Ok, I give up. 7 start thread

[alloy]

It's a Fanuc OT control. I've been searching for examples but haven't found the problem yet.

Edit:

Fro a few examples Ive found there isn't a decimal point on the X and Z.

I might see if deleting them will work tomorrow.

Bed time for bozo now. Later.

 

[mmcmdl]

Hey Alloy , I ran the OT controller and I think I told you I still have the programming manual at home . I'll look for it tomorrow . I think I also have some old programs that I saved . Have a good night !

 

[addertooth]

I don't do CNC (anymore), but I do manually make multi-lead threads. What I am seeing in the picture looks like the offset for the start point is not consistent. With a 7 lead thread, each start is 1/7th the distance of the thread pitch.

For example, with a THREE (3) lead thread which is running at a single pitch of 8 threads per inch, it looks like 24 threads per inch, but has the steepness of 8 threads per inch. Each start Has the Z offset by about 41.66 thousandths (on a manual lathe, the compound is set parallel with the ways, and is the compound handle is cranked to move the cutting tool towards the chuck). This way, you aren't changing your rotational indexing... MUCH easier to do. In your case, the Z offset would be 1/7th of your thread pitch (for a 7 lead thread). What I didn't see clearly stated above, is what your actual actual desired thread pitch is.

Back in the very ancient days of CNC (late 70s and early 80s) we might achieve this by putting in a tool offset in the Z axis for each thread start. Z=Z-(offset value which is 1/7th of the pitch of the major thread).

 

[alloy]

Look forward to seeing your programs.

I've been up since 4am playing with this. Mastercam has 4 different ways of generating code.

I tried G92 and this is the code it came up with for a 7 start. There is a .1035 difference in the thread starts and not .041.66. I think the steepness of the thread is also a problem. Just looks off somehow.

Haven't tried it yet, too early to start up my compressor and shop radio. The neighbors don't like to hear my big compressor pounding away, not to mention some Joplin blaring on the stereo. (I'm very hard of hearing so stereo is fairly loud now days.)

The other thing I'm curious about is how on an identical part blank did they get a 6, 8, and 9 start threads and still use the same driven gear?

N1 %
N2 O1206
N3 (PROGRAM NAME - 7 start)
N9 (TOOL - 5 OFFSET - 5)
N10 (GEAR INSERT INSERT - NONE)
N11 G0 T0505
N12 G18
N13 G97 S400 M03
N14 G0 G54 X2.2 Z2. M8
N15 G99 G92 X1.7938 Z-.61 F.72464
N16 G0 X2.2 Z1.8965
N17 G92 X1.7938 Z-.61 F.72464
N18 G0 X2.2 Z1.793
N19 G92 X1.7938 Z-.61 F.72464
N20 G0 X2.2 Z1.6894
N21 G92 X1.7938 Z-.61 F.72464
N22 G0 X2.2 Z1.5859
N23 G92 X1.7938 Z-.61 F.72464
N24 G0 X2.2 Z1.4824
N25 G92 X1.7938 Z-.61 F.72464
N26 G0 X2.2 Z1.3789
N27 G92 X1.7938 Z-.61 F.72464
N28 X1.7875
N29 X1.7875
N30 X1.7875
N31 X1.7875
N32 X1.7875
N33 X1.7875
N34 X1.7875
N35 X1.7813
Snip...........just repeats

 

[alloy]

Don't know if this helps but the lead = 8.6956 TPI (1 / 0.115) or maybe 3mm lead as 0.115 works out to 2.921 mm

what's the OD and the single depth?

Sorry Jim,

I missed your question.

OD 1.870
Depth .110
Width of gear .610

 

[middle.road]

We know this guy who could possibly handle the CAD end of it for you...

CAD Services Introduction - Bryan (vtcnc)

I've been a member for many years now on Hobby Machinist and am an administrator on the forum. I really value the membership here and have learned so much that I'm not sure would have been learned elsewhere online if it weren't for the friendly culture here on this site. I'm a...

www.hobby-machinist.com

 

[alloy]

We know this guy who could possibly handle the CAD end of it for you.

I may just do that.

 

[Papa Charlie]

I have no experience programming CNC. But looking at the first image in the first post, it appears as though the dropped thread is the 7th one from the end.

 

[alloy]

Not sure which one it is. I've already machined over that thread with another test thread.

Just tried G92. Results, not good.

I like the format of G92, but if it doesn't work them have to keep looking.

Tried G76 again. Alarmed out on the first G76 line.

G92

G92

 

[mmcmdl]

Alloy . Let me get settled in here for a bit . I only had about 2 minutes to try and locate some things and found only a smidgeon of the OT stuff . G76 and G33 can be used , and I think I found the pages . I may take a pic of the sheets and send them to Mike ( Aukai ) and maybe he can post them on here with his better camera . Let me get settled in here at work and I'll get on it . Dave .