[kstrauss]

The thread mills that Tormach sells are all four-flute single-form so they can cut any pitch threads. Assuming that I purchase the right pitch is there any reason that I cannot use a multi-tooth cutter (https://www.maritool.com/p846/Thread...duct_info.html) in a Tormach? I assume that I should start at the bottom of the hole to make best use of the multiple teeth. Any special precautions?

[sharmstr]

I use them all the time, especially the 1/4" NPT from lakeshore.. I start at the bottom and make 2 turns. Depending on the size, I'll make 2 - 4 passes. Watch this: https://www.youtube.com/watch?v=JOb2Sg_Sg2I&t

[IMT]

Multi point work fine and much faster than single point. Yes start at the bottom of the hole and make multiple passes. You should start at the bottom of the hole with a single point also so it climb cuts and throws the chips behind the cutter.

[Warren_3Deee]

I do it all the time and it works great. Mostly I use these for smaller sizes (M3/M4/M5) because the single point tool for these would be such a small diameter. But of course these each have a fixed pitch. For sized above that I use single point so I only need 1 tool that can do almost any thread pitch.

[Steve Seebold]

If you use the tool like the ones in the pictures you’d better get it right the first time because there’d be no way to pick up to make a second pass whereas if you used a single element thread mill, you could make as many passes as necessary.

[kstrauss]

Now I'm confused. Both IMT and sharmstr mentioned that they usually did multiple passes and, depending on the material, it probably isn't practical to make only a single pass.

[joshetect]

I think steve focused in on the tap, not the thread mill.

I have a few single points that I can get most threads with, and only a few multi-point. It really hurts the wallet when you break on of those multipoint threadmills (blind holes get me with those sometimes)

As long as you setup correctly in CAM they work just fine, just not as versatile as the single points, but like said, MUCH faster

[nitewatchman]

I hate to confuse the issue but.

When I need to threadmill a hole, especially if it is an odd size like 2"-16, I will modify a high speed tap to use as a threadmill cutter.

For this I would start with a 3/8"-16 tap and first cut off the incomplete threads from the end. All but one of the flutes are then ground away leaving a single cutting edge. I then load the cutter in a Darex end mill grinder and relieve the cutting edge until there is a small land left on the OD of the tap maybe 0.010"-0.020 wide. This removes the helix and allows the cutter to produce the thread form when rotated.

Cut a lot more threads using these than commerical cutters including things like 5/8"-32 male and female parts.

Gary

[Steve Seebold]

I think steve focused in on the tap, not the thread mill.

I have a few single points that I can get most threads with, and only a few multi-point. It really hurts the wallet when you break on of those multipoint threadmills (blind holes get me with those sometimes)

As long as you setup correctly in CAM they work just fine, just not as versatile as the single points, but like said, MUCH faster

WRONG. I am not focused on tapping holes. I was talking about milling a thread. I would use a single element threading tool. That way, if you need to make a second or third pass you can do it successfully. Whereas if you try to cut a thread with a tool like the one in the picture, there’s no way to sync up the spindle with the cutting tool.

[TurboStep]

WRONG. I am not focused on tapping holes. I was talking about milling a thread. I would use a single element threading tool. That way, if you need to make a second or third pass you can do it successfully. Whereas if you try to cut a thread with a tool like the one in the picture, there’s no way to sync up the spindle with the cutting tool.

WRONG! Steve, I think you should watch a few thread milling videos. There's no spindle sync involved.
Step


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[CitizenOfDreams]

When I need to threadmill a hole, especially if it is an odd size like 2"-16, I will modify a high speed tap to use as a threadmill cutter.

Thanks for the idea! I found a broken M5 tap and ground off all the teeth except one. Now I have a homebrewed single point thread cutter.

I tried it out with ThreadingMOP CamBam plugin. Works great in acrylic plastic (which is pretty much all my toy machine can mill).

[mountaindew]

I hate to confuse the issue but.

. I then load the cutter in a Darex end mill grinder and relieve the cutting edge

Gary

I lust for such tools

WRONG! Steve, I think you should watch a few thread milling videos. There's no spindle sync involved.
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Easy to see 4 tool paths in the still picture above. The tool shown was wrong until I seen the smaller one to right.

[hitachibos]

you need to have the "helical interpolation" option to thread mill. for moving 3 axis in an arc.

[TurboStep]

you need to have the "helical interpolation" option to thread mill. for moving 3 axis in an arc.

Nope! No options necessary (or even available). This is the Tormach forum - all available features are provided as standard at no extra cost.
Step

[IMT]

When was last time a control was sold that couldn't do helical interpolation?

[TurboStep]

When was last time a control was sold that couldn't do helical interpolation?

I've never been anywhere near a Fanuc controller but their support page:
https://www.fanucamerica.com/home/fa...rt/cnc-options
Says:

Often it requires just an activation of software options that were not part of the original machine tool package. If you are not sure which options are currently on your system, contact our Options Team and they can help determine which options simply need to be turned on and which ones are available for purchase on your specific system.

Some of our most popular options include:

Helical interpolation

It doesn't seem be be a question of being able to do helical interpolation, but rather having the feature enabled or installed. On the other hand, if an option doesn't need to be purchased, then why disable it in the first place?
Step

[mountaindew]

I use them all the time, especially the 1/4" NPT from lakeshore.. I start at the bottom and make 2 turns. Depending on the size, I'll make 2 - 4 passes.

Sprutcam also has a setting for thread taper found in NPT profiles so a user can get away with using a single point thread mill. I bet Fusion does also!

[RCaffin]

In the beginning ... it took a whole extra circuit board to do helical milling, and they were expensive. But that was a long time ago.

It seems that Fanuc have kept this approach to making an extra profit today, when any modern CNC package does helical (and up to 6 axis continuous) at ZERO extra cost. It's just software after all, but it seems that Fanuc can screw their customers extra for it. Which is why many Fanuc owners are ripping out the Fanuc stuff and replacing it.

Cheers
Roger

[IMT]

20+ years ago I ran Cincinnatis with the 850 control (which was replaced with the 2100 around 1997) and they could do helical interpolation. Surprised than any control sold today would not have it.

[kstrauss]

Playing a little more with conversational thread milling it appears that rather than using cutter compensation Tormach pulls the cutter diameter from the tool table and then hard codes it into the generated gcode. Has anyone fixed PP to do it right and/or sent a "feature" request to Tormach? It would be helpful to be able to generate code once and then update the tool table when one changes cutters.