OK all you'se HSS hand-grinding goofballs.....

A

alinwa

oft dis'd member
I've got all sorts of customey lathe bit grinds, almost all of them featuring some sort of ground in "chip-breaker" or "rake" slot on the top. Now here's my problem........ I like SHARP bits with no burrs and the minute I have to start fiddling with "height" (actually approach angle) because it's cutting funny, it takes me longer than it should to get it fixed BECAUSE I have to fiddle with that stupid slot on top. I fiddle-fart around until it's about toasted, making heat, then finally re-grind it.

So here's what I've taken to doing...... in the interest of K.I.S.S.

NO MORE TOP GRINDING GROOVES!!!!

For approach angle I just grind steeper relief on the bottom and for side-rake I grind the top off FLAT at the angle I want for rake. I rough it in and finish it on the belt sander.

NOW..... when I want to retouch the edge I just pull out a small flat Arkansas slip stone, couple drops of oil and with gentle finger pressure wipe the bue off and make a new shiney top surface. ba-da-BOOM, brandy-new sharp.

My lathe bits look stupider than they useta', instead of a whole rack of twinkly complicated looking grinds they look positively bland..... but they CUT! And they're dead easy to keep cutting. And if I want a chip breaker I clamp one onto the top of the bit.

thoughts?

al
 
http://youtu.be/LKGkkGFsF50

Hi Al,

What you are doing will work perfectly. There is an easier system with indexable HSS inserts. They are inexpensive, you can buy them one at a time and you can sharpen them with a wet stone in less than a minute.

Bob
 
Hi Bob (and Butch, nice talking with you today, got my X-drive working!!! Still haven't figured out where the little 1.25x.25x.75 plate and pin go though...)

Those Warner inserts do look the ticket.
 
Al,

If I'm understanding you correctly, I grind HSS just like you mention above. It works just fine. In fact, it's how I was taught/learned.

I sharpen them the same way, too.

I've never put a chipbreaker or such on a tool.

Justin
 
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Thanks guys..... you're making me feel better.


so here's a pic I scrounged off the 'net

http://images.search.yahoo.com/imag...b=13gtcmrtj&sigi=137ppmeln&.crumb=8GyHYoF.bFQ

of a very simple grind, THE WAY I LEARN'T IT way back in the day...... even this simple grind is a bugger to sharpen (notice that the one in the pic is ready)


I guess my question is "WHY" did I learn it this way? I'm guessing it's about rocker toolheads and measuring the ht and finding center etc etc which used to be all complicated.. Now with Aloris style tooling it's just eyeball and GO! Fake up/down if it's pushing/digging. Rake it if it's pulling/tearing/peeling....I dunno if it's the newer style tooling or if I'm just older but coming back into simple machining after 30yrs hiatus it's shore a lot easier now....
 
I sure do like my Arthur R Warner HSS incert tools. Perfect for the speeds my lathe operates best at. Lee
 
Al,

Some candid's I snapped of some HSS tools I have.

From left to right, RH turning, boring bar made from a dowel pin, boring bar with a chamfering tool on the off-side and a RH tool on the back side, small boring bar with a groove tool on the arse end, internal threading tool, and my crowning bit. I ground up the crowning bit, the rest were done by The Dad circa 1968. He was, and still is, hell-on-wheels when it comes to grinding tools.

In the picture of the crowning tool all by it's lonesome, you can clearly see how I drug a stone across the top to re-sharpen. This tool has worked great on every crown I've done...always passing the Q-tip test with flying colors. I did see a pic posted by I believe Dennis Sorenson that showed his crowning tool that had a chip breaker on it. I may grind up something similar and give it a whirl.

I do think I'm going to look into a Warner internal threading tool for truing up action threads.

Justin


View attachment 13207View attachment 13208
 
Hey enough about them Wonderful Warners now!!! :)

I'm luring, I'm luring....

BTW Justin, pix no workee for me.
 
#$!& me! I give up.

They show up on my home computer, but not on my work computer...or anybody else's.

Justin
 
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Justin,

I believe that you can only see it there because you've "attached" a file that is resident on your PC. What you have to do first is upload the file to the BR Central server - where it will be located as one of your files - then select that file and attach it to your posting.

Use the Insert Image icon in the second row of buttons you see when you generate a posting from the full edit function. It's the third from the right (the one with a little tree). Follow the instruction to Add an Image from your computer by browsing for the file you want.

John

P1050570.jpg
 
John,

Thanks...I think I got it.

It would have been quicker to just have shipped the bits up to Al to look at...

Are the attachments there?

Justin
 

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I have some carbide insert bits. But when I first got my lathe, I did a lot of reading, and it all pointed me in the direction of learning to grind my own lathe bits. I started off by buying lots of bits on ebay, and simply resharpening the ones that looked like the bits I had seen in the South Bend and Sheldon books. Then I decided to grind my own from blanks that vcame with some of those lots. I ground a threading bit in a 3/8" square bit. The biggest bit my toolholder will take is 1/2". I have a craftsman grinder with 8" wheels, and it takes a LONG time to grind a bit from a blank, what with having to stop and let it cool off after 10-20 seconds of grinding. My question is: How long does or should it typically take to grind, say, a 60 degree threading bit from a blank piece of 1/2" HSS? From the reading I did, it seems to be of utmost importance to not let the HSS discolor from heat while grinding, is it really a "disaster" if the bit gets too hot? I usually grind until the bit is to hot for my fingers, then quench. When the water gets pretty warm from quenching, I change it out to cool water from the tap. Is this a waste of time?
 
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