Question: What are the generally agreed upon flaws of the X2 mini-mill?

[Nelson_2008]

Hello,

I'm considering buying an X2 type mini-mill such as the Harbor Freight #44991
and I'm wondering if anyone can tell me what generally recognized "flaws" it has? For example I'm aware of the noisy gear drive and I've heard that the head can sometimes drop down a little bit, unexpectedly (is this true?).

Are there any other issues with these things? Thanks.

[TXFred]

In stock form, here are the problem.

No column brace. Watch this video I made to demonstrate. You can see the column flexing backwards from the force as it attempts to drill 1/4" holes through steel.

http://www.youtube.com/watch?v=Siwbp9Pfm4s]CNC X2 Column Flex - YouTube

The Z axis rack is not very accurate, and has a lot of backlash.

The gibs are a bad design, and need to be adjusted regularly.

And then there's just general production issues. Depending on where you buy your X2, you could get a good machine, or you could get a complete POS that needs to be completely rebuilt before it's any good.

[Nelson_2008]

Thanks for the info.

I wonder if the newer version of this machine as sold by Micromark or LMS is any better as far as the issues you've mentioned?

Also, I'm wondering, what kind of spindle bearings do these things have? Do they use the same type ball-bearings that the mini-lathes use?

[TXFred]

The upper bearing is the same as on the mini-lathe. The lower bearing is larger to accommodate the R8 spindle's larger diameter.

Frederic

[mchabot]

1. Flex in column
2. Gear train will break
3. Simple deep groove bearing
4. Undersized gibs
5. CC motor: can overheat quickly

The good news is that most of these flaws can be corrected: column brace, changing gibs, move to belt drive, change bearings with taper roller bearings. Use of a tree phase induction motor or big threadmill motor.

[TXFred]

CC motor: can overheat quickly

Good point. I'd forgotten about the motor's inadequate cooling. Here's how I fixed it on my mill. All it takes is a lathe and a PC cooling fan.

http://www.youtube.com/watch?v=W7d2842ZQBk]X2 Motor Fan Upgrade - YouTube

Frederic

[hoss2006]

LMS's HiTorque Mini Mill, Solid Column takes care of several of the problems though for that price
I'd get a G0704 instead.
LittleMachineShop.com - HiTorque Mini Mill, Solid Column
Hoss

[wizard]

That is something you shouldn't underestimate, upgrading just the column is expensive in both time and money. Further the fixes are at best half a$$ed.

I realize the entry costs are pretty low and that many don't "need" a larger mill but you pretty much get what you pay for.

On the other hand it seems like none of the Chinese manufactures can build a mill that costs less than $1500 that has a decent motor/controller so don't look upscale expecting a better set of electrics. Electrics however are easy to fix or upgrade. A decent approach to many of X2's mechanical issues does not exist.

Hello,

I'm considering buying an X2 type mini-mill such as the Harbor Freight #44991
and I'm wondering if anyone can tell me what generally recognized "flaws" it has? For example I'm aware of the noisy gear drive and I've heard that the head can sometimes drop down a little bit, unexpectedly (is this true?).

Are there any other issues with these things? Thanks.

Motors
Spindle speed
Spindle bearings


Look to be honest here no machine is perfect. You can only judge suitability against what you intend to do with it.

[Marc N Fournier]

Ah Frederic !..

You are the one who came out with that PC fan modification..

Very cleaver. I had seen it before. Did not tie the two of you together..

On the flex subject. Is it part Z torque, Z feed and part spindle drill speed that can cause that amount of flex to be induced ?

Scary video by the way. Judging by the mouvement does it or does not affect the precision of the hole drilled ?

Oh and head droop is a problem until you throw the LMS air spring at it (or similar) or convert to CNC and ball screws.

My Grizzly X2 droops on me, and is a general mess. Eventually get it back together and running.

Marc

[Nelson_2008]

Yes, I know no machine is perfect. What I set out to do is to get an idea of the "generally recognized" shortcomings of the X2, from various users' perspectives...in order to try to figure out what I can or cannot live with.

And the replies have been helpful. (Thanks to all who replied).

To me it seems the G0704 is both the best value and the overall nicer machine, but the size (primarily the weight) of the machine is more than I wanted.

So I think I might take another look at milling attachments for lathes...something to get me by until I can make room for the G0704.

That is something you shouldn't underestimate, upgrading just the column is expensive in both time and money. Further the fixes are at best half a$$ed.

I realize the entry costs are pretty low and that many don't "need" a larger mill but you pretty much get what you pay for.

On the other hand it seems like none of the Chinese manufactures can build a mill that costs less than $1500 that has a decent motor/controller so don't look upscale expecting a better set of electrics. Electrics however are easy to fix or upgrade. A decent approach to many of X2's mechanical issues does not exist.

Motors
Spindle speed
Spindle bearings


Look to be honest here no machine is perfect. You can only judge suitability against what you intend to do with it.

[TXFred]

On the flex subject. Is it part Z torque, Z feed and part spindle drill speed that can cause that amount of flex to be induced ?

Scary video by the way. Judging by the mouvement does it or does not affect the precision of the hole drilled ?

I'm sure that my feeds and speeds were not ideal when I was drilling that hole. And the drill may have been blunt. I filmed it before I learned about modified split point drills, so machining forces were higher than they should have been.

The hole being drilled was a through hole for a bolt, and did not need to be very precise. I never noticed a problem.

Frederic

[Bob La Londe]

Yes, I know no machine is perfect. What I set out to do is to get an idea of the "generally recognized" shortcomings of the X2, from various users' perspectives...in order to try to figure out what I can or cannot live with.

And the replies have been helpful. (Thanks to all who replied).

To me it seems the G0704 is both the best value and the overall nicer machine, but the size (primarily the weight) of the machine is more than I wanted.

So I think I might take another look at milling attachments for lathes...something to get me by until I can make room for the G0704.

Or lathe work with mills.

G0704 setup as a lathe...

This totally sold me that the G0704 is an awesome machine for the price.