A2Z CNC Quick Change Tool Post

[RollaJohn]

I have just purchased from LMS the A2Z CNC tool post for my 7x14 lathe. Now I have a question about this tool post. When mounted with the dove tails oriented one facing the chuck and the other facing parallel to the ways, the operating handle on mine points away from me towards the work between centers. The handle's arc is from the chuck to the tail stock over the work. This to me seems 180o in the wrong direction.

Do I drill and tap another hole on the opposite side for the handle?
Do I send the unit back because of faulty handle orientation?
Or is there something I'm missing in how this device works?

I know there are many users of this QCTP on mini lathes out there, and its hard for me to believe that mine is the only one with this problem. After all the cam that operates the clamping pistons and the handle boss are one piece and made by a CNC controlled machine!! So the location of the handle should be controlled by the program.

How does your example of this tool post sit on your lathe? What am I missing?

 

[black85vette]

Try taking the tool holder off, rotate the handle 180 degrees and then put the tool holder back on. My handle will work in two positions. If that is not it, unbolt and take the handle assembly off and see if it can go back on in the right position.

 

[90LX_Notch]

A cnc program has nothing to do with it if it was loaded 180 degrees out on a fixture during manufacturing.

 

[rcmadness]

In this case CNC is part of the company name that makes it. "A2Z CNC"
I am with Blackvet on this one, Try turning the whole thing, if that does not work, remove the mechanism cap and see what you need to do to turn the handle assembly 180 degree's.

What ever you do I would not recommend drilling and tap an new hole. My wedge type was the same way and all I did was remove the handle cap and turn it CC until it slipped the threads on the wedges and took it 180 degrees more, turned in CW and it grabbed a different spot on the drive assembly and the handle was where it needed to be.

 

[Artie]

I just checked mine as per Back85vette suggests, mine can do it... I am unfamiliar with your tool post holder... wana drop some pics in? Otherwise we are pretty blind.......

Rob T

 

[RollaJohn]

Thankyou all for your replies. This is the tool post in question. The cam only has a single lobe so when rotated it engages the piston at each end of about a 90o arc.

The image shows how the manufacturer states the handle should point when the tool holder is in place and locked. As purchased my handle cannot get to this position with a tool holder mounted. My handle in the locked position is 90o counterclockwise from what is shown. Therefore pointing towards the tail stock.

After more study and disassembling of the tool post and pondering my options I have decided the best method to rectify the situation is to remove a few thousandths from the length of the one piston thus allowing the handle and cam to rotate further.

The handle position when using the other dovetail, used when facing or boring, is not in the way. Although this piston also protrudes slightly from the tool post body when changing tool holders causing a bit of fiddling to get the holder past the piston. I may do a bit of surgery to that piston also.

 

[black85vette]

After seeing the picture I have a question. Is that the orientation of the QCTP when you use it? Not sure if there is a "correct" way but I have mine rotated 90 degrees clockwise from that picture. That puts my facing tools to the far side of the tool post not the near side, if that makes sense.

 

[winklmj]

Here's where mine locks up with a turning tool mounted.

With a boring tool mounted the handle points more towards the operator.

If both pistons protrude too far the problem could be:

1) The slot at the bottom of the the tool holder dovetails is not deep enough. Is the handle position the same with all holders? If so I'd suspect either the pistons or cam.
2) The lobe on the tool-post cam is too tall--making the pistons stick out too far.

Got a 4-jaw? Could try taking the cam down a bit. Or, as you say, just drill and tap another hole and move the handle to a diff position. Or just contact the A2Z folks and get another.

 

[RollaJohn]

Yes, I have the tool post mounted with the holder as shown in the illustration I posted and as winklmj shows. In fact my tool post and lathe are the same as winklmj's. Except mine doesn't have winklmj's handle mod for the mounting cap screw shown and my tool post handle points toward the live center and creates an interference problem. If it would get to the position when locked as winklmj's does I would be satisfied.

From the A2Z instruction sheet:

"INSTALLATION
The tool post is installed on the compound or cross slide of the
lathe with a one dovetail facing the chuck and the other parallel to
the spindle as in the diagram."

(Then there is a very faint diagram showing this arrangement.)

When the tool post is mounted in this manner you can switch from the spindle cutting tools to a boring tool by just changing the tool holders without rotating the tool post. And IMHO it will make it easier to get the cutting tool close to the chuck without the tool post interfering. But what ever works for you is OK.

I purchased the tool post and tool holders from LMS in their #3486 Mini Lathe Tooling Package. All the tool holders fit the same resulting in the handle in the same position.

I have seen tool holders with a shallow vertical slot milled in the bottom of the dovetail slot on the tool holder to give a clearance for the piston. These do not. This would be another option instead of doing a mod to the piston and would leave the tool post in the original condition. In the case of a SNAFU it would be less expensive to replace tool holders than the tool post. Besides future tool holders may fit differently than my present examples.

 

[winklmj]

All my tool holders have a very tiny "slot" where the pistons ride that is deeper than the bottom of the dovetails (I think this is a common way of making dovetails). When I made my clones of the A2Z holders, I copied this detail to make sure they all mounted the same way. You can just barely make it out in the pic below. I got one too deep and a slight difference does affect where it locks up at. If you don't want to mess with the tool post or cam, and have access to a mill, this would be another way of fixing it. Since all your holders are the same, try it on one to get it dialed then rinse-and-repeat.

 

[black85vette]

This would be another option instead of doing a mod to the piston and would leave the tool post in the original condition. In the case of a SNAFU it would be less expensive to replace tool holders than the tool post. Besides future tool holders may fit differently than my present examples.

Everything you said here makes perfect sense to me. Sounds like you came up with an excellent solution.

 

[TroyO]

I had an A2Z toolpost on my 8X for a while, when I got it I had the opposite issue. The cam would swing by the pistons and barely achieve lockup. Luckily, A2Z is in Denver where I live so I stopped by the shop for them to take a look at it.

They fitted some different pistons to it and it's worked fine. Apparantly they have some dimensioning issues and had some runs of parts that don't quite fit. Mine were too loose, yours may be too tight.

I've since added a AXA 100 toolpost to mine so I have an A2Z toolpost, a couple of broken Cutoff tool holders (Has anyone got those to work? Mine keept slicing off the bottom ridge when you tighten a blade down in it?) and a boring bar holder if you are interested in them.

I'll let them go cheap! (I already sold off 7 of the regular toolholders.)

I finally got around the cutoff toolholder problem by buying a steel cutoff blade holder that clamps in to a regular toolholder. The part that holds the tool is the same concept as the A2Z holder, but made of steel and with a thicker bottom ridge. I got it off Ebay, but can't seem to find them again and I don't recall the sellers name.

 

[Davyboy]

Maybe a dumb question.... Are you turning CW or CCW to lock it?

Davyboy