[smokediver576]

Ok, I'm a little bit confused here. I ordered 4 of the Tormach fixture plates along with the locating pins (see link below for what I got)

32624 - Aluminum Fixture Plate, 20"x9.5"x10mm

31855 - 5/8" T-Nut with Locating Pin (Blind)

All good so far right..... I've just got my mill up and running however realized that the center line of my Y axis is not centered over the center T-slot in the table. In fact, the Y center is actually 15/16" (.9375") towards the front of the machine.

Is this normal? Why would the center T-Slot not line up with the center of the Y axis?

Yes, I've referenced the machine and all and I get 9.5" of true travel in the Y position.

I know this sounds like a total newbie moment but I'm just disappointed that my new fixture plates cannot be used to the maximum work area. The location holes are in the center of the plate......

Thanks guys!

[SCzEngrgGroup]

"Why would the center T-Slot not line up with the center of the Y axis?" - Why would it? There is not a reason in the world for having such an alignment.

Regards,
Ray L.

[smokediver576]

"Why would the center T-Slot not line up with the center of the Y axis?" - Why would it? There is not a reason in the world for having such an alignment.

Regards,
Ray L.

I would have thought that if you have a 9 1/2" Y Axis work area that it would line up with the table (which is 9 1/2" wide)..... Seems strange that Tormach would sell a fixture plate that does not let you use the full work area of the plate (within the range of the X/Y machine axis that is).

But hey, if that's the way it is then I'll adjust, adapt and overcome!

Thanks for letting me know Ray

[tmarks11]

You could always ditch the t-nuts and drill locating pins and threaded holes into the table itself, with the plate located perfectly...

It does seem strange that they didn't locate the holes on the fixture plate off center so the plate would be centered correctly.

I don't think the fault here is in the mill, but in the design of fixture plate. I doubt any mill in existence has the center slot perfectly aligned at the center of travel. I could be wrong, but that is not a feature that jumps out as important.

You should provide feedback to Tormach. This seems like such a simple thing for them to get wrong, and so easy to correct.

[SCzEngrgGroup]

I would have thought that if you have a 9 1/2" Y Axis work area that it would line up with the table (which is 9 1/2" wide)..... Seems strange that Tormach would sell a fixture plate that does not let you use the full work area of the plate (within the range of the X/Y machine axis that is).

But hey, if that's the way it is then I'll adjust, adapt and overcome!

Thanks for letting me know Ray

I've got three CNC mills here, and have worked on several others. Not one has had the center of the table lined up with the spindle at the center of Y travel. In some cases, it's off by several inches. Even worse, in some cases, between the asymmetrical travels, and the position of the column relative to the back of the table, It's impossible to machine a part that is larger than several inches less than the Y travel. Now THAT seems stupid to me, to have more travel than you can really use on a single part, without crashing into the column. Even though my largest machines have 14.5" and 115" of Y travel, I have parts that use every bit of that range. It would really suck if I couldn't do that.

As smokediver said, in your case, I'd say the fault is in the design of the tooling plate. I would've made it so it was centered, just to provide maximum support for a part that requires the full Y travel of the machine.

Regards,
Ray L.

[Hirudin]

My Brother machine lines up basically perfectly. The front and rear edges of the table are the limits of the Y travel. I mean, I haven't tested it with an edge finder to see if it's off by a few thousandths or not, but it's very close. The same is true for the X axis, but the table sticks out 50mm on each side. It seems like this is the most logical arrangement.

[philbur]

My Brother machine lines up basically perfectly.

Tormach PCNC 1100 or 770 or .....?

Phil

[Hirudin]

Hehe...

I know it's sacrilege to bring up other makes, but I got the impression the OP was asking a general question about mills.

If this is suppose to be a Tormach echochamber, where all information not strictly related to current Tormach® brand products shall be banished, I can attempt to refrain from mentioning the outside world.

[vmax549]

You may see that problem on machines that started life as a manual machine design then adapted to CNC. During teh adaptation design consesions were made due to component clearances so the table travel ended up offset to the centerline of the table.

(;-) TP

[smokediver576]

Tormach PCNC 1100 or 770 or .....?

Phil

2012 - Tormach PCNC 1100 - Series 3. Guess I should have added that little tidbit.

[philbur]

Hehe...

I know it's sacrilege to bring up other makes, but I got the impression the OP was asking a general question about mills.

If this is suppose to be a Tormach echochamber, where all information not strictly related to current Tormach® brand products shall be banished, I can attempt to refrain from mentioning the outside world.

You seem a little paranoid, the only problem was that your post was ambiguous, the question was "name the machine you are referring to". Without a name for your brothers' machine other members may assume you are talking about a Tormach and then start to look for why their machine doesn't match your brothers'.

Phil

[LeeWay]

Hoo boy. What we have here....is a FAILURE to communicate.

[SCzEngrgGroup]

You seem a little paranoid, the only problem was that your post was ambiguous, the question was "name the machine you are referring to". Without a name for your brothers' machine other members may assume you are talking about a Tormach and then start to look for why their machine doesn't match your brothers'.

Phil

Brother is the MAKE of his machine: Brother International - Machine Tools

It is a commercial VMC.

Regards,
Ray L.

[tmarks11]

You may see that problem on machines that started life as a manual machine design then adapted to CNC. During teh adaptation design consesions were made due to component clearances so the table travel ended up offset to the centerline of the table. Yes, it draws some design cues from a RF45, but that is all (design cues)... not castings.

Nice conjecture. Except that the Tormach casting was designed from the ground up to be CNC, so that argument doesn't really apply. Yes it got some design cues from an RF45... but that is all. Not castings.

Since most work is done in a vise, and you really don't end up with the fixed jaw of the vise mounted off the back of the table, having more movement in the +Y direction just makes sense... that is where the workpiece is.

And look at bridgeport mills; again, not symmetrical in motion... because the work piece (in a vise) is not mounted symmetrical to the table, so it doesn't matter where the center t-slot lies.

[philbur]

Ops, seems I initiated the misunderstanding, my apologies.

Phil

[SCzEngrgGroup]

Since most work is done in a vise, and you really don't end up with the fixed jaw of the vise mounted off the back of the table, having more movement in the +Y direction just makes sense... that is where the workpiece is.

And look at bridgeport mills; again, not symmetrical in motion... because the work piece (in a vise) is not mounted symmetrical to the table, so it doesn't matter where the center t-slot lies.

That argument doesn't seem terribly compelling to me. Nothing you hold in a vise is going to come anywhere near the physical limits of travel of any good-sized machine. Only a large part or fixture bolted to the table will.

For maximum flexibility, you'd really want the spindle to be forward of the center-point of Y axis travel, to allow plenty of rear over-hang. In reality, many, if not most, machines I've seen have just the opposite.

Regards,
Ray L.

[Hirudin]

Ops, seems I initiated the misunderstanding, my apologies.

Phil

I'm sorry as well for snapping a little. I probably am a little paranoid.

[vmax549]

I think you will find it DID start out as a manual mill "design" and was adapted to a CNC. WHY ELSE would the table center be offset to the total travel center. It only makes sense. Very few designer will start from absolute scratch when you can be 80 % done with the engineering specifications/design standards by starting with a design then adapt what you need from there.

(;-) TP