Help with qctp picture

[richz]

I found a picture of this qctp on Pinterest. It references this site. Would it be possible for some to help me find the original posting?

[polaraligned]

Did you try Google image search?

[J Tiers]

If you want to know how it works, that is pretty evident from a quick look at the parts.

A reasonable system, if perhaps a little less than the "Q" part of QCTP.

[George Bulliss]

I found a picture of this qctp on Pinterest. It references this site. Would it be possible for some to help me find the original posting?

Looks like it's from this page:
https://bbs.homeshopmachinist.net/fo...-tools/page106

[Doozer]

Not trying to go off topic here,
but Q? Does anyone know what
a Hardinge HLV quick change tool
post looks like? They have a side
and a front dovetail and the locking
elements is in the corner, and will
lock a toolholder in either position.
It is a tee nut of sorts, tightened
by a draw screw, diagonally through
the body of the tool post. Much like
the pictured above, but diagonally.
It is super simple, with just 2 moving
parts basically. It is just a bit smaller
than the AXA size. I wonder why
no one copies the Hardinge tool
post design? Some copyright issue?
Surely it has expired years ago.
I am half tempted to measure it up
and draw it in Solidworks and post
it here, if there is no legal issue
to do so. What do you all think ? ? ?

--Doozer

[Bob Engelhardt]

Looks like it's from this page:
https://bbs.homeshopmachinist.net/fo...-tools/page106

Page 106 if you're using the default posts per page. Here is the specific post:

https://bbs.homeshopmachinist.net/forum/general/40153-shop-made-tools?p=1228493#post1228493

[MrWhoopee]

[QUOTE=Doozer;n1982993]Not trying to go off topic here,
but Q? Does anyone know what
a Hardinge HLV quick change tool
post looks like? They have a side
and a front dovetail and the locking
elements is in the corner, and will
lock a toolholder in either position.
It is a tee nut of sorts, tightened
by a draw screw, diagonally through
the body of the tool post. Much like
the pictured above, but diagonally.
It is super simple, with just 2 moving
parts basically. It is just a bit smaller
than the AXA size. I wonder why
no one copies the Hardinge tool
post design? Some copyright issue?
Surely it has expired years ago.
I am half tempted to measure it up
and draw it in Solidworks and post
it here, if there is no legal issue
to do so. What do you all think ? ? ?

--Doozer


Looks like an interesting design. I'm sure that if there was patent protection it's long since expired.

Aloris won the QCTP design contest for the same reason that Microsoft won the OS contest.
I have no idea what that reason is.

[BCRider]

Looks like an interesting design. I'm sure that if there was patent protection it's long since expired.

Aloris won the QCTP design contest for the same reason that Microsoft won the OS contest.
I have no idea what that reason is.

Same reason that VHS won over the slightly better Sony Beta format. They flooded the market with a slightly cheaper option that was always better in only one way.

I don't like the method this post uses because it causes a hinge. The fairly narrow dovetail key is going to pull the holder into the flat surfaces and away from hard contact with the fixed portion of the dovetail. And that will cause it to loose registration pressure with the actual dovetail. At that point it will permit the tool holder block to hinge cutter down until it touches the fixed dovetails at the top of the rear and bottom of the front dovetail.

If you want to make a post of this style you'd be far better off with the MLA style where the whole dovetail post is split and wedges the holder for the whole height of the dovetail in the holder.

For the same reason the MLA style is better than this one the wedge style Aloris design is better than the center ram style Aloris design. Namely that the dovetail is locked hard for the whole length.

That Hardinge design is still not a two sided wedge lock. But it at least pulls one side of the dovetail solidly into lock. So I'd say it's a lot better than the full dovetail key shown in the opening post.

[J Tiers]

Not trying to go off topic here,
but Q? ..................... ? ? ?

--Doozer

The toolpost appears to be OK as far as the C,T and P portion of "QCTP", but may not be so great, as shown, with the "Q" portion. If the lever were part of the post, and not a wrench that must have "therbligs" expended on it to "find, orient, grasp, transport, align and force" in order to release the first tool, and then again to reverse the process to install the new one, it would be better, and have the "Q" portion of "QCTP" covered as well.

................

I don't like the method this post uses because it causes a hinge. The fairly narrow dovetail key is going to pull the holder into the flat surfaces and away from hard contact with the fixed portion of the dovetail. And that will cause it to loose registration pressure with the actual dovetail. At that point it will permit the tool holder block to hinge cutter down until it touches the fixed dovetails at the top of the rear and bottom of the front dovetail.

..........................

Not seeing it.

The "puller" appears to be in the middle. It apparently pulls the part either into the front of the dovetail, OR against the main part of the post. Either is in principle no worse than a piston post.

I agree that the wedge post is likely better, but it is better than the piston post as well. Almost every post aside from the wedge relies on some form of tension and resistance to bending.

AND, if you look at the innards of the wedge post, you will find that there is more "post" that IS NOT there, than there is "post" which is actually there. The "post" is mostly hollowed out, and additionally it has a couple of significant slots cut right through it.

So if you like nit-picking designs, one can make an argument that the post shown, if the slowness of changing can be fixed, is not bad compared to other "PRO" units.

[Randy]

... Does anyone know what
a Hardinge HLV quick change tool
post looks like?...

I didn't know it when I built mine, but it looks similar to Hardinge. I based the dovetail clamp on John Stevenson's design. The body indexes at 15° intervals, so a single clamp suffices. The first QCTP I ever saw was a KDK, which has a single dovetail, so that was in my mind from the start.

[BCRider]

....Not seeing it.

The "puller" appears to be in the middle. It apparently pulls the part either into the front of the dovetail, OR against the main part of the post. Either is in principle no worse than a piston post.

I agree that the wedge post is likely better, but it is better than the piston post as well. Almost every post aside from the wedge relies on some form of tension and resistance to bending.

AND, if you look at the innards of the wedge post, you will find that there is more "post" that IS NOT there, than there is "post" which is actually there. The "post" is mostly hollowed out, and additionally it has a couple of significant slots cut right through it.

So if you like nit-picking designs, one can make an argument that the post shown, if the slowness of changing can be fixed, is not bad compared to other "PRO" units.

In the case of the Hardinge style and the similar one shown by Randy the puller acts against just one side of the dovetail of the holder to force the other full length side into solid contact. So those are better.

The one in the first picture though has the puller as a full dovetail shape and pulls both sides inwards. This pulls the holder away from the dovetails of the post leaving any clearance free to cause some play. This is not as good as the usual style piston tool posts because those at least force both sides of the dovetail solidly into contact. In short the one in the first post is not really any better than a flat surface with an anti rotation pin. Because of the way the puller acts on both sides of the holder's dovetail there's no firm locking force seen by the dovetail other than from the puller. If the puller were a one sided version like Randy's or the Hardinge unit that would make the one in the first post at least that good. But it fails to use the dovetail it has for the primary function of ensuring a firm and repeatable contact.

[J Tiers]

............. This is not as good as the usual style piston tool posts because those at least force both sides of the dovetail solidly into contact. In short the one in the first post is not really any better than a flat surface with an anti rotation pin. Because of the way the puller acts on both sides of the holder's dovetail there's no firm locking force seen by the dovetail other than from the puller. If the puller were a one sided version like Randy's or the Hardinge unit that would make the one in the first post at least that good. But it fails to use the dovetail it has for the primary function of ensuring a firm and repeatable contact.

Some push, some pull. Solidity is no worse on one than the other. We were NOT discussing the accuracy, just the solidity.

If you want to argue about the dovetail and alignment, which is a fair point, then there are others pretty bad also.... The type that you may even be referencing, where a taper piece is forced down by a screw and opens the split dovetail to wedge the part, for instance.

There, you have a split, and the way the dovetail opens up may or may not put it in the same place every time. Depends on many things, including how springy the post is, and which side is weaker than the other.

Slice up them hairs any way you like, the wedge comes out on top most all the time, and the competition may not be even close.

[BCRider]

I'll grant you that in many a case we are talking hairs. But the one in the opening post compared to many seems to have a lot more split ends....

In my searching around for home shop made options before I broke down and bought an Aloris clone I was leaning heavily towards the one in the YT link below that borrows heavily on the MLA-23 DESIGN .

Shop Made Quick Change Toolpost - YouTube

Yes it's a split post style. But I'm thinking that it avoids the usual flexible feature you are describing by having the cone that forces the spreading of the dovetail also being the force that pulls the post down against the top of the slide.

And splitting hairs or not I'm confident that this is a better design in all respects.

What finally made me go with the Aloris clone was the separation between locking the post in position from the tool holder clamping. The gain being that I could remove and replace a holder and it would still hold the setting for the cut to within a thou or so.

[wierdscience]

Not trying to go off topic here,
but Q? Does anyone know what
a Hardinge HLV quick change tool
post looks like? They have a side
and a front dovetail and the locking
elements is in the corner, and will
lock a toolholder in either position.
It is a tee nut of sorts, tightened
by a draw screw, diagonally through
the body of the tool post. Much like
the pictured above, but diagonally.
It is super simple, with just 2 moving
parts basically. It is just a bit smaller
than the AXA size. I wonder why
no one copies the Hardinge tool
post design? Some copyright issue?
Surely it has expired years ago.
I am half tempted to measure it up
and draw it in Solidworks and post
it here, if there is no legal issue
to do so. What do you all think ? ? ?

--Doozer

Actually somebody did. Scaled down to fit a Unimat/Sherline/Taig lathe, but the same principle of design.

https://www.homemadetools.net/forum/small-quick-change-tool-post-66191

[Randy]

What finally made me go with the Aloris clone was the separation between locking the post in position from the tool holder clamping. The gain being that I could remove and replace a holder and it would still hold the setting for the cut to within a thou or so.

Exactly. "Quick change" isn't quick if it's not repeatable.