Toolpath for dovetail o-rings?

[JVizzi]

I searched the forum and couldn't find anything. I do alot of Parker Hannifin dovetail o-rings and I'm just not sure of a good toolpath to use to run the dovetail cutter. It basically needs to plunge in and follow the centerline of the groove. The only thing I can figure is to use a contour and pick the outer wall and "leave stock" 1/2 width of groove.

 

Anybody else come accross this problem?

[crazy^millman]

3D contour will do this just need to draw your geometry to match the motion you are looking for. You can make 2D contour work just need ot keep in mind your stop and start point when picking your chains. Use the extend arrow on the chains and you can see the start selection.

[Rstewart]

Just turn Cutter Comp to OFF, and No Lead-In Lead-Out.

[taperlength]

Usually to get a good finish (32 or better),  it's best to use a dovetail cutter slightly undersize.  Mill the first pass down the center and with a few tenths stock on the floor.

Then a finish pass along both sides, climb milling each way.  Harvey Tool and others sell these undersize dovetail cutters.

[civiceg]

I honestly have never machined undersized and then climb both sides, too slow, just right down the center to the correct depth. Very shiny, easily a 32 and good luck measuring the surface finish. I would rough the groove width to the right size with an endmill and leave .001/.002 on the floor for the dovetail tool to finish the bottom and have no mismatch. Chaining can be done a few different ways, depending if the groove exits the wall. 

[guitar]

I honestly have never machined undersized and then climb both sides, too slow, just right down the center to the correct depth. Very shiny, easily a 32 and good luck measuring the surface finish. I would rough the groove width to the right size with an endmill and leave .001/.002 on the floor for the dovetail tool to finish the bottom and have no mismatch. Chaining can be done a few different ways, depending if the groove exits the wall. 

 You are machining undersized when you rough the center with an end mill. Rough the center leaving stock on left/right/bottom. Then 1 pass each side with the Dove. We never cut to size. Tolerance on the tool grind is usually more than the tolerance on the groove. We get tools from ABtools. Beautiful finish.

[civiceg]

No I stagger my depth cuts to finish the slot with the endmill if the endmill diameter wasn't in the middle of the +/- .001 width. Most of the time I would get the proper sized endmill and if running true it might cut a few tenths bigger than nominal with taking a full diameter cut. 

 

Neck dimensions yes, but angle profile and bottom width were always well within. The neck and depth were the only things tied up +/- .001. 

[jlw™]

Wow, so much hostility.

 

Fwiw I rough with an endmill then dove straight to depth in the middle then climb up one side and back down the other. I've never seen a dovetail with a tolerance tighter than that of the cutter.

 

Also, given he said he wanted to plunge in then follow the center of the groove I can see what Ron was pointing at with 3d contour. To say he clearly doesn't know what he's talking about is a bit over the top. There's always more than one way to skin a cat. I personally try to be open minded to other techniques, even if I don't use it I'll store it for later.

[Watcher]

Wow, so much hostility.

 

Fwiw I rough with an endmill then dove straight to depth in the middle then climb up one side and back down the other. I've never seen a dovetail with a tolerance tighter than that of the cutter.

 

Also, given he said he wanted to plunge in then follow the center of the groove I can see what Ron was pointing at with 3d contour. To say he clearly doesn't know what he's talking about is a bit over the top. There's always more than one way to skin a cat. I personally try to be open minded to other techniques, even if I don't use it I'll store it for later.

 

I don´t get why guitar has to find a way to attack Ron like that. Honestly, I´m glad I don´t know you in person.

[gcode]

here's an old o-ring file I did a few years back  ( a zipped X9)

 

edit... forgot to attach the file

 

 

 

 

o-ring.zip

[Guest]

I dunno, seems to me someone may be in need of a timeout.

[gcode]

I just hid a half dozen posts

Let keep it civil please

[civiceg]

OP was asking about the dovetail cutter tool path, which you can not use a 3d countour on. The endmill to rough or finish the slot sure, but not the dovetail.

[Guest]

OP was asking about the dovetail cutter tool path, which you can not use a 3d countour on. The endmill to rough or finish the slot sure, but not the dovetail.

 

Actually you can.....but I don't have the time or wherewithal to go over it 

[civiceg]

What draw your entry line and plunge with the 3d contour? You cant ramp, which is what I imagined what was being suggested.

[JVizzi]

Thanks for the suggestions/discussion. I ended up going with the idea I mentioned in my OP and it worked just fine. But I can see the 3d contour method working much easier. You just need to first draw the centerline of the groove, and a vertical plunge line, which I will try next opportunity.

[crazy^millman]

Thanks for the suggestions/discussion. I ended up going with the idea I mentioned in my OP and it worked just fine. But I can see the 3d contour method working much easier. You just need to first draw the centerline of the groove, and a vertical plunge line, which I will try next opportunity.

Glad you got it figured out and you can define the exact entry and exit using that vertical line. I have done many parts that have an odd ball start place and by using the vertical line you can use trim/break then break the centerline to get exact control. Remember 30 years ago having to trig all of it out, now you draw a line and done. I wanted to give an out of the box method to approach it. What crazy people do we seem to think out of the box. For roughing these grooves you have the start circle and can get real trick and make one operation. I have used a circle for the start hole drawn to centerline and then the oring groove of the shape I cutting center line use 2d contour and ramp. Can always use the hole/helix for the start hole and contour like I assume you did here.

 

I find myself telling people all the time what we do is as much art as it is science. Creativity is as much of this profession as anything and at the end of the day as long as we get the job done and the part comes out correct that is all that matters.

 

Sorry I still get a laugh out of what was up before.

[guitar]

"Glad you got it figured out and you can define the exact entry and exit using that vertical line. "

 

LOL. Why would you want to? Just create entry/exit points using 2d paths like everyone else on the planet.  You can even control the entry feed over ride using this method. Creating vertical lines for entry/exit is non productive. It's like creating a 3d tool path when a taper mill can be used, and faster. Really, now. Teach him the correct way to do it. Life is much easier that way.

[crazy^millman]

"Glad you got it figured out and you can define the exact entry and exit using that vertical line. "

 

LOL. Why would you want to? Just create entry/exit points using 2d paths like everyone else on the planet.  You can even control the entry feed over ride using this method. Creating vertical lines for entry/exit is non productive. It's like creating a 3d tool path when a taper mill can be used, and faster. Really, now. Teach him the correct way to do it. Life is much easier that way.

 

Why wouldn't you? Does it make a good part or not? So now only your way is the right and correct way?

 

There you go again making it fit your narrative. Did I say it was the right way or the only way? No not once I have every said that. Hate on and have a great day doing it.

[DanielGingras]

The problem at hand appears to have been solved and the purpose of this thread has been met.