Engraving /Micromachining tool holding advice needed.

Flynth said:
This is nice. If we weren't located half a world away I would be interested in buying it off you (if you didn't need it) :)

As an example what difference a thou of runout makes I took two microscope pictures of test pcbs milled. Those were done with 10 degree 0.1mm v bit (2.5thou ),10k rpm, 130mm/min (5.1in/min) feed, 0.04 doc (1 thou) 2 passes so total depth 0.08mm (2 thou). I estimate the width of the cut is 0.11mm (around 2.5 thou) on the first picture and 0.15mm (3.5 thou) on the second. It is not a huge difference, but I think it will affect the tool life quite a bit.
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BTW, this on on 3018cnc "Pro" version using the same g code. The only difference is the height map. As the pcb is not flat and it is glued to a piece of mdf it wouldn't be possible without a height map.



I always considered 3018 an engraver rather than a "mill" (even in quote marks ;-) I assume we have the same device. I have the so called Pro version that uses thick bakelite as y supports rather than aluminium extrusions. I think they are OK. They feel very stiff in hand. I'm not expecting miracles from it, but with some upgrades it should be possible to cut aluminium with tiny cutters at high speed and shallow doc. My main issue with it so far was the runout and the flexibility of the spindle mount. Imbalance caused by motor's shaft cutout is enough to cause vibration in the mount... I think it is because they saved money by designing large empty cavities in the plastic. If it was a solid block of plastic it would be much better. I'm considering 3d printing a new z mount from abs with close to 100% infill. That should be much more solid. Of course aluminium would be better.

Here is a photo of the above pcb being cut.
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Coming back to the original subject :)


Yes, definitely. With the ER holder I hope it will fit the bearings nicely and I'll be able to "dust grind" the taper to make it true once it is assembled.

Having to wait for that adapter a long time I may end up making my own equivalent before it arrives...

Also, why magneto bearings? Did you just happen to have them, or are they in some way better for a spindle?
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same as mine, mine is the big one it was about $220 of amazon with collets and some bits but i got it hooked up ready to go using easal from inventables i had it ready to go and it said turn on spindle so i did i went back and it could not find the machine and i cant get it connected to it and i dont know how and i cant figure it out :( and yes all of the cables are connected maybe should not have bought the cheapest one
 
Flynth, no, I don't need it, I have 3 more just like it and enough projects to choke a horse right now. The unit weighs about 912 grams as it sits. No idea what shipping something like it would cost?
 
Steve-F said:
Flynth, no, I don't need it, I have 3 more just like it and enough projects to choke a horse right now. The unit weighs about 912 grams as it sits. No idea what shipping something like it would cost?
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i would be interested where you got them i am trying to upgrade mine to
 
We have engravers at work and they upgraded to digital motors and spindles, making the old ones non compatible any more. They were offered to me then:<)
 
Sure Braeden, I don't know what to ask for one? At least you are "local" so shipping should be reasonable :<)
 
I think because they lend themselves to the task fairly well with the races being removable from the cages and being fairly close tolerance for not a lot of money, but nothing more than that. Any decent bearings will probably do!

I tried grinding my Bridgeport spindle after replacing the bearings, but found I couldn't get it as true as hard turning did. Your mileage may vary!
 
I have never sold on Ebay, only purchased and I don't have the time to monitor transactions. Are you a seller?
 
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