Rough finish on a Grizzly G0602 Lathe

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Hello,
I have a Grizzly G 0602 lathe about six months old. It is mounted on the optional workbench with splash guard, leveled.
This little lathe cut great in the beginning, glass smooth cutting C1018 or stainless or bronze using either HSS or carbide.
I changed out the tool holder to a quick change system and machined the new anchor piece to a tight fit.
Some time after changing to the quick change setup, changing the gearing and moving the belt between high and low speeds i started getting a smeared and or line finish. These tiny little lines perfectly spaced on all my cuts. Also if I take more than 5 thousands i get a smeared finish, rough and ugly.
This happens when i use carbide or hss.
Everything has been tightened down and I check squareness of the tool holder by using a 1 2 3 block against the chuck then tighten it down.
My tool holder is spot on to the middle of the work, I double checked the tightness on the chuck, switched back and forth from the quick change tool holder to the original tool holder. Adjusted the jib, rechecked level, checked gear spacing, used different speeds and feeds and nothing will give me that finish i used to get.
To change my belt from low speeds to high speeds i have to loosen the motor mounts as per the manual, this is a process because the bottom nuts are pinned up against the splash guard that is secured to the table. No wrench will fit, i tried to even modify a thin wrench and no dice, with the workbench splash guard on i have to lift the lathe a bit to tighten or loosen the motor to allow the belt to be installed or removed. This being said i have to check level each time i change from high to low or the reverse.
Oh the steel i have been using is 1018 so that has stayed constant just the finish is horrible.
Any suggestions would be great, i am at a loss for what i am missing.
Thank you,
TWS

 

[DDoug]

Is this a continuation of that thread ?

rough finish

Hello, I am new to this forum and am hoping for some help. I am running a small Grizzly G0602 lathe. When i first got it it gave a mirror finish using either HSS or Carbide. this was from 0 hours to about 5 hours on the lathe. I decided to switch to a quick change tool post and the finish go a...

www.practicalmachinist.com

 

[[email protected]]

Basically, needed to add more info and be more specific from the first post

 

[doug925]

Hmmm, a couple of thoughts:
Grizzly is not known for being able to take much of a cut, as it is a hobby machine. No offense.

1) Did anything else change? Did you do any other adjustment, leveling, etc? (Was it crashed? )

2) Is your QC tool post & nut plate sitting flat?
Did you stone and clean the mating surfaces prior to makeup?
Is the QC post making uniform contact to the compound, across it's surface? (A quick bluing will testify)

3) 1018 likes to tear, and the finish is usually crappy.
(Caveat: Adjust SFM and feed accordingly)
Try cutting some 4140HT or something in between Rc28-36 and see if the finish looks the same. Try the same on some 6061-t6 or acetal. Does the finish still look the same?

4) If the lines are spaced regularly, it is possibly slop in the feed, or (more likely) bearing / bearing preload on the spindle.

5) Since you brought up changing the speed range, is the belt correctly tensioned?

6) Could the belt pulley or the motor mount bolts be lose?

A quick $0.02

Doug

 

[Conrad Hoffman]

The finish is usually bad on 1018. Are you sure that's what you were using before? Sneaky trick for good finishes on 1018- try a shear tool.

 

[michiganbuck]

A tool nose radius is often good for a better finish, proper rake angles for steel and aluminum,
Be sure nothing has come loose to cause any vibration, then your set up as to what part size and length, diameter and how do you hold it, what RPM, depth of cut, feed rate, Is your cutting tool fingernail sharp, have the spindle bearings found/pushed tight in their place and now they need end play adjustment, loop looking at the cutting edge OK, is the chuck tight to the spindle, are the cross and compound gibbs tight, is it snowing, is your dog happy, did your wife or girlfriend approve of buying the machine.

Just kidding, snowing doesn't really matter unless you are shivering and leaning on the machine.

 

[Milacron]

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