Trouble parting off mild steel Southbend 9A

All good advice above. One thing nobody mentioned, but might be worth considering is maybe you are using junky cut off blades? I recently bought some nice looking shinny, import blades from a reputable supplier, and they acted exactly like you describe: wouldn't cut, broke, blew up with load bangs. But they looked really swell - ground and polished to high sheen. They were just made out of the wrong type of steel.

I had an old, NOS, English blade in my tool box, so in frustration tried that. Saw a world of difference. No problem cutting 3" material. Iam still using it. Hoping against hope it doesn't destroy itself and leave me with no cutt off tooling!

Keep trying,
Glenn
 
I'm starting to think this is just me, but I have not had great luck using lubrication when
parting aluminum. It seems to me that when I am parting dry everything is fine, but when
I lubricate with WD-40 or oil, the parting tool seems to rub rather than cut. Now maybe if
I used a lube specifically for aluminum that would help, but I have found that I tend to have
better luck with parting dry. Now for steel, I use oil and that seems to work fine for me.

I also like this style cut off blade:

1/8 x 1/2 x 4-1/2 Inch 8% Cobalt Parallel Type Cut-Off Blade-P3S
https://www.amazon.com/dp/B00N405KBW/ref=cm_cr_ryp_prd_ttl_sol_11

It has relieved sides and a convex top which helps curl the chip for me. I also like the
wider blade (1/8") which seems to wander less on me, though as others have said it is
important to keep as little stick out as possible. I have actually bought an additional
parting blade holder. I keep one with very little stick out (maybe 1/2") and the other
with maybe 1" stick out. For most of what I do I can just swap from one to the other
as I get deeper in the cut rather than having to change the stick out, then recenter
the tool holder to get it back on center.
 
I use a carbide insert parting tool on my SB 9A. I won't say no problems but they do work.
 
You need a good cutting oil. Sorry WD-40 and lubricating oil just doesn't cut it! Oatly or what I use Mobil Metcut 766, works much better. Sharpen the end of the blade with a 3 to 5 degree bevel. This will let the part cut off without leaving a tit on it. Oh, put the lathe in back gear with that large of OD.
 
Ken,

Thanks for the advise! Next time I'll try actual cutting fluids meant for the job I am doing rather
than just trying to reuse the lubes I have on hand. Sometimes being cheap doesn't
actually pay. :)
 
You must log in or register to reply here.
Back
Top