Quick Change Toolpost and Holder systems

I've finally got some 2" and 1" square stock to make a QCTP and a stock of toolholders. I want to make good use of my expensive dovetail cutter, so I'll copy the popular design that uses 'pistons' to push the toolholders out away from the block and against the dovetails.

But.. I have no idea how the pistons are made to work given there is a blooming great stud in the middle of the block.

Can anyone who has one of these explain/photograph how they work for me?

Thanks

Neil

Neil

Why the piston style may I ask ?

Do you think it is the best type ?

Chris

I imagine it has the best repeatability and it locks block and holder solid, whilst being quick. I don't like the approach where one dovetail has to be screwed up (how can a moving dovetail be more accurate?)

But if you know better ways I'm eager to hear any suggestions.

Neil

No not at all, it was a genuine question.

Check my post count, I'm new and am in the beginner class.

Hi Neil,

I am slowly building a QCTP according to the Nakamura design which is of the type you are looking as it sounds. Drawings are here:

**LINK**

BR

/Peter

Thyanks Peter,

that's exactly what I was looking for, although Chris's comment has got me looking at Dikinson toolposts tyope designs that pull instead of push. But that design wopuldn't let me use my dovetail cutter !

Neil

So, you buy a new cutter and then dovetail everything in sight

It's a sickness you know

Hi Neil

Have you looked at the design that John Stevenson came up with, try this link **LINK**

Lets you use your dovetail cutter as much as you want.

Keith

There is a link here with some useful (maybe) comments on toolposts.

Thanks for the links to John and Harold's designs too.

Lots to think about, especially as this is for a mini lathe. I use 5/16" tools (although in theory you could fit 1/2" they would be too high. This means I can make the holdersfrom 1" square, but it does mean the main block will be small, probably too small for the John S. design. I will look up Harolds article as I have MEW 50 somewhere.

The Nakamura design is what I was thinking of, but there are a few dimnsions missing, none beyond working out from common sense.

Neil

Hi Neil,

I have come as far as making the base block for the QCTP, if you want I can take some measurements on mine tomorrow. It is adapted and made for a SIEG C3 mini lathe. This is how it looked before getting som color.

BR

/Peter

Edited By Peter E on 30/08/2012 22:51:30

Not a lover of those dovetail that push out, they never align the same every time.

I have four of them as well, two unused.

Dickson style are the best way.

Couple of problems I don't like with the Dickson type is too many sticky up bits to foul turnings on.

I much prefer sunken grub screws to keep things smoother.

Another pet hate on the Dickson ones is they can and do shake loose easily on deep interupted cuts as the cam is only a friction cam and has no locking ability.

For those without a dovetail cutter, Norman Patent toolholders are easy to make, but use a lot of metal by the time you have made a few.

This one-off "lathe to die for", made by Rolls Royce, has one fitted LINK.

Here's how to make them on a minilathe LINK .

Andy

The tool on that RR lathe appears to be upside down

Anyone know why?

Andy,

That GJH lathe looks a little gem ... thanks for sharing the link.

Amazing what can be done when needs must:

If a Pultra isn't good enough, AND you have Rolls Royce crafstsmen.

MichaelG.

P.S.

I didn't know that the Toyo ML1 borrowed the design, either.

... Two interestng bits of info. to start the day ! Thanks.

Adding Model Engineers Workshop no 140 to the list of info and drawings for a QCTP of the sought after style. Jim W made one for a mini lathe-ish size as well as for a Unimat sized machine. Good descriptions and drawings. I used those as base for my work.

I have understood it so that it is important to be quite accurate when doing the dove tailing to get the desired precision and repeatability while at the same time get the easy fit required for easy use.

For my Unimat clone I made a slimmed down version of the Norman Patent type as can be seen in the following two pictures. They also work very well, and I am very pleased with their perfomance. The only draw-back I think is that the setting screw poking out below makes it a little cumbersome to efficiently store many toolholders.

BR

/Peter

Edited By Katy Purvis on 01/06/2015 12:55:00

Slight diversion ... I just found this Patent from 1913 by F.D. Van Norman; which features what we tend to think of as a "Myford Tool Boat".

I think we can reasonably assume that he was "the" Norman.

I will investigate further.

MichaelG.

.

From this page, I quote: "In 1888, Mr. Charles E. and Fred D. Van Norman founded the Waltham Watch Tool Company, to manufacture tools for use in the Jewelry trade."

... "WW" being the standard for the "inverted vee" lathe bed, as used by Pultra and many others.

Edited By Michael Gilligan on 31/08/2012 08:21:10

1910 version of the Patent referenced above.

... and as a further diversion; have a look at his designs for:

an Engraving and Die Sinking Machine  ... That's Nice !!

and a High Speed Spindle ... That's Cool

Edited By Michael Gilligan on 31/08/2012 09:19:54

Edited By Michael Gilligan on 31/08/2012 09:28:46

Peter E,

Clicking on either of your links comes up with " Page not found "

Any chance of checking it out?

Len. P.