but I doubt they do.

I’m tempted to think that the Myford-Dickson toolpost gained its reputation as a “must-have” accessory for the Series 7  topslide when 1/4″ and 5/16″ HSS toolbits were the order of the day, and since then many of us (including myself) have been seduced by the toolholder capacity for 10/12mm carbide tools, and our reckless inference that these would therefore be a practical proposition!

I’ve seen, and considered, various solutions over the years – including skimming the topslide, skimming the toolholder bases, and making a wider toolpost (all of which have their drawbacks in my opinion) –  but if you really want to utilise your existing 12mm tooling in a quick-change toolpost, perhaps the best idea might be to consider making a solid (lower!) block that fits in place of topslide, and mount the toolpost directly to that.
As an example, check out the one made by the “Optical Mechanic” on YouTube.

The topslide (and some 6mm tooling!) can then be refitted when actually needed – say for screwcutting and taper turning.

 

Clem.

[Rod Clemett]

On Rod Clemett Said:

[…]

I’m tempted to think that the Myford-Dickson toolpost gained its reputation as a “must-have” accessory for the Series 7  topslide when 1/4″ and 5/16″ HSS toolbits were the order of the day, and since then many of us (including myself) have been seduced by the toolholder capacity for 10/12mm carbide tools, and our reckless inference that these would therefore be a practical proposition!

I’ve seen, and considered, various solutions over the years – including skimming the topslide, skimming the toolholder bases, and making a wider toolpost (all of which have their drawbacks in my opinion) –  but if you really want to utilise your existing 12mm tooling in a quick-change toolpost, perhaps the best idea might be to consider making a solid (lower!) block that fits in place of topslide, and mount the toolpost directly to that.
As an example, check out the one made by the “Optical Mechanic” on YouTube.

The topslide (and some 6mm tooling!) can then be refitted when actually needed – say for screwcutting and taper turning.

 

Clem.

That sums it up nicely, I think

MichaelG.

.

https://www.youtube.com/watch?v=JuIBumjxWrc

[John HaineParticipant @johnhaine32865]

+1 for replacing the top slide with something more solid unless you really need it.

 

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