New toy for the shop, CNC Mill

[hotrodsonoma]

I want one.lol
then would have to learn to use it.

[Etype R]

Thanks Rob, figuring out how to hold the part can take quite a bit of time. I spent a couple hours thinking about how I wanted to hold down those little brackets. The other night I used that same fixture plate to cut a rear shock mount for a tube frame, and found out that having oversized holes (0.125") is not ridgid enough... I picked up a 3mm drill bit and a #31 and #32 bit today. Going to cut a new fixture bar tomorrow, and see which bit gives me the best fit for a m3 screw.

I also had some deflection on those brackets, not sure if it was from the loose hikes in the fixture, from climb milling, or something else.

[rob_b]

Take this with a grain of salt as I have exactly 1 credit hour of formal machining training, I just try new things a lot... But my favorite method of cutting hard to fixture parts is to use material that is thicker than your final part. Do all your top work leaving extra carrier material, however much the part/material needs to remain motionless during cutting. Cut .01"-.02 deeper than you need to then flip the part and face from the back to final size. Done. Well it might be a little more involved but I'm sure you get the idea. I've been cutting Delrin light bars that only have two .089" thru holes (basically can't bolt it down in any way) using this method machining all sides in only two setups.

[Etype R]

I've used that technique on some parts at work, its easier with thicker parts though.

Another part I have been working on, are some scx10 frame plates. I've made these with a drill press in the past for a couple of my rigs. I am going to build a new cage for my 4runner build. Also needed a couple sets for one of my friends, so this was a simple little part to do on the cnc.

I drilled a pile of plates a few weeks ago, milled the ends to length. I was going to leave them 1/2" tall, as it was just a simple drilling operation. But I ran into a clearance issue when I dropped a proline floor pan over the frame.



So I drilled and tapped a quick fixture that I could bolt the plates to, and ran a cutout program.



Switched to climb milling for the finish pass to remove the last 0.015"



And the finished part on my scx10

[Etype R]

I found someone who makes a belt drive conversion kit for my mill, hoping to have the parts in about a month. Will be upgrading the bearings as well, so I can crank up the speed to 6000RPMs without cooking the bearings.

After I get the belt drive finished, I want to work on adding a power draw bar.

[Etype R]

Finally got my belt drive kit, it was well worth the wait and the price. Its super quiet now, and the ability to crank it up to 6000RPMs is sweet.




I have a few small oddball parts to machine. Then I want to try making a set of beadlocks.

[Etype R]

Machined a V block jaw for my vice, might make the second one tomorrow after work. Going to use these to fixture some beadlocks, and anything else round that I might need to machine the ends of.

I decided to use a 3d profile to machine the v notch, mainly because I did not feel like having to flip the part over and relocating my edges again. And I still need to order some larger ball end mills, as well as a few radius bits. I ended up cutting the 3d profile with a 1/2" square endmill which is not ideal for 3d surface work.



Had to see how it held a wheel, so I grabbed a old blank Eritex beadlock rim I had.



Now I just need to model some wheel designs in solidworks, and get some aluminum bar stock.



Ohh and I also bought a old 7x11 bandsaw awhile back. Stripped it down, repainted it, all new bearings, new motor, and rewired it. Figured it would help cut some pucks so I could make a set of beadlocks. That and I have been wanting a decent metal cutting bandsaw for some time now.

Ignore the fact that the bearings are backwards... I forgot to double check the before picture when I put it back together.

[Crawling Calvin]

Belt drive on a small machine is a must.

V block looks pretty good. Advantage is if your going to just use one to rough out side 1 you don't have to worry about the overall accuracy of it. That said keep up the good prototyping and your on the right track overall honestly

[rob_b]

Nice work on the jaw and the saw. Been thinking that I need to make a nice multi-V fixed jaw for a while now. Seems like a pretty useful piece. I picked up a little 5x6 horizontal/vertical saw for myself from Enco yesterday (15% off and free freight). I'm tired of risking my fingers cutting aluminum stock on my wood miter saw Keep us updated

[Calderwood]

Originally Posted by rob_b

cutting aluminum stock on my wood miter saw

Good to know I'm not the only one...

[Etype R]

Finally cut something that resembles a wheel! Stopped at the steel yard this morning and picked up some aluminum round stock.

I've been wanting to do this since I got the CNC mill, but of course I haven't planned anything for it yet. So I still need to order a 2mm ball endmill for cutting the tire bead grove. I also want to order a radius edge bull nose endmill for doing all of the pocket work.

And I never did model up a wheel in solidworks, I kept putting it off. So I modeled up a simple design this morning to get my feet wet and test the V block.

Before I started, I squared up the vise on the bandsaw the best I could and made a cut. Saw made quick work through the aluminum



Verifying the toolpath, had a few cut depths off the first time I checked it.



And putting the mill to work, just using air through the coolant hoses. Misting a little WD40 on the part here and there.



Flipped it over and cut the backside. The finish looks worse in the picture then it really is. But I will probably order a 3/8" endmill with a 0.020" corner radius for cutting the pockets.



And the unfinished wheel.



Pretty happy with the results, being my first attempt at a wheel.

[Etype R]

So I decided to see how close a 1.9 Axial beadlock ring was to fitting my bolt pattern. Must be my lucky day, just had to drill out the holes to 3mm and it bolted up perfect. Also bead blasted the rim to give it a more uniform finish.

[rob_b]

Nice

[diesel kawboy]

I can see that it's time to collect on my transport and rigging fees! Awesome job Mike. I'm excited to see them.

[Crawling Calvin]

Lookin pretty snazzy!

Few pointers:
If you can on the pockets, drill an entry hole for the end mill. Even if it is smaller than the tool it helps prevent the center from "plunging" and that is what end mills hate!

Try running a roughing tool (can just be a regular old end mill that isn't dead sharp any more) around to clear stock and then come along with a brand new one dedicated strictly to finishing. it helps you maintain dimensional accuracy better and means you can usually pull off a much nicer finish

Your spot on using the air blast aimed at the tools. Nothing is worse than an end mill packing up mid cut

Overall good looking rim and nothing a little bead blast can't fix

[Etype R]

I hate doing tool changes right now, planning on a air powered tool release. So doing what I can to limit them. Ramping in for my cuts rather then a straight plunge. Also running a finish profile on everything.

I've been doing some research on the power drawbar, and I have a few options. I picked up a 4" air cylinder cheap, but even at 150psi it would only put out 1900lbs of force. I would need 200psi to bit the 2500lb mark I want. So the first option is a pressure booster and high pressure fittings. I could also use a can lever to increase the force. The last option is to find a multi stage air cylinder, which seems ideal.

[C*H*U*D]

One thing you can do to cut down on your tool changes is to run more parts at once. It looks like you can easily do 2 at a time with your vise, so cut a set of soft jaws to hold two. That cuts your tool changes in half. Or machine a fixture to do 4. Cut two on one side, and two on the backside. That way you're getting a pair of wheels off with each cycle.

How much are you leaving for your finish passes?

[Etype R]

I might make a soft jaw for 2 at a time. I made a set of soft jaws at work to books 3 parts at a time, and it works really well. I've only had a few parts slip lose. But with the time saved in setup is with scraping a few parts here and there.

Finish pass has been 0.015", default in my cam software. I was thinking about doing that down to 0.006" with the smaller endmills I am using. I also should have ran a finish pass on the face of the pocket, not just the profile.

[rob_b]

Depending on material a spring pass is a good idea too.

[Duuuuuuuude]

Be careful...wheels are addicting...