gouging stainless

[Krown Kustoms]

Im not sure if Im in the right spot, but here goes.
I was cutting 304 down to make a 1" dia fly cutter on a 7 x 12 lathe.
I bumped the carriage and gouged the 304, broke the tool bit, and now I cant get rid of the chatter.
I took the carriage off and re-alligned the jibs and still bad chatter.
I think I bent something.
I also have ground 3 more tool bits in different angles and still no dice.
Does anyone know what else to check, I dont think you can bend the bed ways... can you?
I dont have any tight spots in the travel or in the cross slide and the tooling still goes to center.
thanks -B-

 

[rake60]

Have you checked the spindle for end play?

Rick

 

[va4ngo]

Is it possible the cross slide nut has been damaged?

 

[Lakc]

I run into similar problems myself. My "theory", is a small lathe cant take a big enough cut to get past the work hardened chatter area, and of course, if you only had a few thou left to the final diameter nothing can hog that out, but a bigger lathe with a more rigid tool is the idea. I can take decent cuts with my lathe but if I have chatter from one problem or another it continues to exist right down to the final diameter, even if I am reducing a .5" bar to .25". Sometimes a file helps, but I believe the real fix is a toolpost or centerless grinder.

 

[kustomkb]

If you mean you can't get rid of the chatter in your current piece, try to push the cutter up against the work and spin the chuck by hand or go as slow as possible. Similarily chatter can be removed from a spotface or countersink,
It also helps to put a small piece of a rag or paper towel under the cutter and cut through the fabric into the work.

 

[Krown Kustoms]

Sorry I wasnt clear, everything I cut chatters now.
Not so much worried about the piece its only a fly cutter I can cut the shank smaller.
I checked the cross slide nut and adjusted it, I completely went through the lathe (cleaned, lubed, adjusted...) a few days ago, even took the spindle out. I may have to do it again.
I will check the runout today at the chuck, I didnt think about thr bearings.
-B-
A friend has a 9 inch SB in good condition he wants to get rid of for room to put a bigger one, I think I have a good spot for a new (to me) South Bend. If I can repair the 7x I will keep it for smaller work.

 

[rake60]

Most of the 7 X lathes use ball bearings in the headstock for
the spindle. They are easily damaged.

Rick

 

[Krown Kustoms]

Thanks Rake,
I have a little slop in the head, thats probably what it is.
I checked everything else and it looks better than it did when I got it new.
-B-

 

[Lakc]

Ouch, that becomes a big blunder. Can you try adjusting the preload on the headstock bearings?
Jeff

 

[vlmarshall]

I have a little slop in the head, thats probably what it is.

Ah, rotten luck. Sorry to hear it.

 

[rake60]

If it does turn out to be a damaged bearing, it is really not a big thing.
The bearings are inexpensive and easy to change.
There isn't much preload adjustment available to them since they are
radial bearings.

Rick

 

[Krown Kustoms]

Ok,
I had a set of bearings from a while ago
-The gear train was making a horrible noise so I immediately thought it was the bearings. Turns out it was the plastic lead screw gears, they weren't meshed very good-
Before I figured it out I ordered new bearings,
I put them in today and I guess that was it.
The old bearing has a bit of a rattle to it.
I still cant take but a .005 cut on stainless but I can live with that as long as there is no chatter.
I am now looking into ways to make it more rigid, I have seen a few ways but the one that looks the best requires doing away with the combo slide, I use that a lot to cut tapers so I'm not completely sold yet.
Maybe if I get the SB I will do it.
thanks all
-B-
now back to the fly cutter
-note to self, don't spray hot stainless with WD-40 it hardens and is a pain to cut-

 

[jihe]

Are your saddle gibs shimmed or do you still have the opposing screw adjustments? I have found that screw adjustment method to be kind of unreliable. If you adjust them with an indicator and rocking the saddle by hand, they may still flex when greater force is applied.

 

[Krown Kustoms]

I had some slop there also, I took the slide off and tightened the gibs.
Im only getting .001 - .002 now.
thanks -B-

 

[Krown Kustoms]

Oh, by the way
Here is the bearing destroying demon if anyone is interested.
-B-

 

[ariz]

at least it is a very good flycutter ;D

 

[vlmarshall]

Nice-looking flycutter, sitting there innocently. ;D

-note to self, don't spray hot stainless with WD-40 it hardens and is a pain to cut-

No kidding... in a scrapheap somewhere out there is the first piece of 304 stainless I ever worked on, thrown away with a .375" drill still welded in it. :

 

[Krown Kustoms]

Thanks everyone,
I was going to make a half inch one to take .125 HSS just for the heck of it, but I used the last of the .5 stainless on the crankshaft on my tiny four.
The only other sizes I have is 1.25 and 2.25, and thats not going to happen this year (knee deep in swarf)
Cutting half down to .195 is enough swarf for me.
-B-