Grizzly G0602 Lathe Rough Finish

I had rigidity issues with my lathe (not a grizzly) since day #1. I assumed it just wasn't a large enough machine to be rigid. After years of using it like this I was stoning my ways and other surfaces and whike I was at it I decided to stone the bottom of my Chinese aloris-style QCTP for the first time ever. In doing so discovered that it was nowhere near flat. It was appalling how not-flat it was.

If you got a similar QCTP there is a possibility that was your problem while you were using it. If the problem remained after switching back to the OEM toolpost, perhaps a bungled bottom surface of your QCTP could have damaged the top surface of your compound? <- that last sentence has a question mark to indicate that it's an admittedly far stretch. But wouldn't hurt to check.
 
I did change my spindle bearings out to nachi’s after a year. The ones it comes with are just to help keep them affordable at best.
 
I installed the six bolt compound clamp, its really tight but helped a bit. Still having issues with 1018 steel but harder steel is cutting much cleaner.
Thanks to all of you who helped with this issue
 
TWS said:
I installed the six bolt compound clamp, its really tight but helped a bit. Still having issues with 1018 steel but harder steel is cutting much cleaner.
Thanks to all of you who helped with this issue
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Just out of curiosity, what style tool holder and inserts are you using?
 
The only thing you seem to have changed is the nut. Can I suggest that the toolpost clamp is bottoming out somewhere giving the impression it is tight?
 
G-ManBart said:
Just out of curiosity, what style tool holder and inserts are you using?
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Shars and Dorian tool holders for AXA setup. I have used inserts from China, Sandvik, Kennametal Kyocera and Mitsubishi materials
 
Parlo said:
The only thing you seem to have changed is the nut. Can I suggest that the toolpost clamp is bottoming out somewhere giving the impression it is tight?
Click to expand...
I will double check that.
 
TWS said:
Shars and Dorian tool holders for AXA setup. I have used inserts from China, Sandvik, Kennametal Kyocera and Mitsubishi materials
Click to expand...
Sorry, I should have been more specific....like CCMT, CNMG, etc, type inserts as well as the size (i.e. CCMT 32.51 or something similar). I ask because you mentioned using a DOC of .005 or .0025 previously and those are quite low.

It's possible to have a DOC that is too shallow and it causes chatter...the tool doesn't stabilize in the cut and just bounces. The general rule is you want at least 1/2 of the insert radius for the DOC. For a CCMT 32.51 you're looking at a radius of .0156" so you'd want to start somewhere like .008 or .010 to see what happens.

I'm not sure if you mentioned it or not, but I would use a 123 block between the tool holder and the face of the chuck to be certain the tool is square to the work. That's not to say the tool holder will only work when set like that, but as a starting point it help you'll eliminate a variable.

Also, it sounds silly, but when checking tool height you have to do it with the QCTP lever tightened...the tool can move a fair amount as you tighten the handle.

If you think of it, when you set up to take the next series of cuts, take a couple of pictures showing your overall setup and the results and post them. There might be a clue that shows up that someone might spot.
 
If your tool holder is touching the compound, that's a problem. You may have to grind off the bottoms of your tool holders. Some tool holders are too tall for the Grizzly G0602/G0752Z. I had to grind off the bottom of several holders on my G0752Z.
 
My take:
1) take cuts (with cabide inserts) that are at or deeper than the tip radius. e.g. CCMT0604 would be .4mm/0.0157" tip radius.
2) For G0602/G0752/KC1022 lathe and AXA, there is no point using a tool holder bigger than 3/8 shank/10mm. A 12mm shank fits as well. The issue being the tip has to be at centre, but often the AXA holder bottoms out.
3) Spindle bearing preload. No idea what the correect setting is for these lathes but if loose you will have quality issues further away from the chuck as well as terrible results with parting.
4) if you haven't replaced the compound with a solid tool post, then ensure that the compound gibs are snug, and the tool post is set over the mounting area, not extended.

More input : https://www.chaski.org/homemachinist/viewtopic.php?t=77497

gerrit
 
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