Would you flush these bearings? (G0602 Headstock) + leveling feet options

[deadwood83]

I recently upgraded to a G0602Z from literally the cheapest 7x14 I could find on fleabay ($410 USD) and the differences so far are.... vast.

On the 7x14 I put a 750w sewing servo, re-milled the underside of the bed ways, rebuilt the tailstock foot, trued the tailstock casting, trued the saddle gib mounts, built new saddle gibs, replaced the compound with a solid block of A36, and added the Clough42 ELS.

My mill (WMD25VB from the PM OEM for the 25MV) I have become completely enamored with the BLDC drive, so I found a controller and motor combo from overseas to retrofit an 1100W BLDC in place of the heinously noisy 1PH AC motor on the 602. I might also replace the cogged back-drive belt with a j-profile serpentine belt just for some extra quiet. The ELS will move to the 0602 as well, probably utilizing a 2:1 gearbox ratio as fabrikator has shown on here.

I searched high and low for headstock lubrication because Grizzly says oil, some threads on CNC sites from the early 2010's say to use the grease the bearings shipped in, others with replacement bearings say grease, SKF lubeselect for bearings shows a whole other profile for lathe spindles (angular contact BB w/ LGTL2 grease) and it's all very confusing. For now I have decided that since the ball oilers are there and are a potential ingress for contaminants, it would be best to just keep oil in there so the contaminants can hopefully be flushed out. I come from a motorcycle, automotive, firearm, 3d printing, and mech-E background so my instinct is that a tapered roller should have grease and get re-packed every few years if not sealed. Others have mentioned oil weeping from the bearings which I have not seen happen on my 602. It was incredibly difficult to even get oil to go into the oilers This made me think there was a bunch of garbage in there since an open TRB should weep oil from behind a flimsy painted steel cover.

I noticed others mentioning swarf, grinding dust, etc in the bearings from factory so my thinking was this:
- Use a hydraulic oiler to 'flush' the bearings with a cheap 30-50WW motorcycle oil (fewer friction additives safe for wet clutches and typ. non-detergent)
- Flush the 'improper' oil with mfg-recommended ISO32 (Hey, Vactra 1 is ISO32, that's convenient, and gearbox says ISO68 which is vactra 2 though to be honest I am considering just using vactra 2 on everything since the only real difference is viscosity at 40C and if I hit the flash point of ANY vactra then my machine has serious problems anyway.)

I already tried the flush on the front (facing chuck) bearing and it took a lot of hydraulic pressure at first but eventually began to puke out a blackish-grey goop. I kept flushing (and it got noticeably easier) until clean oil was ejected. I think I did okay, but wanted to get HM's take before I continue with the rear bearing.

On a sidenote, I am trying to figure out the lowest-profile way of leveling the lathe bed feet. I need my machines to be portable (eventually) because I live in a small townhome, so it lives on a 44" US General toolchest with a 1.5" solid birch butcher block top with the chest on carrymaster knockoff leveling casters. My machines live in my 3rd bedr-- carpeted machine shop and I'm 5'10". Direct on the butcher block, the lathe carriage handwheel is slightly below 90* elbow angle and the cross-slide handwheel is slightly above a 90* elbow which feels nice (miles ahead of my 34" wood bench the 7x14 occupies which resulted in back pain rather quickly) but I can feel waviness in the butcher block top with my fingers so I know this will need some sort of feet between the lathe and benchtop to achieve level. I have seen several different solutions involving jacking screws either on pads made to the size of the feet (above chip pan) or on spans going front to back (below chip pan).

Attached is a section view of what I think a low profile mount might look like using 6" wide by 8" long 1/4" steel. Bottom plate is threaded 1/2-20 at the front/back with jack screws and lock nuts. Bolts have a 3mm stud turned from the head which goes through the top plate (beneath chip pan) to keep them aligned. Center is 1/2-13 through both plates and top/cabinet only snug-ish. Would 1/4" plate be strong enough?

 

[RJSakowski]

A problem with leveling the 602 is that the lathe has only a single mounting bolt for the headstock and the tailstock so that twist in the bed is removed by shimming under the four contact points on each end. To that end, any attempt to level when mounting on a flexible base can create an unstable situation. My 602 stand has a four ft. section of 7" channel under it and the web on the channel is .21" thick. Any attempt to shim would create localized distortion of the channel along with some twist in the lathe bed. To correct the situation, I mounted blocks of 7/8" steel plate under the lathe feet. These are securely fastened to the channel with four cap screws which now creates a more stable platform for the lathe. Any distortion from adding shims niw has to occur in the lathe bed.

IMO, 1/4" plate isn't thick enough to provide a stable base unless it is strengthened with ribs below. I understand your desire to keep the lathe as low as possible. I am 5'10" as well. The base of my 602 sits 32.5" above the floor and my elbow position is similar to what you describe. The 7/8" blocks offer another feature for me which is to increase the clearance below the bed which makes cleanup easier.

With regard to bearing lubrication, I use 30W oil. I have some concern about the front oiler as oil runs though rather quickly. It would seem to me that there would be some sort of retardant like an oil wick which may be missing on the front oiler. No issues with the rear oiler. I just oil more frequently to compensate.

 

[RJSakowski]

To continue, I replaced the OEM motor with a 2.5 hp brushed d.c motor and a controller of my own design. Noise isn't a real concern for me but I wanted the ability to run at very low rpm and I am now capable of running as low as 10 rpm with sufficient torque and over a 50:1 speed range on any given belt setting. I am in the process of building a Prony brake for measuring torque so I can plot torque vs. rpm curves for the lathe but early testing indicates that I can generate belt slipping torque at 10 rpm.

I installed the Clough42 ELS and use a 1:1 pulley ratio on the lead screw and 2:1 gearing in the gear box. I run a NEMA 27 stepper which fits nicely under the lathe bed. This configuration generates about 100 lb. of force to drive the carriage. Details of my install can be found in greenail's Electronic Lead Screw thread.

 

[John281]

I have the G0752 (G0602 + variable speed) on a tool chest at 37" high. I'm also 5'10" and this is good height so that I'm never leaning over. Others might feel that it's too high but it works for me. I removed the wheels from the bench and made some legs with adjustable feet so I could get the benchtop level and flat on my slightly sloping garage floor.
To allow me to deal with any twist in the bed I added plates to each end of the bed and these plates have adjustable "feet" so I can jack any corner up or down. Admittedly, the wood benchtop is somewhat flexible so it's not perfect but seems to work. The lathe is still secured to the bench with the two original bolts. Under the chip tray is another plate of steel to help distribute the point loads.

 

[rabler]

I have the G0752 (G0602 + variable speed) on a tool chest at 37" high.

Looks like you've modified it to do LH threading.
What does the extra geartrain on the back of the headstock do? Just gear storage?

 

[deadwood83]

To continue, I replaced the OEM motor with a 2.5 hp brushed d.c motor and a controller of my own design. Noise isn't a real concern for me but I wanted the ability to run at very low rpm and I am now capable of running as low as 10 rpm with sufficient torque and over a 50:1 speed range on any given belt setting. I am in the process of building a Prony brake for measuring torque so I can plot torque vs. rpm curves for the lathe but early testing indicates that I can generate belt slipping torque at 10 rpm.

I installed the Clough42 ELS and use a 1:1 pulley ratio on the lead screw and 2:1 gearing in the gear box. I run a NEMA 27 stepper which fits nicely under the lathe bed. This configuration generates about 100 lb. of force to drive the carriage. Details of my install can be found in greenail's Electronic Lead Screw thread.

Thank you for the insight! I fell back on my roots and "did the math" and with a 1200lb point load in the center of a 1/4" plate of A36 (Young's modulus 29mil PSI) max deflection would be half a tenth in the center. I can get to full tenths if the 1/4" plate is extended to each edge of the chip pan, but then that number falls back to sub-tenth if we consider a two point load (each edge of the casting) about 3" from each adjustment point (front/rear). I will attach the results from an online calc showing a 2400lb total load (1200lbs at each casting edge) having 3 hundred-thousandths of an inch deflection.

I fully intend to copy your placement of the motor including using the 2:1 reduction at the gearbox. This would also allow an incredibly slow feed for tangential/shear tools since you can drop the ELS to .001"/rev and then further drop the gearbox to 1:1, achieving half a thou feed, or custom intermediate threads. I have just a NEMA24 so hopefully there will be less casting overhang removal. I have some carbide burrs and a 3/4hp pendant flex shaft just waiting for me to get all sooty and nasty with cast iron dust. It won't be fast, but it will be way less mess than an angle grinder. I need to stock up on black trash bags first though so I can mask off the rest of the machine. I also have the Belfanti plate made after your own design pending install.

I have the G0752 (G0602 + variable speed) on a tool chest at 37" high. I'm also 5'10" and this is good height so that I'm never leaning over. Others might feel that it's too high but it works for me. I removed the wheels from the bench and made some legs with adjustable feet so I could get the benchtop level and flat on my slightly sloping garage floor.
To allow me to deal with any twist in the bed I added plates to each end of the bed and these plates have adjustable "feet" so I can jack any corner up or down. Admittedly, the wood benchtop is somewhat flexible so it's not perfect but seems to work. The lathe is still secured to the bench with the two original bolts. Under the chip tray is another plate of steel to help distribute the point loads.

Oh my. That is both simple and elegant. It would work well with the central/under-bed NEMA mount too. Hmmmmm. I need to revisit my design now. If a plate were fastened to each end and clearance slotted through the chip guard (then sealed with silicone or something) then the weak mount point issue would be eliminated since torsional stresses would be directed through both the main bolts and the ends where you fastened. The same plate (at the headstock end) would then be used to mount the ELS stepper. I have a TIG setup so the whole thing could be made out of wildly inexpensive 1/4" P&O plate.

Looks like some CAD is on the menu for post-work activities today.

 

[John281]

Looks like you've modified it to do LH threading.
What does the extra geartrain on the back of the headstock do? Just gear storage?

Yes, I added the reverse tumbler.
Those pegs are where I store the change gears.

 

[deadwood83]

You know what? I feel silly. I went through a few revisions of what I wanted to do before I realized that an incredibly strong and fracture-resistant construction method involves bimetallic laminates. My lathe lives in a climate controlled home, so the CdT (coefficient, delta T) difference between iron and structural steel may as well be nil.

It took me a while to realize I was overcomplicating things a lot. Just stick a plate on either side of the contact area of the foot (above and below) and that flimsy mount tab will not be going anywhere. Then shim, level with jacking screws, whatever your heart desires. Realistically I will never run flood coolant on my tool chest so I figure a couple bolt holes through the chip pan to accommodate the leveling method will be favorable in the long term compared to leaning over, adjusting, standing back up, checking the level, etc. (rearfootidea.jpg)

Since the mounting bolt is offset (force vectors red arrow) from the leveling feet (also red arrow) (to cheat a bit more stability/microadjustment by separating the mount points by a greater distance) it will apply a torque (green arrow) about the mounting point on the bottom plate. To prevent creating a bending moment in the iron, the rear end extends up the outward face of the tailstock mount and is secured by two bolts (I will shorten the plate in the CAD later) set at a height equal to the offset of the main through-bolt (purple distance l). This won't normalize it completely, but the normal force of the bed to the vertical plate (orange vector) (which will be TIG welded to the cross-plate) will make it almost a net zero (statics.jpg).

Remember how I said I was overthinking things before? Yeah, I'm decades into trying to break that habit.