If the boss wants to time the rotation of the bar to the Z movement there is a way to do it. Put the job in the spindle so you are rotating the job, clamp the threading bar to the table, flip the machine on its side and call it a lathe. Better still, get a lathe.

If you checked for linearized output then you would not get arcs with I & J - you would get a large number of small line segments in XYZ approximating a helix. Is this what you are getting? Let's see a code sample. How noisy was this job running? That's a fairly chunky thread for this method. Perhaps a stability problem?

Did it work OK the way you ran it? It sounds OK for a manual machine but maybe not for CNC. What sort of cycle were you using?

Was the diameter jumping about before you fixed the taper problem? I have seen something like this when we programmed out a taper - the X axis resolution on the machine was actually coarser than the displayed resolution so the taper correction was being applied in radial steps of 0.002mm. On a very fine taper this left clearly visible steps.

Watch it with the endmill. Some endmills have quite a lot of "dish". If you plunge a hole it finishes up deeper at the edge of hole than at centre. As MCM says you need a flat bottom cutter. Manufacturers can supply but, over here at least, you do need to ask for it.

Do you actually need to represent the dimples with surface data? Can the dimples be produced by just hitting the spots with a ballnose cutter?

I have a Kryle VMC535 miller, Fanuc OM, Mcam V9.1 level 3. The Kryle is equipped with a 3R reference plate and the machine XYZ = 0 point is set to a particular hole on the plate and not changed. Numerous different jobs go on this machine - some are repeat jobs held in a fixture and others arrive in a hurry, are machined in vices or chuck, and are never seen again. I am fairly new to Fanuc (getting excuses in early!) and here's how it works for now - I construct geometry around an obvious part datum and then put a datum shift into the program by typing the shift into 3 of the miscellaneous reals and sending these out with G52. Are there any pitfalls in what I am doing ? What method would you recommend for moving my datum about ? Thanks

Inconel 718 age hardened. I am using WNT CNMG120408 in grade CCN2120. Still looking for optimum settings but 30m/min, 2mm doc, .07mm/rev gives good tool life and excellent surface finish. Over the next few days I'll push up the speed. But here's the funny thing - I bought one of those xxxx looking toolholders to make use of the 'unused' 100 degree corner of the CNMG inserts with a 15 degree lead. Result - tool life much improved at increased doc.

I'm assuming your cutter is something like a rounded off T-slot cutter with R=5/16 and that the cutter major diameter is over 1inch greater than the shank diameter so that you can cut 1/2inch deep. Sketch up your thread profile on cad and position your cutter profile against it in as many positions as you think you may need to get the cusp height down to what is acceptable - probably an odd number - about 9 positions should be enough. Jot down the cutter centre positions. Thread mill using these figures for radius & depth with radius compensation off. You will get a distorted thread form. If the cutter dia is small compared to the bore then the distortion is small but it's beyond me to quantify it.

In V9.1 I have seen overcutting happen when the tool is wrongly defined. If instead of a touch off point in Z/X you select the tool nose radius centre point it can overcut but doesn't show in the backplot. Not sure about the rapid though.

You've convinced me. I'll make the move. And probably start asking "How do you... " on this site. Thanks for your time.

A while ago there was a thread titled "How many of you guyz are still using 9.1". Most answers were along the lines of "No way". Well I use 9.1 and I'm very happy with it. I have Mill L3 and Lathe running on XP Pro, programming for a 3axis VMC, a 4axis VMC and 2 x 2 axis lathes. Now recently this forum has become a massive grumble about the bugs in X4 and X4MU1. I am quite willing to spend on an upgrade to X4 and was intending to do so as soon as MU1 was released but now I'm not so sure. Will I end up tearing out my few remaining strands of hair? On the machines described will I find any benefits? To put it another way, how many of you guyz regret upgrading to X4? Thanks

Is turning out of the question? What about a Swiss type lathe, shaft first, support in a sub spindle. Part off with a biased tool and polish off the pip.

We also have the same problem on manual and cnc, internal and external threads, and as yet I don't know why. Sometimes we solve the problem by adjusting wear offset, sometimes by tool geometry offset and sometimes by programming so it's total confusion. I wonder if the problem is due to the rounding of the insert being of a smaller radius, or truncation being less, than that used in the threads in the tables (my tables were probably compiled in the 1960s). If that were the case then when you got a touch-off position, the insert flanks would be further from the surface than anticipated. It's got me thinking - I'll see if the insert manufacturers have their own set of tables for threading depths.

Sorry - I meant to add Mill L3 V9.1 SP2 Win XP pro Post is a slight modification of MPFAN

Yes I know it's very old but I need to put it into more regular use to be able to justify upgrading to X4 I set the wcs at some 3d point I want to use as a datum. I generate a toolpath and take a look at the nci file. I can see the wcs origin clearly defined as parameters 10,11,12 in a 1027 line. PP guide describes these parameters as Global post variables, and names them t_origin_x, ..y, ..z If I refer to (say) t_origin_x in any way in the post I get a posting error and: Variable not defined:t_origin_x Any ideas? Thank you

A couple of things you could try: If cycle time is not critical you're still a bit quick on RPM If it's possible to drop centre height a touch that might help, especially if you are rubbing at all due to helix angle Use a partial form insert so that the it doesn't suddenly increase its engagement as you get to depth - in the past we have even got out of trouble by using a neutral T insert for ISO/Unified and neutral D for Whitworth - but it still leaves you some work to do. Best of luck

Ooops - sorry for wasting time. Did a search and found lots of similar episodes and things to try.

Lathe V9.1 I have a component, dia 42mm, length 108mm, to be turned from both ends. I put toolpaths for 1st end in a group and generated and used perfectly good code. Used stock flip in a group of its own then 2nd end toolpaths in yet another group. Again generated good code. So far so good. Subsequently I wished to tweak some geometry on 1st end but found it difficult. If I adjusted the stock that I could see - which was flipped - it had no effect on the 1st end toolpaths. The only way that I was able to do it was by deleting the stock flip, tweak geometry, re-apply stock flip, then cut & paste it between the two other groups. A lot of trouble for frequent changes. What am I missing ? Thank you V9.1 SP 2 Mill L3, Lathe Windows XP Pro

Reading this forum I have been amazed at how many US firms are still using inches. I suspect that you will have to bite the bullet sooner rather than later and work in metric before your customers get an Indian firm to machine their parts. Quote: The machines, machinists, cutting tools and measuring tools will all be English. Do your CNC machines and CMMs actually care whether the data are metric or English ? You must be planning to use metric tools if there are tapped holes, reamed holes, thread milling, formed radii, etc. English measuring tools with metric drawings - you can tie yourselves in knots here. It's quite easy converting dimensions but it can be a bit of a bugger with tolerances - you end up with silly situations. e.g 3.00mm , tolerance +0.02mm - about a thou but not precisely so. Convert - 0.000787in On an English micrometer you can round up to 8 tenths - and go out of tolerance Round off to 7 tenths and struggle that bit more and spend an hour arguing about it. Realize then that it depends on adding first to the nominal dimension: result 0.118897 - call it 0.119 No - that's out of tolerance. Why bother ? Thousands of features on 24 sheets ? Buy a metric instrument: 3.02 The quality of the drawings / models is a completely separate issue from the units that have been used. If they have errors in metric then they would still have errors after conversion to English. Work in metric, find the errors, report them to your customer, become a part of the loop and charge them for it. Best of luck

I have recently acquired a Kryle VMC / Fanuc O-M with a quantity of System3R tooling including a matrix plate. I'm not sure of the best way to use it with Mastercam (V9.1 level 3). I would like to set a datum on the matrix plate and never change it, then put fixtures for numerous short-run jobs on the plate. I can either program jobs at a position in space in relation to my never changing datum - that fills me with dread - or I can set a datum shift to a local point - maybe using G52. Any experiences of this sort of thing ?