Atlas 618-Cutting Results

C

CAW

Registered
Registered
Joined
Feb 26, 2014
Messages
12
I have problems with the quality of the cut on my lathe. I turn primarily low carbon (1018) steel or aluminum for turning on my lathe. I normally use the lowest speed with the bull gear engaged. I used HSS index bits on an A2Z tool post.

My cuts leave fine lines like on a phonograph records; I am unable to get a real smooth cut unless I file or sandpaper the cut. I have used faster speeds, but it does not seem to make a difference. I have used larger lathes in the past and the cuts were very smooth.

My observation is that HSS index bits produce a better cut than carbide index bits; at least on my lathe.

Any suggestions on how to obtain a smooth or finish cut on my lathe?

Curtis
 
Curtis not sure quite what you are describing. Is it the fine feed of the tool cutter, or more like some sort of vibration superimposed on the cut? Is the lathe well secured to the bench? And how about any belt vibration?

David
 
A way to describe it is that the cut looks like very fine threads. Like the lines on a 45 rpm record.
 
Did you try honing a small radius on the tip of the tool?

Vince
 
Are you using the powered long feed? If so what is it set to. I normally do my finish cut on aluminum by hand with a sort of rounded nose HSS lathe tool.

David
 
ditto what the others have said - if the HSS tool has a very sharp point you'll need a high spindle speed and very low longitudinal feed with just a skim cut to get a smooth finish. WD40 helps too, stops the tool from digging in. You can get a smooth finish, just takes a lot longer. Or you could grind a small radius on the nose of the tool or even use a dedicated round nose finishing tool. You should be able to find some combination that works with a bit of trial and error.
 
Maybe have a close look (magnifier) at your cutting edge. You are using the exact same machine as I am with a very similar tool setup. I'm also using HSS but not inserts. Very recently my cuts were exactly as you describe -- very very fine like a record groove. Took a close look at my edge and there was a tiny chip off it right at the cutting radius. I took a pass or two on the grinder to refresh the edge, then honed it like I always do. Major difference, nice and smooth cuts again.

I'd also look at your feed and speed rates as others have suggested -- you should able to run faster than the lowest speed all the time which might improve things for you.
-frank
 
THE WAY TO REMOVE FEED LINES IS WITH A CUTTER TIP LARGER THAN THE FEED LINES ...SEVERLA WAYS TO DO THIS ...\ SET A KNIFE EDGE TOOL ( LIKE A SHEEP FOOT BLADE OR LIKE A CARBIDE TIP A STYLE ( BUT USE hIGH SPEED)
SET THIS AS FLAT AS POSSIBLE W; OUT CHATTER TAKING A 3 THOU OR SO DOC..
NEXT GRIND A FLAT NOSE TOOL , FULL WIDTH BUT W/ FORNT A7 SIDE CLEARANCE & FRONT TO BACK CLEARANCE ...SET THSI A S FLAT AS POSSIBLE AGAINN 3 THOU DOC
GRIND A SHEAR BIT ...60 DEG ANGLE RUNNING SW X NE W/ CLEARANCE IN FRONT ..SET THE BIT SO THE WORK IS NEAR CENTER ,,THIS ANGLE CUT ERASES THE FEED LINES ....& GIVES A DEAD SMOOTH FINISH AGAN UNDER 3 THOU DOC ......A 1/32 FLAT ON THE END OF TEH BIT WORKS BETTER THAN A LARGE RADIUS , BUT NOT AS WELL AS THE OTHER WAYS THE ROUND NOSE DOES NOT CUT ACROSS THE LINES UNLESS A DEEP CUT IS MADE OR A HORRENDOUSLY LARGE CHATTERING RADIUS IS USED ......
ALL THE ABOVE REFERS TO 1018 STEEL
BEST WISHES
DOC
ps ...GET MACHINE TOOL OPERATION BY BURGHARDT VOL I ONLATHES VOL 2 ON MILLS SHAPERS GRINDERS PLANERS ABT $ 10 ..ANY EDITION ON ABE BOOKS ...AMAZON ,.....EBAY........AFTER 55 YRS I STILL REFER TO THEM
 
You must log in or register to reply here.
Back
Top