Sieg X2 Mini-mill - Counterbalance or not?

[Vogavt]

I've cnc'd my mill with xylotex 4axis board, cnc4pc C11, 454oz stepper motors, and Ron Steele's kit.

Seems to be working fine with the exception of what appears to be a downward drift of the Z-axis. I've read several articles over the past few days about gas struts, added weights, 2:1 pulleys to decrease the weight at the added expense of length of cable, springs from the ceiling, etc.

The question I pose here is whether it is necessary to worry with counterbalance at all since I've made the cnc modification. During my perusal of the net, I found a comment on another site and read that to be the case.

Seems to make sense, but many brains are smarter that any single one.

Thoughts? Experiences?

Regards,

Vogavt

[TroyO]

I've never seen or done a CNC, LOL... but, it would seem to me that if the motors can yank around the unsupported head without issue, then why bother?

It would seem the motors would have an easier time of it the higher the TPI on the leadscrew.

I guess it depends on speed v. accuracy v. expense of larger motors?

(Edit, meant the higher the TPI on the leadscrew.)

[BobWarfield]

A counterweight will equalize the forths in both directions because it overcomes the gravity in one direction. However, you'll still have inertia with an actual counterweight. Gas springs don't.

In the end, hard to believe a small machine like that really needs a counterweight. The head just isn't that heavy.

I'm pretty sure Hoss experimented with a counterweight on his X2. You should ask him if it was worth the trouble.

Best,

BW

[hoss2006]

A system with 50 or more volts doesn't really need any counter balancing to get good Z performance
but a 24 V like the xylotex can use all the help it can get.
A counter weight with a cable attached to the head and a couple pulleys works great.
The weight can be anything you have lying around, paint can full of old nails, old brake rotor,etc.
Cable can be a length of dog line in the pets dept, they come plastic coated.
Attach the pulleys in the rafters if you can, the weight can be put out of sight behind the mill.
It definitely make a difference.
Hoss

[BobWarfield]

Glad I suggested the Hossmeister be consulted!

Darn, those Xylotexes must be pretty gutless. I have one on my widgitmaster mini-router, but it doesn't take much to operate it so I never really noticed.

Cheers,

BW

[knudsen]

I'm using 27 1/2 lb + 6" x 3/4" water pipe, flange, cap and some bolts to secure it and it works well on my manual x2. I weighed the head on an old scale at 30# when I had it off to replace a blasted gear. I used gym weights, chrome pulleys and pipe parts because I wanted it purdy like the rest of the shop (yeah, right!).

[vlmarshall]

Darn, those Xylotexes must be pretty gutless.

Yeah, 24 volts just isn't enough to really drive a stepper. I love the Geckos I bought for my lathe, if my mill's Xylotex ever burns out like so many seem to do ( mine has been running for years now, however gutless it may be ) I'll gladly upgrade to Gecko drives on it as well, especially since the first-generation Xylotex cards are no longer serviced.

[Vogavt]

Gentlemen,
Thanks for all the comments! Yes, I'd seen Hoss's counterbalance during my quest for knowledge.

I didn't think about the 24v system being an issue. I'll get started on it and see what I can come up with. It's going to be an issue with me since I've got the mill housed in a coolant box. Gonna take some engineering to figure this out.

I may wind up doing the rafter deal, but since I've got Ron Steele's kit I've got to figure out the best place to harness the head of the mill.

Thanks again!