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This is a very sweet deal, considering they offer the ballnut in the price quoted as well. The end machining actually covers both ends and it’s standard for the mentioned bearing blocks (like the ones I got). Their drawing is better than mine too, I wouldn’t have to explain anything.
That would have saved me a month for sure and wouldn’t have cost more, considering I had to spend extra for the shaft clamps.
Now you tell me, royal advisor? You are relieved from your duties.
No, I take it back. There are not so many of you out there.
EDIT:
I just noticed that with “incl. BTW” the price is a bit higher, but still not bad.
This is very true for the big fishes here unfortunately. Not so much for the little ones which are getting taxed out.
We are the only nation in modern history that lost a quarter of it’s GDP in time of peace. Which of course happened once the “bail out” programs kicked in. I could carry on, but it’s not of the present topic.
Thank you, CNCCAT. They acknowledged the mistake and refunded the machining fee.
We are therefore overcoming the threading issue and making the ballscrews funtional with shaft collars (in effect without spending extra). Can’t wait, can’t wait.
Also both girls have been waking up crying for different reasons and calling for mommy. So since Valentine’s has been postponed, let’s figure out some feeds and speeds for acrylic instead. I’m curious to see if a single flute 1/8 end mill is going to make any visible difference in finishing.
I am 15 years ahead of you and if you are going to spend the time the girls keep you awake on CNC there lies a big future ahead of you.
So if you have time to spare can you please make the sickest cleanest electrical installation to your machine, the machine lines you designed are clean and please do not spoil that like the SO3.
The barber paradox. Or what happens when you make a dustshoe for a new Z axis while using this Z axis without a dustshoe. Or Inventables launched a limited edition of the X-Controller with coconut sprinkles.
Plus N45 magnets. Plus brush. Plus many bad words to fit the brush and one little chip . I made the slot too tight and wasn’t in the mood to make another one.
Shooting handheld and wide open here (too narrow depth of field). What you cannot see clearly is the hidden right angle connector that does the trick for requirement #3. It’s something like this.
Here’s some behind the scenes footage of cutting trochoids at full depth (turn the volume down, it’s loud). I never had the chance to try HSM toolpaths on acrylic before. It behaved just fine and the walls look smooth even before a finishing pass.
There’s something so satisfying (and so hypnotic) when watching a bit cutting. And if someone thinks we’re weirdos for watching bits cutting they just don’t get how much science and how much planning and how much trial and error took place before that bit started cutting. Also, we’re weirdos.
And they fit perfect 2 out of 3 ballnuts. I’m keeping them for the 2 Y’s. Here’s a clip demonstrating one ballnut with the old bearings and one with the new.
However, the third ballnut is still a bit tight even with the 0.1244" bearings. I’m expecting another two smaller sizes to test.
I’m still saving ~$70, but wasting ~1 month. Is it worth it? If you have the time and will to experiment and learn your machine inside out, maybe. If you want to get done with it, definitely not. I have mixed feelings cause I want to learn my machine inside out but I also want to get done with it.
I would not recommend it to someone else though. So, even though the original post says this is not a guide, that particular case has been a very good lesson learned to share with prospective DIY ballscrew CNC builders.
Lesson for prospective DIY ballscrew CNC builders #1: Do not mix ballscrews and ballnuts, just get them as a kit.
When purchased in a kit, the ball bearings in each ballnut have been matched in the factory to be a perfect fit for that particular ballscrew-ballnut pair. A hair of a hair in diameter diff can make an impact. Too big: friction. Too small: backlash.
Here’s the matching process.
It took me around 15mins to repack a ballnut the first time, around 8mins this time. I thought I was quick, but the dude in the purple boxers is done in under 1min.
The X and Y plates will be cut by the B-Carve itself to replace the temporary ones once it’s operational. Since both X and Y plates are end plates, they are rather easily replaceable. The Z plate will be sandwiched, so let’s save some time and make it now on the X-Carve (which is still wearing it’s brother’s Z axis). It’s the only 8mm one.
I didn’t really have to finish it. I just wanted to try this out (no anodizing or powder coating option right now). And it fits the black-metal-black-metal pattern of the Z axis.
Let me share an educational failure as well. And a cure.
The Z plate above was the first aluminum part I ever cut. Before trying out the final piece, I tested on a scrap piece in order to fine tune the cut settings. The most challenging parts were the M4 holes (4mm dia, 8mm deep) due to poor chip evacuation. While testing a helical bore operation with a 1/8" bit at 1mm pitch (which at this diameter translates to ~10deg helical ramping) I did not like the sound it was making and paused the operation. It took me no more than two seconds to hit the power button on the router.
These couple of seconds when the router was spinning while standing still were enough to weld a little alu mushroom at the tip of the bit.
NaOH to the rescue. This comes with big bright X’s and skulls on the packaging. If you are going to try this, watch your skin, your eyes, your lungs (i.e. do it outside with gloves, eye protection and respirator) . I diluted about a teaspoon in what was about two fingers of water in a jam jar ( I should patent this as a new concentration unit of measurement).
I eventually settled with 0.5mm helical pitch ( ~5deg at the given diameter) for the final piece. Frequent spraying with WD-40 also helped with clearing the chips.
The aluminium build up depends on the softness of the aluminium used, standard extrusion is sticking easily while the 6082 should machine better. WD40 is always a good idea.
NaOH work very well, I have done the same myself a few times
Be aware that the dilluted water will heat up (quite a bit depending on the amount of NaOH added)
