HF Micro-Mill Conversion

[anoel]

I finished converting my HF Micro Mill this weekend. So far so good, My first test cut after tweaking turned out rather decent...

I'll try to have a decent part produced with it to show here soon. Gotta clean up the mess now...

[CNCadmin]

Nice job, what kinda backlash do you have?

[anoel]

Thanks the backlash comp is set at with the stock screws is right at .003" on both the X and Y. I'm not using the stock leadscrew on the Z I replaced it with a 3/8"-16 Stainless threaded rod and homemade Delrin nut and so far have no backlash comp set on it.

[Deviant]

I do see one problem though. There is beer, but no hammer? How can you work on something without a hammer?

What steppers/drivers are you using?

[anoel]

Oh there "IS" a "well worn" hammer there. it's lying on the bench just out of sight of the camera.

I'm using the New Unipolar Chopper from HobbyCNC. (Works Beautifully)

The steppers are 144oz. American Precision Industries motors that I got from forum member.

[Deviant]

*grins*

What's the feed rate on that guy. I'm trying to get a rough idea on what mine will be. When I convert the HF mini mill.

Was there any reason you picked the micro mill over the mini mill? Personally, I like the look of the micro better, and really don't car for the 3 drill press style handle on the mini.

I haven't purchased the mini mill yet, but I stop by randomly and lay claim to the display model at HF.

Spoke with the manager, they are going to do price matching on homeir's. Just trying to gather more info before I hand over the cash. ((sorry for rambling))

[anoel]

I wish that I had gone with the mini-mill personally for a couple of reasons.

#1 reason is that MT2 for the Micro-Mill tooling is Way more expensive and less common than the R8 tooling of the Mini-Mill. The difference in tooling costs more than makes up for the price difference.

#2 the X and Y construction of the Mini is a bit better.

#3 the Mini-is Just beefier in the column and makes for a more rigid machine.

The Z on the Mini is a a bit trickier to convert but there have been several proven ways to convert that axis.

But in all I'm quite suprised at the Micro-Mill's performance when cutting.

I've done rapids of 28 ipm so far but that's a bit too fast for actual cutting on this little mill with anything but the lightest Depth of Cut.

[Deviant]

Yea, the beefy bit and the r8 tooling is the only thing still catching my eye about the mini mill.

I'm still struggling with building one from scratch, maybe for the next mill. Since I'd like to do small production runs, and not deal with the readjustment of the ways.

When you get a chance can you post some better pictures of stepper mounts.

What software are you using to convert your model to code?

Thanks for the prompt replies.

[strat]

i bought one of these yesterday ( what am i getting myself into ) i noticed you have like a shock on it for your z could i get the source for that from ya?

[MIKE JEFFERS]

hello
I cnc'd my micro mill a few months ago and have been running it a lot to get an idea
of its capabilities, and its not too bad my z axis motor (180 oz) isn't strong enough
so a pulse width of 30000 is set ,slow but reliable and the gibs need tweaked a bit
a second machine is on the bench fitted with brass gibs ,lapped slideways and
thrust bearings so we'll see if it makes much difference.
i run mine using finger collets i tried an ER25 collet chuck but the finish was not as good as the spindle collet , maybe you could try one as an experiment.

[anoel]

I ended up doing a 2:1 reduction on my steppers. And like the results much better. There's a yahoo group that discusses CNCing this mill.

http://groups.yahoo.com/group/hf47158toCNC/

You can see pics of my 2:1 conversion in the RenegadeCNC folder in the Photos section. I ditched the leadscrew on the Z and made a new brass nut fot it. I ended up turning 1/2" - 10 Acme screw and using delrin nuts on the X-Y as well to make up for the 2:1 reduction losses too. (I'm going to remake these nuts out of brass soon) I ended up pulling the steppers and controller from this machine to use on my new router, I've got to replace them soon as I'm itching to cut metal again. Do you have a lathe? A lathe has been even more handy than having a mill lately.

[itsme]

Hi there,

I also got a Micro Mill over the weekend. It is pretty decent and the quality is better than I expected. I spent a good 8 or 9 hours rebuilding it and setting it all up, and then proceeded to plug it in and give it its first run. Would you believe that I turned the switch on and...wait for it...nothing happened! I've tried all sorts and still nothing. What luck, they make thousands of these things and I end up getting the one that doesn't work...so it's back to the supplier on Saturday (a 3 hour drive one-way) to have it sorted out.

Anoel, I see that you were saying that the X-Y setup on the Micro is not as good as the Mini Mill. My Micro Mill came with a different base to the American ones. I think it is the base that you can buy as an 'upgrade' to give you more y travel (I think (???) I've seen them at littlemachineshop.com, but may be wrong). It seems very good. The one thing that I do prefer about the Micro Mill compared to the Mini Mill is the fact that the table has got 3 t-slots and is a lot wider. I also think the z axis leadscrew setup is better on the Micro for a CNC conversion, although the actual leadscrew supplied with the machine is not as substantial as the leadscrews on the X and Y axes. The z leadscrew should be easy to change though.

I can't wait to get my conversion done. I've got some 250ozin motors, a Xylotex unipolar board and a computer waiting - I just need a power supply (and a spindle that actually rotates when turned on...). I can't wait to start cutting metal. I have so many things I want to make!

Regards
Warren