[SCzEngrgGroup]

What if the problem is no necessarily the dovetails, but a misshapen gib strip, causing X axis to slide slightly off kilter. Seems like that would be detectable because you could rock the axis by applying pressure, so maybe that is not it.

An experienced machine repair shop could determine that quickly, and correct it easily. Even the gibs, in fact especially the gibs, are NOT inter-changeable, and require scraping to make them at all usable. However, it would be extremely difficult for a bad gib to cause what is shown in the videos.

Regards,
Ray L.

[tmarks11]

However, it would be extremely difficult for a bad gib to cause what is shown in the videos.

I figured that was a faint hope. Bad gib would probably just mean the table would rock no matter how tight you tightened it.

[chuckorlando]

I'm not sure any of this stuff is scraped machine to machine. If this machine was done by hand like people seem to think, how would it be out to begin with? Let alone bowe gibs and the like.

I bet a dollar to a donut they grind them then flake them to look scraped.

[SCzEngrgGroup]

I'm not sure any of this stuff is scraped machine to machine. If this machine was done by hand like people seem to think, how would it be out to begin with? Let alone bowe gibs and the like.

I bet a dollar to a donut they grind them then flake them to look scraped.

Call Tormach, tell them you damaged or lost one of your gibs, and ask them for a replacement. See what they say....

Regards,
Ray L.

[chuckorlando]

Call tormach and ask how they hand scraped a bowe gib to a straight way

But you would not even have to try an end up doing this with a grinder and flaking. Easy peasy

[CNCer__]

I was just trying to help, but I guess you know more than me, but hey, I've only been doing this for 55 plus years so what do I know.

Good luck.

Steve, I apologise for being a bit rude with my last reply to you. I was, and I'm still 100% sure that there was nothing wrong with the clamping method. I was checking it for any loose, play, etc.
I've only12 plus years of experience with some successes and patents, also registered in your country, ...but most of that in the micro CNC word. It's completely different animal, different specs, machines, equipment, etc.. Full respect for your experience, 55 plus years ...LOL that is something. Call me a newbie and I'll accept that. Backing to the test method, holding equipment in the vice and potential twist, play, etc. see the video test below. I agree that the loose movable jaw can twist but once something is clamped this jaw should not show any twist, play, etc.
The granite square was clamped for this test in the same vice with low force, manually by fingers (no handle). The DTI was measuring any movement between jaws. The force was added from both sides for each jaw. This testing force was higher, I say minimum 1000 times than pushing force generated by the DTI stylus in the original test.
Clamping Granite Square in the Vice - Hi-Res Video Test


Thanks again guys for your valuable replies. I still have hope that all this is caused just by the gib. The Y-axis gib has wrong geometry - bowed sliding surface and a flat back surface, so no bent as the one of these surfaces is almost perfectly flat. It was already discussed here:

[PCNC 1100] Y-Axis Gibb Issue

Gib Geometry (post #24) - video

Lateral displacement of work table (post #25) caused by the incorrect geometry of this gib - video with some data

[TomKerekes]

Hi CNCer,

Have you considered correcting this with software?

Regards

[oneineight]

It's comforting to realize that this forum is populated by adults.
Looking forward to reading about the resolution of this problem.

[popspipes]

I tried clamping a right trianglar piece of stock in my vise, It ran way out on the indicator, flipping it over made the same error in the other direction.

I would clamp a stud in the vise, sit the hole in the granite square over the stud and hold it down with a nut and plastic washer and align one axis to that, then check the other.
To prove the theory in your video, check not only the x axis of the square but also the fixed jaw of the vise, if they are equal then you can assume its clamped correctly.

Better yet, bolt it to the table in a similar manner for the test using a plastic or wood spacer under the nut so as to not damage the granite square.

Lets hope the error is in the method of testing and not the machine itself..

[flick]

Sweet merciful crap, he dialed both sides of the square in his video. Dialing the vise is irrelevant, it's the fixture, not the reference. The square could be held in place with a vise, a stud, double sided tape, or just gravity and good intentions. The indicator isn't going to move the square, and as long as the square doesn't move then it and it ALONE tells us everything we need to know about the squareness of the axes.

[popspipes]

Sweet merciful crap, he dialed both sides of the square in his video. Dialing the vise is irrelevant, it's the fixture, not the reference. The square could be held in place with a vise, a stud, double sided tape, or just gravity and good intentions. The indicator isn't going to move the square, and as long as the square doesn't move then it and it ALONE tells us everything we need to know about the squareness of the axes.

All I was getting at is that I couldnt clamp a triangular object and get it to align with the vise jaw by putting clamping pressure on one corner of it as was shown in the video.

The more the clamping pressure the more the indicator moved, not a solid clamping solution, just my opinion though........

[flick]

All I was getting at is that I couldnt clamp a triangular object and get it to align with the vise jaw by putting clamping pressure on one corner of it as was shown in the video.

The more the clamping pressure the more the indicator moved, not a solid clamping solution, just my opinion though........

And it wouldn't be good clamping practice if you were trying to get a workpiece to align with the vise, or if you were trying to secure the work against cutting forces. Maybe that's where some of the concern expressed in this thread comes from. Machinists are habitual creatures. We like doing things the way we know works. Usually, what works is to square up the vise and place a substantial reference face of the work against the fixed jaw. By following this practice we can infer that the work is aligned with the machine axis and secure against cutting forces.

But in this case, the method portrayed in the videos works just fine, because there are no cutting forces to secure against, and the alignment of the square is determined directly instead of by inference. I wouldn't be surprised if the vise was aligned before all this, and OP had to knock it OUT of alignment to get the square INTO alignment. And there's absolutely nothing wrong with that.

[popspipes]

And it wouldn't be good clamping practice if you were trying to get a workpiece to align with the vise, or if you were trying to secure the work against cutting forces. Maybe that's where some of the concern expressed in this thread comes from. Machinists are habitual creatures. We like doing things the way we know works. Usually, what works is to square up the vise and place a substantial reference face of the work against the fixed jaw. By following this practice we can infer that the work is aligned with the machine axis and secure against cutting forces.

But in this case, the method portrayed in the videos works just fine, because there are no cutting forces to secure against, and the alignment of the square is determined directly instead of by inference. I wouldn't be surprised if the vise was aligned before all this, and OP had to knock it OUT of alignment to get the square INTO alignment. And there's absolutely nothing wrong with that.

I am old and my wife says very opinionated and set in my ways ha!

I checked my machine with a 2" piece of aluminum barstock in the vise on parallels with the X zeroed, made several light cuts in Y, flipped the part and measured a few tenths in 2", pretty much right on, good enough for the parts I make....

[CNCer__]

It's comforting to realize that this forum is populated by adults.
Looking forward to reading about the resolution of this problem.

I'll update with progress on this. Tormach support manager is out of office until Wednesday, so I've to wait.

[Steve Seebold]

I would put a piece of stock in the "CENTER" of the vise, drill and tap a 3/8-16 hole in it, clamp your square to it, indicate the long edge straight THEN check the Y axis for square. But what do I know? I've only been doing this sinse I was 15 years old. I'm 72 now.

My PCNC 1100 Seeies II is a little over 5 years old and it's dead on square. I've checked it with a .0001 Interapid indicator.

[CNCer__]

My PCNC 1100 Seeies II is a little over 5 years old and it's dead on square. I've checked it with a .0001 Interapid indicator.

As I wrote in the last PM to you Steve, I really wish to have your Tormach mill, fully finished, inspected and made to spec.. The Chinese manufacturer was not so kind sending my PCNC 1100.

[MJKProjects]

I'll update with progress on this. Tormach support manager is out of office until Wednesday, so I've to wait.

Please kindly update on perpendicularity issue. As a prospective Tormach customer I am interested in Tormach's response. How is this issue to be rectified?
Regards
MJK

[Steve Seebold]

As I wrote in the last PM to you Steve, I really wish to have your Tormach mill, fully finished, inspected and made to spec.. The Chinese manufacturer was not so kind sending my PCNC 1100.

Try something new. Put a part in the machine make a CNC program and cut all 4 sides, then tell us how out of square it is.

[CadRhino]

Good advice Steve

Try something new. Put a part in the machine make a CNC program and cut all 4 sides, then tell us how out of square it is.

[Zetopan]

Try something new. Put a part in the machine make a CNC program and cut all 4 sides, then tell us how out of square it is.

And be sure to always use positive approach to eliminate any backlash!