First CNC fart

[Errol Groff]

I have god results using mineral spirits as a lubricant for milling aluminum. Much cheaper than WD 40. Can be brushed on or sprayed on with a recycled squirt bottle. Also, my usual attitude is what do I have more of, time or money and the answer is usually time. So I tend to take a lot of shallow cuts, ie .025 DOC instead of trying to plunge in and take a lot at one whack. Fewer broken mills that way although I have broken my share!

As always, this is what works for me, YMMV.

Errol Groff

[BobWarfield]

Errol, I have also heard both Kerosene and Milk (?!??) recommended when cutting aluminum. I have tried the Kerosene (didn't want a sour milk smell in the shop!) with fairly good results on the lathe, but WD-40 works better for me on the mill.

Best,

BW

[wildcat]

I gave this another try yesterday and had more success but another broke endmill for a different reason. The stock was being held in a vice and during the final contouring (actually turning the final corner no less) I think the forces of the vice started to be relieved and the endmill got squeezed. Perhaps I will have to start buying endmills by the box? Thanks for everyone's suggestions. I taped an airline to mill to blow across the part and that made a HUGE difference. I posted more notes in the Photo Gallery but here is the sequence.

[BobWarfield]

Nice, got a lot closer before breakage that time, eh?

Wildcat, did you write the g-code by hand or are you using a CAM program?

I can see where the vise may have squeezed the end mill. For a part like this, I think a lot of folks would have drilled the center hole and bolted the part to a tooling plate so you could go all the way around it without squeezing anything. Clamp the edges outside the cut path for additional rigidity and holding power.

You could also mill the spokes and hub in the vise and then do the bolting to mill the outside wheel cut.

Looks like you're having fun!

Best,

BW

[zcases]

Is that an idler for a snowmobile......let me guess an Arctic Cat by your name. Nice job. Hope you could get going faster than 3ipm on that.....sometimes the faster feed will also help reduce heat because at a real slow feed theres a lot of "rubbing" of the flutes, rather than having them get a good bite and have the chip pull the heat out.

[project5k]

thats a really pretty part.. i hope i can get to that stage sometime...

[Randall]

I have seen this part before. How did you program it? Was it in bobcad?
Thanks
Randy

[wildcat]

A similar one was on the cover of Digital Machinist. I drew up roughly the shape they had except they had an additional "twisted star" radiating from the center. I have no idea how to draw that. I hope they will consider making the G-Code available for the parts described in their magazine.

http://www.homeshopmachinist.net/?pa...gitalmachinist