Grizzly G0602 Lathe Rough Finish

[TWS]

Speaking of things which for some reason could be loose, have you checked that the chuck is tight against the spindle? The clamps only prevent the chuck from flying off, but the back plate needs to be snug against the spindle register.

@tq60 's method is good. You have to find what is loose...

I have checked the tightness of the chuck, good to go, seated well against the spindle and the mating surfaces were cleaned to insure a good fit

 

[DonP]

Yes I do, both hand and power feeding

Ok I recently discovered a problem within the carriage of my 10x22 that caused finish oroblem when under power feed but not hand feed. It appears that is not relevant to your issue.

 

[RJSakowski]

There is a YouTube video by Clough42 about a problem with his G0602 cross slide. Take a look and see if yours has the same issue. Basically, there was an interference condition with the dovetails. This wouldn’t explain why your lathe changed, though, but something to look at.
Also, I’ve noticed that over tightening the compound hold down bolts can cause the cross slide casting to deform enough to make the gibs looser. I tend to agree that poor rigidity somewhere is contributing to the poor finish.

Changing the compound clamp (https://www.hobby-machinist.com/threads/improved-g0602-compound-clamp.34796/) to the six bolt design greatly increased rigidity. Tightening the clamping screws does loosen the gib but my gib is adjusted with the bolts tightened as I would not conceivably operate with a loose compound. My clamp is made with an approximate .007" clearance between the clamp and the cross slide to ensure that there is always clamping pressure on the compound and given the thickness of the clamp, some distortion is inevitable. It takes 60 oz-in. of torque to turn the cross slide crank with loose bolts vs. 17 oz-in. of torque when the bolts are tightened.

 

[TWS]

Changing the compound clamp (https://www.hobby-machinist.com/threads/improved-g0602-compound-clamp.34796/) to the six bolt design greatly increased rigidity. Tightening the clamping screws does loosen the gib but my gib is adjusted with the bolts tightened as I would not conceivably operate with a loose compound. My clamp is made with an approximate .007" clearance between the clamp and the cross slide to ensure that there is always clamping pressure on the compound and given the thickness of the clamp, some distortion is inevitable. It takes 60 oz-in. of torque to turn the cross slide crank with loose bolts vs. 17 oz-in. of torque when the bolts are tightened.

I checked the cross slide issue from Clough42s video. I cant get a feeler gauge between so it is good to go.
Will be going with the six bolt compound clamp as i have checked everything i can think of and followed all the suggestions from this forum.
Thanks again for your input

 

[RJSakowski]

I always use the amount of torque required to move the cross slide rather than relying on a feeler gage. Proper clearance will only be a thou or so and it would be difficult to assess that adjustment with a feeler gage. Even on my Tormach CNC, I measure the torque. There I slowly tighten the gib, looking for the point where the required torque begins to rise and back off ever so slightly. While measuring the torque is the most accirate way to adjust, on the cross slide, you can do a fairly good adjustment just by feel. When you start to notice some drag, you are there.

However, I don't believe that a loose gib is your problem, based on your description. The key clue is everything was good before you switched to to the QCTP. The second clue is that when you switched back, the problem persisted. That would tell me something that you did on the process of changing the tool post made a change to the characteristics of the lathe.

One thing that I would check. You said that you made the new tee nut for a tight fit. I usually leave clearnce for a loose fit. A long shot, but check your cross slide to make sure you didn't crack the casting. The QCTP stud shouldn't protrude enough to bottom out on the floor of the slot. I milled mine flush with the bottom of the tee nut. Also check for a chamfer or fillet on the tee nut. With no clearance, the nut would hang up there making for less secure tightening.

 

[Christianstark]

Spindle speed, DOC, and feed rates have done a world of difference for my surface quality. If one or several are off the results can go South fast. What do the chips look like?

 

[GunsOfNavarone]

I also have the g0602(Z) I put a VFD on it and Clough's ELS (and RJsakowski's 6 bolt compound clamp). I use a AXA QCTP with carbide only. If your chips aren't turning color, you're probably being too cautious. On 1018 (depending on diameter) I take .040" DOC and feed at .005" per rev. When I was new with it, I did .010" to .025" and who knows the feed rate I used. The only thing that makes everything I'm suggesting irrelevant, you say when you go back to stock, it NOW cuts poorly. I have to add, close isn't always close enough with tool height. Do you have a height gauge? gage blocks? I didn't realize when I first bought my lathe how deep the tool rabbit hole goes, even though everyone here warned me, it.never.stops.
Setting it based on the nipple left on facing or parting and eyeballing a carbide tool to that isn't consistent or accurate enough (for me when that was a technique I used early off) I made the Armstong type parting tool like Winky's workshop, but altered to use carbide. .004" is the difference of it working flawless or breaking an insert....A SHEET OF PAPER THICKNESS! I think when your new to this, the VERY SMALL is just shrugged off, after enough time you will spend a great deal of time focusing on the smallest of measurements.
GOOD LUCK, welcome to the forum, there is a great deal of knowledge around here that has saved my backside more than once!

 

[TWS]

Spindle speed, DOC, and feed rates have done a world of difference for my surface quality. If one or several are off the results can go South fast. What do the chips look like?

Chips curl off in a long string, maybe some bluing, that is the closest color I can compare to.

 

[TWS]

I also have the g0602(Z) I put a VFD on it and Clough's ELS (and RJsakowski's 6 bolt compound clamp). I use a AXA QCTP with carbide only. If your chips aren't turning color, you're probably being too cautious. On 1018 (depending on diameter) I take .040" DOC and feed at .005" per rev. When I was new with it, I did .010" to .025" and who knows the feed rate I used. The only thing that makes everything I'm suggesting irrelevant, you say when you go back to stock, it NOW cuts poorly. I have to add, close isn't always close enough with tool height. Do you have a height gauge? gage blocks? I didn't realize when I first bought my lathe how deep the tool rabbit hole goes, even though everyone here warned me, it.never.stops.
Setting it based on the nipple left on facing or parting and eyeballing a carbide tool to that isn't consistent or accurate enough (for me when that was a technique I used early off) I made the Armstong type parting tool like Winky's workshop, but altered to use carbide. .004" is the difference of it working flawless or breaking an insert....A SHEET OF PAPER THICKNESS! I think when your new to this, the VERY SMALL is just shrugged off, after enough time you will spend a great deal of time focusing on the smallest of measurements.
GOOD LUCK, welcome to the forum, there is a great deal of knowledge around here that has saved my backside more than once!

Let me try that. I have my lathe tore apart right now checking the jib strip and waiting to add the six bolt compound clamp. As soon as i have it back together i will take a bit deeper cuts. Thank you

 

[stupoty]

just checked that today. runout was .0003 on my ten thousands indicator.

Did you give it a push / pull to see if the preload has loosened at all ? Can be hard to notice with the weight of spindle plus chuck.

Stu