[EvolveES]

Hello,

I have read this forum for years and just recently joined. This last year we got a Tormach PCNC1100 Series 3 and i have enjoyed every chip i have made. I've gotten comfortable with Mastercam and getting the machine to do what i want but now we are getting into some work that would routinely call for +/-0.002" and i have noticed some problems.

We haven't had much difficulty hitting +/-0.002" on smaller parts held in the vice, but i am worried about making larger fixtures for larger parts with the issues i am seeing. The main one seems to be the flatness of the mill table. If i put a depth gauge in the spindle and zero it at the top left corner and then check other points on the table i am seeing some variation. The worst of the variation seems to be from the top right to the bottom right corners, it is going from -.0035 to +.003 when compared to the top left (that's a total variation of 0.0065" over 9" of Y travel!). Is there anything to be done about this? I have leveled the machine with shims under the feet and this seems to be the closest it wants to get to flat.

My second issue is when i measure the edge of the center precision T-slot i am getting a variation of 0.0115", i have always wondered why the vices we use will not align with the keys in them. Is there any adjustment that can be done for this? I am debating running an endmill down one edge of the slot to straighten it, but that will only get the 18" that the mill can travel...still may be better than it is now though.

My best solution i can think of for all of this is to get a Tosa Tool Plate and level it in the Z direction with shims under it, and then align it to the X travel and do all of the fixturing from there?

Other than that the machine seems to be in great adjustment, all backlashes are < 0.0005" and the spindle nose runout is < 0.0002

Thank you for any help

[MichaelHenry]

Have you checked tram on your mill? My very early Series 1 was out quite a bit and I corrected it by shimming the four corners between the mill base and the top of the cabinet.

Mike

[SCzEngrgGroup]

If a dial indicator in the spindle shows variation in height as the table is moved around, that suggests the table itself it not consistent height w.r.t. to the ways. One way to fix that would be to remove the table, and have it ground, referencing off the ways. That should get you near perfect. The crooked T-slots could be fixed at the same time. The whole thing would be fairly quick, and should not be hideously expensive - certainly much cheaper than a Tosa tooling plate! Removing the table is not fun, but not really all that hard either.

Regards,
Ray L.

[tmarks11]

My second issue is when i measure the edge of the center precision T-slot i am getting a variation of 0.0115", i have always wondered why the vices we use will not align with the keys in them.

Which is why a lot of shops with professional level equipment don't rely on vise keys to align their vise. Sweeping a vise with a DTI to align within 0.001" should only take you 2 minutes (with some practice). I bought a set of keys (DAMW), but haven't even bothered to install them to see if they work.

Why do you call it "precision t-slot"? It looks like it is milled, not ground, just like any other (non-precision) t-slot I see on other machinery.

wrt to table flatness... I am thinking it is not that the table is not flat (although that might be true), but is that the head or column is out of tram.

I don't agree with all of the approaches John took in the video below, but what he did works... and you can see an amazing change in indicated readings from a pretty simple process:
https://www.youtube.com/watch?v=lle-k_ccFAA

[SCzEngrgGroup]

I am thinking it is not that the table is not flat (although that might be true), but is that the head or column is out of tram.

Tram cannot explain the table appearing to rise and fall as it's moved side-to-side. That can only result from either the table being thicker or thinner, as measured from the table surface to the horizontal portion of the ways, at various locations, or the machine base twisting, a LOT, as the table is moved. The Tormach base is a big, beefy casting, and it's not going to move significantly just due to the weight of the table. You can tilt the column 10 degrees, and a dial indicator in the spindle should show no rise and fall of the table surface.

Regards,
Ray L.

[tmarks11]

Tram cannot explain the table appearing to rise and fall as it's moved side-to-side.

Maybe my reading comprehension sucks, but I didn't get that from his post. I didn't see anywhere where he talked about dips or valleys.

The worst of the variation seems to be from the top right to the bottom right corners, it is going from -.0035 to +.003 when compared to the top left (that's a total variation of 0.0065" over 9" of Y travel!)

Sounds like a two-dimensional tramming problem (tram error in X and Y). Before grinding the table, I would see if I could solve by shimming, attacking one dimension at a time. Much easier on a bridgeport.

[instructor37]

Tram error would show up if he were sweeping his indicator in a circle over the table. With the indicator held in a fixed point above the table and getting a variation as the table moves under it indicates the table is not flat.

[EvolveES]

Thank you for all of the great advice everyone! To answer a few questions i was moving the Z up and back down each time because i wasn't sure about dragging the tip of the depth gauge, i will repeat the tests with an Interapid dial i have. with the Z backlash at <.0005 i don't think it would be too far off to move it up and down (at least compared to the 0.006 i'm seeing).

I think for me a surface plate would probably work best, i am thinking about shimming it up with as thin of shims as possible to keep good contact with the table and preserve Z height, and then plug all of the holes with set screws. I like the idea of making my own but that limits me to just a little over the 9.5" x 18" work area of the tormach if i want to keep it true (i fear if i move it and resurface it will not be consistent due to the warp in the table. Tosa sells a aluminum tool plate for like $500-$600 but i wonder how much i would ding it up setting vices, turn tables, and other heavy fixtures on it.

Looks like i should start saving up for the Tosa Tool Plate lol in the mean time i am going to tram it again and double check the shims under the feet, spindle squareness etc and see if i can find any other culprit.

Thanks again everyone, this is one of the most helpful forums i have been on!

[SCzEngrgGroup]

"i am worried about making larger fixtures for larger parts with the issues i am seeing. The main one seems to be the flatness of the mill table."

I read his explanation as saying that the Z distance from spindle nose to table top surface varies, based on table position, by as much as +/-0.003".

Regards,
Ray L.

[Steve Seebold]

I ALWAYS use soft jaws in my vise. I will indicate the vise straight and then machine a step in the jaws and I get a surface that's parallel to the axis of the machine.

I took the steel jaws out of my vise right after I got it, so it's probably been 3 years since I started using aluminum soft haws. For the price I get them for, I won't be going back to steel jaws any time soon.

When I get a job that requires a stronger jaw. I'll make some out of 7075 aluminum. The jaws I buy are made from 6061.

[SCzEngrgGroup]

I ALWAYS use soft jaws in my vise. I will indicate the vise straight and then machine a step in the jaws and I get a surface that's parallel to the axis of the machine.

I took the steel jaws out of my vise right after I got it, so it's probably been 3 years since I started using aluminum soft haws. For the price I get them for, I won't be going back to steel jaws any time soon.

When I get a job that requires a stronger jaw. I'll make some out of 7075 aluminum. The jaws I buy are made from 6061.

And that relates to the topic of this thread how??

[Steve Seebold]

And that relates to the topic of this thread how??

You wouldn't understand.

[tmarks11]

And that relates to the topic of this thread how??

Steve is pointing out how milling the soft jaws parallel to the axis gets rid of any inaccuracy in the "precision t-slot", allowing the vise keys to be used and still achieve good accuracy.

Good tip.

You wouldn't understand.

But Steve, I suspect others besides Ray missed your point, so instead of sniping, how about just helping out. Bickering in this forum probably drives away a number of would-be Tormach customers.

[vingchocho]

But Steve, I suspect others besides Ray missed your point, so instead of sniping, how about just helping out. Bickering in this forum probably drives away a number of would-be Tormach customers.

The bickering was clearly instigated by ray so calling steve on it is utterly ridiculous. how about you keep remarks like this off the forum because you are not helping either.

[popspipes]

And that relates to the topic of this thread how??

Alignment is whats relevant to the topic.

I do the same here as I machine 99% parts in the vise.

[philbur]

Alignment is whats relevant to the topic.

I do the same here as I machine 99% parts in the vise.

Nothing like digging up a body that's long dead and giving it one last kick just to make sure it really is dead.(chair)

Phil

[adamvs]

Alignment is whats relevant to the topic.

I do the same here as I machine 99% parts in the vise.

Naw, I'm glad this thread is still alive because it's something that plagues a lot of us. I checked mine, and thought, ok out by .0015 at the most, not too bad. But after reading this I now know it could be tuned a lot better. If there any pics around of the front support, third leg, I, for one, would like to see'em. Also would like to know what you used for shims.

[DLawrence]

I cut a piece of 5/8 thick steel plate 10" X 7" and slid it in from the side under and around to the front, to spread the front center temporary"3rd leg" weight out.


There was just room to slide the end if a slim crowbar in and raise the base casting enough to get a piece if .250 squair keystock in centered.

Measuring both sides with feelers revealed an astounding 100 thou difference........... I am letting it "rest" 48 hours in the three point position ,

hopefully some of the twist will spring out of the base.

I got an asortment pack of about a dozen 6" X 10" stainless steel shims from MSC they start at .001 and go up to .032

Going to try cutting them into an L shape about an inch wide , each leg 3" long

Dave Lawrence

[CadRhino]

I ordered a pack of precision brass shims off Amazon and cut them with a 3/8" center notch to slide the shims around the bolt.
Used a hand crowbar like tactical keychain used on his video. Worked great but I stopped before I got it perfect. It is currently good enough for my work.

Naw, I'm glad this thread is still alive because it's something that plagues a lot of us. I checked mine, and thought, ok out by .0015 at the most, not too bad. But after reading this I now know it could be tuned a lot better. If there any pics around of the front support, third leg, I, for one, would like to see'em. Also would like to know what you used for shims.

[waltpermenter]

I ALWAYS use soft jaws in my vise. I will indicate the vise straight and then machine a step in the jaws and I get a surface that's parallel to the axis of the machine.

I took the steel jaws out of my vise right after I got it, so it's probably been 3 years since I started using aluminum soft haws. For the price I get them for, I won't be going back to steel jaws any time soon.

When I get a job that requires a stronger jaw. I'll make some out of 7075 aluminum. The jaws I buy are made from 6061.

I understood what you were saying Steve, great tip.
walt