Edge finish when cutting birch plywood

lol I knew it would :slight_smile:

sweet job man yeah you want to get a mortise compression tool and its not so hard on the machine

Ah ha, good idea. When I was ordering the tool I had no idea what ā€œmortise compressionā€ meant, but now I totally understand the value of having a shorter up cut :slight_smile:

Though with the 7.5 mm stepdown, I can get through 3/4" plywood in just three passes. Totally changes the amount of time a project takes! That said, you can totally feel the lateral forces being applied to the stock, especially when taking sharp turns.

oh yeah for sure man

yeah curious what setting do you have the router on?

and what tool did you buy if you dont mind ?

yeah you can feel the machine load up sometimes but thats not something a little motor tuning and bracing canā€™t fix the belts and frame with handle it

Originally on setting ā€œ1ā€, but I bumped it up to ā€œ2ā€ to get closer to the 16000 RPM that I ran my feeds & speeds at.

Whiteside UD2102: https://www.whitesiderouterbits.com/products/ud2102. Got it off Amazon yesterday and put it to the test today.

Whatā€™s your spindle rpm for 150IPM @ 7.5mm? Thatā€™s an aggressive cut. Itā€™s not torquing your z-axis?

I have my DeWalt 611 at setting 2, which should be roughly 16-17K RPM. It is aggressive but no, I donā€™t see any torque on the Z-axis. Perhaps it would be worth upgrading to the linear Z though, just to be safe.

Photo of the finish is in my project thread:

(sorry, on my phone so canā€™t copy it over to here)

If you are using Vcarve, you can have the profile toolpath perform a last pass with a very small .(02 inch) allowance. This will cause the last pass to be a full depth pass that removes the allowance amount all the way around the profile. The result will be a very smooth edge that needs very little (if any) sanding.

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I have used this quite a bit but be careful when you use it to make sure that the piece is well secured (not just the scrap around it). Even though it is a really light pass, because it is cutting the entire edge, it can still be a bit aggressive. I have had several pieces get ripped apart because what was being cut out wasnā€™t secure enough and it grabbed just enough to rip the tabs and yank the bit in.

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Yes indeed! I have messed up a few parts because the tabs broke on the finish pass. Now I usually use double sided tape and tabs to secure the part being cut out. It is amazing how much force that last pass can apply even though it is cutting only .02 inch.

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Huh. Interesting. I havenā€™t been able to rough that fast that deep on the XC with a 1/4" cutter without seeing a bit of twist in the Z on the X passage. But, my 65mm spindle is quite tall. Iā€™ll try choking down on it so it doesnā€™t have as much deflection leverage below the Z axis.

Maybe I donā€™t know what exactly to be looking for. If I take a video next time I do this, would you mind taking a look and telling me what you think?

The XC is a pretty flimsy machine. If you are overdriving the cutter you will see the it drag slightly behind the gantry direction, torquing the Z assembly a bit, and it will be slightly off axis. Itā€™s just another type of deflection. Overdrive it too much and it will stall or skip. Or if a narrower bit, might simply break.

A little single axis drag might not hurt on straight X or Y through cuts since it is still perpendicular on the radial plane and cutting through. But on an arc or diagonal you will be off both intended radial plane and axis, get a variable tapered wall and bottom.

The lower the axis on the spindle coupling, the less leverage for this kind of deflection, like the difference between holding a pencil near the tip or back towards the eraser. And why you are best to use minimum length cutters for the job.

Sure, post a video.

Alright, looks like Iā€™m a liar. There was some sort of mixup at Home Depot and I guess Iā€™ve been cutting pine plywood and not birch :expressionless:

Anyway, hereā€™s video as promised. 7.5mm @ 150 IPM:

oh yes the x-carve is very capable of that :slight_smile:

there is no sound? I would love to hear the sound of the machine you can tell alot by that do you have a video with sound?

Hereā€™s the full video with sound: https://photos.app.goo.gl/SlYTnWTFjgYmwYHf1

The sound is horrendous, much louder and worse than my last run. Thatā€™s not normal, is it? Might be pushing this past what it should be doing.

@RohanSingh

Holy Crap!!!

yeah your taxing the Router not the machine from the sound of it

what setting is the dewalt on?

its trying to stall the router you need more rpm which will give you more horsepower on that router

but yes dont do that again lol your are close to breaking something up the rpm and try again you only going .29"in soft plywood thats not to deep just need more hp at the bit

Heh. Big difference. On the Janka scale birches are up between 900 and 1400, and the pines used in common grade plywood is somewhere between 350 and 600 (though some pines like red pine are actually up in the hardwood range above hard maple.)

Birch itself isnā€™t super tough. I bet the glue in baltic birch causes more resistance than the wood itself. Your pine plywood will have big fat 1/8" or 3/32" veneers and half or one third the glue of the 1/16" veneers in comparable thickness birch ply.

But your setup looks fine. Canā€™t really see with the dust extraction in the way, but can tell itā€™s not bogging down. Easier to tell by ear - you will hear it double down and chatter on crossgrain.

Yup, not going to try it again until I figure out the issue. I was sweating the whole time but didnā€™t want to stop it partway through the piece.

It was all so nice earlier, not sure what changed :frowning:

I had the DeWalt on setting 2. Could try 3 or 4 but that seems a bit insane.