Bi-directional Single-Pass Tenon Cuts?

[Clint Buechlein]

Jeremy,

Attached are pictures when I run your code for the part in your original picture. Picture 1 is the entrance, 2 is the gap between tenons, 3 the exit, and 4 is a shot down the edge. There is a lip I can barely catch my fingernail on, nothing near as bad as what you are seeing. It was cut on our demo Cut Center, it should be results similar to what you'd see on your 45. On the 41, its a tossup due to its age and what may be worn. I did run the same feeds and speeds, though the Cut Center would have faster accelerations than what either of your machines would be, but if anything that would make it worse.

There is a slight bit of fuzz on the outside of the tenon, though I'd say that issue is due to the outline tool having a 3/8" upspiral in the compression bit and it being MDF.

That all being said, for giggles sake try bumping up the diameter of your tool. With me running the code, the only differences will be tool diameter accuracy, type of tool, how good of shape the collet is in, or possible machine mechanical issues. The tool I used was measured off the high tolerance tool sensor that can measure diameter, so the diameter should be accurate. The tool is our standard Cut Ready 3/8 compression. Not sure on the amount of use the collet has, though I know it is not brand new. We don't see any issues in our cutting so I'd assume the machine is in good mechanical standards.

-Clint-

[Jeremy Schiffer]

Thanks for checking that for me, Clint. What you have looks exactly like what we get from our 45. There is a ridge there, and on the assembled parts it leaves a small visible gap. If we could have the Single-Pass Tenon cut do a climb then conventional cut, that ridge (and resultant gap) would be totally non-existent. I don't know how difficult that would be to add to CN, but it sure would make me happy.

Now, about our 41: Just a couple hours ago, we FINALLY discovered what was responsible for the extreme amount of deflection: The lower few bolts that hold the Z-axis rails in place were completely loose, and that was allowing the rails themselves to slide back and forth on the mounting plate. We've never checked them before, but after 12 years of work, I guess ya gotta make sure everything stays tight. So, to anyone reading this who may be having excessive deflection, don't forget to check this. We were checking the ball nut, the Y axis bearings, and the spindle bearing itself - never thought to check the actual mounting bolts for the rails. I'm guessing now the 41 will show the small ridge like the 45 does.

[Jeremy Schiffer]

My post duplicated for some reason, just deleted it

[Clint Buechlein]

Thanks for checking that for me, Clint. What you have looks exactly like what we get from our 45. There is a ridge there, and on the assembled parts it leaves a small visible gap. If we could have the Single-Pass Tenon cut do a climb then conventional cut, that ridge (and resultant gap) would be totally non-existent. I don't know how difficult that would be to add to CN, but it sure would make me happy.

Now, about our 41: Just a couple hours ago, we FINALLY discovered what was responsible for the extreme amount of deflection: The lower few bolts that hold the Z-axis rails in place were completely loose, and that was allowing the rails themselves to slide back and forth on the mounting plate. We've never checked them before, but after 12 years of work, I guess ya gotta make sure everything stays tight. So, to anyone reading this who may be having excessive deflection, don't forget to check this. We were checking the ball nut, the Y axis bearings, and the spindle bearing itself - never thought to check the actual mounting bolts for the rails. I'm guessing now the 41 will show the small ridge like the 45 does.

Jeremy,

The pictures make it look worse than what it is. When I say I can barely catch my fingernail, its me having to put effort into trying to get my fingernail to catch. You may still try upping your diameter a little and see if that clears it up. Looking at my part in hand I wouldn't see there being a gap when it goes together, though I haven't cut a mating part to try.

I am unsure of what the difficulty of adding it in, though I can request. Also not sure what it would be called as it is no longer a single pass .

Glad you were able to find something on your 41. Always the unexpected non wear items that surprise you.

-Clint-

[Jeremy Schiffer]

I am unsure of what the difficulty of adding it in, though I can request. Also not sure what it would be called as it is no longer a single pass .

I'm sure we can come up with a clever name! It just seems like a complimentary feature to the outline climb/conventional option, since this also defines part of the outline of the part.

Won't increasing the tool diameter simply make the part that much larger, but not change the tenon/outline cut relationship? (I use the same tool, same tool number, for each of the cuts.) It would also affect any other rout operations performed with that tool. If the single pass tenon could call upon a different tool, then we could cheat the diameter like that without affecting anything else. Of course, then theoretically, the opposite ridge would exist at either end of the cut, because technically the cause of this issue is deflection, so the cutline isn't straight, but an arc.

I think I'm too picky. lol

[Neville Bastian]

If Thermwood are going to modify the dadoe cutting to get the outline straight could they come up with a idea to hold the panel in place when you push them together. Some guys keep pushing for using pins but thats a pain if you need to disassemble. If you had a clothes peg system which meant the dadoe tongue was not full length and the dadoe groove was not full but had a raised section. Thus you push them together but you can force them apart. I wouldnt think you would need to have different styles for particlboard, mdf or ply.
I could draw this but I dont think my Autocad skills are as good as Jeremy.

Regards Neville

[Jeremy Schiffer]

Hey Neville

Remember YouBuild? That had a very clever blind dado that was tapered, so that you had to offset it to put it together, then slide it sideways to line it up which (due to the taper) tightened up the joint and held it fast together. Be cool if that joinery could be put into ecabs. There was also another dado that required a special barbed bit...