CX605 Down Feed Tune Up

[YYCHM]

Here is some one that replaced the universal joint with a solid shaft.

http://www.hteck.ca/lathe-mill/mill_v-feed/mill_v-feed.html

 

[YYCHM]

In April I had a plastic spindle drive gear disintegrate. Member Brian H bailed me out by sending me his spare (Thanks Brian). Shortly after the gear failed I ordered two more gears (backups) from BB. Come July BB still hadn't supplied my spare gears:-( I gave up and ordered the LMS belt drive and air spring upgrade kit.

At $300 landed it's a pricy upgrade for a $900 mill. Worth it?

Boy, I'm impressed. The belt drive was well put together and installed without a problem. The mill runs a LOT smoother with less noise and the air spring really changes how the down feed behaves. Spindle travel increased from 7" to 10".

The kit arrived within a week. Installation took maybe 4 hours at most (I picked at it after work drilling and tapping one hole at a time in the evenings).

What has resurfaced is an excessive amount of backlash in the down feed. Once taken up the analog dial does match my DRO, so that's good. I didn't shim the new Z-axis rack when I installed as I didn't have any shim stock long enough to accommodate the longer rack (a future project).

If you have a mini-mill this upgrade is well worth it IMHO.

LMS includes a laminated RPM chart to mount under the RPM/OFF/ON switch. It calibrated well with my $12 tachometer.

 

[Bofobo]

In April I had a plastic spindle drive gear disintegrate. Member Brian H bailed me out by sending me his spare (Thanks Brian). Shortly after the gear failed I ordered two more gears (backups) from BB. Come July BB still hadn't supplied my spare gears:-( I gave up and ordered the LMS belt drive and air spring upgrade kit.

At $300 landed it's a pricy upgrade for a $900 mill. Worth it?

Boy, I'm impressed. The belt drive was well put together and installed without a problem. The mill runs a LOT smoother with less noise and the air spring really changes how the down feed behaves. Spindle travel increased from 7" to 10".

The kit arrived within a week. Installation took maybe 4 hours at most (I picked at it after work drilling and tapping one hole at a time in the evenings).

View attachment 5523

What has resurfaced is an excessive amount of backlash in the down feed. Once taken up the analog dial does match my DRO, so that's good. I didn't shim the new Z-axis rack when I installed as I didn't have any shim stock long enough to accommodate the longer rack (a future project).

If you have a mini-mill this upgrade is well worth it IMHO.

LMS includes a laminated RPM chart to mount under the RPM/OFF/ON switch. It calibrated well with my $12 tachometer.

I dont have long shims in mine only 3 1” pieces. I tried my new treadmill motor conversion today and made .03 cuts like it was nothing. But following your advise on the gib screw for headstock adjustment i found i am missing the nut, and i need to enlarge the relief hole in my dro mounting to replace it

 

[Johnwa]

In April I had a plastic spindle drive gear disintegrate. I didn't shim the new Z-axis rack when I installed as I didn't have any shim stock long enough to accommodate the longer rack (a future project).

.

What size of shimstock do you need?
I have a couple of rolls 6”x100”. I don’t recall the thickness.

Cheers
John

 

[YYCHM]

What size of shimstock do you need?
I have a couple of rolls 6”x100”. I don’t recall the thickness.

Cheers
John

Thanks for the offer John,

I need 0.02" X 3/4" X 13.5" or there abouts. 0.02" worked well with the original rack, the new rack may need something different. I need to play around with it first.

 

[YYCHM]

I dont have long shims in mine only 3 1” pieces.

How in the world did you get three pieces of shim in there without taking the head off ????

 

[Johnwa]

Craig
My shim stock is 0.001” and 0.002”. Probably not the easiest way to get 0.02” but you’re welcome to a section if you want.

John

 

[Bofobo]

How in the world did you get three pieces of shim in there without taking the head off ????

tediously is the short answer, used the rack screws as shim stop pins and dropped them from the top, wedging to get them to drop, moving the head as needed to access screws.

 

[eric_brackenbury]

That blurb is here..

http://www.machinistblog.com/the-mini-mill-head-drop-problem/

It may simply be one of those "don't believe everything you read on the internet" situations. Dunno.

More on z-axis backlash here.

http://www.machinistblog.com/an-easy-way-to-reduce-the-mini-mills-z-axis-backlash/

Another thing suggested is to slot the screw holes on the fine feed worm gear mounting block as a means of improving the mesh between the fine feed worm gear and the down feed shaft.

I don't think I'll attempt that mod, I'm pretty happy with the improvement gained so far.

Good info thanks for the links, I have a metal rolling mill so can roll copper sheet and try that.