Myford / Dixon Toolpost limitation

Is there a practical solution to the bottoming out problem of Dixon toolholders onto the Myford crossslide base, when using tools over 10mm high (approx)

It is extreemly frustrating having to machine the base of some 12.5 mm high lathe tools, to acheive centre.

If you have remedied this problem. Would appreciate the "workaround"

Hi Rod, this item on ebay may solve your problem, allows up to 12mm tooling to be used.

the item number is 370603937747

HTH

Rod,

This aspect of the Super 7 has puzzled me and caused frustration for years. It is part of the general quirkiness the Myford detail design. There are several things that can be done.

1. Stick to 10mm tooling - this is the simplest unless you have a lot of existing 12mm tools.
2. Modify your existing tool holders to be similar to the RDG ones (as the above link) if they are not too hard. The one from RDG may not be compatible with the genuine Dixon post as they state it only fits their tool post.
3. More drastically machine a step in the nose of the top slide - probably not advisable
4. 2 & 3 both stop the tool post being moved round more than a few degrees which would make it difficult to always get the correct tool alignment with the work.
5. Abandon the top slide and make a substantial distance piece to mount in its place on the cross slide of such a height that the Dixon tool holder can be lowered to the desired level. Something like the Gibraltar tool post from Hemmingway.
6. Buy a Colchester!

Edited By Eric Clark on 03/10/2012 15:54:54

Edited By Eric Clark on 03/10/2012 15:55:18

I agree - why make life difficult by using 1/2" tools? Surely, even if you have some 1/2" tools, a change to 10mm will be a much cheaper and easier option than mucking about buying new or modifying old toolholders ? Do you have some special need for 1/2" tools?

N

Thank you gentlemen! - To explain:

I have three lathes. All have the same size Dixon and all toolholders will interchange if required.

The non-Myfords all happily accept 12mm tooling (which I would `nt call "industrial" and so you will see that I am kinda locked in. Current thinking is make an overhung block on the "V" clamp priciple. That will allow clearance of either the existing toolholders or a new design, to both drop the 12 mm tools to C/hieght and permit rotation.

Been studying this!!!

How about moving or at least making a second location for, the toolblock pivot.

Looks like about 15mm north west would permit clearance & rotation also?

Let you know............

The converse - there seems to be a convention that mini-lathes should use 1/4" square tools, while 5/16" toolsteel works fine, normally without packing or just a thin shim.

Neil

The bore of my Dickson type toolpost was considerably larger than the mounting stud.

What I did was to machine a top-hat washer that was a close fit in the toolblock bore and drilled to be a close sliding fit on the stud. The rim of the top hat was 1/32" thick (which rasied the toolblock up) and of such a diameter that the toolholder would not foul it when the block was rotated with the toolholder in the lowest position.

I did this, not particularly to raise the toolblock, but to try and prevent swarf getting between the toolblock and mounting surface of the topslide and scoring either or both.

Dave

The Emerald Isle

The diameter of such a "washer" would have to beat least as large as the block or else th "toolpost" would be less stable and hence prone to vibration under cutting forces.

I had the same problem on my ML7 but on my Myford 254S there is more adjustment so. However as I recall RDG also sell a 12mm tipped tool with reduced shank.

Raising the block is of no help. The problem is caused by the top of the top slide being a fixed dimension below the centre height so the bottom of the tool holder fouls the top of the top slide before a 12 mm tool can be lowered enough.

i had the same problem and i had to machine off 1. 2 mm the bottom but my original ones are Genuine Myford holders have the letter W stamped on them and they work fine .

Kevin

Steam Dave

I heve sent you a PM.

N

Decided to make a beefed up modified version of nifty/amigos/qctp design to overhang the base and to allow rotation.

If there is anyone familiar with this or having made one. I would like to know if the "fixing shaft" clamps the "body" to the surface. Or if it clamps through the eccentric cam by means of the shoulder on top of the "fixing shaft" It can be done either way. Which is best?

Since this is for the Myford I will post design and build

Hi,

RDG list toolholders as "Myford size" which look suspiciously like the Dickson holders I have.

Regards

Terry

I decided to use the "japanese" basis for an overhung QCTP design. The green base represents the contact area of the Myford topslide. (Approx. 2,6"x2.6" All toolholders will drop below the top plane of this part and still rotate, until limited by the sides of the topslide. There are many variations that can be made to personal taste. But I publish the basic part and min. dimensions in case anyone else is looking for a similar type of "workaround"

Can offer the 2D and 3D files to any interested party.

"Prostrate myself before you!"

Put the top slide away in a cupboard until needed and make a raising block to fit on the cross slide.

Advantages are: Far more rigid, allows you to use 1/2" tools and holders with no modification, stops the top slide fouling the tailstock and most importantly for a Myford owner it keeps the paint pristine on the top slide if its packed away nicely.

Disadvantages are: You have to unpack the top slide for the odd taper turning job about 4 times per year.

John S.

Edited By John Stevenson on 14/10/2012 10:02:09

John

Yes I have a crossslide block. It is not QC but the old 4 way rachet type. Pain itb to move it and have not used it for years.

Peter E

I would like to discuss your design with you if possible?

Forgot one!

Edited By Rod Ashton on 14/10/2012 11:31:18

.

Rod, I think you missunderstand, not a 4 way turret type, just a hefty packing block to replave the top slide.

Please ignore the coachwork, it's a working lathe.