Tips Of Lathe Tool Bits Rolling Up.

A photo would really help. The tip should not deform at all. Something like this happened to me once when I was just starting out. The tool was from a garage sale lot. I reground it, and it cut just fine, for one inch. I paid more attention to the grinding sparks, noting that it matched the A-2 coupon in my spark test standards. Not HSS. It turned out to be a brazed carbide bit minus the little piece of carbide. I posted a photo, and it was confirmed.
 
HF brazed carbide isn't worth the effort in my opinion, particularly when the HSS is so much easier to use (and grind to various profiles). I do a lot with 6061 and some with 7075 plus a little with various cast aluminium parts. The only time I've used solid carbide is the ball end milling cutter. Alu-alloy doesn't stick as easily to carbide tools but it will stick if your trying to use recommended speeds and feeds without flood coolant (or, usually, much slower than recommended rpm/feed)
If your in a production shop were 'time is money' go with the charts, if your in a garage or basement (etc) start slow and speed up to where machine is happy. It's way cheaper and less frustrating in the long run
BTW, carbide won't (can't) roll the edges, way too brittle
 
Maybe the brazed HF cutters are NFG but I have been delighted with the set of 1/4" insert cutters I bought from them. The largest depth of cut I have tried so far is 0.040" on cold rolled mystery steel at approx 125 FPM. Cut like butter and made a 4' long swarf coil. Thats about as far as I plan to go because the chip breaker groove is about that size and it doesn't seem right to go deeper than that. Maybe I will try it just to see. I've honestly been amazed at how well these things cut. With the performance so far, it may be a long time before I have to buy some name brand inserts.
 
BarnyardEngineering said:
By "rolled up" I mean the sharp tip of the bit is bent upwards.

I just don't understand how it can bend UP when the force of the cut is DOWN.

This happened while facing and while boring. Spindle is turning in the correct direction. It does not even have reverse.
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Carbide tips don't bend. If you have been turning for a year now and the problem started with aluminum, my bet is build up of aluminum on the tool. Very common since some al alloys are very gummy. How has your turning of steel been going? Photos would been a boon to help us help you.
 
Ummm, guys, have you noticed the date when this thread was active?
 
Yep, over a year old. I did look for post date but didn't see it, too small and too faint. I prefer post dates to be easily seen to prevent this sort of thing
 
Happens a lot when new members join up and wish to share their knowledge. They eventually figure out where the dates are. Just didn't want you to think the OP was being unresponsive. :)
 
mikey said:
Happens a lot when new members join up and wish to share their knowledge. They eventually figure out where the dates are. Just didn't want you to think the OP was being unresponsive. :)
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Barnyard hasn't been back since April 2017, I hope all is well with him. Still am curious about how the problem was solved.
 
Well, the problem was never solved. I got so frustrated with the lathe I quit trying. It's been sitting in my garage gathering dust ever since. I've been considering kicking the whole thing to the curb.

I know the HF stuff isn't great but it was all I could lay my hands on at the time. I had no clue about grinding tool bits and all I could find on the subject was "you gotta try different angles and feeds and speeds until you find out what works for you." When you don't even have a good starting point, such advice is WORTHLESS, hence my frustration.

The best luck I had was after watching a This Old Tony video on grinding tool bits. I was able to have a modicum of success with a crude bit I ground from a chunk of HSS that came with the lathe. But my enthusiasm was already beaten down pretty badly.
 
Yikes, sorry to read that. The only utter and persistent frustration I have had was with some gummy aluminum. Seems like I tried everything to prevent it building on the tool tip but to no avail. It sure felt good when I turned some free machining steel and got excellent results. Was your success with turning steel not encouraging?
 
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